* [PATCH v9 00/21] job: replace AioContext lock with job_mutex
@ 2022-07-06 20:15 Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 01/21] job.c: make job_mutex and job_lock/unlock() public Emanuele Giuseppe Esposito
` (21 more replies)
0 siblings, 22 replies; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito
In this series, we want to remove the AioContext lock and instead
use the already existent job_mutex to protect the job structures
and list. This is part of the work to get rid of AioContext lock
usage in favour of smaller granularity locks.
In order to simplify reviewer's job, job lock/unlock functions and
macros are added as empty prototypes (nop) in patch 1.
They are converted to use the actual job mutex only in the last
patch. In this way we can freely create locking sections
without worrying about deadlocks with the aiocontext lock.
Patch 2 defines what fields in the job structure need protection.
Patches 3-6 are in preparation to the job locks, moving functions
from global to static and introducing helpers.
Patch 7-9 introduce the (nop) job lock into the job API and
its users, and patches 10-13 categorize respectively locked and
unlocked functions in the job API.
Patches 14-17 take care of protecting job->aio_context, and
finally patch 18 makes the prototypes in patch 1 use the
job_mutex and removes all aiocontext lock at the same time.
Tested this series by running unit tests, qemu-iotests and qtests
(x86_64).
---
v9:
* merge patch 6 and 7 to 5.
* additional "taken with job lock/unlock" added and propagated in callers
* protect iostatus field of BlockJobs
* move all blockjob patches torward the end of the serie
v8:
* reorganize patch ordering according with Vladimir proposal
* minor nitpicks
v7:
* s/temporary/temporarly
* double identical locking comment to the same function
* patch 2: add "Protected by AioContext lock" to better categorize fields in
job.h
* use same comment style in all function headers ("Just like {funct}, but
called between job_lock and job_unlock")
v6:
* patch 4 and 6 squashed with patch 19 (enable job lock and
reduce/remove AioContext lock)
* patch 19: job_unref_locked read the aiocontext inside the
job lock.
v5:
* just restructured patches a little bit better, as there were
functions used before they were defined.
* rebased on kwolf/block branch and API split serie
v4:
* move "protected by job_mutex" from patch 2 to 15, where the job_mutex is
actually added.
* s/aio_co_enter/aio_co_schedule in job.c, and adjust tests accordingly.
* remove job_get_aio_context, add job_set_aio_context. Use "fake rwlock"
to protect job->aiocontext.
* get rid of useless getters method, namely:
job_get_status
job_get_pause_count
job_get_paused
job_get_busy
They are all used only by tests, and such getter is pretty useless.
Replace with job_lock(); assert(); job_unlock();
* use job lock macros instead of job lock/unlock in unit tests.
* convert also blockjob functions to have _locked
* put the job_lock/unlock patches before the _locked ones
* replace aio_co_enter in job.c and detect change of context
v3:
* add "_locked" suffix to the functions called under job_mutex lock
* rename _job_lock in real_job_lock
* job_mutex is now public, and drivers like monitor use it directly
* introduce and protect job_get_aio_context
* remove mirror-specific APIs and just use WITH_JOB_GUARD
* more extensive use of WITH_JOB_GUARD and JOB_LOCK_GUARD
RFC v2:
* use JOB_LOCK_GUARD and WITH_JOB_LOCK_GUARD
* mu(u)ltiple typos in commit messages
* job API split patches are sent separately in another series
* use of empty job_{lock/unlock} and JOB_LOCK_GUARD/WITH_JOB_LOCK_GUARD
to avoid deadlocks and simplify the reviewer job
* move patch 11 (block_job_query: remove atomic read) as last
Emanuele Giuseppe Esposito (20):
job.c: make job_mutex and job_lock/unlock() public
job.h: categorize fields in struct Job
job.c: API functions not used outside should be static
aio-wait.h: introduce AIO_WAIT_WHILE_UNLOCKED
job.c: add job_lock/unlock while keeping job.h intact
job: move and update comments from blockjob.c
blockjob: introduce block_job _locked() APIs
jobs: add job lock in find_* functions
jobs: use job locks also in the unit tests
block/mirror.c: use of job helpers in drivers to avoid TOC/TOU
jobs: group together API calls under the same job lock
commit and mirror: create new nodes using bdrv_get_aio_context, and
not the job aiocontext
jobs: protect job.aio_context with BQL and job_mutex
job.c: enable job lock/unlock and remove Aiocontext locks
block_job_query: remove atomic read
blockjob.h: categorize fields in struct BlockJob
blockjob: rename notifier callbacks as _locked
blockjob: protect iostatus field in BlockJob struct
blockjob: remove unused functions
job: remove unused functions
Paolo Bonzini (1):
job: detect change of aiocontext within job coroutine
block.c | 20 +-
block/commit.c | 4 +-
block/mirror.c | 21 +-
block/replication.c | 6 +-
blockdev.c | 129 +++---
blockjob.c | 131 ++++---
include/block/aio-wait.h | 17 +-
include/block/blockjob.h | 45 ++-
include/qemu/job.h | 264 +++++++++----
job-qmp.c | 87 ++---
job.c | 646 +++++++++++++++++++------------
monitor/qmp-cmds.c | 7 +-
qemu-img.c | 41 +-
tests/unit/test-bdrv-drain.c | 80 ++--
tests/unit/test-block-iothread.c | 8 +-
tests/unit/test-blockjob-txn.c | 24 +-
tests/unit/test-blockjob.c | 107 +++--
17 files changed, 1009 insertions(+), 628 deletions(-)
--
2.31.1
^ permalink raw reply [flat|nested] 53+ messages in thread
* [PATCH v9 01/21] job.c: make job_mutex and job_lock/unlock() public
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 02/21] job.h: categorize fields in struct Job Emanuele Giuseppe Esposito
` (20 subsequent siblings)
21 siblings, 0 replies; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito, Vladimir Sementsov-Ogievskiy
job mutex will be used to protect the job struct elements and list,
replacing AioContext locks.
Right now use a shared lock for all jobs, in order to keep things
simple. Once the AioContext lock is gone, we can introduce per-job
locks.
To simplify the switch from aiocontext to job lock, introduce
*nop* lock/unlock functions and macros.
We want to always call job_lock/unlock outside the AioContext locks,
and not vice-versa, otherwise we might get a deadlock. This is not
straightforward to do, and that's why we start with nop functions.
Once everything is protected by job_lock/unlock, we can change the nop into
an actual mutex and remove the aiocontext lock.
Since job_mutex is already being used, add static
real_job_{lock/unlock} for the existing usage.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
---
include/qemu/job.h | 24 ++++++++++++++++++++++++
job.c | 35 +++++++++++++++++++++++------------
2 files changed, 47 insertions(+), 12 deletions(-)
diff --git a/include/qemu/job.h b/include/qemu/job.h
index c105b31076..d1192ffd61 100644
--- a/include/qemu/job.h
+++ b/include/qemu/job.h
@@ -303,6 +303,30 @@ typedef enum JobCreateFlags {
JOB_MANUAL_DISMISS = 0x04,
} JobCreateFlags;
+extern QemuMutex job_mutex;
+
+#define JOB_LOCK_GUARD() /* QEMU_LOCK_GUARD(&job_mutex) */
+
+#define WITH_JOB_LOCK_GUARD() /* WITH_QEMU_LOCK_GUARD(&job_mutex) */
+
+/**
+ * job_lock:
+ *
+ * Take the mutex protecting the list of jobs and their status.
+ * Most functions called by the monitor need to call job_lock
+ * and job_unlock manually. On the other hand, function called
+ * by the block jobs themselves and by the block layer will take the
+ * lock for you.
+ */
+void job_lock(void);
+
+/**
+ * job_unlock:
+ *
+ * Release the mutex protecting the list of jobs and their status.
+ */
+void job_unlock(void);
+
/**
* Allocate and return a new job transaction. Jobs can be added to the
* transaction using job_txn_add_job().
diff --git a/job.c b/job.c
index 075c6f3a20..2b4ffca9d4 100644
--- a/job.c
+++ b/job.c
@@ -32,6 +32,12 @@
#include "trace/trace-root.h"
#include "qapi/qapi-events-job.h"
+/*
+ * job_mutex protects the jobs list, but also makes the
+ * struct job fields thread-safe.
+ */
+QemuMutex job_mutex;
+
static QLIST_HEAD(, Job) jobs = QLIST_HEAD_INITIALIZER(jobs);
/* Job State Transition Table */
@@ -74,17 +80,22 @@ struct JobTxn {
int refcnt;
};
-/* Right now, this mutex is only needed to synchronize accesses to job->busy
- * and job->sleep_timer, such as concurrent calls to job_do_yield and
- * job_enter. */
-static QemuMutex job_mutex;
+void job_lock(void)
+{
+ /* nop */
+}
+
+void job_unlock(void)
+{
+ /* nop */
+}
-static void job_lock(void)
+static void real_job_lock(void)
{
qemu_mutex_lock(&job_mutex);
}
-static void job_unlock(void)
+static void real_job_unlock(void)
{
qemu_mutex_unlock(&job_mutex);
}
@@ -450,21 +461,21 @@ void job_enter_cond(Job *job, bool(*fn)(Job *job))
return;
}
- job_lock();
+ real_job_lock();
if (job->busy) {
- job_unlock();
+ real_job_unlock();
return;
}
if (fn && !fn(job)) {
- job_unlock();
+ real_job_unlock();
return;
}
assert(!job->deferred_to_main_loop);
timer_del(&job->sleep_timer);
job->busy = true;
- job_unlock();
+ real_job_unlock();
aio_co_enter(job->aio_context, job->co);
}
@@ -481,13 +492,13 @@ void job_enter(Job *job)
* called explicitly. */
static void coroutine_fn job_do_yield(Job *job, uint64_t ns)
{
- job_lock();
+ real_job_lock();
if (ns != -1) {
timer_mod(&job->sleep_timer, ns);
}
job->busy = false;
job_event_idle(job);
- job_unlock();
+ real_job_unlock();
qemu_coroutine_yield();
/* Set by job_enter_cond() before re-entering the coroutine. */
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 02/21] job.h: categorize fields in struct Job
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 01/21] job.c: make job_mutex and job_lock/unlock() public Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 03/21] job.c: API functions not used outside should be static Emanuele Giuseppe Esposito
` (19 subsequent siblings)
21 siblings, 0 replies; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito, Vladimir Sementsov-Ogievskiy
Categorize the fields in struct Job to understand which ones
need to be protected by the job mutex and which don't.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
---
include/qemu/job.h | 61 +++++++++++++++++++++++++++-------------------
1 file changed, 36 insertions(+), 25 deletions(-)
diff --git a/include/qemu/job.h b/include/qemu/job.h
index d1192ffd61..876e13d549 100644
--- a/include/qemu/job.h
+++ b/include/qemu/job.h
@@ -40,27 +40,52 @@ typedef struct JobTxn JobTxn;
* Long-running operation.
*/
typedef struct Job {
+
+ /* Fields set at initialization (job_create), and never modified */
+
/** The ID of the job. May be NULL for internal jobs. */
char *id;
- /** The type of this job. */
+ /**
+ * The type of this job.
+ * All callbacks are called with job_mutex *not* held.
+ */
const JobDriver *driver;
- /** Reference count of the block job */
- int refcnt;
-
- /** Current state; See @JobStatus for details. */
- JobStatus status;
-
- /** AioContext to run the job coroutine in */
- AioContext *aio_context;
-
/**
* The coroutine that executes the job. If not NULL, it is reentered when
* busy is false and the job is cancelled.
+ * Initialized in job_start()
*/
Coroutine *co;
+ /** True if this job should automatically finalize itself */
+ bool auto_finalize;
+
+ /** True if this job should automatically dismiss itself */
+ bool auto_dismiss;
+
+ /** The completion function that will be called when the job completes. */
+ BlockCompletionFunc *cb;
+
+ /** The opaque value that is passed to the completion function. */
+ void *opaque;
+
+ /* ProgressMeter API is thread-safe */
+ ProgressMeter progress;
+
+
+ /** Protected by AioContext lock */
+
+ /** AioContext to run the job coroutine in */
+ AioContext *aio_context;
+
+ /** Reference count of the block job */
+ int refcnt;
+
+ /** Current state; See @JobStatus for details. */
+ JobStatus status;
+
/**
* Timer that is used by @job_sleep_ns. Accessed under job_mutex (in
* job.c).
@@ -112,14 +137,6 @@ typedef struct Job {
/** Set to true when the job has deferred work to the main loop. */
bool deferred_to_main_loop;
- /** True if this job should automatically finalize itself */
- bool auto_finalize;
-
- /** True if this job should automatically dismiss itself */
- bool auto_dismiss;
-
- ProgressMeter progress;
-
/**
* Return code from @run and/or @prepare callback(s).
* Not final until the job has reached the CONCLUDED status.
@@ -134,12 +151,6 @@ typedef struct Job {
*/
Error *err;
- /** The completion function that will be called when the job completes. */
- BlockCompletionFunc *cb;
-
- /** The opaque value that is passed to the completion function. */
- void *opaque;
-
/** Notifiers called when a cancelled job is finalised */
NotifierList on_finalize_cancelled;
@@ -167,6 +178,7 @@ typedef struct Job {
/**
* Callbacks and other information about a Job driver.
+ * All callbacks are invoked with job_mutex *not* held.
*/
struct JobDriver {
@@ -472,7 +484,6 @@ void job_yield(Job *job);
*/
void coroutine_fn job_sleep_ns(Job *job, int64_t ns);
-
/** Returns the JobType of a given Job. */
JobType job_type(const Job *job);
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 03/21] job.c: API functions not used outside should be static
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 01/21] job.c: make job_mutex and job_lock/unlock() public Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 02/21] job.h: categorize fields in struct Job Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 04/21] aio-wait.h: introduce AIO_WAIT_WHILE_UNLOCKED Emanuele Giuseppe Esposito
` (18 subsequent siblings)
21 siblings, 0 replies; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito, Vladimir Sementsov-Ogievskiy
job_event_* functions can all be static, as they are not used
outside job.c.
Same applies for job_txn_add_job().
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
---
include/qemu/job.h | 18 ------------------
job.c | 22 +++++++++++++++++++---
2 files changed, 19 insertions(+), 21 deletions(-)
diff --git a/include/qemu/job.h b/include/qemu/job.h
index 876e13d549..4b64eb15f7 100644
--- a/include/qemu/job.h
+++ b/include/qemu/job.h
@@ -358,18 +358,6 @@ JobTxn *job_txn_new(void);
*/
void job_txn_unref(JobTxn *txn);
-/**
- * @txn: The transaction (may be NULL)
- * @job: Job to add to the transaction
- *
- * Add @job to the transaction. The @job must not already be in a transaction.
- * The caller must call either job_txn_unref() or job_completed() to release
- * the reference that is automatically grabbed here.
- *
- * If @txn is NULL, the function does nothing.
- */
-void job_txn_add_job(JobTxn *txn, Job *job);
-
/**
* Create a new long-running job and return it.
*
@@ -431,12 +419,6 @@ void job_progress_set_remaining(Job *job, uint64_t remaining);
*/
void job_progress_increase_remaining(Job *job, uint64_t delta);
-/** To be called when a cancelled job is finalised. */
-void job_event_cancelled(Job *job);
-
-/** To be called when a successfully completed job is finalised. */
-void job_event_completed(Job *job);
-
/**
* Conditionally enter the job coroutine if the job is ready to run, not
* already busy and fn() returns true. fn() is called while under the job_lock
diff --git a/job.c b/job.c
index 2b4ffca9d4..cafd597ba4 100644
--- a/job.c
+++ b/job.c
@@ -125,7 +125,17 @@ void job_txn_unref(JobTxn *txn)
}
}
-void job_txn_add_job(JobTxn *txn, Job *job)
+/**
+ * @txn: The transaction (may be NULL)
+ * @job: Job to add to the transaction
+ *
+ * Add @job to the transaction. The @job must not already be in a transaction.
+ * The caller must call either job_txn_unref() or job_completed() to release
+ * the reference that is automatically grabbed here.
+ *
+ * If @txn is NULL, the function does nothing.
+ */
+static void job_txn_add_job(JobTxn *txn, Job *job)
{
if (!txn) {
return;
@@ -427,12 +437,18 @@ void job_progress_increase_remaining(Job *job, uint64_t delta)
progress_increase_remaining(&job->progress, delta);
}
-void job_event_cancelled(Job *job)
+/**
+ * To be called when a cancelled job is finalised.
+ */
+static void job_event_cancelled(Job *job)
{
notifier_list_notify(&job->on_finalize_cancelled, job);
}
-void job_event_completed(Job *job)
+/**
+ * To be called when a successfully completed job is finalised.
+ */
+static void job_event_completed(Job *job)
{
notifier_list_notify(&job->on_finalize_completed, job);
}
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 04/21] aio-wait.h: introduce AIO_WAIT_WHILE_UNLOCKED
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (2 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 03/21] job.c: API functions not used outside should be static Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 05/21] job.c: add job_lock/unlock while keeping job.h intact Emanuele Giuseppe Esposito
` (17 subsequent siblings)
21 siblings, 0 replies; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito, Vladimir Sementsov-Ogievskiy
Same as AIO_WAIT_WHILE macro, but if we are in the Main loop
do not release and then acquire ctx_ 's aiocontext.
Once all Aiocontext locks go away, this macro will replace
AIO_WAIT_WHILE.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
---
include/block/aio-wait.h | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/include/block/aio-wait.h b/include/block/aio-wait.h
index 54840f8622..a61f82c617 100644
--- a/include/block/aio-wait.h
+++ b/include/block/aio-wait.h
@@ -59,10 +59,13 @@ typedef struct {
extern AioWait global_aio_wait;
/**
- * AIO_WAIT_WHILE:
+ * _AIO_WAIT_WHILE:
* @ctx: the aio context, or NULL if multiple aio contexts (for which the
* caller does not hold a lock) are involved in the polling condition.
* @cond: wait while this conditional expression is true
+ * @unlock: whether to unlock and then lock again @ctx. This apples
+ * only when waiting for another AioContext from the main loop.
+ * Otherwise it's ignored.
*
* Wait while a condition is true. Use this to implement synchronous
* operations that require event loop activity.
@@ -75,7 +78,7 @@ extern AioWait global_aio_wait;
* wait on conditions between two IOThreads since that could lead to deadlock,
* go via the main loop instead.
*/
-#define AIO_WAIT_WHILE(ctx, cond) ({ \
+#define _AIO_WAIT_WHILE(ctx, cond, unlock) ({ \
bool waited_ = false; \
AioWait *wait_ = &global_aio_wait; \
AioContext *ctx_ = (ctx); \
@@ -92,11 +95,11 @@ extern AioWait global_aio_wait;
assert(qemu_get_current_aio_context() == \
qemu_get_aio_context()); \
while ((cond)) { \
- if (ctx_) { \
+ if (unlock && ctx_) { \
aio_context_release(ctx_); \
} \
aio_poll(qemu_get_aio_context(), true); \
- if (ctx_) { \
+ if (unlock && ctx_) { \
aio_context_acquire(ctx_); \
} \
waited_ = true; \
@@ -105,6 +108,12 @@ extern AioWait global_aio_wait;
qatomic_dec(&wait_->num_waiters); \
waited_; })
+#define AIO_WAIT_WHILE(ctx, cond) \
+ _AIO_WAIT_WHILE(ctx, cond, true)
+
+#define AIO_WAIT_WHILE_UNLOCKED(ctx, cond) \
+ _AIO_WAIT_WHILE(ctx, cond, false)
+
/**
* aio_wait_kick:
* Wake up the main thread if it is waiting on AIO_WAIT_WHILE(). During
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 05/21] job.c: add job_lock/unlock while keeping job.h intact
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (3 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 04/21] aio-wait.h: introduce AIO_WAIT_WHILE_UNLOCKED Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-08 19:25 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 06/21] job: move and update comments from blockjob.c Emanuele Giuseppe Esposito
` (16 subsequent siblings)
21 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito
With "intact" we mean that all job.h functions implicitly
take the lock. Therefore API callers are unmodified.
This means that:
- many static functions that will be always called with job lock held
become _locked, and call _locked functions
- all public functions take the lock internally if needed, and call _locked
functions
- all public functions called internally by other functions in job.c will have a
_locked counterpart (sometimes public), to avoid deadlocks (job lock already taken).
These functions are not used for now.
- some public functions called only from exernal files (not job.c) do not
have _locked() counterpart and take the lock inside. Others won't need
the lock at all because use fields only set at initialization and
never modified.
job_{lock/unlock} is independent from real_job_{lock/unlock}.
Note: at this stage, job_{lock/unlock} and job lock guard macros
are *nop*
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
include/qemu/job.h | 138 ++++++++++-
job.c | 605 ++++++++++++++++++++++++++++++++-------------
2 files changed, 558 insertions(+), 185 deletions(-)
diff --git a/include/qemu/job.h b/include/qemu/job.h
index 4b64eb15f7..5709e8d4a8 100644
--- a/include/qemu/job.h
+++ b/include/qemu/job.h
@@ -358,8 +358,15 @@ JobTxn *job_txn_new(void);
*/
void job_txn_unref(JobTxn *txn);
+/*
+ * Same as job_txn_unref(), but called with job lock held.
+ * Might release the lock temporarily.
+ */
+void job_txn_unref_locked(JobTxn *txn);
+
/**
* Create a new long-running job and return it.
+ * Called with job_mutex *not* held.
*
* @job_id: The id of the newly-created job, or %NULL for internal jobs
* @driver: The class object for the newly-created job.
@@ -380,17 +387,25 @@ void *job_create(const char *job_id, const JobDriver *driver, JobTxn *txn,
*/
void job_ref(Job *job);
+/* Same as job_ref(), but called with job lock held. */
+void job_ref_locked(Job *job);
+
/**
* Release a reference that was previously acquired with job_ref() or
* job_create(). If it's the last reference to the object, it will be freed.
*/
void job_unref(Job *job);
+/* Same as job_unref(), but called with job lock held. */
+void job_unref_locked(Job *job);
+
/**
* @job: The job that has made progress
* @done: How much progress the job made since the last call
*
* Updates the progress counter of the job.
+ *
+ * May be called with mutex held or not held.
*/
void job_progress_update(Job *job, uint64_t done);
@@ -401,6 +416,8 @@ void job_progress_update(Job *job, uint64_t done);
*
* Sets the expected end value of the progress counter of a job so that a
* completion percentage can be calculated when the progress is updated.
+ *
+ * May be called with mutex held or not held.
*/
void job_progress_set_remaining(Job *job, uint64_t remaining);
@@ -416,6 +433,8 @@ void job_progress_set_remaining(Job *job, uint64_t remaining);
* length before, and job_progress_update() afterwards.
* (So the operation acts as a parenthesis in regards to the main job
* operation running in background.)
+ *
+ * May be called with mutex held or not held.
*/
void job_progress_increase_remaining(Job *job, uint64_t delta);
@@ -426,11 +445,19 @@ void job_progress_increase_remaining(Job *job, uint64_t delta);
*/
void job_enter_cond(Job *job, bool(*fn)(Job *job));
+/*
+ * Same as job_enter_cond(), but called with job lock held.
+ * Might release the lock temporarily.
+ */
+void job_enter_cond_locked(Job *job, bool(*fn)(Job *job));
+
/**
* @job: A job that has not yet been started.
*
* Begins execution of a job.
* Takes ownership of one reference to the job object.
+ *
+ * Called with job_mutex *not* held.
*/
void job_start(Job *job);
@@ -438,6 +465,7 @@ void job_start(Job *job);
* @job: The job to enter.
*
* Continue the specified job by entering the coroutine.
+ * Called with job_mutex *not* held.
*/
void job_enter(Job *job);
@@ -446,6 +474,8 @@ void job_enter(Job *job);
*
* Pause now if job_pause() has been called. Jobs that perform lots of I/O
* must call this between requests so that the job can be paused.
+ *
+ * Called with job_mutex *not* held.
*/
void coroutine_fn job_pause_point(Job *job);
@@ -453,6 +483,7 @@ void coroutine_fn job_pause_point(Job *job);
* @job: The job that calls the function.
*
* Yield the job coroutine.
+ * Called with job_mutex *not* held.
*/
void job_yield(Job *job);
@@ -463,6 +494,8 @@ void job_yield(Job *job);
* Put the job to sleep (assuming that it wasn't canceled) for @ns
* %QEMU_CLOCK_REALTIME nanoseconds. Canceling the job will immediately
* interrupt the wait.
+ *
+ * Called with job_mutex *not* held.
*/
void coroutine_fn job_sleep_ns(Job *job, int64_t ns);
@@ -475,21 +508,40 @@ const char *job_type_str(const Job *job);
/** Returns true if the job should not be visible to the management layer. */
bool job_is_internal(Job *job);
-/** Returns whether the job is being cancelled. */
+/**
+ * Returns whether the job is being cancelled.
+ * Called with job_mutex *not* held.
+ */
bool job_is_cancelled(Job *job);
+/* Same as job_is_cancelled(), but called with job lock held. */
+bool job_is_cancelled_locked(Job *job);
+
/**
* Returns whether the job is scheduled for cancellation (at an
* indefinite point).
+ * Called with job_mutex *not* held.
*/
bool job_cancel_requested(Job *job);
-/** Returns whether the job is in a completed state. */
+/**
+ * Returns whether the job is in a completed state.
+ * Called with job_mutex *not* held.
+ */
bool job_is_completed(Job *job);
-/** Returns whether the job is ready to be completed. */
+/* Same as job_is_completed(), but called with job lock held. */
+bool job_is_completed_locked(Job *job);
+
+/**
+ * Returns whether the job is ready to be completed.
+ * Called with job_mutex *not* held.
+ */
bool job_is_ready(Job *job);
+/* Same as job_is_ready(), but called with job lock held. */
+bool job_is_ready_locked(Job *job);
+
/**
* Request @job to pause at the next pause point. Must be paired with
* job_resume(). If the job is supposed to be resumed by user action, call
@@ -497,24 +549,45 @@ bool job_is_ready(Job *job);
*/
void job_pause(Job *job);
+/* Same as job_pause(), but called with job lock held. */
+void job_pause_locked(Job *job);
+
/** Resumes a @job paused with job_pause. */
void job_resume(Job *job);
+/*
+ * Same as job_resume(), but called with job lock held.
+ * Might release the lock temporarily.
+ */
+void job_resume_locked(Job *job);
+
/**
* Asynchronously pause the specified @job.
* Do not allow a resume until a matching call to job_user_resume.
*/
void job_user_pause(Job *job, Error **errp);
+/* Same as job_user_pause(), but called with job lock held. */
+void job_user_pause_locked(Job *job, Error **errp);
+
/** Returns true if the job is user-paused. */
bool job_user_paused(Job *job);
+/* Same as job_user_paused(), but called with job lock held. */
+bool job_user_paused_locked(Job *job);
+
/**
* Resume the specified @job.
* Must be paired with a preceding job_user_pause.
*/
void job_user_resume(Job *job, Error **errp);
+/*
+ * Same as job_user_resume(), but called with job lock held.
+ * Might release the lock temporarily.
+ */
+void job_user_resume_locked(Job *job, Error **errp);
+
/**
* Get the next element from the list of block jobs after @job, or the
* first one if @job is %NULL.
@@ -523,6 +596,9 @@ void job_user_resume(Job *job, Error **errp);
*/
Job *job_next(Job *job);
+/* Same as job_next(), but called with job lock held. */
+Job *job_next_locked(Job *job);
+
/**
* Get the job identified by @id (which must not be %NULL).
*
@@ -530,6 +606,9 @@ Job *job_next(Job *job);
*/
Job *job_get(const char *id);
+/* Same as job_get(), but called with job lock held. */
+Job *job_get_locked(const char *id);
+
/**
* Check whether the verb @verb can be applied to @job in its current state.
* Returns 0 if the verb can be applied; otherwise errp is set and -EPERM
@@ -537,27 +616,48 @@ Job *job_get(const char *id);
*/
int job_apply_verb(Job *job, JobVerb verb, Error **errp);
-/** The @job could not be started, free it. */
+/* Same as job_apply_verb, but called with job lock held. */
+int job_apply_verb_locked(Job *job, JobVerb verb, Error **errp);
+
+/**
+ * The @job could not be started, free it.
+ * Called with job_mutex *not* held.
+ */
void job_early_fail(Job *job);
-/** Moves the @job from RUNNING to READY */
+/**
+ * Moves the @job from RUNNING to READY.
+ * Called with job_mutex *not* held.
+ */
void job_transition_to_ready(Job *job);
/** Asynchronously complete the specified @job. */
void job_complete(Job *job, Error **errp);
+/*
+ * Same as job_complete(), but called with job lock held.
+ * Might release the lock temporarily.
+ */
+void job_complete_locked(Job *job, Error **errp);
+
/**
* Asynchronously cancel the specified @job. If @force is true, the job should
* be cancelled immediately without waiting for a consistent state.
*/
void job_cancel(Job *job, bool force);
+/* Same as job_cancel(), but called with job lock held. */
+void job_cancel_locked(Job *job, bool force);
+
/**
* Cancels the specified job like job_cancel(), but may refuse to do so if the
* operation isn't meaningful in the current state of the job.
*/
void job_user_cancel(Job *job, bool force, Error **errp);
+/* Same as job_user_cancel(), but called with job lock held. */
+void job_user_cancel_locked(Job *job, bool force, Error **errp);
+
/**
* Synchronously cancel the @job. The completion callback is called
* before the function returns. If @force is false, the job may
@@ -571,7 +671,14 @@ void job_user_cancel(Job *job, bool force, Error **errp);
*/
int job_cancel_sync(Job *job, bool force);
-/** Synchronously force-cancels all jobs using job_cancel_sync(). */
+/* Same as job_cancel_sync, but called with job lock held. */
+int job_cancel_sync_locked(Job *job, bool force);
+
+/**
+ * Synchronously force-cancels all jobs using job_cancel_sync_locked().
+ *
+ * Called with job_lock *not* held.
+ */
void job_cancel_sync_all(void);
/**
@@ -590,6 +697,9 @@ void job_cancel_sync_all(void);
*/
int job_complete_sync(Job *job, Error **errp);
+/* Same as job_complete_sync, but called with job lock held. */
+int job_complete_sync_locked(Job *job, Error **errp);
+
/**
* For a @job that has finished its work and is pending awaiting explicit
* acknowledgement to commit its work, this will commit that work.
@@ -600,12 +710,18 @@ int job_complete_sync(Job *job, Error **errp);
*/
void job_finalize(Job *job, Error **errp);
+/* Same as job_finalize(), but called with job lock held. */
+void job_finalize_locked(Job *job, Error **errp);
+
/**
* Remove the concluded @job from the query list and resets the passed pointer
* to %NULL. Returns an error if the job is not actually concluded.
*/
void job_dismiss(Job **job, Error **errp);
+/* Same as job_dismiss(), but called with job lock held. */
+void job_dismiss_locked(Job **job, Error **errp);
+
/**
* Synchronously finishes the given @job. If @finish is given, it is called to
* trigger completion or cancellation of the job.
@@ -615,6 +731,14 @@ void job_dismiss(Job **job, Error **errp);
*
* Callers must hold the AioContext lock of job->aio_context.
*/
-int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp), Error **errp);
+int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp),
+ Error **errp);
+
+/*
+ * Same as job_finish_sync(), but called with job lock held.
+ * Might release the lock temporarily.
+ */
+int job_finish_sync_locked(Job *job, void (*finish)(Job *, Error **errp),
+ Error **errp);
#endif
diff --git a/job.c b/job.c
index cafd597ba4..37485e162a 100644
--- a/job.c
+++ b/job.c
@@ -38,6 +38,7 @@
*/
QemuMutex job_mutex;
+/* Protected by job_mutex */
static QLIST_HEAD(, Job) jobs = QLIST_HEAD_INITIALIZER(jobs);
/* Job State Transition Table */
@@ -113,18 +114,25 @@ JobTxn *job_txn_new(void)
return txn;
}
-static void job_txn_ref(JobTxn *txn)
+/* Called with job_mutex held. */
+static void job_txn_ref_locked(JobTxn *txn)
{
txn->refcnt++;
}
-void job_txn_unref(JobTxn *txn)
+void job_txn_unref_locked(JobTxn *txn)
{
if (txn && --txn->refcnt == 0) {
g_free(txn);
}
}
+void job_txn_unref(JobTxn *txn)
+{
+ JOB_LOCK_GUARD();
+ job_txn_unref_locked(txn);
+}
+
/**
* @txn: The transaction (may be NULL)
* @job: Job to add to the transaction
@@ -134,8 +142,10 @@ void job_txn_unref(JobTxn *txn)
* the reference that is automatically grabbed here.
*
* If @txn is NULL, the function does nothing.
+ *
+ * Called with job_mutex held.
*/
-static void job_txn_add_job(JobTxn *txn, Job *job)
+static void job_txn_add_job_locked(JobTxn *txn, Job *job)
{
if (!txn) {
return;
@@ -145,19 +155,21 @@ static void job_txn_add_job(JobTxn *txn, Job *job)
job->txn = txn;
QLIST_INSERT_HEAD(&txn->jobs, job, txn_list);
- job_txn_ref(txn);
+ job_txn_ref_locked(txn);
}
-static void job_txn_del_job(Job *job)
+/* Called with job_mutex held. */
+static void job_txn_del_job_locked(Job *job)
{
if (job->txn) {
QLIST_REMOVE(job, txn_list);
- job_txn_unref(job->txn);
+ job_txn_unref_locked(job->txn);
job->txn = NULL;
}
}
-static int job_txn_apply(Job *job, int fn(Job *))
+/* Called with job_mutex held, but releases it temporarily. */
+static int job_txn_apply_locked(Job *job, int fn(Job *))
{
AioContext *inner_ctx;
Job *other_job, *next;
@@ -170,7 +182,7 @@ static int job_txn_apply(Job *job, int fn(Job *))
* we need to release it here to avoid holding the lock twice - which would
* break AIO_WAIT_WHILE from within fn.
*/
- job_ref(job);
+ job_ref_locked(job);
aio_context_release(job->aio_context);
QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
@@ -188,7 +200,7 @@ static int job_txn_apply(Job *job, int fn(Job *))
* can't use a local variable to cache it.
*/
aio_context_acquire(job->aio_context);
- job_unref(job);
+ job_unref_locked(job);
return rc;
}
@@ -197,7 +209,8 @@ bool job_is_internal(Job *job)
return (job->id == NULL);
}
-static void job_state_transition(Job *job, JobStatus s1)
+/* Called with job_mutex held. */
+static void job_state_transition_locked(Job *job, JobStatus s1)
{
JobStatus s0 = job->status;
assert(s1 >= 0 && s1 < JOB_STATUS__MAX);
@@ -212,7 +225,7 @@ static void job_state_transition(Job *job, JobStatus s1)
}
}
-int job_apply_verb(Job *job, JobVerb verb, Error **errp)
+int job_apply_verb_locked(Job *job, JobVerb verb, Error **errp)
{
JobStatus s0 = job->status;
assert(verb >= 0 && verb < JOB_VERB__MAX);
@@ -226,6 +239,12 @@ int job_apply_verb(Job *job, JobVerb verb, Error **errp)
return -EPERM;
}
+int job_apply_verb(Job *job, JobVerb verb, Error **errp)
+{
+ JOB_LOCK_GUARD();
+ return job_apply_verb_locked(job, verb, errp);
+}
+
JobType job_type(const Job *job)
{
return job->driver->job_type;
@@ -236,19 +255,32 @@ const char *job_type_str(const Job *job)
return JobType_str(job_type(job));
}
-bool job_is_cancelled(Job *job)
+bool job_is_cancelled_locked(Job *job)
{
/* force_cancel may be true only if cancelled is true, too */
assert(job->cancelled || !job->force_cancel);
return job->force_cancel;
}
-bool job_cancel_requested(Job *job)
+bool job_is_cancelled(Job *job)
+{
+ JOB_LOCK_GUARD();
+ return job_is_cancelled_locked(job);
+}
+
+/* Called with job_mutex held. */
+static bool job_cancel_requested_locked(Job *job)
{
return job->cancelled;
}
-bool job_is_ready(Job *job)
+bool job_cancel_requested(Job *job)
+{
+ JOB_LOCK_GUARD();
+ return job_cancel_requested_locked(job);
+}
+
+bool job_is_ready_locked(Job *job)
{
switch (job->status) {
case JOB_STATUS_UNDEFINED:
@@ -270,7 +302,13 @@ bool job_is_ready(Job *job)
return false;
}
-bool job_is_completed(Job *job)
+bool job_is_ready(Job *job)
+{
+ JOB_LOCK_GUARD();
+ return job_is_ready_locked(job);
+}
+
+bool job_is_completed_locked(Job *job)
{
switch (job->status) {
case JOB_STATUS_UNDEFINED:
@@ -292,17 +330,24 @@ bool job_is_completed(Job *job)
return false;
}
+bool job_is_completed(Job *job)
+{
+ JOB_LOCK_GUARD();
+ return job_is_completed_locked(job);
+}
+
static bool job_started(Job *job)
{
return job->co;
}
-static bool job_should_pause(Job *job)
+/* Called with job_mutex held. */
+static bool job_should_pause_locked(Job *job)
{
return job->pause_count > 0;
}
-Job *job_next(Job *job)
+Job *job_next_locked(Job *job)
{
if (!job) {
return QLIST_FIRST(&jobs);
@@ -310,7 +355,13 @@ Job *job_next(Job *job)
return QLIST_NEXT(job, job_list);
}
-Job *job_get(const char *id)
+Job *job_next(Job *job)
+{
+ JOB_LOCK_GUARD();
+ return job_next_locked(job);
+}
+
+Job *job_get_locked(const char *id)
{
Job *job;
@@ -323,6 +374,13 @@ Job *job_get(const char *id)
return NULL;
}
+Job *job_get(const char *id)
+{
+ JOB_LOCK_GUARD();
+ return job_get_locked(id);
+}
+
+/* Called with job_mutex *not* held. */
static void job_sleep_timer_cb(void *opaque)
{
Job *job = opaque;
@@ -336,6 +394,8 @@ void *job_create(const char *job_id, const JobDriver *driver, JobTxn *txn,
{
Job *job;
+ JOB_LOCK_GUARD();
+
if (job_id) {
if (flags & JOB_INTERNAL) {
error_setg(errp, "Cannot specify job ID for internal job");
@@ -345,7 +405,7 @@ void *job_create(const char *job_id, const JobDriver *driver, JobTxn *txn,
error_setg(errp, "Invalid job ID '%s'", job_id);
return NULL;
}
- if (job_get(job_id)) {
+ if (job_get_locked(job_id)) {
error_setg(errp, "Job ID '%s' already in use", job_id);
return NULL;
}
@@ -375,7 +435,7 @@ void *job_create(const char *job_id, const JobDriver *driver, JobTxn *txn,
notifier_list_init(&job->on_ready);
notifier_list_init(&job->on_idle);
- job_state_transition(job, JOB_STATUS_CREATED);
+ job_state_transition_locked(job, JOB_STATUS_CREATED);
aio_timer_init(qemu_get_aio_context(), &job->sleep_timer,
QEMU_CLOCK_REALTIME, SCALE_NS,
job_sleep_timer_cb, job);
@@ -386,21 +446,27 @@ void *job_create(const char *job_id, const JobDriver *driver, JobTxn *txn,
* consolidating the job management logic */
if (!txn) {
txn = job_txn_new();
- job_txn_add_job(txn, job);
- job_txn_unref(txn);
+ job_txn_add_job_locked(txn, job);
+ job_txn_unref_locked(txn);
} else {
- job_txn_add_job(txn, job);
+ job_txn_add_job_locked(txn, job);
}
return job;
}
-void job_ref(Job *job)
+void job_ref_locked(Job *job)
{
++job->refcnt;
}
-void job_unref(Job *job)
+void job_ref(Job *job)
+{
+ JOB_LOCK_GUARD();
+ job_ref_locked(job);
+}
+
+void job_unref_locked(Job *job)
{
GLOBAL_STATE_CODE();
@@ -410,7 +476,9 @@ void job_unref(Job *job)
assert(!job->txn);
if (job->driver->free) {
+ job_unlock();
job->driver->free(job);
+ job_lock();
}
QLIST_REMOVE(job, job_list);
@@ -422,6 +490,12 @@ void job_unref(Job *job)
}
}
+void job_unref(Job *job)
+{
+ JOB_LOCK_GUARD();
+ job_unref_locked(job);
+}
+
void job_progress_update(Job *job, uint64_t done)
{
progress_work_done(&job->progress, done);
@@ -439,36 +513,41 @@ void job_progress_increase_remaining(Job *job, uint64_t delta)
/**
* To be called when a cancelled job is finalised.
+ * Called with job_mutex held.
*/
-static void job_event_cancelled(Job *job)
+static void job_event_cancelled_locked(Job *job)
{
notifier_list_notify(&job->on_finalize_cancelled, job);
}
/**
* To be called when a successfully completed job is finalised.
+ * Called with job_mutex held.
*/
-static void job_event_completed(Job *job)
+static void job_event_completed_locked(Job *job)
{
notifier_list_notify(&job->on_finalize_completed, job);
}
-static void job_event_pending(Job *job)
+/* Called with job_mutex held. */
+static void job_event_pending_locked(Job *job)
{
notifier_list_notify(&job->on_pending, job);
}
-static void job_event_ready(Job *job)
+/* Called with job_mutex held. */
+static void job_event_ready_locked(Job *job)
{
notifier_list_notify(&job->on_ready, job);
}
-static void job_event_idle(Job *job)
+/* Called with job_mutex held. */
+static void job_event_idle_locked(Job *job)
{
notifier_list_notify(&job->on_idle, job);
}
-void job_enter_cond(Job *job, bool(*fn)(Job *job))
+void job_enter_cond_locked(Job *job, bool(*fn)(Job *job))
{
if (!job_started(job)) {
return;
@@ -495,9 +574,16 @@ void job_enter_cond(Job *job, bool(*fn)(Job *job))
aio_co_enter(job->aio_context, job->co);
}
+void job_enter_cond(Job *job, bool(*fn)(Job *job))
+{
+ JOB_LOCK_GUARD();
+ job_enter_cond_locked(job, fn);
+}
+
void job_enter(Job *job)
{
- job_enter_cond(job, NULL);
+ JOB_LOCK_GUARD();
+ job_enter_cond_locked(job, NULL);
}
/* Yield, and schedule a timer to reenter the coroutine after @ns nanoseconds.
@@ -505,100 +591,129 @@ void job_enter(Job *job)
* is allowed and cancels the timer.
*
* If @ns is (uint64_t) -1, no timer is scheduled and job_enter() must be
- * called explicitly. */
-static void coroutine_fn job_do_yield(Job *job, uint64_t ns)
+ * called explicitly.
+ *
+ * Called with job_mutex held, but releases it temporarily.
+ */
+static void coroutine_fn job_do_yield_locked(Job *job, uint64_t ns)
{
real_job_lock();
if (ns != -1) {
timer_mod(&job->sleep_timer, ns);
}
job->busy = false;
- job_event_idle(job);
+ job_event_idle_locked(job);
real_job_unlock();
+ job_unlock();
qemu_coroutine_yield();
+ job_lock();
/* Set by job_enter_cond() before re-entering the coroutine. */
assert(job->busy);
}
-void coroutine_fn job_pause_point(Job *job)
+/* Called with job_mutex held, but releases it temporarily. */
+static void coroutine_fn job_pause_point_locked(Job *job)
{
assert(job && job_started(job));
- if (!job_should_pause(job)) {
+ if (!job_should_pause_locked(job)) {
return;
}
- if (job_is_cancelled(job)) {
+ if (job_is_cancelled_locked(job)) {
return;
}
if (job->driver->pause) {
+ job_unlock();
job->driver->pause(job);
+ job_lock();
}
- if (job_should_pause(job) && !job_is_cancelled(job)) {
+ if (job_should_pause_locked(job) && !job_is_cancelled_locked(job)) {
JobStatus status = job->status;
- job_state_transition(job, status == JOB_STATUS_READY
- ? JOB_STATUS_STANDBY
- : JOB_STATUS_PAUSED);
+ job_state_transition_locked(job, status == JOB_STATUS_READY
+ ? JOB_STATUS_STANDBY
+ : JOB_STATUS_PAUSED);
job->paused = true;
- job_do_yield(job, -1);
+ job_do_yield_locked(job, -1);
job->paused = false;
- job_state_transition(job, status);
+ job_state_transition_locked(job, status);
}
if (job->driver->resume) {
+ job_unlock();
job->driver->resume(job);
+ job_lock();
}
}
-void job_yield(Job *job)
+void coroutine_fn job_pause_point(Job *job)
+{
+ JOB_LOCK_GUARD();
+ job_pause_point_locked(job);
+}
+
+void job_yield_locked(Job *job)
{
assert(job->busy);
/* Check cancellation *before* setting busy = false, too! */
- if (job_is_cancelled(job)) {
+ if (job_is_cancelled_locked(job)) {
return;
}
- if (!job_should_pause(job)) {
- job_do_yield(job, -1);
+ if (!job_should_pause_locked(job)) {
+ job_do_yield_locked(job, -1);
}
- job_pause_point(job);
+ job_pause_point_locked(job);
+}
+
+void job_yield(Job *job)
+{
+ JOB_LOCK_GUARD();
+ job_yield_locked(job);
}
void coroutine_fn job_sleep_ns(Job *job, int64_t ns)
{
+ JOB_LOCK_GUARD();
assert(job->busy);
/* Check cancellation *before* setting busy = false, too! */
- if (job_is_cancelled(job)) {
+ if (job_is_cancelled_locked(job)) {
return;
}
- if (!job_should_pause(job)) {
- job_do_yield(job, qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + ns);
+ if (!job_should_pause_locked(job)) {
+ job_do_yield_locked(job, qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + ns);
}
- job_pause_point(job);
+ job_pause_point_locked(job);
}
-/* Assumes the block_job_mutex is held */
-static bool job_timer_not_pending(Job *job)
+/* Assumes the job_mutex is held */
+static bool job_timer_not_pending_locked(Job *job)
{
return !timer_pending(&job->sleep_timer);
}
-void job_pause(Job *job)
+void job_pause_locked(Job *job)
{
job->pause_count++;
if (!job->paused) {
- job_enter(job);
+ job_enter_cond_locked(job, NULL);
}
}
-void job_resume(Job *job)
+void job_pause(Job *job)
+{
+ JOB_LOCK_GUARD();
+ job_pause_locked(job);
+}
+
+void job_resume_locked(Job *job)
{
assert(job->pause_count > 0);
job->pause_count--;
@@ -607,12 +722,18 @@ void job_resume(Job *job)
}
/* kick only if no timer is pending */
- job_enter_cond(job, job_timer_not_pending);
+ job_enter_cond_locked(job, job_timer_not_pending_locked);
}
-void job_user_pause(Job *job, Error **errp)
+void job_resume(Job *job)
+{
+ JOB_LOCK_GUARD();
+ job_resume_locked(job);
+}
+
+void job_user_pause_locked(Job *job, Error **errp)
{
- if (job_apply_verb(job, JOB_VERB_PAUSE, errp)) {
+ if (job_apply_verb_locked(job, JOB_VERB_PAUSE, errp)) {
return;
}
if (job->user_paused) {
@@ -620,15 +741,27 @@ void job_user_pause(Job *job, Error **errp)
return;
}
job->user_paused = true;
- job_pause(job);
+ job_pause_locked(job);
}
-bool job_user_paused(Job *job)
+void job_user_pause(Job *job, Error **errp)
+{
+ JOB_LOCK_GUARD();
+ job_user_pause_locked(job, errp);
+}
+
+bool job_user_paused_locked(Job *job)
{
return job->user_paused;
}
-void job_user_resume(Job *job, Error **errp)
+bool job_user_paused(Job *job)
+{
+ JOB_LOCK_GUARD();
+ return job_user_paused_locked(job);
+}
+
+void job_user_resume_locked(Job *job, Error **errp)
{
assert(job);
GLOBAL_STATE_CODE();
@@ -636,132 +769,168 @@ void job_user_resume(Job *job, Error **errp)
error_setg(errp, "Can't resume a job that was not paused");
return;
}
- if (job_apply_verb(job, JOB_VERB_RESUME, errp)) {
+ if (job_apply_verb_locked(job, JOB_VERB_RESUME, errp)) {
return;
}
if (job->driver->user_resume) {
+ job_unlock();
job->driver->user_resume(job);
+ job_lock();
}
job->user_paused = false;
- job_resume(job);
+ job_resume_locked(job);
+}
+
+void job_user_resume(Job *job, Error **errp)
+{
+ JOB_LOCK_GUARD();
+ job_user_resume_locked(job, errp);
}
-static void job_do_dismiss(Job *job)
+/* Called with job_mutex held, but releases it temporarily. */
+static void job_do_dismiss_locked(Job *job)
{
assert(job);
job->busy = false;
job->paused = false;
job->deferred_to_main_loop = true;
- job_txn_del_job(job);
+ job_txn_del_job_locked(job);
- job_state_transition(job, JOB_STATUS_NULL);
- job_unref(job);
+ job_state_transition_locked(job, JOB_STATUS_NULL);
+ job_unref_locked(job);
}
-void job_dismiss(Job **jobptr, Error **errp)
+void job_dismiss_locked(Job **jobptr, Error **errp)
{
Job *job = *jobptr;
/* similarly to _complete, this is QMP-interface only. */
assert(job->id);
- if (job_apply_verb(job, JOB_VERB_DISMISS, errp)) {
+ if (job_apply_verb_locked(job, JOB_VERB_DISMISS, errp)) {
return;
}
- job_do_dismiss(job);
+ job_do_dismiss_locked(job);
*jobptr = NULL;
}
+void job_dismiss(Job **jobptr, Error **errp)
+{
+ JOB_LOCK_GUARD();
+ job_dismiss_locked(jobptr, errp);
+}
+
void job_early_fail(Job *job)
{
+ JOB_LOCK_GUARD();
assert(job->status == JOB_STATUS_CREATED);
- job_do_dismiss(job);
+ job_do_dismiss_locked(job);
}
-static void job_conclude(Job *job)
+/* Called with job_mutex held. */
+static void job_conclude_locked(Job *job)
{
- job_state_transition(job, JOB_STATUS_CONCLUDED);
+ job_state_transition_locked(job, JOB_STATUS_CONCLUDED);
if (job->auto_dismiss || !job_started(job)) {
- job_do_dismiss(job);
+ job_do_dismiss_locked(job);
}
}
-static void job_update_rc(Job *job)
+/* Called with job_mutex held. */
+static void job_update_rc_locked(Job *job)
{
- if (!job->ret && job_is_cancelled(job)) {
+ if (!job->ret && job_is_cancelled_locked(job)) {
job->ret = -ECANCELED;
}
if (job->ret) {
if (!job->err) {
error_setg(&job->err, "%s", strerror(-job->ret));
}
- job_state_transition(job, JOB_STATUS_ABORTING);
+ job_state_transition_locked(job, JOB_STATUS_ABORTING);
}
}
-static void job_commit(Job *job)
+/* Called with job_mutex held, but releases it temporarily */
+static void job_commit_locked(Job *job)
{
assert(!job->ret);
GLOBAL_STATE_CODE();
if (job->driver->commit) {
+ job_unlock();
job->driver->commit(job);
+ job_lock();
}
}
-static void job_abort(Job *job)
+/* Called with job_mutex held, but releases it temporarily */
+static void job_abort_locked(Job *job)
{
assert(job->ret);
GLOBAL_STATE_CODE();
if (job->driver->abort) {
+ job_unlock();
job->driver->abort(job);
+ job_lock();
}
}
-static void job_clean(Job *job)
+/* Called with job_mutex held, but releases it temporarily */
+static void job_clean_locked(Job *job)
{
GLOBAL_STATE_CODE();
if (job->driver->clean) {
+ job_unlock();
job->driver->clean(job);
+ job_lock();
}
}
-static int job_finalize_single(Job *job)
+/* Called with job_mutex held, but releases it temporarily */
+static int job_finalize_single_locked(Job *job)
{
- assert(job_is_completed(job));
+ int job_ret;
+
+ assert(job_is_completed_locked(job));
/* Ensure abort is called for late-transactional failures */
- job_update_rc(job);
+ job_update_rc_locked(job);
if (!job->ret) {
- job_commit(job);
+ job_commit_locked(job);
} else {
- job_abort(job);
+ job_abort_locked(job);
}
- job_clean(job);
+ job_clean_locked(job);
if (job->cb) {
- job->cb(job->opaque, job->ret);
+ job_ret = job->ret;
+ job_unlock();
+ job->cb(job->opaque, job_ret);
+ job_lock();
}
/* Emit events only if we actually started */
if (job_started(job)) {
- if (job_is_cancelled(job)) {
- job_event_cancelled(job);
+ if (job_is_cancelled_locked(job)) {
+ job_event_cancelled_locked(job);
} else {
- job_event_completed(job);
+ job_event_completed_locked(job);
}
}
- job_txn_del_job(job);
- job_conclude(job);
+ job_txn_del_job_locked(job);
+ job_conclude_locked(job);
return 0;
}
-static void job_cancel_async(Job *job, bool force)
+/* Called with job_mutex held, but releases it temporarily */
+static void job_cancel_async_locked(Job *job, bool force)
{
GLOBAL_STATE_CODE();
if (job->driver->cancel) {
+ job_unlock();
force = job->driver->cancel(job, force);
+ job_lock();
} else {
/* No .cancel() means the job will behave as if force-cancelled */
force = true;
@@ -770,7 +939,9 @@ static void job_cancel_async(Job *job, bool force)
if (job->user_paused) {
/* Do not call job_enter here, the caller will handle it. */
if (job->driver->user_resume) {
+ job_unlock();
job->driver->user_resume(job);
+ job_lock();
}
job->user_paused = false;
assert(job->pause_count > 0);
@@ -791,7 +962,8 @@ static void job_cancel_async(Job *job, bool force)
}
}
-static void job_completed_txn_abort(Job *job)
+/* Called with job_mutex held, but releases it temporarily. */
+static void job_completed_txn_abort_locked(Job *job)
{
AioContext *ctx;
JobTxn *txn = job->txn;
@@ -804,7 +976,7 @@ static void job_completed_txn_abort(Job *job)
return;
}
txn->aborting = true;
- job_txn_ref(txn);
+ job_txn_ref_locked(txn);
/*
* We can only hold the single job's AioContext lock while calling
@@ -812,7 +984,7 @@ static void job_completed_txn_abort(Job *job)
* calls of AIO_WAIT_WHILE(), which could deadlock otherwise.
* Note that the job's AioContext may change when it is finalized.
*/
- job_ref(job);
+ job_ref_locked(job);
aio_context_release(job->aio_context);
/* Other jobs are effectively cancelled by us, set the status for
@@ -827,7 +999,7 @@ static void job_completed_txn_abort(Job *job)
* Therefore, pass force=true to terminate all other jobs as quickly
* as possible.
*/
- job_cancel_async(other_job, true);
+ job_cancel_async_locked(other_job, true);
aio_context_release(ctx);
}
}
@@ -839,11 +1011,11 @@ static void job_completed_txn_abort(Job *job)
*/
ctx = other_job->aio_context;
aio_context_acquire(ctx);
- if (!job_is_completed(other_job)) {
- assert(job_cancel_requested(other_job));
- job_finish_sync(other_job, NULL, NULL);
+ if (!job_is_completed_locked(other_job)) {
+ assert(job_cancel_requested_locked(other_job));
+ job_finish_sync_locked(other_job, NULL, NULL);
}
- job_finalize_single(other_job);
+ job_finalize_single_locked(other_job);
aio_context_release(ctx);
}
@@ -852,110 +1024,129 @@ static void job_completed_txn_abort(Job *job)
* even if the job went away during job_finalize_single().
*/
aio_context_acquire(job->aio_context);
- job_unref(job);
+ job_unref_locked(job);
- job_txn_unref(txn);
+ job_txn_unref_locked(txn);
}
-static int job_prepare(Job *job)
+/* Called with job_mutex held, but releases it temporarily */
+static int job_prepare_locked(Job *job)
{
GLOBAL_STATE_CODE();
if (job->ret == 0 && job->driver->prepare) {
+ job_unlock();
job->ret = job->driver->prepare(job);
- job_update_rc(job);
+ job_lock();
+ job_update_rc_locked(job);
}
return job->ret;
}
-static int job_needs_finalize(Job *job)
+/* Called with job_mutex held */
+static int job_needs_finalize_locked(Job *job)
{
return !job->auto_finalize;
}
-static void job_do_finalize(Job *job)
+/* Called with job_mutex held */
+static void job_do_finalize_locked(Job *job)
{
int rc;
assert(job && job->txn);
/* prepare the transaction to complete */
- rc = job_txn_apply(job, job_prepare);
+ rc = job_txn_apply_locked(job, job_prepare_locked);
if (rc) {
- job_completed_txn_abort(job);
+ job_completed_txn_abort_locked(job);
} else {
- job_txn_apply(job, job_finalize_single);
+ job_txn_apply_locked(job, job_finalize_single_locked);
}
}
-void job_finalize(Job *job, Error **errp)
+void job_finalize_locked(Job *job, Error **errp)
{
assert(job && job->id);
- if (job_apply_verb(job, JOB_VERB_FINALIZE, errp)) {
+ if (job_apply_verb_locked(job, JOB_VERB_FINALIZE, errp)) {
return;
}
- job_do_finalize(job);
+ job_do_finalize_locked(job);
+}
+
+void job_finalize(Job *job, Error **errp)
+{
+ JOB_LOCK_GUARD();
+ job_finalize_locked(job, errp);
}
-static int job_transition_to_pending(Job *job)
+/* Called with job_mutex held. */
+static int job_transition_to_pending_locked(Job *job)
{
- job_state_transition(job, JOB_STATUS_PENDING);
+ job_state_transition_locked(job, JOB_STATUS_PENDING);
if (!job->auto_finalize) {
- job_event_pending(job);
+ job_event_pending_locked(job);
}
return 0;
}
void job_transition_to_ready(Job *job)
{
- job_state_transition(job, JOB_STATUS_READY);
- job_event_ready(job);
+ JOB_LOCK_GUARD();
+ job_state_transition_locked(job, JOB_STATUS_READY);
+ job_event_ready_locked(job);
}
-static void job_completed_txn_success(Job *job)
+/* Called with job_mutex held. */
+static void job_completed_txn_success_locked(Job *job)
{
JobTxn *txn = job->txn;
Job *other_job;
- job_state_transition(job, JOB_STATUS_WAITING);
+ job_state_transition_locked(job, JOB_STATUS_WAITING);
/*
* Successful completion, see if there are other running jobs in this
* txn.
*/
QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
- if (!job_is_completed(other_job)) {
+ if (!job_is_completed_locked(other_job)) {
return;
}
assert(other_job->ret == 0);
}
- job_txn_apply(job, job_transition_to_pending);
+ job_txn_apply_locked(job, job_transition_to_pending_locked);
/* If no jobs need manual finalization, automatically do so */
- if (job_txn_apply(job, job_needs_finalize) == 0) {
- job_do_finalize(job);
+ if (job_txn_apply_locked(job, job_needs_finalize_locked) == 0) {
+ job_do_finalize_locked(job);
}
}
-static void job_completed(Job *job)
+/* Called with job_mutex held. */
+static void job_completed_locked(Job *job)
{
- assert(job && job->txn && !job_is_completed(job));
+ assert(job && job->txn && !job_is_completed_locked(job));
- job_update_rc(job);
+ job_update_rc_locked(job);
trace_job_completed(job, job->ret);
if (job->ret) {
- job_completed_txn_abort(job);
+ job_completed_txn_abort_locked(job);
} else {
- job_completed_txn_success(job);
+ job_completed_txn_success_locked(job);
}
}
-/** Useful only as a type shim for aio_bh_schedule_oneshot. */
+/**
+ * Useful only as a type shim for aio_bh_schedule_oneshot.
+ * Called with job_mutex *not* held, but releases it temporarily.
+ */
static void job_exit(void *opaque)
{
Job *job = (Job *)opaque;
AioContext *ctx;
+ JOB_LOCK_GUARD();
- job_ref(job);
+ job_ref_locked(job);
aio_context_acquire(job->aio_context);
/* This is a lie, we're not quiescent, but still doing the completion
@@ -963,9 +1154,9 @@ static void job_exit(void *opaque)
* drain block nodes, and if .drained_poll still returned true, we would
* deadlock. */
job->busy = false;
- job_event_idle(job);
+ job_event_idle_locked(job);
- job_completed(job);
+ job_completed_locked(job);
/*
* Note that calling job_completed can move the job to a different
@@ -974,7 +1165,7 @@ static void job_exit(void *opaque)
* the job underneath us.
*/
ctx = job->aio_context;
- job_unref(job);
+ job_unref_locked(job);
aio_context_release(ctx);
}
@@ -985,37 +1176,47 @@ static void job_exit(void *opaque)
static void coroutine_fn job_co_entry(void *opaque)
{
Job *job = opaque;
+ int ret;
assert(job && job->driver && job->driver->run);
- assert(job->aio_context == qemu_get_current_aio_context());
- job_pause_point(job);
- job->ret = job->driver->run(job, &job->err);
- job->deferred_to_main_loop = true;
- job->busy = true;
+ WITH_JOB_LOCK_GUARD() {
+ assert(job->aio_context == qemu_get_current_aio_context());
+ job_pause_point_locked(job);
+ }
+ ret = job->driver->run(job, &job->err);
+ WITH_JOB_LOCK_GUARD() {
+ job->ret = ret;
+ job->deferred_to_main_loop = true;
+ job->busy = true;
+ }
aio_bh_schedule_oneshot(qemu_get_aio_context(), job_exit, job);
}
void job_start(Job *job)
{
- assert(job && !job_started(job) && job->paused &&
- job->driver && job->driver->run);
- job->co = qemu_coroutine_create(job_co_entry, job);
- job->pause_count--;
- job->busy = true;
- job->paused = false;
- job_state_transition(job, JOB_STATUS_RUNNING);
+ assert(qemu_in_main_thread());
+
+ WITH_JOB_LOCK_GUARD() {
+ assert(job && !job_started(job) && job->paused &&
+ job->driver && job->driver->run);
+ job->co = qemu_coroutine_create(job_co_entry, job);
+ job->pause_count--;
+ job->busy = true;
+ job->paused = false;
+ job_state_transition_locked(job, JOB_STATUS_RUNNING);
+ }
aio_co_enter(job->aio_context, job->co);
}
-void job_cancel(Job *job, bool force)
+void job_cancel_locked(Job *job, bool force)
{
if (job->status == JOB_STATUS_CONCLUDED) {
- job_do_dismiss(job);
+ job_do_dismiss_locked(job);
return;
}
- job_cancel_async(job, force);
+ job_cancel_async_locked(job, force);
if (!job_started(job)) {
- job_completed(job);
+ job_completed_locked(job);
} else if (job->deferred_to_main_loop) {
/*
* job_cancel_async() ignores soft-cancel requests for jobs
@@ -1027,102 +1228,150 @@ void job_cancel(Job *job, bool force)
* choose to call job_is_cancelled() to show that we invoke
* job_completed_txn_abort() only for force-cancelled jobs.)
*/
- if (job_is_cancelled(job)) {
- job_completed_txn_abort(job);
+ if (job_is_cancelled_locked(job)) {
+ job_completed_txn_abort_locked(job);
}
} else {
- job_enter(job);
+ job_enter_cond_locked(job, NULL);
}
}
-void job_user_cancel(Job *job, bool force, Error **errp)
+void job_cancel(Job *job, bool force)
{
- if (job_apply_verb(job, JOB_VERB_CANCEL, errp)) {
+ JOB_LOCK_GUARD();
+ job_cancel_locked(job, force);
+}
+
+void job_user_cancel_locked(Job *job, bool force, Error **errp)
+{
+ if (job_apply_verb_locked(job, JOB_VERB_CANCEL, errp)) {
return;
}
- job_cancel(job, force);
+ job_cancel_locked(job, force);
+}
+
+void job_user_cancel(Job *job, bool force, Error **errp)
+{
+ JOB_LOCK_GUARD();
+ job_user_cancel_locked(job, force, errp);
}
/* A wrapper around job_cancel() taking an Error ** parameter so it may be
* used with job_finish_sync() without the need for (rather nasty) function
- * pointer casts there. */
-static void job_cancel_err(Job *job, Error **errp)
+ * pointer casts there.
+ *
+ * Called with job_mutex held.
+ */
+static void job_cancel_err_locked(Job *job, Error **errp)
{
- job_cancel(job, false);
+ job_cancel_locked(job, false);
}
/**
* Same as job_cancel_err(), but force-cancel.
+ * Called with job_mutex held.
*/
-static void job_force_cancel_err(Job *job, Error **errp)
+static void job_force_cancel_err_locked(Job *job, Error **errp)
{
- job_cancel(job, true);
+ job_cancel_locked(job, true);
}
-int job_cancel_sync(Job *job, bool force)
+int job_cancel_sync_locked(Job *job, bool force)
{
if (force) {
- return job_finish_sync(job, &job_force_cancel_err, NULL);
+ return job_finish_sync_locked(job, &job_force_cancel_err_locked, NULL);
} else {
- return job_finish_sync(job, &job_cancel_err, NULL);
+ return job_finish_sync_locked(job, &job_cancel_err_locked, NULL);
}
}
+int job_cancel_sync(Job *job, bool force)
+{
+ JOB_LOCK_GUARD();
+ return job_cancel_sync_locked(job, force);
+}
+
void job_cancel_sync_all(void)
{
Job *job;
AioContext *aio_context;
+ JOB_LOCK_GUARD();
- while ((job = job_next(NULL))) {
+ while ((job = job_next_locked(NULL))) {
aio_context = job->aio_context;
aio_context_acquire(aio_context);
- job_cancel_sync(job, true);
+ job_cancel_sync_locked(job, true);
aio_context_release(aio_context);
}
}
+int job_complete_sync_locked(Job *job, Error **errp)
+{
+ return job_finish_sync_locked(job, job_complete_locked, errp);
+}
+
int job_complete_sync(Job *job, Error **errp)
{
- return job_finish_sync(job, job_complete, errp);
+ JOB_LOCK_GUARD();
+ return job_complete_sync_locked(job, errp);
}
-void job_complete(Job *job, Error **errp)
+void job_complete_locked(Job *job, Error **errp)
{
/* Should not be reachable via external interface for internal jobs */
assert(job->id);
GLOBAL_STATE_CODE();
- if (job_apply_verb(job, JOB_VERB_COMPLETE, errp)) {
+ if (job_apply_verb_locked(job, JOB_VERB_COMPLETE, errp)) {
return;
}
- if (job_cancel_requested(job) || !job->driver->complete) {
+ if (job_cancel_requested_locked(job) || !job->driver->complete) {
error_setg(errp, "The active block job '%s' cannot be completed",
job->id);
return;
}
+ job_unlock();
job->driver->complete(job, errp);
+ job_lock();
}
-int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp), Error **errp)
+void job_complete(Job *job, Error **errp)
+{
+ JOB_LOCK_GUARD();
+ job_complete_locked(job, errp);
+}
+
+int job_finish_sync_locked(Job *job,
+ void (*finish)(Job *, Error **errp),
+ Error **errp)
{
Error *local_err = NULL;
int ret;
- job_ref(job);
+ job_ref_locked(job);
if (finish) {
finish(job, &local_err);
}
if (local_err) {
error_propagate(errp, local_err);
- job_unref(job);
+ job_unref_locked(job);
return -EBUSY;
}
+ job_unlock();
AIO_WAIT_WHILE(job->aio_context,
(job_enter(job), !job_is_completed(job)));
+ job_lock();
- ret = (job_is_cancelled(job) && job->ret == 0) ? -ECANCELED : job->ret;
- job_unref(job);
+ ret = (job_is_cancelled_locked(job) && job->ret == 0)
+ ? -ECANCELED : job->ret;
+ job_unref_locked(job);
return ret;
}
+
+int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp), Error **errp)
+{
+ JOB_LOCK_GUARD();
+ return job_finish_sync_locked(job, finish, errp);
+}
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 06/21] job: move and update comments from blockjob.c
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (4 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 05/21] job.c: add job_lock/unlock while keeping job.h intact Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-11 8:56 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 07/21] blockjob: introduce block_job _locked() APIs Emanuele Giuseppe Esposito
` (15 subsequent siblings)
21 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito
This comment applies more on job, it was left in blockjob as in the past
the whole job logic was implemented there.
Note: at this stage, job_{lock/unlock} and job lock guard macros
are *nop*.
No functional change intended.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
blockjob.c | 20 --------------------
job.c | 14 ++++++++++++++
2 files changed, 14 insertions(+), 20 deletions(-)
diff --git a/blockjob.c b/blockjob.c
index 4868453d74..7da59a1f1c 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -36,21 +36,6 @@
#include "qemu/main-loop.h"
#include "qemu/timer.h"
-/*
- * The block job API is composed of two categories of functions.
- *
- * The first includes functions used by the monitor. The monitor is
- * peculiar in that it accesses the block job list with block_job_get, and
- * therefore needs consistency across block_job_get and the actual operation
- * (e.g. block_job_set_speed). The consistency is achieved with
- * aio_context_acquire/release. These functions are declared in blockjob.h.
- *
- * The second includes functions used by the block job drivers and sometimes
- * by the core block layer. These do not care about locking, because the
- * whole coroutine runs under the AioContext lock, and are declared in
- * blockjob_int.h.
- */
-
static bool is_block_job(Job *job)
{
return job_type(job) == JOB_TYPE_BACKUP ||
@@ -433,11 +418,6 @@ static void block_job_event_ready(Notifier *n, void *opaque)
}
-/*
- * API for block job drivers and the block layer. These functions are
- * declared in blockjob_int.h.
- */
-
void *block_job_create(const char *job_id, const BlockJobDriver *driver,
JobTxn *txn, BlockDriverState *bs, uint64_t perm,
uint64_t shared_perm, int64_t speed, int flags,
diff --git a/job.c b/job.c
index 37485e162a..de3d368086 100644
--- a/job.c
+++ b/job.c
@@ -32,6 +32,20 @@
#include "trace/trace-root.h"
#include "qapi/qapi-events-job.h"
+/*
+ * The job API is composed of two categories of functions.
+ *
+ * The first includes functions used by the monitor. The monitor is
+ * peculiar in that it accesses the block job list with job_get, and
+ * therefore needs consistency across job_get and the actual operation
+ * (e.g. job_user_cancel). To achieve this consistency, the caller
+ * calls job_lock/job_unlock itself around the whole operation.
+ *
+ *
+ * The second includes functions used by the block job drivers and sometimes
+ * by the core block layer. These delegate the locking to the callee instead.
+ */
+
/*
* job_mutex protects the jobs list, but also makes the
* struct job fields thread-safe.
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 07/21] blockjob: introduce block_job _locked() APIs
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (5 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 06/21] job: move and update comments from blockjob.c Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-11 12:04 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 08/21] jobs: add job lock in find_* functions Emanuele Giuseppe Esposito
` (14 subsequent siblings)
21 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito
Just as done with job.h, create _locked() functions in blockjob.h
These functions will be later useful when caller has already taken
the lock. All blockjob _locked functions call job _locked functions.
Note: at this stage, job_{lock/unlock} and job lock guard macros
are *nop*.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
blockjob.c | 52 ++++++++++++++++++++++++++++++++--------
include/block/blockjob.h | 18 ++++++++++++++
2 files changed, 60 insertions(+), 10 deletions(-)
diff --git a/blockjob.c b/blockjob.c
index 7da59a1f1c..0d59aba439 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -44,21 +44,27 @@ static bool is_block_job(Job *job)
job_type(job) == JOB_TYPE_STREAM;
}
-BlockJob *block_job_next(BlockJob *bjob)
+BlockJob *block_job_next_locked(BlockJob *bjob)
{
Job *job = bjob ? &bjob->job : NULL;
GLOBAL_STATE_CODE();
do {
- job = job_next(job);
+ job = job_next_locked(job);
} while (job && !is_block_job(job));
return job ? container_of(job, BlockJob, job) : NULL;
}
-BlockJob *block_job_get(const char *id)
+BlockJob *block_job_next(BlockJob *bjob)
{
- Job *job = job_get(id);
+ JOB_LOCK_GUARD();
+ return block_job_next_locked(bjob);
+}
+
+BlockJob *block_job_get_locked(const char *id)
+{
+ Job *job = job_get_locked(id);
GLOBAL_STATE_CODE();
if (job && is_block_job(job)) {
@@ -68,6 +74,12 @@ BlockJob *block_job_get(const char *id)
}
}
+BlockJob *block_job_get(const char *id)
+{
+ JOB_LOCK_GUARD();
+ return block_job_get_locked(id);
+}
+
void block_job_free(Job *job)
{
BlockJob *bjob = container_of(job, BlockJob, job);
@@ -256,14 +268,14 @@ static bool job_timer_pending(Job *job)
return timer_pending(&job->sleep_timer);
}
-bool block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
+bool block_job_set_speed_locked(BlockJob *job, int64_t speed, Error **errp)
{
const BlockJobDriver *drv = block_job_driver(job);
int64_t old_speed = job->speed;
GLOBAL_STATE_CODE();
- if (job_apply_verb(&job->job, JOB_VERB_SET_SPEED, errp) < 0) {
+ if (job_apply_verb_locked(&job->job, JOB_VERB_SET_SPEED, errp) < 0) {
return false;
}
if (speed < 0) {
@@ -277,7 +289,9 @@ bool block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
job->speed = speed;
if (drv->set_speed) {
+ job_unlock();
drv->set_speed(job, speed);
+ job_lock();
}
if (speed && speed <= old_speed) {
@@ -285,18 +299,24 @@ bool block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
}
/* kick only if a timer is pending */
- job_enter_cond(&job->job, job_timer_pending);
+ job_enter_cond_locked(&job->job, job_timer_pending);
return true;
}
+bool block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
+{
+ JOB_LOCK_GUARD();
+ return block_job_set_speed_locked(job, speed, errp);
+}
+
int64_t block_job_ratelimit_get_delay(BlockJob *job, uint64_t n)
{
IO_CODE();
return ratelimit_calculate_delay(&job->limit, n);
}
-BlockJobInfo *block_job_query(BlockJob *job, Error **errp)
+BlockJobInfo *block_job_query_locked(BlockJob *job, Error **errp)
{
BlockJobInfo *info;
uint64_t progress_current, progress_total;
@@ -320,7 +340,7 @@ BlockJobInfo *block_job_query(BlockJob *job, Error **errp)
info->len = progress_total;
info->speed = job->speed;
info->io_status = job->iostatus;
- info->ready = job_is_ready(&job->job),
+ info->ready = job_is_ready_locked(&job->job),
info->status = job->job.status;
info->auto_finalize = job->job.auto_finalize;
info->auto_dismiss = job->job.auto_dismiss;
@@ -333,6 +353,12 @@ BlockJobInfo *block_job_query(BlockJob *job, Error **errp)
return info;
}
+BlockJobInfo *block_job_query(BlockJob *job, Error **errp)
+{
+ JOB_LOCK_GUARD();
+ return block_job_query_locked(job, errp);
+}
+
static void block_job_iostatus_set_err(BlockJob *job, int error)
{
if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
@@ -478,7 +504,7 @@ fail:
return NULL;
}
-void block_job_iostatus_reset(BlockJob *job)
+void block_job_iostatus_reset_locked(BlockJob *job)
{
GLOBAL_STATE_CODE();
if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
@@ -488,6 +514,12 @@ void block_job_iostatus_reset(BlockJob *job)
job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
}
+void block_job_iostatus_reset(BlockJob *job)
+{
+ JOB_LOCK_GUARD();
+ block_job_iostatus_reset_locked(job);
+}
+
void block_job_user_resume(Job *job)
{
BlockJob *bjob = container_of(job, BlockJob, job);
diff --git a/include/block/blockjob.h b/include/block/blockjob.h
index 6525e16fd5..8b65d3949d 100644
--- a/include/block/blockjob.h
+++ b/include/block/blockjob.h
@@ -92,6 +92,9 @@ typedef struct BlockJob {
*/
BlockJob *block_job_next(BlockJob *job);
+/* Same as block_job_next(), but called with job lock held. */
+BlockJob *block_job_next_locked(BlockJob *job);
+
/**
* block_job_get:
* @id: The id of the block job.
@@ -102,6 +105,9 @@ BlockJob *block_job_next(BlockJob *job);
*/
BlockJob *block_job_get(const char *id);
+/* Same as block_job_get(), but called with job lock held. */
+BlockJob *block_job_get_locked(const char *id);
+
/**
* block_job_add_bdrv:
* @job: A block job
@@ -145,6 +151,12 @@ bool block_job_has_bdrv(BlockJob *job, BlockDriverState *bs);
*/
bool block_job_set_speed(BlockJob *job, int64_t speed, Error **errp);
+/*
+ * Same as block_job_set_speed(), but called with job lock held.
+ * Might release the lock temporarily.
+ */
+bool block_job_set_speed_locked(BlockJob *job, int64_t speed, Error **errp);
+
/**
* block_job_query:
* @job: The job to get information about.
@@ -153,6 +165,9 @@ bool block_job_set_speed(BlockJob *job, int64_t speed, Error **errp);
*/
BlockJobInfo *block_job_query(BlockJob *job, Error **errp);
+/* Same as block_job_query(), but called with job lock held. */
+BlockJobInfo *block_job_query_locked(BlockJob *job, Error **errp);
+
/**
* block_job_iostatus_reset:
* @job: The job whose I/O status should be reset.
@@ -162,6 +177,9 @@ BlockJobInfo *block_job_query(BlockJob *job, Error **errp);
*/
void block_job_iostatus_reset(BlockJob *job);
+/* Same as block_job_iostatus_reset(), but called with job lock held. */
+void block_job_iostatus_reset_locked(BlockJob *job);
+
/*
* block_job_get_aio_context:
*
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 08/21] jobs: add job lock in find_* functions
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (6 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 07/21] blockjob: introduce block_job _locked() APIs Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-11 12:20 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 09/21] jobs: use job locks also in the unit tests Emanuele Giuseppe Esposito
` (13 subsequent siblings)
21 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito
Both blockdev.c and job-qmp.c have TOC/TOU conditions, because
they first search for the job and then perform an action on it.
Therefore, we need to do the search + action under the same
job mutex critical section.
Note: at this stage, job_{lock/unlock} and job lock guard macros
are *nop*.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
blockdev.c | 67 +++++++++++++++++++++++++++++++++++++-----------------
job-qmp.c | 57 ++++++++++++++++++++++++++++++++--------------
2 files changed, 86 insertions(+), 38 deletions(-)
diff --git a/blockdev.c b/blockdev.c
index 9230888e34..71f793c4ab 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3302,9 +3302,13 @@ out:
aio_context_release(aio_context);
}
-/* Get a block job using its ID and acquire its AioContext */
-static BlockJob *find_block_job(const char *id, AioContext **aio_context,
- Error **errp)
+/*
+ * Get a block job using its ID and acquire its AioContext.
+ * Called with job_mutex held.
+ */
+static BlockJob *find_block_job_locked(const char *id,
+ AioContext **aio_context,
+ Error **errp)
{
BlockJob *job;
@@ -3312,7 +3316,7 @@ static BlockJob *find_block_job(const char *id, AioContext **aio_context,
*aio_context = NULL;
- job = block_job_get(id);
+ job = block_job_get_locked(id);
if (!job) {
error_set(errp, ERROR_CLASS_DEVICE_NOT_ACTIVE,
@@ -3329,13 +3333,16 @@ static BlockJob *find_block_job(const char *id, AioContext **aio_context,
void qmp_block_job_set_speed(const char *device, int64_t speed, Error **errp)
{
AioContext *aio_context;
- BlockJob *job = find_block_job(device, &aio_context, errp);
+ BlockJob *job;
+
+ JOB_LOCK_GUARD();
+ job = find_block_job_locked(device, &aio_context, errp);
if (!job) {
return;
}
- block_job_set_speed(job, speed, errp);
+ block_job_set_speed_locked(job, speed, errp);
aio_context_release(aio_context);
}
@@ -3343,7 +3350,10 @@ void qmp_block_job_cancel(const char *device,
bool has_force, bool force, Error **errp)
{
AioContext *aio_context;
- BlockJob *job = find_block_job(device, &aio_context, errp);
+ BlockJob *job;
+
+ JOB_LOCK_GUARD();
+ job = find_block_job_locked(device, &aio_context, errp);
if (!job) {
return;
@@ -3353,14 +3363,14 @@ void qmp_block_job_cancel(const char *device,
force = false;
}
- if (job_user_paused(&job->job) && !force) {
+ if (job_user_paused_locked(&job->job) && !force) {
error_setg(errp, "The block job for device '%s' is currently paused",
device);
goto out;
}
trace_qmp_block_job_cancel(job);
- job_user_cancel(&job->job, force, errp);
+ job_user_cancel_locked(&job->job, force, errp);
out:
aio_context_release(aio_context);
}
@@ -3368,57 +3378,69 @@ out:
void qmp_block_job_pause(const char *device, Error **errp)
{
AioContext *aio_context;
- BlockJob *job = find_block_job(device, &aio_context, errp);
+ BlockJob *job;
+
+ JOB_LOCK_GUARD();
+ job = find_block_job_locked(device, &aio_context, errp);
if (!job) {
return;
}
trace_qmp_block_job_pause(job);
- job_user_pause(&job->job, errp);
+ job_user_pause_locked(&job->job, errp);
aio_context_release(aio_context);
}
void qmp_block_job_resume(const char *device, Error **errp)
{
AioContext *aio_context;
- BlockJob *job = find_block_job(device, &aio_context, errp);
+ BlockJob *job;
+
+ JOB_LOCK_GUARD();
+ job = find_block_job_locked(device, &aio_context, errp);
if (!job) {
return;
}
trace_qmp_block_job_resume(job);
- job_user_resume(&job->job, errp);
+ job_user_resume_locked(&job->job, errp);
aio_context_release(aio_context);
}
void qmp_block_job_complete(const char *device, Error **errp)
{
AioContext *aio_context;
- BlockJob *job = find_block_job(device, &aio_context, errp);
+ BlockJob *job;
+
+ JOB_LOCK_GUARD();
+ job = find_block_job_locked(device, &aio_context, errp);
if (!job) {
return;
}
trace_qmp_block_job_complete(job);
- job_complete(&job->job, errp);
+ job_complete_locked(&job->job, errp);
aio_context_release(aio_context);
}
void qmp_block_job_finalize(const char *id, Error **errp)
{
AioContext *aio_context;
- BlockJob *job = find_block_job(id, &aio_context, errp);
+ BlockJob *job;
+
+ JOB_LOCK_GUARD();
+ job = find_block_job_locked(id, &aio_context, errp);
if (!job) {
return;
}
trace_qmp_block_job_finalize(job);
- job_ref(&job->job);
- job_finalize(&job->job, errp);
+ job_ref_locked(&job->job);
+ job_finalize_locked(&job->job, errp);
/*
* Job's context might have changed via job_finalize (and job_txn_apply
@@ -3426,23 +3448,26 @@ void qmp_block_job_finalize(const char *id, Error **errp)
* one.
*/
aio_context = block_job_get_aio_context(job);
- job_unref(&job->job);
+ job_unref_locked(&job->job);
aio_context_release(aio_context);
}
void qmp_block_job_dismiss(const char *id, Error **errp)
{
AioContext *aio_context;
- BlockJob *bjob = find_block_job(id, &aio_context, errp);
+ BlockJob *bjob;
Job *job;
+ JOB_LOCK_GUARD();
+ bjob = find_block_job_locked(id, &aio_context, errp);
+
if (!bjob) {
return;
}
trace_qmp_block_job_dismiss(bjob);
job = &bjob->job;
- job_dismiss(&job, errp);
+ job_dismiss_locked(&job, errp);
aio_context_release(aio_context);
}
diff --git a/job-qmp.c b/job-qmp.c
index 829a28aa70..ac11a6c23c 100644
--- a/job-qmp.c
+++ b/job-qmp.c
@@ -29,14 +29,19 @@
#include "qapi/error.h"
#include "trace/trace-root.h"
-/* Get a job using its ID and acquire its AioContext */
-static Job *find_job(const char *id, AioContext **aio_context, Error **errp)
+/*
+ * Get a block job using its ID and acquire its AioContext.
+ * Called with job_mutex held.
+ */
+static Job *find_job_locked(const char *id,
+ AioContext **aio_context,
+ Error **errp)
{
Job *job;
*aio_context = NULL;
- job = job_get(id);
+ job = job_get_locked(id);
if (!job) {
error_setg(errp, "Job not found");
return NULL;
@@ -51,71 +56,86 @@ static Job *find_job(const char *id, AioContext **aio_context, Error **errp)
void qmp_job_cancel(const char *id, Error **errp)
{
AioContext *aio_context;
- Job *job = find_job(id, &aio_context, errp);
+ Job *job;
+
+ JOB_LOCK_GUARD();
+ job = find_job_locked(id, &aio_context, errp);
if (!job) {
return;
}
trace_qmp_job_cancel(job);
- job_user_cancel(job, true, errp);
+ job_user_cancel_locked(job, true, errp);
aio_context_release(aio_context);
}
void qmp_job_pause(const char *id, Error **errp)
{
AioContext *aio_context;
- Job *job = find_job(id, &aio_context, errp);
+ Job *job;
+
+ JOB_LOCK_GUARD();
+ job = find_job_locked(id, &aio_context, errp);
if (!job) {
return;
}
trace_qmp_job_pause(job);
- job_user_pause(job, errp);
+ job_user_pause_locked(job, errp);
aio_context_release(aio_context);
}
void qmp_job_resume(const char *id, Error **errp)
{
AioContext *aio_context;
- Job *job = find_job(id, &aio_context, errp);
+ Job *job;
+
+ JOB_LOCK_GUARD();
+ job = find_job_locked(id, &aio_context, errp);
if (!job) {
return;
}
trace_qmp_job_resume(job);
- job_user_resume(job, errp);
+ job_user_resume_locked(job, errp);
aio_context_release(aio_context);
}
void qmp_job_complete(const char *id, Error **errp)
{
AioContext *aio_context;
- Job *job = find_job(id, &aio_context, errp);
+ Job *job;
+
+ JOB_LOCK_GUARD();
+ job = find_job_locked(id, &aio_context, errp);
if (!job) {
return;
}
trace_qmp_job_complete(job);
- job_complete(job, errp);
+ job_complete_locked(job, errp);
aio_context_release(aio_context);
}
void qmp_job_finalize(const char *id, Error **errp)
{
AioContext *aio_context;
- Job *job = find_job(id, &aio_context, errp);
+ Job *job;
+
+ JOB_LOCK_GUARD();
+ job = find_job_locked(id, &aio_context, errp);
if (!job) {
return;
}
trace_qmp_job_finalize(job);
- job_ref(job);
- job_finalize(job, errp);
+ job_ref_locked(job);
+ job_finalize_locked(job, errp);
/*
* Job's context might have changed via job_finalize (and job_txn_apply
@@ -123,21 +143,24 @@ void qmp_job_finalize(const char *id, Error **errp)
* one.
*/
aio_context = job->aio_context;
- job_unref(job);
+ job_unref_locked(job);
aio_context_release(aio_context);
}
void qmp_job_dismiss(const char *id, Error **errp)
{
AioContext *aio_context;
- Job *job = find_job(id, &aio_context, errp);
+ Job *job;
+
+ JOB_LOCK_GUARD();
+ job = find_job_locked(id, &aio_context, errp);
if (!job) {
return;
}
trace_qmp_job_dismiss(job);
- job_dismiss(&job, errp);
+ job_dismiss_locked(&job, errp);
aio_context_release(aio_context);
}
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 09/21] jobs: use job locks also in the unit tests
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (7 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 08/21] jobs: add job lock in find_* functions Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-11 13:08 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 10/21] block/mirror.c: use of job helpers in drivers to avoid TOC/TOU Emanuele Giuseppe Esposito
` (12 subsequent siblings)
21 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito
Add missing job synchronization in the unit tests, with
explicit locks.
We are deliberately using _locked functions wrapped by a guard
instead of a normal call because the normal call will be removed
in future, as the only usage is limited to the tests.
In other words, if a function like job_pause() is/will be only used
in tests to avoid:
WITH_JOB_LOCK_GUARD(){
job_pause_locked();
}
then it is not worth keeping job_pause(), and just use the guard.
Note: at this stage, job_{lock/unlock} and job lock guard macros
are *nop*.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
tests/unit/test-bdrv-drain.c | 76 +++++++++++++++++---------
tests/unit/test-block-iothread.c | 8 ++-
tests/unit/test-blockjob-txn.c | 24 +++++---
tests/unit/test-blockjob.c | 94 ++++++++++++++++++++++++--------
4 files changed, 141 insertions(+), 61 deletions(-)
diff --git a/tests/unit/test-bdrv-drain.c b/tests/unit/test-bdrv-drain.c
index 36be84ae55..0db056ea63 100644
--- a/tests/unit/test-bdrv-drain.c
+++ b/tests/unit/test-bdrv-drain.c
@@ -943,61 +943,83 @@ static void test_blockjob_common_drain_node(enum drain_type drain_type,
}
}
- g_assert_cmpint(job->job.pause_count, ==, 0);
- g_assert_false(job->job.paused);
- g_assert_true(tjob->running);
- g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
+ WITH_JOB_LOCK_GUARD() {
+ g_assert_cmpint(job->job.pause_count, ==, 0);
+ g_assert_false(job->job.paused);
+ g_assert_true(tjob->running);
+ g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
+ }
do_drain_begin_unlocked(drain_type, drain_bs);
- if (drain_type == BDRV_DRAIN_ALL) {
- /* bdrv_drain_all() drains both src and target */
- g_assert_cmpint(job->job.pause_count, ==, 2);
- } else {
- g_assert_cmpint(job->job.pause_count, ==, 1);
+ WITH_JOB_LOCK_GUARD() {
+ if (drain_type == BDRV_DRAIN_ALL) {
+ /* bdrv_drain_all() drains both src and target */
+ g_assert_cmpint(job->job.pause_count, ==, 2);
+ } else {
+ g_assert_cmpint(job->job.pause_count, ==, 1);
+ }
+ g_assert_true(job->job.paused);
+ g_assert_false(job->job.busy); /* The job is paused */
}
- g_assert_true(job->job.paused);
- g_assert_false(job->job.busy); /* The job is paused */
do_drain_end_unlocked(drain_type, drain_bs);
if (use_iothread) {
- /* paused is reset in the I/O thread, wait for it */
+ /*
+ * Here we are waiting for the paused status to change,
+ * so don't bother protecting the read every time.
+ *
+ * paused is reset in the I/O thread, wait for it
+ */
while (job->job.paused) {
aio_poll(qemu_get_aio_context(), false);
}
}
- g_assert_cmpint(job->job.pause_count, ==, 0);
- g_assert_false(job->job.paused);
- g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
+ WITH_JOB_LOCK_GUARD() {
+ g_assert_cmpint(job->job.pause_count, ==, 0);
+ g_assert_false(job->job.paused);
+ g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
+ }
do_drain_begin_unlocked(drain_type, target);
- if (drain_type == BDRV_DRAIN_ALL) {
- /* bdrv_drain_all() drains both src and target */
- g_assert_cmpint(job->job.pause_count, ==, 2);
- } else {
- g_assert_cmpint(job->job.pause_count, ==, 1);
+ WITH_JOB_LOCK_GUARD() {
+ if (drain_type == BDRV_DRAIN_ALL) {
+ /* bdrv_drain_all() drains both src and target */
+ g_assert_cmpint(job->job.pause_count, ==, 2);
+ } else {
+ g_assert_cmpint(job->job.pause_count, ==, 1);
+ }
+ g_assert_true(job->job.paused);
+ g_assert_false(job->job.busy); /* The job is paused */
}
- g_assert_true(job->job.paused);
- g_assert_false(job->job.busy); /* The job is paused */
do_drain_end_unlocked(drain_type, target);
if (use_iothread) {
- /* paused is reset in the I/O thread, wait for it */
+ /*
+ * Here we are waiting for the paused status to change,
+ * so don't bother protecting the read every time.
+ *
+ * paused is reset in the I/O thread, wait for it
+ */
while (job->job.paused) {
aio_poll(qemu_get_aio_context(), false);
}
}
- g_assert_cmpint(job->job.pause_count, ==, 0);
- g_assert_false(job->job.paused);
- g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
+ WITH_JOB_LOCK_GUARD() {
+ g_assert_cmpint(job->job.pause_count, ==, 0);
+ g_assert_false(job->job.paused);
+ g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
+ }
aio_context_acquire(ctx);
- ret = job_complete_sync(&job->job, &error_abort);
+ WITH_JOB_LOCK_GUARD() {
+ ret = job_complete_sync_locked(&job->job, &error_abort);
+ }
g_assert_cmpint(ret, ==, (result == TEST_JOB_SUCCESS ? 0 : -EIO));
if (use_iothread) {
diff --git a/tests/unit/test-block-iothread.c b/tests/unit/test-block-iothread.c
index 94718c9319..89e7f0fffb 100644
--- a/tests/unit/test-block-iothread.c
+++ b/tests/unit/test-block-iothread.c
@@ -456,7 +456,9 @@ static void test_attach_blockjob(void)
}
aio_context_acquire(ctx);
- job_complete_sync(&tjob->common.job, &error_abort);
+ WITH_JOB_LOCK_GUARD() {
+ job_complete_sync_locked(&tjob->common.job, &error_abort);
+ }
blk_set_aio_context(blk, qemu_get_aio_context(), &error_abort);
aio_context_release(ctx);
@@ -630,7 +632,9 @@ static void test_propagate_mirror(void)
BLOCKDEV_ON_ERROR_REPORT, BLOCKDEV_ON_ERROR_REPORT,
false, "filter_node", MIRROR_COPY_MODE_BACKGROUND,
&error_abort);
- job = job_get("job0");
+ WITH_JOB_LOCK_GUARD() {
+ job = job_get_locked("job0");
+ }
filter = bdrv_find_node("filter_node");
/* Change the AioContext of src */
diff --git a/tests/unit/test-blockjob-txn.c b/tests/unit/test-blockjob-txn.c
index c69028b450..d3b0bb24be 100644
--- a/tests/unit/test-blockjob-txn.c
+++ b/tests/unit/test-blockjob-txn.c
@@ -116,8 +116,10 @@ static void test_single_job(int expected)
job = test_block_job_start(1, true, expected, &result, txn);
job_start(&job->job);
- if (expected == -ECANCELED) {
- job_cancel(&job->job, false);
+ WITH_JOB_LOCK_GUARD() {
+ if (expected == -ECANCELED) {
+ job_cancel_locked(&job->job, false);
+ }
}
while (result == -EINPROGRESS) {
@@ -160,13 +162,15 @@ static void test_pair_jobs(int expected1, int expected2)
/* Release our reference now to trigger as many nice
* use-after-free bugs as possible.
*/
- job_txn_unref(txn);
+ WITH_JOB_LOCK_GUARD() {
+ job_txn_unref_locked(txn);
- if (expected1 == -ECANCELED) {
- job_cancel(&job1->job, false);
- }
- if (expected2 == -ECANCELED) {
- job_cancel(&job2->job, false);
+ if (expected1 == -ECANCELED) {
+ job_cancel_locked(&job1->job, false);
+ }
+ if (expected2 == -ECANCELED) {
+ job_cancel_locked(&job2->job, false);
+ }
}
while (result1 == -EINPROGRESS || result2 == -EINPROGRESS) {
@@ -219,7 +223,9 @@ static void test_pair_jobs_fail_cancel_race(void)
job_start(&job1->job);
job_start(&job2->job);
- job_cancel(&job1->job, false);
+ WITH_JOB_LOCK_GUARD() {
+ job_cancel_locked(&job1->job, false);
+ }
/* Now make job2 finish before the main loop kicks jobs. This simulates
* the race between a pending kick and another job completing.
diff --git a/tests/unit/test-blockjob.c b/tests/unit/test-blockjob.c
index 4c9e1bf1e5..17755e58db 100644
--- a/tests/unit/test-blockjob.c
+++ b/tests/unit/test-blockjob.c
@@ -211,8 +211,11 @@ static CancelJob *create_common(Job **pjob)
bjob = mk_job(blk, "Steve", &test_cancel_driver, true,
JOB_MANUAL_FINALIZE | JOB_MANUAL_DISMISS);
job = &bjob->job;
- job_ref(job);
- assert(job->status == JOB_STATUS_CREATED);
+ WITH_JOB_LOCK_GUARD() {
+ job_ref_locked(job);
+ assert(job->status == JOB_STATUS_CREATED);
+ }
+
s = container_of(bjob, CancelJob, common);
s->blk = blk;
@@ -231,12 +234,14 @@ static void cancel_common(CancelJob *s)
aio_context_acquire(ctx);
job_cancel_sync(&job->job, true);
- if (sts != JOB_STATUS_CREATED && sts != JOB_STATUS_CONCLUDED) {
- Job *dummy = &job->job;
- job_dismiss(&dummy, &error_abort);
+ WITH_JOB_LOCK_GUARD() {
+ if (sts != JOB_STATUS_CREATED && sts != JOB_STATUS_CONCLUDED) {
+ Job *dummy = &job->job;
+ job_dismiss_locked(&dummy, &error_abort);
+ }
+ assert(job->job.status == JOB_STATUS_NULL);
+ job_unref_locked(&job->job);
}
- assert(job->job.status == JOB_STATUS_NULL);
- job_unref(&job->job);
destroy_blk(blk);
aio_context_release(ctx);
@@ -251,6 +256,10 @@ static void test_cancel_created(void)
cancel_common(s);
}
+/*
+ * This test always runs in the main loop, so there is no
+ * need to protect job->status.
+ */
static void test_cancel_running(void)
{
Job *job;
@@ -264,6 +273,10 @@ static void test_cancel_running(void)
cancel_common(s);
}
+/*
+ * This test always runs in the main loop, so there is no
+ * need to protect job->status.
+ */
static void test_cancel_paused(void)
{
Job *job;
@@ -274,13 +287,19 @@ static void test_cancel_paused(void)
job_start(job);
assert(job->status == JOB_STATUS_RUNNING);
- job_user_pause(job, &error_abort);
+ WITH_JOB_LOCK_GUARD() {
+ job_user_pause_locked(job, &error_abort);
+ }
job_enter(job);
assert(job->status == JOB_STATUS_PAUSED);
cancel_common(s);
}
+/*
+ * This test always runs in the main loop, so there is no
+ * need to protect job->status.
+ */
static void test_cancel_ready(void)
{
Job *job;
@@ -298,6 +317,10 @@ static void test_cancel_ready(void)
cancel_common(s);
}
+/*
+ * This test always runs in the main loop, so there is no
+ * need to protect job->status.
+ */
static void test_cancel_standby(void)
{
Job *job;
@@ -312,13 +335,19 @@ static void test_cancel_standby(void)
job_enter(job);
assert(job->status == JOB_STATUS_READY);
- job_user_pause(job, &error_abort);
+ WITH_JOB_LOCK_GUARD() {
+ job_user_pause_locked(job, &error_abort);
+ }
job_enter(job);
assert(job->status == JOB_STATUS_STANDBY);
cancel_common(s);
}
+/*
+ * This test always runs in the main loop, so there is no
+ * need to protect job->status.
+ */
static void test_cancel_pending(void)
{
Job *job;
@@ -333,7 +362,9 @@ static void test_cancel_pending(void)
job_enter(job);
assert(job->status == JOB_STATUS_READY);
- job_complete(job, &error_abort);
+ WITH_JOB_LOCK_GUARD() {
+ job_complete_locked(job, &error_abort);
+ }
job_enter(job);
while (!job->deferred_to_main_loop) {
aio_poll(qemu_get_aio_context(), true);
@@ -345,6 +376,10 @@ static void test_cancel_pending(void)
cancel_common(s);
}
+/*
+ * This test always runs in the main loop, so there is no
+ * need to protect job->status.
+ */
static void test_cancel_concluded(void)
{
Job *job;
@@ -359,7 +394,9 @@ static void test_cancel_concluded(void)
job_enter(job);
assert(job->status == JOB_STATUS_READY);
- job_complete(job, &error_abort);
+ WITH_JOB_LOCK_GUARD() {
+ job_complete_locked(job, &error_abort);
+ }
job_enter(job);
while (!job->deferred_to_main_loop) {
aio_poll(qemu_get_aio_context(), true);
@@ -369,7 +406,9 @@ static void test_cancel_concluded(void)
assert(job->status == JOB_STATUS_PENDING);
aio_context_acquire(job->aio_context);
- job_finalize(job, &error_abort);
+ WITH_JOB_LOCK_GUARD() {
+ job_finalize_locked(job, &error_abort);
+ }
aio_context_release(job->aio_context);
assert(job->status == JOB_STATUS_CONCLUDED);
@@ -459,36 +498,45 @@ static void test_complete_in_standby(void)
bjob = mk_job(blk, "job", &test_yielding_driver, true,
JOB_MANUAL_FINALIZE | JOB_MANUAL_DISMISS);
job = &bjob->job;
+ /* Job did not start, so status is safe to read*/
assert(job->status == JOB_STATUS_CREATED);
/* Wait for the job to become READY */
job_start(job);
aio_context_acquire(ctx);
+ /*
+ * Here we are waiting for the status to change, so don't bother
+ * protecting the read every time.
+ */
AIO_WAIT_WHILE(ctx, job->status != JOB_STATUS_READY);
aio_context_release(ctx);
/* Begin the drained section, pausing the job */
bdrv_drain_all_begin();
- assert(job->status == JOB_STATUS_STANDBY);
+ WITH_JOB_LOCK_GUARD() {
+ assert(job->status == JOB_STATUS_STANDBY);
+ }
/* Lock the IO thread to prevent the job from being run */
aio_context_acquire(ctx);
/* This will schedule the job to resume it */
bdrv_drain_all_end();
- /* But the job cannot run, so it will remain on standby */
- assert(job->status == JOB_STATUS_STANDBY);
+ WITH_JOB_LOCK_GUARD() {
+ /* But the job cannot run, so it will remain on standby */
+ assert(job->status == JOB_STATUS_STANDBY);
- /* Even though the job is on standby, this should work */
- job_complete(job, &error_abort);
+ /* Even though the job is on standby, this should work */
+ job_complete_locked(job, &error_abort);
- /* The test is done now, clean up. */
- job_finish_sync(job, NULL, &error_abort);
- assert(job->status == JOB_STATUS_PENDING);
+ /* The test is done now, clean up. */
+ job_finish_sync_locked(job, NULL, &error_abort);
+ assert(job->status == JOB_STATUS_PENDING);
- job_finalize(job, &error_abort);
- assert(job->status == JOB_STATUS_CONCLUDED);
+ job_finalize_locked(job, &error_abort);
+ assert(job->status == JOB_STATUS_CONCLUDED);
- job_dismiss(&job, &error_abort);
+ job_dismiss_locked(&job, &error_abort);
+ }
destroy_blk(blk);
aio_context_release(ctx);
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 10/21] block/mirror.c: use of job helpers in drivers to avoid TOC/TOU
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (8 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 09/21] jobs: use job locks also in the unit tests Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-11 13:15 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 11/21] jobs: group together API calls under the same job lock Emanuele Giuseppe Esposito
` (11 subsequent siblings)
21 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito
Once job lock is used and aiocontext is removed, mirror has
to perform job operations under the same critical section,
using the helpers prepared in previous commit.
Note: at this stage, job_{lock/unlock} and job lock guard macros
are *nop*.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
block/mirror.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/block/mirror.c b/block/mirror.c
index d8ecb9efa2..b38676e19d 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -654,9 +654,13 @@ static int mirror_exit_common(Job *job)
BlockDriverState *target_bs;
BlockDriverState *mirror_top_bs;
Error *local_err = NULL;
- bool abort = job->ret < 0;
+ bool abort;
int ret = 0;
+ WITH_JOB_LOCK_GUARD() {
+ abort = job->ret < 0;
+ }
+
if (s->prepared) {
return 0;
}
@@ -1152,8 +1156,10 @@ static void mirror_complete(Job *job, Error **errp)
s->should_complete = true;
/* If the job is paused, it will be re-entered when it is resumed */
- if (!job->paused) {
- job_enter(job);
+ WITH_JOB_LOCK_GUARD() {
+ if (!job->paused) {
+ job_enter_cond_locked(job, NULL);
+ }
}
}
@@ -1173,8 +1179,11 @@ static bool mirror_drained_poll(BlockJob *job)
* from one of our own drain sections, to avoid a deadlock waiting for
* ourselves.
*/
- if (!s->common.job.paused && !job_is_cancelled(&job->job) && !s->in_drain) {
- return true;
+ WITH_JOB_LOCK_GUARD() {
+ if (!s->common.job.paused && !job_is_cancelled_locked(&job->job)
+ && !s->in_drain) {
+ return true;
+ }
}
return !!s->in_flight;
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 11/21] jobs: group together API calls under the same job lock
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (9 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 10/21] block/mirror.c: use of job helpers in drivers to avoid TOC/TOU Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-11 13:26 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 12/21] commit and mirror: create new nodes using bdrv_get_aio_context, and not the job aiocontext Emanuele Giuseppe Esposito
` (10 subsequent siblings)
21 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito
Now that the API offers also _locked() functions, take advantage
of it and give also the caller control to take the lock and call
_locked functions.
This makes sense especially when we have for loops, because it
makes no sense to have:
for(job = job_next(); ...)
where each job_next() takes the lock internally.
Instead we want
JOB_LOCK_GUARD();
for(job = job_next_locked(); ...)
Note: at this stage, job_{lock/unlock} and job lock guard macros
are *nop*.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
block.c | 20 +++++++++++-------
blockdev.c | 12 ++++++++---
blockjob.c | 52 +++++++++++++++++++++++++++++++---------------
job-qmp.c | 4 +++-
job.c | 5 ++++-
monitor/qmp-cmds.c | 7 +++++--
qemu-img.c | 41 +++++++++++++++++++++---------------
7 files changed, 93 insertions(+), 48 deletions(-)
diff --git a/block.c b/block.c
index 2c00dddd80..d0db104d71 100644
--- a/block.c
+++ b/block.c
@@ -4978,9 +4978,12 @@ static void bdrv_close(BlockDriverState *bs)
void bdrv_close_all(void)
{
- assert(job_next(NULL) == NULL);
GLOBAL_STATE_CODE();
+ WITH_JOB_LOCK_GUARD() {
+ assert(job_next_locked(NULL) == NULL);
+ }
+
/* Drop references from requests still in flight, such as canceled block
* jobs whose AIO context has not been polled yet */
bdrv_drain_all();
@@ -6165,13 +6168,16 @@ XDbgBlockGraph *bdrv_get_xdbg_block_graph(Error **errp)
}
}
- for (job = block_job_next(NULL); job; job = block_job_next(job)) {
- GSList *el;
+ WITH_JOB_LOCK_GUARD() {
+ for (job = block_job_next_locked(NULL); job;
+ job = block_job_next_locked(job)) {
+ GSList *el;
- xdbg_graph_add_node(gr, job, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_JOB,
- job->job.id);
- for (el = job->nodes; el; el = el->next) {
- xdbg_graph_add_edge(gr, job, (BdrvChild *)el->data);
+ xdbg_graph_add_node(gr, job, X_DBG_BLOCK_GRAPH_NODE_TYPE_BLOCK_JOB,
+ job->job.id);
+ for (el = job->nodes; el; el = el->next) {
+ xdbg_graph_add_edge(gr, job, (BdrvChild *)el->data);
+ }
}
}
diff --git a/blockdev.c b/blockdev.c
index 71f793c4ab..5b79093155 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -150,12 +150,15 @@ void blockdev_mark_auto_del(BlockBackend *blk)
return;
}
- for (job = block_job_next(NULL); job; job = block_job_next(job)) {
+ JOB_LOCK_GUARD();
+
+ for (job = block_job_next_locked(NULL); job;
+ job = block_job_next_locked(job)) {
if (block_job_has_bdrv(job, blk_bs(blk))) {
AioContext *aio_context = job->job.aio_context;
aio_context_acquire(aio_context);
- job_cancel(&job->job, false);
+ job_cancel_locked(&job->job, false);
aio_context_release(aio_context);
}
@@ -3745,7 +3748,10 @@ BlockJobInfoList *qmp_query_block_jobs(Error **errp)
BlockJobInfoList *head = NULL, **tail = &head;
BlockJob *job;
- for (job = block_job_next(NULL); job; job = block_job_next(job)) {
+ JOB_LOCK_GUARD();
+
+ for (job = block_job_next_locked(NULL); job;
+ job = block_job_next_locked(job)) {
BlockJobInfo *value;
AioContext *aio_context;
diff --git a/blockjob.c b/blockjob.c
index 0d59aba439..bce05a9096 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -99,7 +99,9 @@ static char *child_job_get_parent_desc(BdrvChild *c)
static void child_job_drained_begin(BdrvChild *c)
{
BlockJob *job = c->opaque;
- job_pause(&job->job);
+ WITH_JOB_LOCK_GUARD() {
+ job_pause_locked(&job->job);
+ }
}
static bool child_job_drained_poll(BdrvChild *c)
@@ -111,8 +113,10 @@ static bool child_job_drained_poll(BdrvChild *c)
/* An inactive or completed job doesn't have any pending requests. Jobs
* with !job->busy are either already paused or have a pause point after
* being reentered, so no job driver code will run before they pause. */
- if (!job->busy || job_is_completed(job)) {
- return false;
+ WITH_JOB_LOCK_GUARD() {
+ if (!job->busy || job_is_completed_locked(job)) {
+ return false;
+ }
}
/* Otherwise, assume that it isn't fully stopped yet, but allow the job to
@@ -127,7 +131,9 @@ static bool child_job_drained_poll(BdrvChild *c)
static void child_job_drained_end(BdrvChild *c, int *drained_end_counter)
{
BlockJob *job = c->opaque;
- job_resume(&job->job);
+ WITH_JOB_LOCK_GUARD() {
+ job_resume_locked(&job->job);
+ }
}
static bool child_job_can_set_aio_ctx(BdrvChild *c, AioContext *ctx,
@@ -475,13 +481,15 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
job->ready_notifier.notify = block_job_event_ready;
job->idle_notifier.notify = block_job_on_idle;
- notifier_list_add(&job->job.on_finalize_cancelled,
- &job->finalize_cancelled_notifier);
- notifier_list_add(&job->job.on_finalize_completed,
- &job->finalize_completed_notifier);
- notifier_list_add(&job->job.on_pending, &job->pending_notifier);
- notifier_list_add(&job->job.on_ready, &job->ready_notifier);
- notifier_list_add(&job->job.on_idle, &job->idle_notifier);
+ WITH_JOB_LOCK_GUARD() {
+ notifier_list_add(&job->job.on_finalize_cancelled,
+ &job->finalize_cancelled_notifier);
+ notifier_list_add(&job->job.on_finalize_completed,
+ &job->finalize_completed_notifier);
+ notifier_list_add(&job->job.on_pending, &job->pending_notifier);
+ notifier_list_add(&job->job.on_ready, &job->ready_notifier);
+ notifier_list_add(&job->job.on_idle, &job->idle_notifier);
+ }
error_setg(&job->blocker, "block device is in use by block job: %s",
job_type_str(&job->job));
@@ -493,7 +501,10 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
- if (!block_job_set_speed(job, speed, errp)) {
+ WITH_JOB_LOCK_GUARD() {
+ ret = block_job_set_speed_locked(job, speed, errp);
+ }
+ if (!ret) {
goto fail;
}
@@ -524,7 +535,9 @@ void block_job_user_resume(Job *job)
{
BlockJob *bjob = container_of(job, BlockJob, job);
GLOBAL_STATE_CODE();
- block_job_iostatus_reset(bjob);
+ WITH_JOB_LOCK_GUARD() {
+ block_job_iostatus_reset_locked(bjob);
+ }
}
BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
@@ -558,10 +571,15 @@ BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
action);
}
if (action == BLOCK_ERROR_ACTION_STOP) {
- if (!job->job.user_paused) {
- job_pause(&job->job);
- /* make the pause user visible, which will be resumed from QMP. */
- job->job.user_paused = true;
+ WITH_JOB_LOCK_GUARD() {
+ if (!job->job.user_paused) {
+ job_pause_locked(&job->job);
+ /*
+ * make the pause user visible, which will be
+ * resumed from QMP.
+ */
+ job->job.user_paused = true;
+ }
}
block_job_iostatus_set_err(job, error);
}
diff --git a/job-qmp.c b/job-qmp.c
index ac11a6c23c..cfaf34ffb7 100644
--- a/job-qmp.c
+++ b/job-qmp.c
@@ -194,7 +194,9 @@ JobInfoList *qmp_query_jobs(Error **errp)
JobInfoList *head = NULL, **tail = &head;
Job *job;
- for (job = job_next(NULL); job; job = job_next(job)) {
+ JOB_LOCK_GUARD();
+
+ for (job = job_next_locked(NULL); job; job = job_next_locked(job)) {
JobInfo *value;
AioContext *aio_context;
diff --git a/job.c b/job.c
index de3d368086..9c8792c9e8 100644
--- a/job.c
+++ b/job.c
@@ -1046,11 +1046,14 @@ static void job_completed_txn_abort_locked(Job *job)
/* Called with job_mutex held, but releases it temporarily */
static int job_prepare_locked(Job *job)
{
+ int ret;
+
GLOBAL_STATE_CODE();
if (job->ret == 0 && job->driver->prepare) {
job_unlock();
- job->ret = job->driver->prepare(job);
+ ret = job->driver->prepare(job);
job_lock();
+ job->ret = ret;
job_update_rc_locked(job);
}
return job->ret;
diff --git a/monitor/qmp-cmds.c b/monitor/qmp-cmds.c
index 1ebb89f46c..1897ed7a13 100644
--- a/monitor/qmp-cmds.c
+++ b/monitor/qmp-cmds.c
@@ -133,8 +133,11 @@ void qmp_cont(Error **errp)
blk_iostatus_reset(blk);
}
- for (job = block_job_next(NULL); job; job = block_job_next(job)) {
- block_job_iostatus_reset(job);
+ WITH_JOB_LOCK_GUARD() {
+ for (job = block_job_next_locked(NULL); job;
+ job = block_job_next_locked(job)) {
+ block_job_iostatus_reset_locked(job);
+ }
}
/* Continuing after completed migration. Images have been inactivated to
diff --git a/qemu-img.c b/qemu-img.c
index 4cf4d2423d..289d88a156 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -912,25 +912,30 @@ static void run_block_job(BlockJob *job, Error **errp)
int ret = 0;
aio_context_acquire(aio_context);
- job_ref(&job->job);
- do {
- float progress = 0.0f;
- aio_poll(aio_context, true);
+ WITH_JOB_LOCK_GUARD() {
+ job_ref_locked(&job->job);
+ do {
+ float progress = 0.0f;
+ job_unlock();
+ aio_poll(aio_context, true);
+
+ progress_get_snapshot(&job->job.progress, &progress_current,
+ &progress_total);
+ if (progress_total) {
+ progress = (float)progress_current / progress_total * 100.f;
+ }
+ qemu_progress_print(progress, 0);
+ job_lock();
+ } while (!job_is_ready_locked(&job->job) &&
+ !job_is_completed_locked(&job->job));
- progress_get_snapshot(&job->job.progress, &progress_current,
- &progress_total);
- if (progress_total) {
- progress = (float)progress_current / progress_total * 100.f;
+ if (!job_is_completed_locked(&job->job)) {
+ ret = job_complete_sync_locked(&job->job, errp);
+ } else {
+ ret = job->job.ret;
}
- qemu_progress_print(progress, 0);
- } while (!job_is_ready(&job->job) && !job_is_completed(&job->job));
-
- if (!job_is_completed(&job->job)) {
- ret = job_complete_sync(&job->job, errp);
- } else {
- ret = job->job.ret;
+ job_unref_locked(&job->job);
}
- job_unref(&job->job);
aio_context_release(aio_context);
/* publish completion progress only when success */
@@ -1083,7 +1088,9 @@ static int img_commit(int argc, char **argv)
bdrv_ref(bs);
}
- job = block_job_get("commit");
+ WITH_JOB_LOCK_GUARD() {
+ job = block_job_get_locked("commit");
+ }
assert(job);
run_block_job(job, &local_err);
if (local_err) {
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 12/21] commit and mirror: create new nodes using bdrv_get_aio_context, and not the job aiocontext
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (10 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 11/21] jobs: group together API calls under the same job lock Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-11 13:32 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 13/21] job: detect change of aiocontext within job coroutine Emanuele Giuseppe Esposito
` (9 subsequent siblings)
21 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito
We are always using the given bs AioContext, so there is no need
to take the job ones (which is identical anyways).
This also reduces the point we need to check when protecting
job.aio_context field.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
block/commit.c | 4 ++--
block/mirror.c | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/block/commit.c b/block/commit.c
index 851d1c557a..336f799172 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -370,7 +370,7 @@ void commit_start(const char *job_id, BlockDriverState *bs,
goto fail;
}
- s->base = blk_new(s->common.job.aio_context,
+ s->base = blk_new(bdrv_get_aio_context(bs),
base_perms,
BLK_PERM_CONSISTENT_READ
| BLK_PERM_WRITE_UNCHANGED);
@@ -382,7 +382,7 @@ void commit_start(const char *job_id, BlockDriverState *bs,
s->base_bs = base;
/* Required permissions are already taken with block_job_add_bdrv() */
- s->top = blk_new(s->common.job.aio_context, 0, BLK_PERM_ALL);
+ s->top = blk_new(bdrv_get_aio_context(bs), 0, BLK_PERM_ALL);
ret = blk_insert_bs(s->top, top, errp);
if (ret < 0) {
goto fail;
diff --git a/block/mirror.c b/block/mirror.c
index b38676e19d..1977e25171 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -1728,7 +1728,7 @@ static BlockJob *mirror_start_job(
goto fail;
}
- s->target = blk_new(s->common.job.aio_context,
+ s->target = blk_new(bdrv_get_aio_context(bs),
target_perms, target_shared_perms);
ret = blk_insert_bs(s->target, target, errp);
if (ret < 0) {
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 13/21] job: detect change of aiocontext within job coroutine
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (11 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 12/21] commit and mirror: create new nodes using bdrv_get_aio_context, and not the job aiocontext Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-11 13:59 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 14/21] jobs: protect job.aio_context with BQL and job_mutex Emanuele Giuseppe Esposito
` (8 subsequent siblings)
21 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
From: Paolo Bonzini <pbonzini@redhat.com>
We want to make sure access of job->aio_context is always done
under either BQL or job_mutex. The problem is that using
aio_co_enter(job->aiocontext, job->co) in job_start and job_enter_cond
makes the coroutine immediately resume, so we can't hold the job lock.
And caching it is not safe either, as it might change.
job_start is under BQL, so it can freely read job->aiocontext, but
job_enter_cond is not. In order to fix this, use aio_co_wake():
the advantage is that it won't use job->aiocontext, but the
main disadvantage is that it won't be able to detect a change of
job AioContext.
Calling bdrv_try_set_aio_context() will issue the following calls
(simplified):
* in terms of bdrv callbacks:
.drained_begin -> .set_aio_context -> .drained_end
* in terms of child_job functions:
child_job_drained_begin -> child_job_set_aio_context -> child_job_drained_end
* in terms of job functions:
job_pause_locked -> job_set_aio_context -> job_resume_locked
We can see that after setting the new aio_context, job_resume_locked
calls again job_enter_cond, which then invokes aio_co_wake(). But
while job->aiocontext has been set in job_set_aio_context,
job->co->ctx has not changed, so the coroutine would be entering in
the wrong aiocontext.
Using aio_co_schedule in job_resume_locked() might seem as a valid
alternative, but the problem is that the bh resuming the coroutine
is not scheduled immediately, and if in the meanwhile another
bdrv_try_set_aio_context() is run (see test_propagate_mirror() in
test-block-iothread.c), we would have the first schedule in the
wrong aiocontext, and the second set of drains won't even manage
to schedule the coroutine, as job->busy would still be true from
the previous job_resume_locked().
The solution is to stick with aio_co_wake(), but then detect every time
the coroutine resumes back from yielding if job->aio_context
has changed. If so, we can reschedule it to the new context.
Check for the aiocontext change in job_do_yield_locked because:
1) aio_co_reschedule_self requires to be in the running coroutine
2) since child_job_set_aio_context allows changing the aiocontext only
while the job is paused, this is the exact place where the coroutine
resumes, before running JobDriver's code.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
job.c | 22 +++++++++++++++++++---
1 file changed, 19 insertions(+), 3 deletions(-)
diff --git a/job.c b/job.c
index 9c8792c9e8..405f39566b 100644
--- a/job.c
+++ b/job.c
@@ -581,11 +581,12 @@ void job_enter_cond_locked(Job *job, bool(*fn)(Job *job))
return;
}
- assert(!job->deferred_to_main_loop);
timer_del(&job->sleep_timer);
job->busy = true;
real_job_unlock();
- aio_co_enter(job->aio_context, job->co);
+ job_unlock();
+ aio_co_wake(job->co);
+ job_lock();
}
void job_enter_cond(Job *job, bool(*fn)(Job *job))
@@ -611,6 +612,8 @@ void job_enter(Job *job)
*/
static void coroutine_fn job_do_yield_locked(Job *job, uint64_t ns)
{
+ AioContext *next_aio_context;
+
real_job_lock();
if (ns != -1) {
timer_mod(&job->sleep_timer, ns);
@@ -622,7 +625,20 @@ static void coroutine_fn job_do_yield_locked(Job *job, uint64_t ns)
qemu_coroutine_yield();
job_lock();
- /* Set by job_enter_cond() before re-entering the coroutine. */
+ next_aio_context = job->aio_context;
+ /*
+ * Coroutine has resumed, but in the meanwhile the job AioContext
+ * might have changed via bdrv_try_set_aio_context(), so we need to move
+ * the coroutine too in the new aiocontext.
+ */
+ while (qemu_get_current_aio_context() != next_aio_context) {
+ job_unlock();
+ aio_co_reschedule_self(next_aio_context);
+ job_lock();
+ next_aio_context = job->aio_context;
+ }
+
+ /* Set by job_enter_cond_locked() before re-entering the coroutine. */
assert(job->busy);
}
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 14/21] jobs: protect job.aio_context with BQL and job_mutex
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (12 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 13/21] job: detect change of aiocontext within job coroutine Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-11 14:19 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 15/21] job.c: enable job lock/unlock and remove Aiocontext locks Emanuele Giuseppe Esposito
` (7 subsequent siblings)
21 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito
In order to make it thread safe, implement a "fake rwlock",
where we allow reads under BQL *or* job_mutex held, but
writes only under BQL *and* job_mutex.
The only write we have is in child_job_set_aio_ctx, which always
happens under drain (so the job is paused).
For this reason, introduce job_set_aio_context and make sure that
the context is set under BQL, job_mutex and drain.
Also make sure all other places where the aiocontext is read
are protected.
Note: at this stage, job_{lock/unlock} and job lock guard macros
are *nop*.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
block/replication.c | 6 ++++--
blockjob.c | 3 ++-
include/qemu/job.h | 19 ++++++++++++++++++-
job.c | 12 ++++++++++++
4 files changed, 36 insertions(+), 4 deletions(-)
diff --git a/block/replication.c b/block/replication.c
index 55c8f894aa..2189863df1 100644
--- a/block/replication.c
+++ b/block/replication.c
@@ -148,8 +148,10 @@ static void replication_close(BlockDriverState *bs)
}
if (s->stage == BLOCK_REPLICATION_FAILOVER) {
commit_job = &s->commit_job->job;
- assert(commit_job->aio_context == qemu_get_current_aio_context());
- job_cancel_sync(commit_job, false);
+ WITH_JOB_LOCK_GUARD() {
+ assert(commit_job->aio_context == qemu_get_current_aio_context());
+ job_cancel_sync_locked(commit_job, false);
+ }
}
if (s->mode == REPLICATION_MODE_SECONDARY) {
diff --git a/blockjob.c b/blockjob.c
index bce05a9096..0d120ed126 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -166,12 +166,13 @@ static void child_job_set_aio_ctx(BdrvChild *c, AioContext *ctx,
bdrv_set_aio_context_ignore(sibling->bs, ctx, ignore);
}
- job->job.aio_context = ctx;
+ job_set_aio_context(&job->job, ctx);
}
static AioContext *child_job_get_parent_aio_context(BdrvChild *c)
{
BlockJob *job = c->opaque;
+ assert(qemu_in_main_thread());
return job->job.aio_context;
}
diff --git a/include/qemu/job.h b/include/qemu/job.h
index 5709e8d4a8..c144aabefc 100644
--- a/include/qemu/job.h
+++ b/include/qemu/job.h
@@ -77,7 +77,12 @@ typedef struct Job {
/** Protected by AioContext lock */
- /** AioContext to run the job coroutine in */
+ /**
+ * AioContext to run the job coroutine in.
+ * This field can be read when holding either the BQL (so we are in
+ * the main loop) or the job_mutex.
+ * It can be only written when we hold *both* BQL and job_mutex.
+ */
AioContext *aio_context;
/** Reference count of the block job */
@@ -741,4 +746,16 @@ int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp),
int job_finish_sync_locked(Job *job, void (*finish)(Job *, Error **errp),
Error **errp);
+/**
+ * Sets the @job->aio_context.
+ * Called with job_mutex *not* held.
+ *
+ * This function must run in the main thread to protect against
+ * concurrent read in job_finish_sync_locked(),
+ * takes the job_mutex lock to protect against the read in
+ * job_do_yield_locked(), and must be called when the coroutine
+ * is quiescent.
+ */
+void job_set_aio_context(Job *job, AioContext *ctx);
+
#endif
diff --git a/job.c b/job.c
index 405f39566b..66cae82593 100644
--- a/job.c
+++ b/job.c
@@ -394,6 +394,17 @@ Job *job_get(const char *id)
return job_get_locked(id);
}
+void job_set_aio_context(Job *job, AioContext *ctx)
+{
+ /* protect against read in job_finish_sync_locked and job_start */
+ assert(qemu_in_main_thread());
+ /* protect against read in job_do_yield_locked */
+ JOB_LOCK_GUARD();
+ /* ensure the coroutine is quiescent while the AioContext is changed */
+ assert(job->pause_count > 0);
+ job->aio_context = ctx;
+}
+
/* Called with job_mutex *not* held. */
static void job_sleep_timer_cb(void *opaque)
{
@@ -1380,6 +1391,7 @@ int job_finish_sync_locked(Job *job,
{
Error *local_err = NULL;
int ret;
+ assert(qemu_in_main_thread());
job_ref_locked(job);
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 15/21] job.c: enable job lock/unlock and remove Aiocontext locks
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (13 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 14/21] jobs: protect job.aio_context with BQL and job_mutex Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-11 14:33 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 16/21] block_job_query: remove atomic read Emanuele Giuseppe Esposito
` (6 subsequent siblings)
21 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito
Change the job_{lock/unlock} and macros to use job_mutex.
Now that they are not nop anymore, remove the aiocontext
to avoid deadlocks.
Therefore:
- when possible, remove completely the aiocontext lock/unlock pair
- if it is used by some other function too, reduce the locking
section as much as possible, leaving the job API outside.
- change AIO_WAIT_WHILE in AIO_WAIT_WHILE_UNLOCKED, since we
are not using the aiocontext lock anymore
There is only one JobDriver callback, ->free() that assumes that
the aiocontext lock is held (because it calls bdrv_unref), so for
now keep that under aiocontext lock.
Also remove real_job_{lock/unlock}, as they are replaced by the
public functions.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
blockdev.c | 74 ++++-----------------------
include/qemu/job.h | 22 ++++----
job-qmp.c | 46 +++--------------
job.c | 86 +++++++-------------------------
tests/unit/test-bdrv-drain.c | 4 +-
tests/unit/test-block-iothread.c | 2 +-
tests/unit/test-blockjob.c | 13 ++---
7 files changed, 53 insertions(+), 194 deletions(-)
diff --git a/blockdev.c b/blockdev.c
index 5b79093155..2cd84d206c 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -155,12 +155,7 @@ void blockdev_mark_auto_del(BlockBackend *blk)
for (job = block_job_next_locked(NULL); job;
job = block_job_next_locked(job)) {
if (block_job_has_bdrv(job, blk_bs(blk))) {
- AioContext *aio_context = job->job.aio_context;
- aio_context_acquire(aio_context);
-
job_cancel_locked(&job->job, false);
-
- aio_context_release(aio_context);
}
}
@@ -1836,14 +1831,7 @@ static void drive_backup_abort(BlkActionState *common)
DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
if (state->job) {
- AioContext *aio_context;
-
- aio_context = bdrv_get_aio_context(state->bs);
- aio_context_acquire(aio_context);
-
job_cancel_sync(&state->job->job, true);
-
- aio_context_release(aio_context);
}
}
@@ -1937,14 +1925,7 @@ static void blockdev_backup_abort(BlkActionState *common)
BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);
if (state->job) {
- AioContext *aio_context;
-
- aio_context = bdrv_get_aio_context(state->bs);
- aio_context_acquire(aio_context);
-
job_cancel_sync(&state->job->job, true);
-
- aio_context_release(aio_context);
}
}
@@ -3306,19 +3287,14 @@ out:
}
/*
- * Get a block job using its ID and acquire its AioContext.
- * Called with job_mutex held.
+ * Get a block job using its ID. Called with job_mutex held.
*/
-static BlockJob *find_block_job_locked(const char *id,
- AioContext **aio_context,
- Error **errp)
+static BlockJob *find_block_job_locked(const char *id, Error **errp)
{
BlockJob *job;
assert(id != NULL);
- *aio_context = NULL;
-
job = block_job_get_locked(id);
if (!job) {
@@ -3327,36 +3303,30 @@ static BlockJob *find_block_job_locked(const char *id,
return NULL;
}
- *aio_context = block_job_get_aio_context(job);
- aio_context_acquire(*aio_context);
-
return job;
}
void qmp_block_job_set_speed(const char *device, int64_t speed, Error **errp)
{
- AioContext *aio_context;
BlockJob *job;
JOB_LOCK_GUARD();
- job = find_block_job_locked(device, &aio_context, errp);
+ job = find_block_job_locked(device, errp);
if (!job) {
return;
}
block_job_set_speed_locked(job, speed, errp);
- aio_context_release(aio_context);
}
void qmp_block_job_cancel(const char *device,
bool has_force, bool force, Error **errp)
{
- AioContext *aio_context;
BlockJob *job;
JOB_LOCK_GUARD();
- job = find_block_job_locked(device, &aio_context, errp);
+ job = find_block_job_locked(device, errp);
if (!job) {
return;
@@ -3369,22 +3339,19 @@ void qmp_block_job_cancel(const char *device,
if (job_user_paused_locked(&job->job) && !force) {
error_setg(errp, "The block job for device '%s' is currently paused",
device);
- goto out;
+ return;
}
trace_qmp_block_job_cancel(job);
job_user_cancel_locked(&job->job, force, errp);
-out:
- aio_context_release(aio_context);
}
void qmp_block_job_pause(const char *device, Error **errp)
{
- AioContext *aio_context;
BlockJob *job;
JOB_LOCK_GUARD();
- job = find_block_job_locked(device, &aio_context, errp);
+ job = find_block_job_locked(device, errp);
if (!job) {
return;
@@ -3392,16 +3359,14 @@ void qmp_block_job_pause(const char *device, Error **errp)
trace_qmp_block_job_pause(job);
job_user_pause_locked(&job->job, errp);
- aio_context_release(aio_context);
}
void qmp_block_job_resume(const char *device, Error **errp)
{
- AioContext *aio_context;
BlockJob *job;
JOB_LOCK_GUARD();
- job = find_block_job_locked(device, &aio_context, errp);
+ job = find_block_job_locked(device, errp);
if (!job) {
return;
@@ -3409,16 +3374,14 @@ void qmp_block_job_resume(const char *device, Error **errp)
trace_qmp_block_job_resume(job);
job_user_resume_locked(&job->job, errp);
- aio_context_release(aio_context);
}
void qmp_block_job_complete(const char *device, Error **errp)
{
- AioContext *aio_context;
BlockJob *job;
JOB_LOCK_GUARD();
- job = find_block_job_locked(device, &aio_context, errp);
+ job = find_block_job_locked(device, errp);
if (!job) {
return;
@@ -3426,16 +3389,14 @@ void qmp_block_job_complete(const char *device, Error **errp)
trace_qmp_block_job_complete(job);
job_complete_locked(&job->job, errp);
- aio_context_release(aio_context);
}
void qmp_block_job_finalize(const char *id, Error **errp)
{
- AioContext *aio_context;
BlockJob *job;
JOB_LOCK_GUARD();
- job = find_block_job_locked(id, &aio_context, errp);
+ job = find_block_job_locked(id, errp);
if (!job) {
return;
@@ -3445,24 +3406,16 @@ void qmp_block_job_finalize(const char *id, Error **errp)
job_ref_locked(&job->job);
job_finalize_locked(&job->job, errp);
- /*
- * Job's context might have changed via job_finalize (and job_txn_apply
- * automatically acquires the new one), so make sure we release the correct
- * one.
- */
- aio_context = block_job_get_aio_context(job);
job_unref_locked(&job->job);
- aio_context_release(aio_context);
}
void qmp_block_job_dismiss(const char *id, Error **errp)
{
- AioContext *aio_context;
BlockJob *bjob;
Job *job;
JOB_LOCK_GUARD();
- bjob = find_block_job_locked(id, &aio_context, errp);
+ bjob = find_block_job_locked(id, errp);
if (!bjob) {
return;
@@ -3471,7 +3424,6 @@ void qmp_block_job_dismiss(const char *id, Error **errp)
trace_qmp_block_job_dismiss(bjob);
job = &bjob->job;
job_dismiss_locked(&job, errp);
- aio_context_release(aio_context);
}
void qmp_change_backing_file(const char *device,
@@ -3753,15 +3705,11 @@ BlockJobInfoList *qmp_query_block_jobs(Error **errp)
for (job = block_job_next_locked(NULL); job;
job = block_job_next_locked(job)) {
BlockJobInfo *value;
- AioContext *aio_context;
if (block_job_is_internal(job)) {
continue;
}
- aio_context = block_job_get_aio_context(job);
- aio_context_acquire(aio_context);
- value = block_job_query(job, errp);
- aio_context_release(aio_context);
+ value = block_job_query_locked(job, errp);
if (!value) {
qapi_free_BlockJobInfoList(head);
return NULL;
diff --git a/include/qemu/job.h b/include/qemu/job.h
index c144aabefc..676f69bb2e 100644
--- a/include/qemu/job.h
+++ b/include/qemu/job.h
@@ -75,13 +75,14 @@ typedef struct Job {
ProgressMeter progress;
- /** Protected by AioContext lock */
+ /** Protected by job_mutex */
/**
* AioContext to run the job coroutine in.
- * This field can be read when holding either the BQL (so we are in
- * the main loop) or the job_mutex.
- * It can be only written when we hold *both* BQL and job_mutex.
+ * The job Aiocontext can be read when holding *either*
+ * the BQL (so we are in the main loop) or the job_mutex.
+ * It can only be written when we hold *both* BQL
+ * and the job_mutex.
*/
AioContext *aio_context;
@@ -106,7 +107,7 @@ typedef struct Job {
/**
* Set to false by the job while the coroutine has yielded and may be
* re-entered by job_enter(). There may still be I/O or event loop activity
- * pending. Accessed under block_job_mutex (in blockjob.c).
+ * pending. Accessed under job_mutex.
*
* When the job is deferred to the main loop, busy is true as long as the
* bottom half is still pending.
@@ -322,9 +323,9 @@ typedef enum JobCreateFlags {
extern QemuMutex job_mutex;
-#define JOB_LOCK_GUARD() /* QEMU_LOCK_GUARD(&job_mutex) */
+#define JOB_LOCK_GUARD() QEMU_LOCK_GUARD(&job_mutex)
-#define WITH_JOB_LOCK_GUARD() /* WITH_QEMU_LOCK_GUARD(&job_mutex) */
+#define WITH_JOB_LOCK_GUARD() WITH_QEMU_LOCK_GUARD(&job_mutex)
/**
* job_lock:
@@ -672,7 +673,7 @@ void job_user_cancel_locked(Job *job, bool force, Error **errp);
* Returns the return value from the job if the job actually completed
* during the call, or -ECANCELED if it was canceled.
*
- * Callers must hold the AioContext lock of job->aio_context.
+ * Called with job_lock held.
*/
int job_cancel_sync(Job *job, bool force);
@@ -697,8 +698,7 @@ void job_cancel_sync_all(void);
* function).
*
* Returns the return value from the job.
- *
- * Callers must hold the AioContext lock of job->aio_context.
+ * Called with job_lock held.
*/
int job_complete_sync(Job *job, Error **errp);
@@ -734,7 +734,7 @@ void job_dismiss_locked(Job **job, Error **errp);
* Returns 0 if the job is successfully completed, -ECANCELED if the job was
* cancelled before completing, and -errno in other error cases.
*
- * Callers must hold the AioContext lock of job->aio_context.
+ * Called with job_lock held.
*/
int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp),
Error **errp);
diff --git a/job-qmp.c b/job-qmp.c
index cfaf34ffb7..96d67246d2 100644
--- a/job-qmp.c
+++ b/job-qmp.c
@@ -30,36 +30,27 @@
#include "trace/trace-root.h"
/*
- * Get a block job using its ID and acquire its AioContext.
- * Called with job_mutex held.
+ * Get a block job using its ID. Called with job_mutex held.
*/
-static Job *find_job_locked(const char *id,
- AioContext **aio_context,
- Error **errp)
+static Job *find_job_locked(const char *id, Error **errp)
{
Job *job;
- *aio_context = NULL;
-
job = job_get_locked(id);
if (!job) {
error_setg(errp, "Job not found");
return NULL;
}
- *aio_context = job->aio_context;
- aio_context_acquire(*aio_context);
-
return job;
}
void qmp_job_cancel(const char *id, Error **errp)
{
- AioContext *aio_context;
Job *job;
JOB_LOCK_GUARD();
- job = find_job_locked(id, &aio_context, errp);
+ job = find_job_locked(id, errp);
if (!job) {
return;
@@ -67,16 +58,14 @@ void qmp_job_cancel(const char *id, Error **errp)
trace_qmp_job_cancel(job);
job_user_cancel_locked(job, true, errp);
- aio_context_release(aio_context);
}
void qmp_job_pause(const char *id, Error **errp)
{
- AioContext *aio_context;
Job *job;
JOB_LOCK_GUARD();
- job = find_job_locked(id, &aio_context, errp);
+ job = find_job_locked(id, errp);
if (!job) {
return;
@@ -84,16 +73,14 @@ void qmp_job_pause(const char *id, Error **errp)
trace_qmp_job_pause(job);
job_user_pause_locked(job, errp);
- aio_context_release(aio_context);
}
void qmp_job_resume(const char *id, Error **errp)
{
- AioContext *aio_context;
Job *job;
JOB_LOCK_GUARD();
- job = find_job_locked(id, &aio_context, errp);
+ job = find_job_locked(id, errp);
if (!job) {
return;
@@ -101,16 +88,14 @@ void qmp_job_resume(const char *id, Error **errp)
trace_qmp_job_resume(job);
job_user_resume_locked(job, errp);
- aio_context_release(aio_context);
}
void qmp_job_complete(const char *id, Error **errp)
{
- AioContext *aio_context;
Job *job;
JOB_LOCK_GUARD();
- job = find_job_locked(id, &aio_context, errp);
+ job = find_job_locked(id, errp);
if (!job) {
return;
@@ -118,16 +103,14 @@ void qmp_job_complete(const char *id, Error **errp)
trace_qmp_job_complete(job);
job_complete_locked(job, errp);
- aio_context_release(aio_context);
}
void qmp_job_finalize(const char *id, Error **errp)
{
- AioContext *aio_context;
Job *job;
JOB_LOCK_GUARD();
- job = find_job_locked(id, &aio_context, errp);
+ job = find_job_locked(id, errp);
if (!job) {
return;
@@ -137,23 +120,15 @@ void qmp_job_finalize(const char *id, Error **errp)
job_ref_locked(job);
job_finalize_locked(job, errp);
- /*
- * Job's context might have changed via job_finalize (and job_txn_apply
- * automatically acquires the new one), so make sure we release the correct
- * one.
- */
- aio_context = job->aio_context;
job_unref_locked(job);
- aio_context_release(aio_context);
}
void qmp_job_dismiss(const char *id, Error **errp)
{
- AioContext *aio_context;
Job *job;
JOB_LOCK_GUARD();
- job = find_job_locked(id, &aio_context, errp);
+ job = find_job_locked(id, errp);
if (!job) {
return;
@@ -161,7 +136,6 @@ void qmp_job_dismiss(const char *id, Error **errp)
trace_qmp_job_dismiss(job);
job_dismiss_locked(&job, errp);
- aio_context_release(aio_context);
}
static JobInfo *job_query_single(Job *job, Error **errp)
@@ -198,15 +172,11 @@ JobInfoList *qmp_query_jobs(Error **errp)
for (job = job_next_locked(NULL); job; job = job_next_locked(job)) {
JobInfo *value;
- AioContext *aio_context;
if (job_is_internal(job)) {
continue;
}
- aio_context = job->aio_context;
- aio_context_acquire(aio_context);
value = job_query_single(job, errp);
- aio_context_release(aio_context);
if (!value) {
qapi_free_JobInfoList(head);
return NULL;
diff --git a/job.c b/job.c
index 66cae82593..b23481cfcb 100644
--- a/job.c
+++ b/job.c
@@ -96,21 +96,11 @@ struct JobTxn {
};
void job_lock(void)
-{
- /* nop */
-}
-
-void job_unlock(void)
-{
- /* nop */
-}
-
-static void real_job_lock(void)
{
qemu_mutex_lock(&job_mutex);
}
-static void real_job_unlock(void)
+void job_unlock(void)
{
qemu_mutex_unlock(&job_mutex);
}
@@ -185,7 +175,6 @@ static void job_txn_del_job_locked(Job *job)
/* Called with job_mutex held, but releases it temporarily. */
static int job_txn_apply_locked(Job *job, int fn(Job *))
{
- AioContext *inner_ctx;
Job *other_job, *next;
JobTxn *txn = job->txn;
int rc = 0;
@@ -197,23 +186,14 @@ static int job_txn_apply_locked(Job *job, int fn(Job *))
* break AIO_WAIT_WHILE from within fn.
*/
job_ref_locked(job);
- aio_context_release(job->aio_context);
QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
- inner_ctx = other_job->aio_context;
- aio_context_acquire(inner_ctx);
rc = fn(other_job);
- aio_context_release(inner_ctx);
if (rc) {
break;
}
}
- /*
- * Note that job->aio_context might have been changed by calling fn, so we
- * can't use a local variable to cache it.
- */
- aio_context_acquire(job->aio_context);
job_unref_locked(job);
return rc;
}
@@ -501,8 +481,12 @@ void job_unref_locked(Job *job)
assert(!job->txn);
if (job->driver->free) {
+ AioContext *aio_context = job->aio_context;
job_unlock();
+ /* FIXME: aiocontext lock is required because cb calls blk_unref */
+ aio_context_acquire(aio_context);
job->driver->free(job);
+ aio_context_release(aio_context);
job_lock();
}
@@ -581,20 +565,16 @@ void job_enter_cond_locked(Job *job, bool(*fn)(Job *job))
return;
}
- real_job_lock();
if (job->busy) {
- real_job_unlock();
return;
}
if (fn && !fn(job)) {
- real_job_unlock();
return;
}
timer_del(&job->sleep_timer);
job->busy = true;
- real_job_unlock();
job_unlock();
aio_co_wake(job->co);
job_lock();
@@ -625,13 +605,11 @@ static void coroutine_fn job_do_yield_locked(Job *job, uint64_t ns)
{
AioContext *next_aio_context;
- real_job_lock();
if (ns != -1) {
timer_mod(&job->sleep_timer, ns);
}
job->busy = false;
job_event_idle_locked(job);
- real_job_unlock();
job_unlock();
qemu_coroutine_yield();
job_lock();
@@ -930,12 +908,15 @@ static void job_clean_locked(Job *job)
static int job_finalize_single_locked(Job *job)
{
int job_ret;
+ AioContext *ctx = job->aio_context;
assert(job_is_completed_locked(job));
/* Ensure abort is called for late-transactional failures */
job_update_rc_locked(job);
+ aio_context_acquire(ctx);
+
if (!job->ret) {
job_commit_locked(job);
} else {
@@ -943,6 +924,8 @@ static int job_finalize_single_locked(Job *job)
}
job_clean_locked(job);
+ aio_context_release(ctx);
+
if (job->cb) {
job_ret = job->ret;
job_unlock();
@@ -1006,7 +989,6 @@ static void job_cancel_async_locked(Job *job, bool force)
/* Called with job_mutex held, but releases it temporarily. */
static void job_completed_txn_abort_locked(Job *job)
{
- AioContext *ctx;
JobTxn *txn = job->txn;
Job *other_job;
@@ -1019,54 +1001,31 @@ static void job_completed_txn_abort_locked(Job *job)
txn->aborting = true;
job_txn_ref_locked(txn);
- /*
- * We can only hold the single job's AioContext lock while calling
- * job_finalize_single() because the finalization callbacks can involve
- * calls of AIO_WAIT_WHILE(), which could deadlock otherwise.
- * Note that the job's AioContext may change when it is finalized.
- */
job_ref_locked(job);
- aio_context_release(job->aio_context);
/* Other jobs are effectively cancelled by us, set the status for
* them; this job, however, may or may not be cancelled, depending
* on the caller, so leave it. */
QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
if (other_job != job) {
- ctx = other_job->aio_context;
- aio_context_acquire(ctx);
/*
* This is a transaction: If one job failed, no result will matter.
* Therefore, pass force=true to terminate all other jobs as quickly
* as possible.
*/
job_cancel_async_locked(other_job, true);
- aio_context_release(ctx);
}
}
while (!QLIST_EMPTY(&txn->jobs)) {
other_job = QLIST_FIRST(&txn->jobs);
- /*
- * The job's AioContext may change, so store it in @ctx so we
- * release the same context that we have acquired before.
- */
- ctx = other_job->aio_context;
- aio_context_acquire(ctx);
if (!job_is_completed_locked(other_job)) {
assert(job_cancel_requested_locked(other_job));
job_finish_sync_locked(other_job, NULL, NULL);
}
job_finalize_single_locked(other_job);
- aio_context_release(ctx);
}
- /*
- * Use job_ref()/job_unref() so we can read the AioContext here
- * even if the job went away during job_finalize_single().
- */
- aio_context_acquire(job->aio_context);
job_unref_locked(job);
-
job_txn_unref_locked(txn);
}
@@ -1074,15 +1033,20 @@ static void job_completed_txn_abort_locked(Job *job)
static int job_prepare_locked(Job *job)
{
int ret;
+ AioContext *ctx = job->aio_context;
GLOBAL_STATE_CODE();
+
if (job->ret == 0 && job->driver->prepare) {
job_unlock();
+ aio_context_acquire(ctx);
ret = job->driver->prepare(job);
+ aio_context_release(ctx);
job_lock();
job->ret = ret;
job_update_rc_locked(job);
}
+
return job->ret;
}
@@ -1187,11 +1151,8 @@ static void job_completed_locked(Job *job)
static void job_exit(void *opaque)
{
Job *job = (Job *)opaque;
- AioContext *ctx;
JOB_LOCK_GUARD();
-
job_ref_locked(job);
- aio_context_acquire(job->aio_context);
/* This is a lie, we're not quiescent, but still doing the completion
* callbacks. However, completion callbacks tend to involve operations that
@@ -1201,16 +1162,7 @@ static void job_exit(void *opaque)
job_event_idle_locked(job);
job_completed_locked(job);
-
- /*
- * Note that calling job_completed can move the job to a different
- * aio_context, so we cannot cache from above. job_txn_apply takes care of
- * acquiring the new lock, and we ref/unref to avoid job_completed freeing
- * the job underneath us.
- */
- ctx = job->aio_context;
job_unref_locked(job);
- aio_context_release(ctx);
}
/**
@@ -1338,14 +1290,10 @@ int job_cancel_sync(Job *job, bool force)
void job_cancel_sync_all(void)
{
Job *job;
- AioContext *aio_context;
JOB_LOCK_GUARD();
while ((job = job_next_locked(NULL))) {
- aio_context = job->aio_context;
- aio_context_acquire(aio_context);
job_cancel_sync_locked(job, true);
- aio_context_release(aio_context);
}
}
@@ -1405,8 +1353,8 @@ int job_finish_sync_locked(Job *job,
}
job_unlock();
- AIO_WAIT_WHILE(job->aio_context,
- (job_enter(job), !job_is_completed(job)));
+ AIO_WAIT_WHILE_UNLOCKED(job->aio_context,
+ (job_enter(job), !job_is_completed(job)));
job_lock();
ret = (job_is_cancelled_locked(job) && job->ret == 0)
diff --git a/tests/unit/test-bdrv-drain.c b/tests/unit/test-bdrv-drain.c
index 0db056ea63..4924ceb562 100644
--- a/tests/unit/test-bdrv-drain.c
+++ b/tests/unit/test-bdrv-drain.c
@@ -930,9 +930,9 @@ static void test_blockjob_common_drain_node(enum drain_type drain_type,
tjob->prepare_ret = -EIO;
break;
}
+ aio_context_release(ctx);
job_start(&job->job);
- aio_context_release(ctx);
if (use_iothread) {
/* job_co_entry() is run in the I/O thread, wait for the actual job
@@ -1016,12 +1016,12 @@ static void test_blockjob_common_drain_node(enum drain_type drain_type,
g_assert_true(job->job.busy); /* We're in qemu_co_sleep_ns() */
}
- aio_context_acquire(ctx);
WITH_JOB_LOCK_GUARD() {
ret = job_complete_sync_locked(&job->job, &error_abort);
}
g_assert_cmpint(ret, ==, (result == TEST_JOB_SUCCESS ? 0 : -EIO));
+ aio_context_acquire(ctx);
if (use_iothread) {
blk_set_aio_context(blk_src, qemu_get_aio_context(), &error_abort);
assert(blk_get_aio_context(blk_target) == qemu_get_aio_context());
diff --git a/tests/unit/test-block-iothread.c b/tests/unit/test-block-iothread.c
index 89e7f0fffb..9d7c8be00f 100644
--- a/tests/unit/test-block-iothread.c
+++ b/tests/unit/test-block-iothread.c
@@ -455,10 +455,10 @@ static void test_attach_blockjob(void)
aio_poll(qemu_get_aio_context(), false);
}
- aio_context_acquire(ctx);
WITH_JOB_LOCK_GUARD() {
job_complete_sync_locked(&tjob->common.job, &error_abort);
}
+ aio_context_acquire(ctx);
blk_set_aio_context(blk, qemu_get_aio_context(), &error_abort);
aio_context_release(ctx);
diff --git a/tests/unit/test-blockjob.c b/tests/unit/test-blockjob.c
index 17755e58db..535827ffd9 100644
--- a/tests/unit/test-blockjob.c
+++ b/tests/unit/test-blockjob.c
@@ -228,10 +228,6 @@ static void cancel_common(CancelJob *s)
BlockJob *job = &s->common;
BlockBackend *blk = s->blk;
JobStatus sts = job->job.status;
- AioContext *ctx;
-
- ctx = job->job.aio_context;
- aio_context_acquire(ctx);
job_cancel_sync(&job->job, true);
WITH_JOB_LOCK_GUARD() {
@@ -244,7 +240,6 @@ static void cancel_common(CancelJob *s)
}
destroy_blk(blk);
- aio_context_release(ctx);
}
static void test_cancel_created(void)
@@ -405,11 +400,9 @@ static void test_cancel_concluded(void)
aio_poll(qemu_get_aio_context(), true);
assert(job->status == JOB_STATUS_PENDING);
- aio_context_acquire(job->aio_context);
WITH_JOB_LOCK_GUARD() {
job_finalize_locked(job, &error_abort);
}
- aio_context_release(job->aio_context);
assert(job->status == JOB_STATUS_CONCLUDED);
cancel_common(s);
@@ -503,13 +496,11 @@ static void test_complete_in_standby(void)
/* Wait for the job to become READY */
job_start(job);
- aio_context_acquire(ctx);
/*
* Here we are waiting for the status to change, so don't bother
* protecting the read every time.
*/
- AIO_WAIT_WHILE(ctx, job->status != JOB_STATUS_READY);
- aio_context_release(ctx);
+ AIO_WAIT_WHILE_UNLOCKED(ctx, job->status != JOB_STATUS_READY);
/* Begin the drained section, pausing the job */
bdrv_drain_all_begin();
@@ -529,6 +520,7 @@ static void test_complete_in_standby(void)
job_complete_locked(job, &error_abort);
/* The test is done now, clean up. */
+ aio_context_release(ctx);
job_finish_sync_locked(job, NULL, &error_abort);
assert(job->status == JOB_STATUS_PENDING);
@@ -538,6 +530,7 @@ static void test_complete_in_standby(void)
job_dismiss_locked(&job, &error_abort);
}
+ aio_context_acquire(ctx);
destroy_blk(blk);
aio_context_release(ctx);
iothread_join(iothread);
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 16/21] block_job_query: remove atomic read
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (14 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 15/21] job.c: enable job lock/unlock and remove Aiocontext locks Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-11 14:37 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 17/21] blockjob.h: categorize fields in struct BlockJob Emanuele Giuseppe Esposito
` (5 subsequent siblings)
21 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito
Not sure what the atomic here was supposed to do, since job.busy
is protected by the job lock. Since the whole function
is called under job_mutex, just remove the atomic.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
blockjob.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/blockjob.c b/blockjob.c
index 0d120ed126..bbd297b583 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -341,7 +341,7 @@ BlockJobInfo *block_job_query_locked(BlockJob *job, Error **errp)
info = g_new0(BlockJobInfo, 1);
info->type = g_strdup(job_type_str(&job->job));
info->device = g_strdup(job->job.id);
- info->busy = qatomic_read(&job->job.busy);
+ info->busy = job->job.busy;
info->paused = job->job.pause_count > 0;
info->offset = progress_current;
info->len = progress_total;
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 17/21] blockjob.h: categorize fields in struct BlockJob
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (15 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 16/21] block_job_query: remove atomic read Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-11 14:44 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 18/21] blockjob: rename notifier callbacks as _locked Emanuele Giuseppe Esposito
` (4 subsequent siblings)
21 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito
The same job lock is being used also to protect some of blockjob fields.
Categorize them just as done in job.h.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
include/block/blockjob.h | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)
diff --git a/include/block/blockjob.h b/include/block/blockjob.h
index 8b65d3949d..912e10b083 100644
--- a/include/block/blockjob.h
+++ b/include/block/blockjob.h
@@ -40,10 +40,16 @@ typedef struct BlockJobDriver BlockJobDriver;
* Long-running operation on a BlockDriverState.
*/
typedef struct BlockJob {
- /** Data belonging to the generic Job infrastructure */
+ /**
+ * Data belonging to the generic Job infrastructure.
+ * Protected by job mutex.
+ */
Job job;
- /** Status that is published by the query-block-jobs QMP API */
+ /**
+ * Status that is published by the query-block-jobs QMP API.
+ * Protected by job mutex.
+ */
BlockDeviceIoStatus iostatus;
/** Speed that was set with @block_job_set_speed. */
@@ -55,6 +61,8 @@ typedef struct BlockJob {
/** Block other operations when block job is running */
Error *blocker;
+ /** All notifiers are set once in block_job_create() and never modified. */
+
/** Called when a cancelled job is finalised. */
Notifier finalize_cancelled_notifier;
@@ -70,7 +78,10 @@ typedef struct BlockJob {
/** Called when the job coroutine yields or terminates */
Notifier idle_notifier;
- /** BlockDriverStates that are involved in this block job */
+ /**
+ * BlockDriverStates that are involved in this block job.
+ * Always modified and read under QEMU global mutex (GLOBAL_STATE_CODE)
+ */
GSList *nodes;
} BlockJob;
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 18/21] blockjob: rename notifier callbacks as _locked
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (16 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 17/21] blockjob.h: categorize fields in struct BlockJob Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-11 14:47 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 19/21] blockjob: protect iostatus field in BlockJob struct Emanuele Giuseppe Esposito
` (3 subsequent siblings)
21 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito
They all are called with job_lock held, in job_event_*_locked()
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
blockjob.c | 25 +++++++++++++++----------
1 file changed, 15 insertions(+), 10 deletions(-)
diff --git a/blockjob.c b/blockjob.c
index bbd297b583..a2559b97a7 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -254,7 +254,8 @@ int block_job_add_bdrv(BlockJob *job, const char *name, BlockDriverState *bs,
return 0;
}
-static void block_job_on_idle(Notifier *n, void *opaque)
+/* Called with job_mutex lock held. */
+static void block_job_on_idle_locked(Notifier *n, void *opaque)
{
aio_wait_kick();
}
@@ -374,7 +375,8 @@ static void block_job_iostatus_set_err(BlockJob *job, int error)
}
}
-static void block_job_event_cancelled(Notifier *n, void *opaque)
+/* Called with job_mutex lock held. */
+static void block_job_event_cancelled_locked(Notifier *n, void *opaque)
{
BlockJob *job = opaque;
uint64_t progress_current, progress_total;
@@ -393,7 +395,8 @@ static void block_job_event_cancelled(Notifier *n, void *opaque)
job->speed);
}
-static void block_job_event_completed(Notifier *n, void *opaque)
+/* Called with job_mutex lock held. */
+static void block_job_event_completed_locked(Notifier *n, void *opaque)
{
BlockJob *job = opaque;
const char *msg = NULL;
@@ -419,7 +422,8 @@ static void block_job_event_completed(Notifier *n, void *opaque)
msg);
}
-static void block_job_event_pending(Notifier *n, void *opaque)
+/* Called with job_mutex lock held. */
+static void block_job_event_pending_locked(Notifier *n, void *opaque)
{
BlockJob *job = opaque;
@@ -431,7 +435,8 @@ static void block_job_event_pending(Notifier *n, void *opaque)
job->job.id);
}
-static void block_job_event_ready(Notifier *n, void *opaque)
+/* Called with job_mutex lock held. */
+static void block_job_event_ready_locked(Notifier *n, void *opaque)
{
BlockJob *job = opaque;
uint64_t progress_current, progress_total;
@@ -476,11 +481,11 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
ratelimit_init(&job->limit);
- job->finalize_cancelled_notifier.notify = block_job_event_cancelled;
- job->finalize_completed_notifier.notify = block_job_event_completed;
- job->pending_notifier.notify = block_job_event_pending;
- job->ready_notifier.notify = block_job_event_ready;
- job->idle_notifier.notify = block_job_on_idle;
+ job->finalize_cancelled_notifier.notify = block_job_event_cancelled_locked;
+ job->finalize_completed_notifier.notify = block_job_event_completed_locked;
+ job->pending_notifier.notify = block_job_event_pending_locked;
+ job->ready_notifier.notify = block_job_event_ready_locked;
+ job->idle_notifier.notify = block_job_on_idle_locked;
WITH_JOB_LOCK_GUARD() {
notifier_list_add(&job->job.on_finalize_cancelled,
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 19/21] blockjob: protect iostatus field in BlockJob struct
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (17 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 18/21] blockjob: rename notifier callbacks as _locked Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-11 14:51 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 20/21] blockjob: remove unused functions Emanuele Giuseppe Esposito
` (2 subsequent siblings)
21 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito
iostatus is the only field (together with .job) that needs
protection using the job mutex.
It is set in the main loop (GLOBAL_STATE functions) but read
in I/O code (block_job_error_action).
In order to protect it, change block_job_iostatus_set_err
to block_job_iostatus_set_err_locked(), always called under
job lock.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
blockjob.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/blockjob.c b/blockjob.c
index a2559b97a7..893c8ff08e 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -367,7 +367,8 @@ BlockJobInfo *block_job_query(BlockJob *job, Error **errp)
return block_job_query_locked(job, errp);
}
-static void block_job_iostatus_set_err(BlockJob *job, int error)
+/* Called with job lock held */
+static void block_job_iostatus_set_err_locked(BlockJob *job, int error)
{
if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
job->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
@@ -586,8 +587,8 @@ BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
*/
job->job.user_paused = true;
}
+ block_job_iostatus_set_err_locked(job, error);
}
- block_job_iostatus_set_err(job, error);
}
return action;
}
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 20/21] blockjob: remove unused functions
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (18 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 19/21] blockjob: protect iostatus field in BlockJob struct Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 21/21] job: " Emanuele Giuseppe Esposito
2022-07-11 15:57 ` [PATCH v9 00/21] job: replace AioContext lock with job_mutex Vladimir Sementsov-Ogievskiy
21 siblings, 0 replies; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito
These public functions are not used anywhere, thus can be dropped.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
blockjob.c | 30 ------------------------------
include/block/blockjob.h | 36 +++++++++++++-----------------------
2 files changed, 13 insertions(+), 53 deletions(-)
diff --git a/blockjob.c b/blockjob.c
index 893c8ff08e..bb82e8d04c 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -56,12 +56,6 @@ BlockJob *block_job_next_locked(BlockJob *bjob)
return job ? container_of(job, BlockJob, job) : NULL;
}
-BlockJob *block_job_next(BlockJob *bjob)
-{
- JOB_LOCK_GUARD();
- return block_job_next_locked(bjob);
-}
-
BlockJob *block_job_get_locked(const char *id)
{
Job *job = job_get_locked(id);
@@ -74,12 +68,6 @@ BlockJob *block_job_get_locked(const char *id)
}
}
-BlockJob *block_job_get(const char *id)
-{
- JOB_LOCK_GUARD();
- return block_job_get_locked(id);
-}
-
void block_job_free(Job *job)
{
BlockJob *bjob = container_of(job, BlockJob, job);
@@ -312,12 +300,6 @@ bool block_job_set_speed_locked(BlockJob *job, int64_t speed, Error **errp)
return true;
}
-bool block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
-{
- JOB_LOCK_GUARD();
- return block_job_set_speed_locked(job, speed, errp);
-}
-
int64_t block_job_ratelimit_get_delay(BlockJob *job, uint64_t n)
{
IO_CODE();
@@ -361,12 +343,6 @@ BlockJobInfo *block_job_query_locked(BlockJob *job, Error **errp)
return info;
}
-BlockJobInfo *block_job_query(BlockJob *job, Error **errp)
-{
- JOB_LOCK_GUARD();
- return block_job_query_locked(job, errp);
-}
-
/* Called with job lock held */
static void block_job_iostatus_set_err_locked(BlockJob *job, int error)
{
@@ -532,12 +508,6 @@ void block_job_iostatus_reset_locked(BlockJob *job)
job->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
}
-void block_job_iostatus_reset(BlockJob *job)
-{
- JOB_LOCK_GUARD();
- block_job_iostatus_reset_locked(job);
-}
-
void block_job_user_resume(Job *job)
{
BlockJob *bjob = container_of(job, BlockJob, job);
diff --git a/include/block/blockjob.h b/include/block/blockjob.h
index 912e10b083..7cb4ceaf09 100644
--- a/include/block/blockjob.h
+++ b/include/block/blockjob.h
@@ -93,30 +93,26 @@ typedef struct BlockJob {
*/
/**
- * block_job_next:
+ * block_job_next_locked:
* @job: A block job, or %NULL.
*
* Get the next element from the list of block jobs after @job, or the
* first one if @job is %NULL.
*
* Returns the requested job, or %NULL if there are no more jobs left.
+ * Called with job lock held.
*/
-BlockJob *block_job_next(BlockJob *job);
-
-/* Same as block_job_next(), but called with job lock held. */
BlockJob *block_job_next_locked(BlockJob *job);
/**
- * block_job_get:
+ * block_job_get_locked:
* @id: The id of the block job.
*
* Get the block job identified by @id (which must not be %NULL).
*
* Returns the requested job, or %NULL if it doesn't exist.
+ * Called with job lock held.
*/
-BlockJob *block_job_get(const char *id);
-
-/* Same as block_job_get(), but called with job lock held. */
BlockJob *block_job_get_locked(const char *id);
/**
@@ -152,43 +148,37 @@ void block_job_remove_all_bdrv(BlockJob *job);
bool block_job_has_bdrv(BlockJob *job, BlockDriverState *bs);
/**
- * block_job_set_speed:
+ * block_job_set_speed_locked:
* @job: The job to set the speed for.
* @speed: The new value
* @errp: Error object.
*
* Set a rate-limiting parameter for the job; the actual meaning may
* vary depending on the job type.
- */
-bool block_job_set_speed(BlockJob *job, int64_t speed, Error **errp);
-
-/*
- * Same as block_job_set_speed(), but called with job lock held.
- * Might release the lock temporarily.
+ *
+ * Called with job lock held, but might release it temporarily.
*/
bool block_job_set_speed_locked(BlockJob *job, int64_t speed, Error **errp);
/**
- * block_job_query:
+ * block_job_query_locked:
* @job: The job to get information about.
*
* Return information about a job.
+ *
+ * Called with job lock held.
*/
-BlockJobInfo *block_job_query(BlockJob *job, Error **errp);
-
-/* Same as block_job_query(), but called with job lock held. */
BlockJobInfo *block_job_query_locked(BlockJob *job, Error **errp);
/**
- * block_job_iostatus_reset:
+ * block_job_iostatus_reset_locked:
* @job: The job whose I/O status should be reset.
*
* Reset I/O status on @job and on BlockDriverState objects it uses,
* other than job->blk.
+ *
+ * Called with job lock held.
*/
-void block_job_iostatus_reset(BlockJob *job);
-
-/* Same as block_job_iostatus_reset(), but called with job lock held. */
void block_job_iostatus_reset_locked(BlockJob *job);
/*
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* [PATCH v9 21/21] job: remove unused functions
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (19 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 20/21] blockjob: remove unused functions Emanuele Giuseppe Esposito
@ 2022-07-06 20:15 ` Emanuele Giuseppe Esposito
2022-07-11 15:57 ` [PATCH v9 00/21] job: replace AioContext lock with job_mutex Vladimir Sementsov-Ogievskiy
21 siblings, 0 replies; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-06 20:15 UTC (permalink / raw)
To: qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel,
Emanuele Giuseppe Esposito
These public functions are not used anywhere, thus can be dropped.
Also, since this is the final job API that doesn't use AioContext
lock and replaces it with job_lock, adjust all remaining function
documentation to clearly specify if the job lock is taken or not.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
include/qemu/job.h | 110 +++++++++++++----------------------------
job.c | 119 ++-------------------------------------------
2 files changed, 37 insertions(+), 192 deletions(-)
diff --git a/include/qemu/job.h b/include/qemu/job.h
index 676f69bb2e..3d82b1eaee 100644
--- a/include/qemu/job.h
+++ b/include/qemu/job.h
@@ -361,6 +361,8 @@ JobTxn *job_txn_new(void);
/**
* Release a reference that was previously acquired with job_txn_add_job or
* job_txn_new. If it's the last reference to the object, it will be freed.
+ *
+ * Called with job lock *not* held.
*/
void job_txn_unref(JobTxn *txn);
@@ -390,19 +392,17 @@ void *job_create(const char *job_id, const JobDriver *driver, JobTxn *txn,
/**
* Add a reference to Job refcnt, it will be decreased with job_unref, and then
* be freed if it comes to be the last reference.
+ *
+ * Called with job lock held.
*/
-void job_ref(Job *job);
-
-/* Same as job_ref(), but called with job lock held. */
void job_ref_locked(Job *job);
/**
* Release a reference that was previously acquired with job_ref() or
* job_create(). If it's the last reference to the object, it will be freed.
+ *
+ * Called with job lock held.
*/
-void job_unref(Job *job);
-
-/* Same as job_unref(), but called with job lock held. */
void job_unref_locked(Job *job);
/**
@@ -448,12 +448,8 @@ void job_progress_increase_remaining(Job *job, uint64_t delta);
* Conditionally enter the job coroutine if the job is ready to run, not
* already busy and fn() returns true. fn() is called while under the job_lock
* critical section.
- */
-void job_enter_cond(Job *job, bool(*fn)(Job *job));
-
-/*
- * Same as job_enter_cond(), but called with job lock held.
- * Might release the lock temporarily.
+ *
+ * Called with job lock held, but might release it temporarily.
*/
void job_enter_cond_locked(Job *job, bool(*fn)(Job *job));
@@ -532,11 +528,8 @@ bool job_cancel_requested(Job *job);
/**
* Returns whether the job is in a completed state.
- * Called with job_mutex *not* held.
+ * Called with job lock held.
*/
-bool job_is_completed(Job *job);
-
-/* Same as job_is_completed(), but called with job lock held. */
bool job_is_completed_locked(Job *job);
/**
@@ -552,45 +545,34 @@ bool job_is_ready_locked(Job *job);
* Request @job to pause at the next pause point. Must be paired with
* job_resume(). If the job is supposed to be resumed by user action, call
* job_user_pause() instead.
+ *
+ * Called with job lock held.
*/
-void job_pause(Job *job);
-
-/* Same as job_pause(), but called with job lock held. */
void job_pause_locked(Job *job);
-/** Resumes a @job paused with job_pause. */
-void job_resume(Job *job);
-
-/*
- * Same as job_resume(), but called with job lock held.
- * Might release the lock temporarily.
+/**
+ * Resumes a @job paused with job_pause.
+ * Called with job lock held, but might release it temporarily.
*/
void job_resume_locked(Job *job);
/**
* Asynchronously pause the specified @job.
* Do not allow a resume until a matching call to job_user_resume.
+ * Called with job lock held.
*/
-void job_user_pause(Job *job, Error **errp);
-
-/* Same as job_user_pause(), but called with job lock held. */
void job_user_pause_locked(Job *job, Error **errp);
-/** Returns true if the job is user-paused. */
-bool job_user_paused(Job *job);
-
-/* Same as job_user_paused(), but called with job lock held. */
+/**
+ * Returns true if the job is user-paused.
+ * Called with job lock held.
+ */
bool job_user_paused_locked(Job *job);
/**
* Resume the specified @job.
* Must be paired with a preceding job_user_pause.
- */
-void job_user_resume(Job *job, Error **errp);
-
-/*
- * Same as job_user_resume(), but called with job lock held.
- * Might release the lock temporarily.
+ * Called with job lock held, but might release it temporarily.
*/
void job_user_resume_locked(Job *job, Error **errp);
@@ -599,30 +581,25 @@ void job_user_resume_locked(Job *job, Error **errp);
* first one if @job is %NULL.
*
* Returns the requested job, or %NULL if there are no more jobs left.
+ * Called with job lock held.
*/
-Job *job_next(Job *job);
-
-/* Same as job_next(), but called with job lock held. */
Job *job_next_locked(Job *job);
/**
* Get the job identified by @id (which must not be %NULL).
*
* Returns the requested job, or %NULL if it doesn't exist.
+ * Called with job lock held.
*/
-Job *job_get(const char *id);
-
-/* Same as job_get(), but called with job lock held. */
Job *job_get_locked(const char *id);
/**
* Check whether the verb @verb can be applied to @job in its current state.
* Returns 0 if the verb can be applied; otherwise errp is set and -EPERM
* returned.
+ *
+ * Called with job lock held.
*/
-int job_apply_verb(Job *job, JobVerb verb, Error **errp);
-
-/* Same as job_apply_verb, but called with job lock held. */
int job_apply_verb_locked(Job *job, JobVerb verb, Error **errp);
/**
@@ -637,31 +614,24 @@ void job_early_fail(Job *job);
*/
void job_transition_to_ready(Job *job);
-/** Asynchronously complete the specified @job. */
-void job_complete(Job *job, Error **errp);
-
-/*
- * Same as job_complete(), but called with job lock held.
- * Might release the lock temporarily.
+/**
+ * Asynchronously complete the specified @job.
+ * Called with job lock held, but might release it temporarily.
*/
void job_complete_locked(Job *job, Error **errp);
/**
* Asynchronously cancel the specified @job. If @force is true, the job should
* be cancelled immediately without waiting for a consistent state.
+ * Called with job lock held.
*/
-void job_cancel(Job *job, bool force);
-
-/* Same as job_cancel(), but called with job lock held. */
void job_cancel_locked(Job *job, bool force);
/**
* Cancels the specified job like job_cancel(), but may refuse to do so if the
* operation isn't meaningful in the current state of the job.
+ * Called with job lock held.
*/
-void job_user_cancel(Job *job, bool force, Error **errp);
-
-/* Same as job_user_cancel(), but called with job lock held. */
void job_user_cancel_locked(Job *job, bool force, Error **errp);
/**
@@ -700,9 +670,6 @@ void job_cancel_sync_all(void);
* Returns the return value from the job.
* Called with job_lock held.
*/
-int job_complete_sync(Job *job, Error **errp);
-
-/* Same as job_complete_sync, but called with job lock held. */
int job_complete_sync_locked(Job *job, Error **errp);
/**
@@ -712,19 +679,17 @@ int job_complete_sync_locked(Job *job, Error **errp);
* FIXME: Make the below statement universally true:
* For jobs that support the manual workflow mode, all graph changes that occur
* as a result will occur after this command and before a successful reply.
+ *
+ * Called with job lock held.
*/
-void job_finalize(Job *job, Error **errp);
-
-/* Same as job_finalize(), but called with job lock held. */
void job_finalize_locked(Job *job, Error **errp);
/**
* Remove the concluded @job from the query list and resets the passed pointer
* to %NULL. Returns an error if the job is not actually concluded.
+ *
+ * Called with job lock held.
*/
-void job_dismiss(Job **job, Error **errp);
-
-/* Same as job_dismiss(), but called with job lock held. */
void job_dismiss_locked(Job **job, Error **errp);
/**
@@ -734,14 +699,7 @@ void job_dismiss_locked(Job **job, Error **errp);
* Returns 0 if the job is successfully completed, -ECANCELED if the job was
* cancelled before completing, and -errno in other error cases.
*
- * Called with job_lock held.
- */
-int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp),
- Error **errp);
-
-/*
- * Same as job_finish_sync(), but called with job lock held.
- * Might release the lock temporarily.
+ * Called with job_lock held, but might release it temporarily.
*/
int job_finish_sync_locked(Job *job, void (*finish)(Job *, Error **errp),
Error **errp);
diff --git a/job.c b/job.c
index b23481cfcb..2310a8afca 100644
--- a/job.c
+++ b/job.c
@@ -233,12 +233,6 @@ int job_apply_verb_locked(Job *job, JobVerb verb, Error **errp)
return -EPERM;
}
-int job_apply_verb(Job *job, JobVerb verb, Error **errp)
-{
- JOB_LOCK_GUARD();
- return job_apply_verb_locked(job, verb, errp);
-}
-
JobType job_type(const Job *job)
{
return job->driver->job_type;
@@ -324,7 +318,7 @@ bool job_is_completed_locked(Job *job)
return false;
}
-bool job_is_completed(Job *job)
+static bool job_is_completed(Job *job)
{
JOB_LOCK_GUARD();
return job_is_completed_locked(job);
@@ -349,12 +343,6 @@ Job *job_next_locked(Job *job)
return QLIST_NEXT(job, job_list);
}
-Job *job_next(Job *job)
-{
- JOB_LOCK_GUARD();
- return job_next_locked(job);
-}
-
Job *job_get_locked(const char *id)
{
Job *job;
@@ -368,12 +356,6 @@ Job *job_get_locked(const char *id)
return NULL;
}
-Job *job_get(const char *id)
-{
- JOB_LOCK_GUARD();
- return job_get_locked(id);
-}
-
void job_set_aio_context(Job *job, AioContext *ctx)
{
/* protect against read in job_finish_sync_locked and job_start */
@@ -465,12 +447,6 @@ void job_ref_locked(Job *job)
++job->refcnt;
}
-void job_ref(Job *job)
-{
- JOB_LOCK_GUARD();
- job_ref_locked(job);
-}
-
void job_unref_locked(Job *job)
{
GLOBAL_STATE_CODE();
@@ -499,12 +475,6 @@ void job_unref_locked(Job *job)
}
}
-void job_unref(Job *job)
-{
- JOB_LOCK_GUARD();
- job_unref_locked(job);
-}
-
void job_progress_update(Job *job, uint64_t done)
{
progress_work_done(&job->progress, done);
@@ -580,12 +550,6 @@ void job_enter_cond_locked(Job *job, bool(*fn)(Job *job))
job_lock();
}
-void job_enter_cond(Job *job, bool(*fn)(Job *job))
-{
- JOB_LOCK_GUARD();
- job_enter_cond_locked(job, fn);
-}
-
void job_enter(Job *job)
{
JOB_LOCK_GUARD();
@@ -673,8 +637,9 @@ void coroutine_fn job_pause_point(Job *job)
job_pause_point_locked(job);
}
-void job_yield_locked(Job *job)
+void job_yield(Job *job)
{
+ JOB_LOCK_GUARD();
assert(job->busy);
/* Check cancellation *before* setting busy = false, too! */
@@ -689,12 +654,6 @@ void job_yield_locked(Job *job)
job_pause_point_locked(job);
}
-void job_yield(Job *job)
-{
- JOB_LOCK_GUARD();
- job_yield_locked(job);
-}
-
void coroutine_fn job_sleep_ns(Job *job, int64_t ns)
{
JOB_LOCK_GUARD();
@@ -726,12 +685,6 @@ void job_pause_locked(Job *job)
}
}
-void job_pause(Job *job)
-{
- JOB_LOCK_GUARD();
- job_pause_locked(job);
-}
-
void job_resume_locked(Job *job)
{
assert(job->pause_count > 0);
@@ -744,12 +697,6 @@ void job_resume_locked(Job *job)
job_enter_cond_locked(job, job_timer_not_pending_locked);
}
-void job_resume(Job *job)
-{
- JOB_LOCK_GUARD();
- job_resume_locked(job);
-}
-
void job_user_pause_locked(Job *job, Error **errp)
{
if (job_apply_verb_locked(job, JOB_VERB_PAUSE, errp)) {
@@ -763,23 +710,11 @@ void job_user_pause_locked(Job *job, Error **errp)
job_pause_locked(job);
}
-void job_user_pause(Job *job, Error **errp)
-{
- JOB_LOCK_GUARD();
- job_user_pause_locked(job, errp);
-}
-
bool job_user_paused_locked(Job *job)
{
return job->user_paused;
}
-bool job_user_paused(Job *job)
-{
- JOB_LOCK_GUARD();
- return job_user_paused_locked(job);
-}
-
void job_user_resume_locked(Job *job, Error **errp)
{
assert(job);
@@ -800,12 +735,6 @@ void job_user_resume_locked(Job *job, Error **errp)
job_resume_locked(job);
}
-void job_user_resume(Job *job, Error **errp)
-{
- JOB_LOCK_GUARD();
- job_user_resume_locked(job, errp);
-}
-
/* Called with job_mutex held, but releases it temporarily. */
static void job_do_dismiss_locked(Job *job)
{
@@ -833,12 +762,6 @@ void job_dismiss_locked(Job **jobptr, Error **errp)
*jobptr = NULL;
}
-void job_dismiss(Job **jobptr, Error **errp)
-{
- JOB_LOCK_GUARD();
- job_dismiss_locked(jobptr, errp);
-}
-
void job_early_fail(Job *job)
{
JOB_LOCK_GUARD();
@@ -1080,12 +1003,6 @@ void job_finalize_locked(Job *job, Error **errp)
job_do_finalize_locked(job);
}
-void job_finalize(Job *job, Error **errp)
-{
- JOB_LOCK_GUARD();
- job_finalize_locked(job, errp);
-}
-
/* Called with job_mutex held. */
static int job_transition_to_pending_locked(Job *job)
{
@@ -1232,12 +1149,6 @@ void job_cancel_locked(Job *job, bool force)
}
}
-void job_cancel(Job *job, bool force)
-{
- JOB_LOCK_GUARD();
- job_cancel_locked(job, force);
-}
-
void job_user_cancel_locked(Job *job, bool force, Error **errp)
{
if (job_apply_verb_locked(job, JOB_VERB_CANCEL, errp)) {
@@ -1246,12 +1157,6 @@ void job_user_cancel_locked(Job *job, bool force, Error **errp)
job_cancel_locked(job, force);
}
-void job_user_cancel(Job *job, bool force, Error **errp)
-{
- JOB_LOCK_GUARD();
- job_user_cancel_locked(job, force, errp);
-}
-
/* A wrapper around job_cancel() taking an Error ** parameter so it may be
* used with job_finish_sync() without the need for (rather nasty) function
* pointer casts there.
@@ -1302,12 +1207,6 @@ int job_complete_sync_locked(Job *job, Error **errp)
return job_finish_sync_locked(job, job_complete_locked, errp);
}
-int job_complete_sync(Job *job, Error **errp)
-{
- JOB_LOCK_GUARD();
- return job_complete_sync_locked(job, errp);
-}
-
void job_complete_locked(Job *job, Error **errp)
{
/* Should not be reachable via external interface for internal jobs */
@@ -1327,12 +1226,6 @@ void job_complete_locked(Job *job, Error **errp)
job_lock();
}
-void job_complete(Job *job, Error **errp)
-{
- JOB_LOCK_GUARD();
- job_complete_locked(job, errp);
-}
-
int job_finish_sync_locked(Job *job,
void (*finish)(Job *, Error **errp),
Error **errp)
@@ -1362,9 +1255,3 @@ int job_finish_sync_locked(Job *job,
job_unref_locked(job);
return ret;
}
-
-int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp), Error **errp)
-{
- JOB_LOCK_GUARD();
- return job_finish_sync_locked(job, finish, errp);
-}
--
2.31.1
^ permalink raw reply related [flat|nested] 53+ messages in thread
* Re: [PATCH v9 05/21] job.c: add job_lock/unlock while keeping job.h intact
2022-07-06 20:15 ` [PATCH v9 05/21] job.c: add job_lock/unlock while keeping job.h intact Emanuele Giuseppe Esposito
@ 2022-07-08 19:25 ` Vladimir Sementsov-Ogievskiy
2022-07-11 7:30 ` Emanuele Giuseppe Esposito
0 siblings, 1 reply; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-08 19:25 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
> With "intact" we mean that all job.h functions implicitly
> take the lock. Therefore API callers are unmodified.
>
> This means that:
> - many static functions that will be always called with job lock held
> become _locked, and call _locked functions
> - all public functions take the lock internally if needed, and call _locked
> functions
> - all public functions called internally by other functions in job.c will have a
> _locked counterpart (sometimes public), to avoid deadlocks (job lock already taken).
> These functions are not used for now.
> - some public functions called only from exernal files (not job.c) do not
> have _locked() counterpart and take the lock inside. Others won't need
> the lock at all because use fields only set at initialization and
> never modified.
>
> job_{lock/unlock} is independent from real_job_{lock/unlock}.
>
> Note: at this stage, job_{lock/unlock} and job lock guard macros
> are *nop*
>
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
I think, we still lack some comments on function lock-related interface, but it may be improved later.
[..]
>
> -static int job_txn_apply(Job *job, int fn(Job *))
> +/* Called with job_mutex held, but releases it temporarily. */
Hmm. Yes, it may release it temprorarily when fn() release it.. Not very clear but OK..
> +static int job_txn_apply_locked(Job *job, int fn(Job *))
> {
> AioContext *inner_ctx;
> Job *other_job, *next;
> @@ -170,7 +182,7 @@ static int job_txn_apply(Job *job, int fn(Job *))
> * we need to release it here to avoid holding the lock twice - which would
> * break AIO_WAIT_WHILE from within fn.
> */
> - job_ref(job);
> + job_ref_locked(job);
> aio_context_release(job->aio_context);
>
[..]
> +
> static bool job_started(Job *job)
So we can call it both with mutex locked and without. Hope it never race with job_start.
> {
> return job->co;
> }
>
> -static bool job_should_pause(Job *job)
> +/* Called with job_mutex held. */
[..]
>
> -/** Useful only as a type shim for aio_bh_schedule_oneshot. */
> +/**
> + * Useful only as a type shim for aio_bh_schedule_oneshot.
> + * Called with job_mutex *not* held, but releases it temporarily.
", but releases it temprorarily" is misleading for me. If called with mutext not held, then "releases it temprorarily" is not part of function interface.. Many functions that take some mutex internally do release it temporarily and callers should not care of it.
So, better just "Called with job_mutex *not* held."
> + */
> static void job_exit(void *opaque)
> {
> Job *job = (Job *)opaque;
> AioContext *ctx;
> + JOB_LOCK_GUARD();
>
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 05/21] job.c: add job_lock/unlock while keeping job.h intact
2022-07-08 19:25 ` Vladimir Sementsov-Ogievskiy
@ 2022-07-11 7:30 ` Emanuele Giuseppe Esposito
2022-07-11 10:40 ` Vladimir Sementsov-Ogievskiy
0 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-11 7:30 UTC (permalink / raw)
To: Vladimir Sementsov-Ogievskiy, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
Am 08/07/2022 um 21:25 schrieb Vladimir Sementsov-Ogievskiy:
>> static bool job_started(Job *job)
>
> So we can call it both with mutex locked and without. Hope it never race
> with job_start.
Where exactly do you see it called with mutex not held?
I don't see it anywhere, and if you agree too, we should rename it in
_locked.
Emanuele
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 06/21] job: move and update comments from blockjob.c
2022-07-06 20:15 ` [PATCH v9 06/21] job: move and update comments from blockjob.c Emanuele Giuseppe Esposito
@ 2022-07-11 8:56 ` Vladimir Sementsov-Ogievskiy
0 siblings, 0 replies; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-11 8:56 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
> This comment applies more on job, it was left in blockjob as in the past
> the whole job logic was implemented there.
>
> Note: at this stage, job_{lock/unlock} and job lock guard macros
> are*nop*.
>
> No functional change intended.
>
> Signed-off-by: Emanuele Giuseppe Esposito<eesposit@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 05/21] job.c: add job_lock/unlock while keeping job.h intact
2022-07-11 7:30 ` Emanuele Giuseppe Esposito
@ 2022-07-11 10:40 ` Vladimir Sementsov-Ogievskiy
0 siblings, 0 replies; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-11 10:40 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/11/22 10:30, Emanuele Giuseppe Esposito wrote:
>
>
> Am 08/07/2022 um 21:25 schrieb Vladimir Sementsov-Ogievskiy:
>>> static bool job_started(Job *job)
>>
>> So we can call it both with mutex locked and without. Hope it never race
>> with job_start.
>
> Where exactly do you see it called with mutex not held?
>
> I don't see it anywhere, and if you agree too, we should rename it in
> _locked.
>
Oh, right, I agree.
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 07/21] blockjob: introduce block_job _locked() APIs
2022-07-06 20:15 ` [PATCH v9 07/21] blockjob: introduce block_job _locked() APIs Emanuele Giuseppe Esposito
@ 2022-07-11 12:04 ` Vladimir Sementsov-Ogievskiy
2022-07-11 12:24 ` Emanuele Giuseppe Esposito
0 siblings, 1 reply; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-11 12:04 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
> Just as done with job.h, create _locked() functions in blockjob.h
>
> These functions will be later useful when caller has already taken
> the lock. All blockjob _locked functions call job _locked functions.
>
> Note: at this stage, job_{lock/unlock} and job lock guard macros
> are *nop*.
>
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
We not only create _locked() interfaces, but also make some functions correct relatively to job_mutex that was not correct pre-patch, for example:
block_job_iostatus_reset(): the function doesn't call any job_* APIs, but it access Job fields. After patch fields are accessed under mutex which is correct, and that's the significant change worth mentioning in commit message.
So, more correct is to say, that we make some functions of blockjob API correct relatively to job_mutex and Job fields.
With at least this clarified, I'm OK with the patch as is:
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
What kept in mind after the patch:
1. Some functions still need an update, for example block_job_error_action, that access Job.user_pause without locking the job_mutex. Or, block_job_event_completed that accesses Job.ret..
2. What about BlockJob.nodes field? Shouldn't we protect it by the mutex?
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 08/21] jobs: add job lock in find_* functions
2022-07-06 20:15 ` [PATCH v9 08/21] jobs: add job lock in find_* functions Emanuele Giuseppe Esposito
@ 2022-07-11 12:20 ` Vladimir Sementsov-Ogievskiy
0 siblings, 0 replies; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-11 12:20 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
> Both blockdev.c and job-qmp.c have TOC/TOU conditions, because
> they first search for the job and then perform an action on it.
> Therefore, we need to do the search + action under the same
> job mutex critical section.
>
> Note: at this stage, job_{lock/unlock} and job lock guard macros
> are*nop*.
>
> Signed-off-by: Emanuele Giuseppe Esposito<eesposit@redhat.com>
> Reviewed-by: Stefan Hajnoczi<stefanha@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 07/21] blockjob: introduce block_job _locked() APIs
2022-07-11 12:04 ` Vladimir Sementsov-Ogievskiy
@ 2022-07-11 12:24 ` Emanuele Giuseppe Esposito
0 siblings, 0 replies; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-11 12:24 UTC (permalink / raw)
To: Vladimir Sementsov-Ogievskiy, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
Am 11/07/2022 um 14:04 schrieb Vladimir Sementsov-Ogievskiy:
> On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
>> Just as done with job.h, create _locked() functions in blockjob.h
>>
>> These functions will be later useful when caller has already taken
>> the lock. All blockjob _locked functions call job _locked functions.
>>
>> Note: at this stage, job_{lock/unlock} and job lock guard macros
>> are *nop*.
>>
>> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
>
> We not only create _locked() interfaces, but also make some functions
> correct relatively to job_mutex that was not correct pre-patch, for
> example:
>
> block_job_iostatus_reset(): the function doesn't call any job_* APIs,
> but it access Job fields. After patch fields are accessed under mutex
> which is correct, and that's the significant change worth mentioning in
> commit message.
>
> So, more correct is to say, that we make some functions of blockjob API
> correct relatively to job_mutex and Job fields.
>
> With at least this clarified, I'm OK with the patch as is:
> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
>
>
> What kept in mind after the patch:
>
> 1. Some functions still need an update, for example
> block_job_error_action, that access Job.user_pause without locking the
> job_mutex. Or, block_job_event_completed that accesses Job.ret..
This comes afterward, I didn't check the patches but the end result
covers what you mention above.
>
> 2. What about BlockJob.nodes field? Shouldn't we protect it by the mutex?
>
As I wrote in the comment in patch 17, seems to be always modified under
GLOBAL_STATE_CODE.
Thank you,
Emanuele
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 09/21] jobs: use job locks also in the unit tests
2022-07-06 20:15 ` [PATCH v9 09/21] jobs: use job locks also in the unit tests Emanuele Giuseppe Esposito
@ 2022-07-11 13:08 ` Vladimir Sementsov-Ogievskiy
2022-07-19 12:00 ` Emanuele Giuseppe Esposito
0 siblings, 1 reply; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-11 13:08 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
> Add missing job synchronization in the unit tests, with
> explicit locks.
>
> We are deliberately using _locked functions wrapped by a guard
> instead of a normal call because the normal call will be removed
> in future, as the only usage is limited to the tests.
>
> In other words, if a function like job_pause() is/will be only used
> in tests to avoid:
>
> WITH_JOB_LOCK_GUARD(){
> job_pause_locked();
> }
>
> then it is not worth keeping job_pause(), and just use the guard.
I'm not sure. Why not worth keeping simpler code in tests? But I don't insist.
>
> Note: at this stage, job_{lock/unlock} and job lock guard macros
> are *nop*.
>
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
[..]
> --- a/tests/unit/test-blockjob-txn.c
> +++ b/tests/unit/test-blockjob-txn.c
> @@ -116,8 +116,10 @@ static void test_single_job(int expected)
> job = test_block_job_start(1, true, expected, &result, txn);
> job_start(&job->job);
>
> - if (expected == -ECANCELED) {
> - job_cancel(&job->job, false);
> + WITH_JOB_LOCK_GUARD() {
> + if (expected == -ECANCELED) {
> + job_cancel_locked(&job->job, false);
> + }
> }
"if (expected == ..)" may be kept around LOCK_GUARD section.
>
> while (result == -EINPROGRESS) {
> @@ -160,13 +162,15 @@ static void test_pair_jobs(int expected1, int expected2)
> /* Release our reference now to trigger as many nice
> * use-after-free bugs as possible.
> */
> - job_txn_unref(txn);
[..]
> cancel_common(s);
> }
>
> +/*
> + * This test always runs in the main loop, so there is no
> + * need to protect job->status.
> + */
That made me ask:
1. Are all tests always run in main loop? If yes, why to protect status reading in test_complete_in_standby() ?
2. Maybe, we don't need to protect anything here? Why to protect other things if we run everything in main loop?
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 10/21] block/mirror.c: use of job helpers in drivers to avoid TOC/TOU
2022-07-06 20:15 ` [PATCH v9 10/21] block/mirror.c: use of job helpers in drivers to avoid TOC/TOU Emanuele Giuseppe Esposito
@ 2022-07-11 13:15 ` Vladimir Sementsov-Ogievskiy
0 siblings, 0 replies; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-11 13:15 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
> Once job lock is used and aiocontext is removed, mirror has
> to perform job operations under the same critical section,
> using the helpers prepared in previous commit.
>
> Note: at this stage, job_{lock/unlock} and job lock guard macros
> are*nop*.
>
> Signed-off-by: Emanuele Giuseppe Esposito<eesposit@redhat.com>
> Reviewed-by: Stefan Hajnoczi<stefanha@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 11/21] jobs: group together API calls under the same job lock
2022-07-06 20:15 ` [PATCH v9 11/21] jobs: group together API calls under the same job lock Emanuele Giuseppe Esposito
@ 2022-07-11 13:26 ` Vladimir Sementsov-Ogievskiy
2022-07-19 12:40 ` Emanuele Giuseppe Esposito
0 siblings, 1 reply; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-11 13:26 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
> Now that the API offers also _locked() functions, take advantage
> of it and give also the caller control to take the lock and call
> _locked functions.
>
> This makes sense especially when we have for loops, because it
> makes no sense to have:
>
> for(job = job_next(); ...)
>
> where each job_next() takes the lock internally.
> Instead we want
>
> JOB_LOCK_GUARD();
> for(job = job_next_locked(); ...)
>
> Note: at this stage, job_{lock/unlock} and job lock guard macros
> are *nop*.
>
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
> ---
[..]
>
> diff --git a/blockjob.c b/blockjob.c
> index 0d59aba439..bce05a9096 100644
> --- a/blockjob.c
> +++ b/blockjob.c
> @@ -99,7 +99,9 @@ static char *child_job_get_parent_desc(BdrvChild *c)
> static void child_job_drained_begin(BdrvChild *c)
> {
> BlockJob *job = c->opaque;
> - job_pause(&job->job);
> + WITH_JOB_LOCK_GUARD() {
> + job_pause_locked(&job->job);
> + }
What's the reason for it? I'd keep job_pause().
(and it doesn't correspond to what commit subject presents.)
> }
>
> static bool child_job_drained_poll(BdrvChild *c)
> @@ -111,8 +113,10 @@ static bool child_job_drained_poll(BdrvChild *c)
> /* An inactive or completed job doesn't have any pending requests. Jobs
> * with !job->busy are either already paused or have a pause point after
> * being reentered, so no job driver code will run before they pause. */
> - if (!job->busy || job_is_completed(job)) {
> - return false;
> + WITH_JOB_LOCK_GUARD() {
> + if (!job->busy || job_is_completed_locked(job)) {
> + return false;
> + }
> }
This doesn't correspond to commit subject. I'd put such things to separate commit "correct use of job_mutex in blockjob.c".
>
> /* Otherwise, assume that it isn't fully stopped yet, but allow the job to
> @@ -127,7 +131,9 @@ static bool child_job_drained_poll(BdrvChild *c)
> static void child_job_drained_end(BdrvChild *c, int *drained_end_counter)
> {
> BlockJob *job = c->opaque;
> - job_resume(&job->job);
> + WITH_JOB_LOCK_GUARD() {
> + job_resume_locked(&job->job);
> + }
> }
Again, don't see a reason for such change.
[my comments relate to more similar cases in the patch]
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 12/21] commit and mirror: create new nodes using bdrv_get_aio_context, and not the job aiocontext
2022-07-06 20:15 ` [PATCH v9 12/21] commit and mirror: create new nodes using bdrv_get_aio_context, and not the job aiocontext Emanuele Giuseppe Esposito
@ 2022-07-11 13:32 ` Vladimir Sementsov-Ogievskiy
0 siblings, 0 replies; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-11 13:32 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
> We are always using the given bs AioContext, so there is no need
> to take the job ones (which is identical anyways).
> This also reduces the point we need to check when protecting
> job.aio_context field.
>
> Reviewed-by: Stefan Hajnoczi<stefanha@redhat.com>
> Signed-off-by: Emanuele Giuseppe Esposito<eesposit@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 13/21] job: detect change of aiocontext within job coroutine
2022-07-06 20:15 ` [PATCH v9 13/21] job: detect change of aiocontext within job coroutine Emanuele Giuseppe Esposito
@ 2022-07-11 13:59 ` Vladimir Sementsov-Ogievskiy
0 siblings, 0 replies; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-11 13:59 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
> From: Paolo Bonzini <pbonzini@redhat.com>
>
> We want to make sure access of job->aio_context is always done
> under either BQL or job_mutex. The problem is that using
> aio_co_enter(job->aiocontext, job->co) in job_start and job_enter_cond
> makes the coroutine immediately resume, so we can't hold the job lock.
> And caching it is not safe either, as it might change.
>
> job_start is under BQL, so it can freely read job->aiocontext, but
> job_enter_cond is not. In order to fix this, use aio_co_wake():
> the advantage is that it won't use job->aiocontext, but the
> main disadvantage is that it won't be able to detect a change of
> job AioContext.
>
> Calling bdrv_try_set_aio_context() will issue the following calls
> (simplified):
> * in terms of bdrv callbacks:
> .drained_begin -> .set_aio_context -> .drained_end
> * in terms of child_job functions:
> child_job_drained_begin -> child_job_set_aio_context -> child_job_drained_end
> * in terms of job functions:
> job_pause_locked -> job_set_aio_context -> job_resume_locked
>
> We can see that after setting the new aio_context, job_resume_locked
> calls again job_enter_cond, which then invokes aio_co_wake(). But
> while job->aiocontext has been set in job_set_aio_context,
> job->co->ctx has not changed, so the coroutine would be entering in
> the wrong aiocontext.
>
> Using aio_co_schedule in job_resume_locked() might seem as a valid
> alternative, but the problem is that the bh resuming the coroutine
> is not scheduled immediately, and if in the meanwhile another
> bdrv_try_set_aio_context() is run (see test_propagate_mirror() in
> test-block-iothread.c), we would have the first schedule in the
> wrong aiocontext, and the second set of drains won't even manage
> to schedule the coroutine, as job->busy would still be true from
> the previous job_resume_locked().
>
> The solution is to stick with aio_co_wake(), but then detect every time
> the coroutine resumes back from yielding if job->aio_context
> has changed. If so, we can reschedule it to the new context.
>
> Check for the aiocontext change in job_do_yield_locked because:
> 1) aio_co_reschedule_self requires to be in the running coroutine
> 2) since child_job_set_aio_context allows changing the aiocontext only
> while the job is paused, this is the exact place where the coroutine
> resumes, before running JobDriver's code.
>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Seems reasonable to me, still I don't have the whole picture in mind. Weak:
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
> ---
> job.c | 22 +++++++++++++++++++---
> 1 file changed, 19 insertions(+), 3 deletions(-)
>
> diff --git a/job.c b/job.c
> index 9c8792c9e8..405f39566b 100644
> --- a/job.c
> +++ b/job.c
> @@ -581,11 +581,12 @@ void job_enter_cond_locked(Job *job, bool(*fn)(Job *job))
> return;
> }
>
> - assert(!job->deferred_to_main_loop);
why we remove this assertion?
> timer_del(&job->sleep_timer);
> job->busy = true;
> real_job_unlock();
> - aio_co_enter(job->aio_context, job->co);
> + job_unlock();
> + aio_co_wake(job->co);
> + job_lock();
> }
>
> void job_enter_cond(Job *job, bool(*fn)(Job *job))
> @@ -611,6 +612,8 @@ void job_enter(Job *job)
> */
> static void coroutine_fn job_do_yield_locked(Job *job, uint64_t ns)
> {
> + AioContext *next_aio_context;
> +
> real_job_lock();
> if (ns != -1) {
> timer_mod(&job->sleep_timer, ns);
> @@ -622,7 +625,20 @@ static void coroutine_fn job_do_yield_locked(Job *job, uint64_t ns)
> qemu_coroutine_yield();
> job_lock();
>
> - /* Set by job_enter_cond() before re-entering the coroutine. */
> + next_aio_context = job->aio_context;
> + /*
> + * Coroutine has resumed, but in the meanwhile the job AioContext
> + * might have changed via bdrv_try_set_aio_context(), so we need to move
> + * the coroutine too in the new aiocontext.
> + */
> + while (qemu_get_current_aio_context() != next_aio_context) {
> + job_unlock();
> + aio_co_reschedule_self(next_aio_context);
> + job_lock();
> + next_aio_context = job->aio_context;
> + }
> +
> + /* Set by job_enter_cond_locked() before re-entering the coroutine. */
> assert(job->busy);
> }
>
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 14/21] jobs: protect job.aio_context with BQL and job_mutex
2022-07-06 20:15 ` [PATCH v9 14/21] jobs: protect job.aio_context with BQL and job_mutex Emanuele Giuseppe Esposito
@ 2022-07-11 14:19 ` Vladimir Sementsov-Ogievskiy
2022-07-19 12:48 ` Emanuele Giuseppe Esposito
0 siblings, 1 reply; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-11 14:19 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
> In order to make it thread safe, implement a "fake rwlock",
> where we allow reads under BQL *or* job_mutex held, but
> writes only under BQL *and* job_mutex.
>
> The only write we have is in child_job_set_aio_ctx
also in job_create of course, but it seems safe anyway
> , which always
> happens under drain (so the job is paused).
> For this reason, introduce job_set_aio_context and make sure that
> the context is set under BQL, job_mutex and drain.
> Also make sure all other places where the aiocontext is read
> are protected.
>
> Note: at this stage, job_{lock/unlock} and job lock guard macros
> are *nop*.
>
> Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
> block/replication.c | 6 ++++--
> blockjob.c | 3 ++-
> include/qemu/job.h | 19 ++++++++++++++++++-
> job.c | 12 ++++++++++++
> 4 files changed, 36 insertions(+), 4 deletions(-)
>
> diff --git a/block/replication.c b/block/replication.c
> index 55c8f894aa..2189863df1 100644
> --- a/block/replication.c
> +++ b/block/replication.c
> @@ -148,8 +148,10 @@ static void replication_close(BlockDriverState *bs)
> }
> if (s->stage == BLOCK_REPLICATION_FAILOVER) {
> commit_job = &s->commit_job->job;
> - assert(commit_job->aio_context == qemu_get_current_aio_context());
> - job_cancel_sync(commit_job, false);
> + WITH_JOB_LOCK_GUARD() {
> + assert(commit_job->aio_context == qemu_get_current_aio_context());
> + job_cancel_sync_locked(commit_job, false);
> + }
> }
>
> if (s->mode == REPLICATION_MODE_SECONDARY) {
> diff --git a/blockjob.c b/blockjob.c
> index bce05a9096..0d120ed126 100644
> --- a/blockjob.c
> +++ b/blockjob.c
> @@ -166,12 +166,13 @@ static void child_job_set_aio_ctx(BdrvChild *c, AioContext *ctx,
> bdrv_set_aio_context_ignore(sibling->bs, ctx, ignore);
> }
>
> - job->job.aio_context = ctx;
> + job_set_aio_context(&job->job, ctx);
> }
>
> static AioContext *child_job_get_parent_aio_context(BdrvChild *c)
> {
> BlockJob *job = c->opaque;
> + assert(qemu_in_main_thread());
>
> return job->job.aio_context;
> }
> diff --git a/include/qemu/job.h b/include/qemu/job.h
> index 5709e8d4a8..c144aabefc 100644
> --- a/include/qemu/job.h
> +++ b/include/qemu/job.h
> @@ -77,7 +77,12 @@ typedef struct Job {
>
> /** Protected by AioContext lock */
>
> - /** AioContext to run the job coroutine in */
> + /**
> + * AioContext to run the job coroutine in.
> + * This field can be read when holding either the BQL (so we are in
> + * the main loop) or the job_mutex.
> + * It can be only written when we hold *both* BQL and job_mutex.
> + */
> AioContext *aio_context;
>
> /** Reference count of the block job */
> @@ -741,4 +746,16 @@ int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp),
> int job_finish_sync_locked(Job *job, void (*finish)(Job *, Error **errp),
> Error **errp);
>
> +/**
> + * Sets the @job->aio_context.
> + * Called with job_mutex *not* held.
> + *
> + * This function must run in the main thread to protect against
> + * concurrent read in job_finish_sync_locked(),
> + * takes the job_mutex lock to protect against the read in
> + * job_do_yield_locked(), and must be called when the coroutine
> + * is quiescent.
> + */
> +void job_set_aio_context(Job *job, AioContext *ctx);
> +
> #endif
> diff --git a/job.c b/job.c
> index 405f39566b..66cae82593 100644
> --- a/job.c
> +++ b/job.c
> @@ -394,6 +394,17 @@ Job *job_get(const char *id)
> return job_get_locked(id);
> }
>
> +void job_set_aio_context(Job *job, AioContext *ctx)
> +{
> + /* protect against read in job_finish_sync_locked and job_start */
> + assert(qemu_in_main_thread());
> + /* protect against read in job_do_yield_locked */
> + JOB_LOCK_GUARD();
> + /* ensure the coroutine is quiescent while the AioContext is changed */
> + assert(job->pause_count > 0);
> + job->aio_context = ctx;
> +}
> +
> /* Called with job_mutex *not* held. */
> static void job_sleep_timer_cb(void *opaque)
> {
> @@ -1380,6 +1391,7 @@ int job_finish_sync_locked(Job *job,
> {
> Error *local_err = NULL;
> int ret;
> + assert(qemu_in_main_thread());
>
> job_ref_locked(job);
>
Missed update of block_job_add_bdrv(), block_job_get_aio_context(). Should they have an assertion too?
Also some occurences in test, but that doesn't seem significant.
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 15/21] job.c: enable job lock/unlock and remove Aiocontext locks
2022-07-06 20:15 ` [PATCH v9 15/21] job.c: enable job lock/unlock and remove Aiocontext locks Emanuele Giuseppe Esposito
@ 2022-07-11 14:33 ` Vladimir Sementsov-Ogievskiy
2022-07-19 12:51 ` Emanuele Giuseppe Esposito
0 siblings, 1 reply; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-11 14:33 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
> Change the job_{lock/unlock} and macros to use job_mutex.
>
> Now that they are not nop anymore, remove the aiocontext
> to avoid deadlocks.
>
> Therefore:
> - when possible, remove completely the aiocontext lock/unlock pair
> - if it is used by some other function too, reduce the locking
> section as much as possible, leaving the job API outside.
> - change AIO_WAIT_WHILE in AIO_WAIT_WHILE_UNLOCKED, since we
> are not using the aiocontext lock anymore
>
> There is only one JobDriver callback, ->free() that assumes that
> the aiocontext lock is held (because it calls bdrv_unref), so for
> now keep that under aiocontext lock.
>
> Also remove real_job_{lock/unlock}, as they are replaced by the
> public functions.
>
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
[..]
> static int job_finalize_single_locked(Job *job)
> {
> int job_ret;
> + AioContext *ctx = job->aio_context;
>
> assert(job_is_completed_locked(job));
>
> /* Ensure abort is called for late-transactional failures */
> job_update_rc_locked(job);
>
> + aio_context_acquire(ctx);
so here we acquire aio-context under job_mutex lock? Wouldn't that dead-lock?
> +
> if (!job->ret) {
> job_commit_locked(job);
> } else {
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 16/21] block_job_query: remove atomic read
2022-07-06 20:15 ` [PATCH v9 16/21] block_job_query: remove atomic read Emanuele Giuseppe Esposito
@ 2022-07-11 14:37 ` Vladimir Sementsov-Ogievskiy
0 siblings, 0 replies; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-11 14:37 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
> Not sure what the atomic here was supposed to do, since job.busy
> is protected by the job lock. Since the whole function
> is called under job_mutex, just remove the atomic.
>
> Reviewed-by: Stefan Hajnoczi<stefanha@redhat.com>
> Signed-off-by: Emanuele Giuseppe Esposito<eesposit@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 17/21] blockjob.h: categorize fields in struct BlockJob
2022-07-06 20:15 ` [PATCH v9 17/21] blockjob.h: categorize fields in struct BlockJob Emanuele Giuseppe Esposito
@ 2022-07-11 14:44 ` Vladimir Sementsov-Ogievskiy
2022-07-19 12:53 ` Emanuele Giuseppe Esposito
0 siblings, 1 reply; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-11 14:44 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
> The same job lock is being used also to protect some of blockjob fields.
> Categorize them just as done in job.h.
Thanks!
>
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
> ---
> include/block/blockjob.h | 17 ++++++++++++++---
> 1 file changed, 14 insertions(+), 3 deletions(-)
>
> diff --git a/include/block/blockjob.h b/include/block/blockjob.h
> index 8b65d3949d..912e10b083 100644
> --- a/include/block/blockjob.h
> +++ b/include/block/blockjob.h
> @@ -40,10 +40,16 @@ typedef struct BlockJobDriver BlockJobDriver;
> * Long-running operation on a BlockDriverState.
> */
> typedef struct BlockJob {
> - /** Data belonging to the generic Job infrastructure */
> + /**
> + * Data belonging to the generic Job infrastructure.
> + * Protected by job mutex.
> + */
> Job job;
>
> - /** Status that is published by the query-block-jobs QMP API */
> + /**
> + * Status that is published by the query-block-jobs QMP API.
> + * Protected by job mutex.
> + */
> BlockDeviceIoStatus iostatus;
>
> /** Speed that was set with @block_job_set_speed. */
> @@ -55,6 +61,8 @@ typedef struct BlockJob {
> /** Block other operations when block job is running */
> Error *blocker;
>
> + /** All notifiers are set once in block_job_create() and never modified. */
> +
> /** Called when a cancelled job is finalised. */
> Notifier finalize_cancelled_notifier;
>
> @@ -70,7 +78,10 @@ typedef struct BlockJob {
> /** Called when the job coroutine yields or terminates */
> Notifier idle_notifier;
>
> - /** BlockDriverStates that are involved in this block job */
> + /**
> + * BlockDriverStates that are involved in this block job.
> + * Always modified and read under QEMU global mutex (GLOBAL_STATE_CODE)
> + */
> GSList *nodes;
> } BlockJob;
>
Can we also add GLOBAL_STATE_CODE(); marker into child_job_can_set_aio_ctx() and child_job_set_aio_ctx() ?
Anyway:
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 18/21] blockjob: rename notifier callbacks as _locked
2022-07-06 20:15 ` [PATCH v9 18/21] blockjob: rename notifier callbacks as _locked Emanuele Giuseppe Esposito
@ 2022-07-11 14:47 ` Vladimir Sementsov-Ogievskiy
0 siblings, 0 replies; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-11 14:47 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
> They all are called with job_lock held, in job_event_*_locked()
>
> Signed-off-by: Emanuele Giuseppe Esposito<eesposit@redhat.com>
> Reviewed-by: Stefan Hajnoczi<stefanha@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 19/21] blockjob: protect iostatus field in BlockJob struct
2022-07-06 20:15 ` [PATCH v9 19/21] blockjob: protect iostatus field in BlockJob struct Emanuele Giuseppe Esposito
@ 2022-07-11 14:51 ` Vladimir Sementsov-Ogievskiy
2022-07-19 13:07 ` Emanuele Giuseppe Esposito
0 siblings, 1 reply; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-11 14:51 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
> iostatus is the only field (together with .job) that needs
> protection using the job mutex.
>
> It is set in the main loop (GLOBAL_STATE functions) but read
> in I/O code (block_job_error_action).
>
> In order to protect it, change block_job_iostatus_set_err
> to block_job_iostatus_set_err_locked(), always called under
> job lock.
>
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Seems, that (and previous) patch should go before 15.
> ---
> blockjob.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/blockjob.c b/blockjob.c
> index a2559b97a7..893c8ff08e 100644
> --- a/blockjob.c
> +++ b/blockjob.c
> @@ -367,7 +367,8 @@ BlockJobInfo *block_job_query(BlockJob *job, Error **errp)
> return block_job_query_locked(job, errp);
> }
>
> -static void block_job_iostatus_set_err(BlockJob *job, int error)
> +/* Called with job lock held */
> +static void block_job_iostatus_set_err_locked(BlockJob *job, int error)
> {
> if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
> job->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
> @@ -586,8 +587,8 @@ BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
> */
> job->job.user_paused = true;
> }
> + block_job_iostatus_set_err_locked(job, error);
> }
> - block_job_iostatus_set_err(job, error);
> }
> return action;
> }
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 00/21] job: replace AioContext lock with job_mutex
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
` (20 preceding siblings ...)
2022-07-06 20:15 ` [PATCH v9 21/21] job: " Emanuele Giuseppe Esposito
@ 2022-07-11 15:57 ` Vladimir Sementsov-Ogievskiy
2022-07-19 13:13 ` Emanuele Giuseppe Esposito
21 siblings, 1 reply; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-11 15:57 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
That seems a lot closer!
Now I'm going to vocation from tomorrow up to the end of week, so I'll return next Monday.
On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
> In this series, we want to remove the AioContext lock and instead
> use the already existent job_mutex to protect the job structures
> and list. This is part of the work to get rid of AioContext lock
> usage in favour of smaller granularity locks.
> [..]
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 09/21] jobs: use job locks also in the unit tests
2022-07-11 13:08 ` Vladimir Sementsov-Ogievskiy
@ 2022-07-19 12:00 ` Emanuele Giuseppe Esposito
2022-07-20 13:06 ` Vladimir Sementsov-Ogievskiy
0 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-19 12:00 UTC (permalink / raw)
To: Vladimir Sementsov-Ogievskiy, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
Am 11/07/2022 um 15:08 schrieb Vladimir Sementsov-Ogievskiy:
>
> That made me ask:
>
> 1. Are all tests always run in main loop? If yes, why to protect status
> reading in test_complete_in_standby() ?
>
> 2. Maybe, we don't need to protect anything here? Why to protect other
> things if we run everything in main loop?
I think it's still good example and practice to protect a function if it
needs to be protected and its name ends with _locked. It would just
confuse the reader if we don't protect it.
Emanuele
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 11/21] jobs: group together API calls under the same job lock
2022-07-11 13:26 ` Vladimir Sementsov-Ogievskiy
@ 2022-07-19 12:40 ` Emanuele Giuseppe Esposito
2022-07-20 13:10 ` Vladimir Sementsov-Ogievskiy
0 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-19 12:40 UTC (permalink / raw)
To: Vladimir Sementsov-Ogievskiy, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
Am 11/07/2022 um 15:26 schrieb Vladimir Sementsov-Ogievskiy:
>> }
>> static bool child_job_drained_poll(BdrvChild *c)
>> @@ -111,8 +113,10 @@ static bool child_job_drained_poll(BdrvChild *c)
>> /* An inactive or completed job doesn't have any pending
>> requests. Jobs
>> * with !job->busy are either already paused or have a pause
>> point after
>> * being reentered, so no job driver code will run before they
>> pause. */
>> - if (!job->busy || job_is_completed(job)) {
>> - return false;
>> + WITH_JOB_LOCK_GUARD() {
>> + if (!job->busy || job_is_completed_locked(job)) {
>> + return false;
>> + }
>> }
>
> This doesn't correspond to commit subject. I'd put such things to
> separate commit "correct use of job_mutex in blockjob.c".
>
>> /* Otherwise, assume that it isn't fully stopped yet, but
>> allow the job to
>> @@ -127,7 +131,9 @@ static bool child_job_drained_poll(BdrvChild *c)
>> static void child_job_drained_end(BdrvChild *c, int
>> *drained_end_counter)
>> {
>> BlockJob *job = c->opaque;
>> - job_resume(&job->job);
>> + WITH_JOB_LOCK_GUARD() {
>> + job_resume_locked(&job->job);
>> + }
>> }
>
> Again, don't see a reason for such change.
>
>
> [my comments relate to more similar cases in the patch]
I think you misunderstood: I aim to group API calls under the same lock.
One application of such grouping involves loops, but not only them.
Regarding the single-line WITH_JOB_LOCK_GUARD (job_next, job_pause,
job_resume and similar), I guess I will keep the not-locked function.
Emanuele
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 14/21] jobs: protect job.aio_context with BQL and job_mutex
2022-07-11 14:19 ` Vladimir Sementsov-Ogievskiy
@ 2022-07-19 12:48 ` Emanuele Giuseppe Esposito
0 siblings, 0 replies; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-19 12:48 UTC (permalink / raw)
To: Vladimir Sementsov-Ogievskiy, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
Am 11/07/2022 um 16:19 schrieb Vladimir Sementsov-Ogievskiy:
> On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
>> In order to make it thread safe, implement a "fake rwlock",
>> where we allow reads under BQL *or* job_mutex held, but
>> writes only under BQL *and* job_mutex.
>>
>> The only write we have is in child_job_set_aio_ctx
>
> also in job_create of course, but it seems safe anyway
>
>> , which always
>> happens under drain (so the job is paused).
>> For this reason, introduce job_set_aio_context and make sure that
>> the context is set under BQL, job_mutex and drain.
>> Also make sure all other places where the aiocontext is read
>> are protected.
>>
>> Note: at this stage, job_{lock/unlock} and job lock guard macros
>> are *nop*.
>>
>> Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
>> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
>> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
>> ---
>> block/replication.c | 6 ++++--
>> blockjob.c | 3 ++-
>> include/qemu/job.h | 19 ++++++++++++++++++-
>> job.c | 12 ++++++++++++
>> 4 files changed, 36 insertions(+), 4 deletions(-)
>>
>> diff --git a/block/replication.c b/block/replication.c
>> index 55c8f894aa..2189863df1 100644
>> --- a/block/replication.c
>> +++ b/block/replication.c
>> @@ -148,8 +148,10 @@ static void replication_close(BlockDriverState *bs)
>> }
>> if (s->stage == BLOCK_REPLICATION_FAILOVER) {
>> commit_job = &s->commit_job->job;
>> - assert(commit_job->aio_context ==
>> qemu_get_current_aio_context());
>> - job_cancel_sync(commit_job, false);
>> + WITH_JOB_LOCK_GUARD() {
>> + assert(commit_job->aio_context ==
>> qemu_get_current_aio_context());
>> + job_cancel_sync_locked(commit_job, false);
>> + }
>> }
>> if (s->mode == REPLICATION_MODE_SECONDARY) {
>> diff --git a/blockjob.c b/blockjob.c
>> index bce05a9096..0d120ed126 100644
>> --- a/blockjob.c
>> +++ b/blockjob.c
>> @@ -166,12 +166,13 @@ static void child_job_set_aio_ctx(BdrvChild *c,
>> AioContext *ctx,
>> bdrv_set_aio_context_ignore(sibling->bs, ctx, ignore);
>> }
>> - job->job.aio_context = ctx;
>> + job_set_aio_context(&job->job, ctx);
>> }
>> static AioContext *child_job_get_parent_aio_context(BdrvChild *c)
>> {
>> BlockJob *job = c->opaque;
>> + assert(qemu_in_main_thread());
>> return job->job.aio_context;
>> }
>> diff --git a/include/qemu/job.h b/include/qemu/job.h
>> index 5709e8d4a8..c144aabefc 100644
>> --- a/include/qemu/job.h
>> +++ b/include/qemu/job.h
>> @@ -77,7 +77,12 @@ typedef struct Job {
>> /** Protected by AioContext lock */
>> - /** AioContext to run the job coroutine in */
>> + /**
>> + * AioContext to run the job coroutine in.
>> + * This field can be read when holding either the BQL (so we are in
>> + * the main loop) or the job_mutex.
>> + * It can be only written when we hold *both* BQL and job_mutex.
>> + */
>> AioContext *aio_context;
>> /** Reference count of the block job */
>> @@ -741,4 +746,16 @@ int job_finish_sync(Job *job, void (*finish)(Job
>> *, Error **errp),
>> int job_finish_sync_locked(Job *job, void (*finish)(Job *, Error
>> **errp),
>> Error **errp);
>> +/**
>> + * Sets the @job->aio_context.
>> + * Called with job_mutex *not* held.
>> + *
>> + * This function must run in the main thread to protect against
>> + * concurrent read in job_finish_sync_locked(),
>> + * takes the job_mutex lock to protect against the read in
>> + * job_do_yield_locked(), and must be called when the coroutine
>> + * is quiescent.
>> + */
>> +void job_set_aio_context(Job *job, AioContext *ctx);
>> +
>> #endif
>> diff --git a/job.c b/job.c
>> index 405f39566b..66cae82593 100644
>> --- a/job.c
>> +++ b/job.c
>> @@ -394,6 +394,17 @@ Job *job_get(const char *id)
>> return job_get_locked(id);
>> }
>> +void job_set_aio_context(Job *job, AioContext *ctx)
>> +{
>> + /* protect against read in job_finish_sync_locked and job_start */
>> + assert(qemu_in_main_thread());
>> + /* protect against read in job_do_yield_locked */
>> + JOB_LOCK_GUARD();
>> + /* ensure the coroutine is quiescent while the AioContext is
>> changed */
>> + assert(job->pause_count > 0);
>> + job->aio_context = ctx;
>> +}
>> +
>> /* Called with job_mutex *not* held. */
>> static void job_sleep_timer_cb(void *opaque)
>> {
>> @@ -1380,6 +1391,7 @@ int job_finish_sync_locked(Job *job,
>> {
>> Error *local_err = NULL;
>> int ret;
>> + assert(qemu_in_main_thread());
>> job_ref_locked(job);
>>
>
>
> Missed update of block_job_add_bdrv(), block_job_get_aio_context().
> Should they have an assertion too?
>
> Also some occurences in test, but that doesn't seem significant.
>
Both have GLOBAL_STATE_CODE.
Emanuele
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 15/21] job.c: enable job lock/unlock and remove Aiocontext locks
2022-07-11 14:33 ` Vladimir Sementsov-Ogievskiy
@ 2022-07-19 12:51 ` Emanuele Giuseppe Esposito
0 siblings, 0 replies; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-19 12:51 UTC (permalink / raw)
To: Vladimir Sementsov-Ogievskiy, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
Am 11/07/2022 um 16:33 schrieb Vladimir Sementsov-Ogievskiy:
> On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
>> Change the job_{lock/unlock} and macros to use job_mutex.
>>
>> Now that they are not nop anymore, remove the aiocontext
>> to avoid deadlocks.
>>
>> Therefore:
>> - when possible, remove completely the aiocontext lock/unlock pair
>> - if it is used by some other function too, reduce the locking
>> section as much as possible, leaving the job API outside.
>> - change AIO_WAIT_WHILE in AIO_WAIT_WHILE_UNLOCKED, since we
>> are not using the aiocontext lock anymore
>>
>> There is only one JobDriver callback, ->free() that assumes that
>> the aiocontext lock is held (because it calls bdrv_unref), so for
>> now keep that under aiocontext lock.
>>
>> Also remove real_job_{lock/unlock}, as they are replaced by the
>> public functions.
>>
>> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
>> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
>> ---
>
> [..]
>
>> static int job_finalize_single_locked(Job *job)
>> {
>> int job_ret;
>> + AioContext *ctx = job->aio_context;
>> assert(job_is_completed_locked(job));
>> /* Ensure abort is called for late-transactional failures */
>> job_update_rc_locked(job);
>> + aio_context_acquire(ctx);
>
> so here we acquire aio-context under job_mutex lock? Wouldn't that
> dead-lock?
I'll change it so that job_commit/clean/abort do not take the lock, but
just the aiocontext.
Emanuele
>
>> +
>> if (!job->ret) {
>> job_commit_locked(job);
>> } else {
>
>
>
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 17/21] blockjob.h: categorize fields in struct BlockJob
2022-07-11 14:44 ` Vladimir Sementsov-Ogievskiy
@ 2022-07-19 12:53 ` Emanuele Giuseppe Esposito
0 siblings, 0 replies; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-19 12:53 UTC (permalink / raw)
To: Vladimir Sementsov-Ogievskiy, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
Am 11/07/2022 um 16:44 schrieb Vladimir Sementsov-Ogievskiy:
> On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
>> The same job lock is being used also to protect some of blockjob fields.
>> Categorize them just as done in job.h.
>
> Thanks!
>
>>
>> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
>> ---
>> include/block/blockjob.h | 17 ++++++++++++++---
>> 1 file changed, 14 insertions(+), 3 deletions(-)
>>
>> diff --git a/include/block/blockjob.h b/include/block/blockjob.h
>> index 8b65d3949d..912e10b083 100644
>> --- a/include/block/blockjob.h
>> +++ b/include/block/blockjob.h
>> @@ -40,10 +40,16 @@ typedef struct BlockJobDriver BlockJobDriver;
>> * Long-running operation on a BlockDriverState.
>> */
>> typedef struct BlockJob {
>> - /** Data belonging to the generic Job infrastructure */
>> + /**
>> + * Data belonging to the generic Job infrastructure.
>> + * Protected by job mutex.
>> + */
>> Job job;
>> - /** Status that is published by the query-block-jobs QMP API */
>> + /**
>> + * Status that is published by the query-block-jobs QMP API.
>> + * Protected by job mutex.
>> + */
>> BlockDeviceIoStatus iostatus;
>> /** Speed that was set with @block_job_set_speed. */
>> @@ -55,6 +61,8 @@ typedef struct BlockJob {
>> /** Block other operations when block job is running */
>> Error *blocker;
>> + /** All notifiers are set once in block_job_create() and never
>> modified. */
>> +
>> /** Called when a cancelled job is finalised. */
>> Notifier finalize_cancelled_notifier;
>> @@ -70,7 +78,10 @@ typedef struct BlockJob {
>> /** Called when the job coroutine yields or terminates */
>> Notifier idle_notifier;
>> - /** BlockDriverStates that are involved in this block job */
>> + /**
>> + * BlockDriverStates that are involved in this block job.
>> + * Always modified and read under QEMU global mutex
>> (GLOBAL_STATE_CODE)
>> + */
>> GSList *nodes;
>> } BlockJob;
>>
>
> Can we also add GLOBAL_STATE_CODE(); marker into
> child_job_can_set_aio_ctx() and child_job_set_aio_ctx() ?
Usually for callbacks I feel redundant to add assertions there. It is
enough to look at their definition in the header to understand which
category are they in.
Emanuele
>
> Anyway:
>
> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
>
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 19/21] blockjob: protect iostatus field in BlockJob struct
2022-07-11 14:51 ` Vladimir Sementsov-Ogievskiy
@ 2022-07-19 13:07 ` Emanuele Giuseppe Esposito
2022-07-20 13:15 ` Vladimir Sementsov-Ogievskiy
0 siblings, 1 reply; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-19 13:07 UTC (permalink / raw)
To: Vladimir Sementsov-Ogievskiy, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
Am 11/07/2022 um 16:51 schrieb Vladimir Sementsov-Ogievskiy:
> On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
>> iostatus is the only field (together with .job) that needs
>> protection using the job mutex.
>>
>> It is set in the main loop (GLOBAL_STATE functions) but read
>> in I/O code (block_job_error_action).
>>
>> In order to protect it, change block_job_iostatus_set_err
>> to block_job_iostatus_set_err_locked(), always called under
>> job lock.
>>
>> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
>
> Seems, that (and previous) patch should go before 15.
Why?
>
>> ---
>> blockjob.c | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/blockjob.c b/blockjob.c
>> index a2559b97a7..893c8ff08e 100644
>> --- a/blockjob.c
>> +++ b/blockjob.c
>> @@ -367,7 +367,8 @@ BlockJobInfo *block_job_query(BlockJob *job, Error
>> **errp)
>> return block_job_query_locked(job, errp);
>> }
>> -static void block_job_iostatus_set_err(BlockJob *job, int error)
>> +/* Called with job lock held */
>> +static void block_job_iostatus_set_err_locked(BlockJob *job, int error)
>> {
>> if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
>> job->iostatus = error == ENOSPC ?
>> BLOCK_DEVICE_IO_STATUS_NOSPACE :
>> @@ -586,8 +587,8 @@ BlockErrorAction block_job_error_action(BlockJob
>> *job, BlockdevOnError on_err,
>> */
>> job->job.user_paused = true;
>> }
>> + block_job_iostatus_set_err_locked(job, error);
>> }
>> - block_job_iostatus_set_err(job, error);
>> }
>> return action;
>> }
>
>
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 00/21] job: replace AioContext lock with job_mutex
2022-07-11 15:57 ` [PATCH v9 00/21] job: replace AioContext lock with job_mutex Vladimir Sementsov-Ogievskiy
@ 2022-07-19 13:13 ` Emanuele Giuseppe Esposito
0 siblings, 0 replies; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-19 13:13 UTC (permalink / raw)
To: Vladimir Sementsov-Ogievskiy, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
Am 11/07/2022 um 17:57 schrieb Vladimir Sementsov-Ogievskiy:
> That seems a lot closer!
>
> Now I'm going to vocation from tomorrow up to the end of week, so I'll
> return next Monday.
>
>
> On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
>> In this series, we want to remove the AioContext lock and instead
>> use the already existent job_mutex to protect the job structures
>> and list. This is part of the work to get rid of AioContext lock
>> usage in favour of smaller granularity locks.
>> [..]
>
>
Thank you for the review! Assume that all suggestion I did not reply
will be applied.
Apart from patch 12 and 19, all other patches should be reviewed :)
Emanuele
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 09/21] jobs: use job locks also in the unit tests
2022-07-19 12:00 ` Emanuele Giuseppe Esposito
@ 2022-07-20 13:06 ` Vladimir Sementsov-Ogievskiy
2022-07-20 14:22 ` Emanuele Giuseppe Esposito
0 siblings, 1 reply; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-20 13:06 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/19/22 15:00, Emanuele Giuseppe Esposito wrote:
>
>
> Am 11/07/2022 um 15:08 schrieb Vladimir Sementsov-Ogievskiy:
>>
>> That made me ask:
>>
>> 1. Are all tests always run in main loop? If yes, why to protect status
>> reading in test_complete_in_standby() ?
>>
>> 2. Maybe, we don't need to protect anything here? Why to protect other
>> things if we run everything in main loop?
>
> I think it's still good example and practice to protect a function if it
> needs to be protected and its name ends with _locked. It would just
> confuse the reader if we don't protect it.
>
Agree. But still, I think we should be consistent in such decisions. If you don't want to protect job->status in tests, then you shouldn't protect it in test_complete_in_standby() as well, just to not confuse someone who read the code.
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 11/21] jobs: group together API calls under the same job lock
2022-07-19 12:40 ` Emanuele Giuseppe Esposito
@ 2022-07-20 13:10 ` Vladimir Sementsov-Ogievskiy
0 siblings, 0 replies; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-20 13:10 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/19/22 15:40, Emanuele Giuseppe Esposito wrote:
>
>
> Am 11/07/2022 um 15:26 schrieb Vladimir Sementsov-Ogievskiy:
>>> }
>>> static bool child_job_drained_poll(BdrvChild *c)
>>> @@ -111,8 +113,10 @@ static bool child_job_drained_poll(BdrvChild *c)
>>> /* An inactive or completed job doesn't have any pending
>>> requests. Jobs
>>> * with !job->busy are either already paused or have a pause
>>> point after
>>> * being reentered, so no job driver code will run before they
>>> pause. */
>>> - if (!job->busy || job_is_completed(job)) {
>>> - return false;
>>> + WITH_JOB_LOCK_GUARD() {
>>> + if (!job->busy || job_is_completed_locked(job)) {
>>> + return false;
>>> + }
>>> }
>>
>> This doesn't correspond to commit subject. I'd put such things to
>> separate commit "correct use of job_mutex in blockjob.c".
>>
>>> /* Otherwise, assume that it isn't fully stopped yet, but
>>> allow the job to
>>> @@ -127,7 +131,9 @@ static bool child_job_drained_poll(BdrvChild *c)
>>> static void child_job_drained_end(BdrvChild *c, int
>>> *drained_end_counter)
>>> {
>>> BlockJob *job = c->opaque;
>>> - job_resume(&job->job);
>>> + WITH_JOB_LOCK_GUARD() {
>>> + job_resume_locked(&job->job);
>>> + }
>>> }
>>
>> Again, don't see a reason for such change.
>>
>>
>> [my comments relate to more similar cases in the patch]
>
> I think you misunderstood: I aim to group API calls under the same lock.
> One application of such grouping involves loops, but not only them.
I mean that pre-patch job->busy is accessed without any lock at all. So we not just group correctly locked calls into one critical section, we also fix direct field accesses to be under lock.
>
> Regarding the single-line WITH_JOB_LOCK_GUARD (job_next, job_pause,
> job_resume and similar), I guess I will keep the not-locked function.
>
> Emanuele
>
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 19/21] blockjob: protect iostatus field in BlockJob struct
2022-07-19 13:07 ` Emanuele Giuseppe Esposito
@ 2022-07-20 13:15 ` Vladimir Sementsov-Ogievskiy
2022-07-20 14:06 ` Emanuele Giuseppe Esposito
0 siblings, 1 reply; 53+ messages in thread
From: Vladimir Sementsov-Ogievskiy @ 2022-07-20 13:15 UTC (permalink / raw)
To: Emanuele Giuseppe Esposito, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
On 7/19/22 16:07, Emanuele Giuseppe Esposito wrote:
>
>
> Am 11/07/2022 um 16:51 schrieb Vladimir Sementsov-Ogievskiy:
>> On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
>>> iostatus is the only field (together with .job) that needs
>>> protection using the job mutex.
>>>
>>> It is set in the main loop (GLOBAL_STATE functions) but read
>>> in I/O code (block_job_error_action).
>>>
>>> In order to protect it, change block_job_iostatus_set_err
>>> to block_job_iostatus_set_err_locked(), always called under
>>> job lock.
>>>
>>> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
>>
>> Seems, that (and previous) patch should go before 15.
>
> Why?
As I understand, before patch 15 everything was protected by aio-context lock. After patch 15, this becomes a bug, which we fix now. If we do it before patch 15, we never introduce the bug.. Or what I miss?
>
>>
>>> ---
>>> blockjob.c | 5 +++--
>>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/blockjob.c b/blockjob.c
>>> index a2559b97a7..893c8ff08e 100644
>>> --- a/blockjob.c
>>> +++ b/blockjob.c
>>> @@ -367,7 +367,8 @@ BlockJobInfo *block_job_query(BlockJob *job, Error
>>> **errp)
>>> return block_job_query_locked(job, errp);
>>> }
>>> -static void block_job_iostatus_set_err(BlockJob *job, int error)
>>> +/* Called with job lock held */
>>> +static void block_job_iostatus_set_err_locked(BlockJob *job, int error)
>>> {
>>> if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
>>> job->iostatus = error == ENOSPC ?
>>> BLOCK_DEVICE_IO_STATUS_NOSPACE :
>>> @@ -586,8 +587,8 @@ BlockErrorAction block_job_error_action(BlockJob
>>> *job, BlockdevOnError on_err,
>>> */
>>> job->job.user_paused = true;
>>> }
>>> + block_job_iostatus_set_err_locked(job, error);
>>> }
>>> - block_job_iostatus_set_err(job, error);
>>> }
>>> return action;
>>> }
>>
>>
>
--
Best regards,
Vladimir
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 19/21] blockjob: protect iostatus field in BlockJob struct
2022-07-20 13:15 ` Vladimir Sementsov-Ogievskiy
@ 2022-07-20 14:06 ` Emanuele Giuseppe Esposito
0 siblings, 0 replies; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-20 14:06 UTC (permalink / raw)
To: Vladimir Sementsov-Ogievskiy, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
Am 20/07/2022 um 15:15 schrieb Vladimir Sementsov-Ogievskiy:
> On 7/19/22 16:07, Emanuele Giuseppe Esposito wrote:
>>
>>
>> Am 11/07/2022 um 16:51 schrieb Vladimir Sementsov-Ogievskiy:
>>> On 7/6/22 23:15, Emanuele Giuseppe Esposito wrote:
>>>> iostatus is the only field (together with .job) that needs
>>>> protection using the job mutex.
>>>>
>>>> It is set in the main loop (GLOBAL_STATE functions) but read
>>>> in I/O code (block_job_error_action).
>>>>
>>>> In order to protect it, change block_job_iostatus_set_err
>>>> to block_job_iostatus_set_err_locked(), always called under
>>>> job lock.
>>>>
>>>> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
>>>
>>> Seems, that (and previous) patch should go before 15.
>>
>> Why?
>
> As I understand, before patch 15 everything was protected by aio-context
> lock. After patch 15, this becomes a bug, which we fix now. If we do it
> before patch 15, we never introduce the bug.. Or what I miss?
Makes sense.
Emanuele
>
>>
>>>
>>>> ---
>>>> blockjob.c | 5 +++--
>>>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/blockjob.c b/blockjob.c
>>>> index a2559b97a7..893c8ff08e 100644
>>>> --- a/blockjob.c
>>>> +++ b/blockjob.c
>>>> @@ -367,7 +367,8 @@ BlockJobInfo *block_job_query(BlockJob *job, Error
>>>> **errp)
>>>> return block_job_query_locked(job, errp);
>>>> }
>>>> -static void block_job_iostatus_set_err(BlockJob *job, int error)
>>>> +/* Called with job lock held */
>>>> +static void block_job_iostatus_set_err_locked(BlockJob *job, int
>>>> error)
>>>> {
>>>> if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
>>>> job->iostatus = error == ENOSPC ?
>>>> BLOCK_DEVICE_IO_STATUS_NOSPACE :
>>>> @@ -586,8 +587,8 @@ BlockErrorAction block_job_error_action(BlockJob
>>>> *job, BlockdevOnError on_err,
>>>> */
>>>> job->job.user_paused = true;
>>>> }
>>>> + block_job_iostatus_set_err_locked(job, error);
>>>> }
>>>> - block_job_iostatus_set_err(job, error);
>>>> }
>>>> return action;
>>>> }
>>>
>>>
>>
>
>
^ permalink raw reply [flat|nested] 53+ messages in thread
* Re: [PATCH v9 09/21] jobs: use job locks also in the unit tests
2022-07-20 13:06 ` Vladimir Sementsov-Ogievskiy
@ 2022-07-20 14:22 ` Emanuele Giuseppe Esposito
0 siblings, 0 replies; 53+ messages in thread
From: Emanuele Giuseppe Esposito @ 2022-07-20 14:22 UTC (permalink / raw)
To: Vladimir Sementsov-Ogievskiy, qemu-block
Cc: Kevin Wolf, Hanna Reitz, Paolo Bonzini, John Snow,
Vladimir Sementsov-Ogievskiy, Wen Congyang, Xie Changlong,
Markus Armbruster, Stefan Hajnoczi, Fam Zheng, qemu-devel
Am 20/07/2022 um 15:06 schrieb Vladimir Sementsov-Ogievskiy:
> On 7/19/22 15:00, Emanuele Giuseppe Esposito wrote:
>>
>>
>> Am 11/07/2022 um 15:08 schrieb Vladimir Sementsov-Ogievskiy:
>>>
>>> That made me ask:
>>>
>>> 1. Are all tests always run in main loop? If yes, why to protect status
>>> reading in test_complete_in_standby() ?
>>>
>>> 2. Maybe, we don't need to protect anything here? Why to protect other
>>> things if we run everything in main loop?
>>
>> I think it's still good example and practice to protect a function if it
>> needs to be protected and its name ends with _locked. It would just
>> confuse the reader if we don't protect it.
>>
>
> Agree. But still, I think we should be consistent in such decisions. If
> you don't want to protect job->status in tests, then you shouldn't
> protect it in test_complete_in_standby() as well, just to not confuse
> someone who read the code.
>
>
Ok, I will protect job->status in those tests too.
Emanuele
^ permalink raw reply [flat|nested] 53+ messages in thread
end of thread, other threads:[~2022-07-20 14:25 UTC | newest]
Thread overview: 53+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-07-06 20:15 [PATCH v9 00/21] job: replace AioContext lock with job_mutex Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 01/21] job.c: make job_mutex and job_lock/unlock() public Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 02/21] job.h: categorize fields in struct Job Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 03/21] job.c: API functions not used outside should be static Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 04/21] aio-wait.h: introduce AIO_WAIT_WHILE_UNLOCKED Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 05/21] job.c: add job_lock/unlock while keeping job.h intact Emanuele Giuseppe Esposito
2022-07-08 19:25 ` Vladimir Sementsov-Ogievskiy
2022-07-11 7:30 ` Emanuele Giuseppe Esposito
2022-07-11 10:40 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 06/21] job: move and update comments from blockjob.c Emanuele Giuseppe Esposito
2022-07-11 8:56 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 07/21] blockjob: introduce block_job _locked() APIs Emanuele Giuseppe Esposito
2022-07-11 12:04 ` Vladimir Sementsov-Ogievskiy
2022-07-11 12:24 ` Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 08/21] jobs: add job lock in find_* functions Emanuele Giuseppe Esposito
2022-07-11 12:20 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 09/21] jobs: use job locks also in the unit tests Emanuele Giuseppe Esposito
2022-07-11 13:08 ` Vladimir Sementsov-Ogievskiy
2022-07-19 12:00 ` Emanuele Giuseppe Esposito
2022-07-20 13:06 ` Vladimir Sementsov-Ogievskiy
2022-07-20 14:22 ` Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 10/21] block/mirror.c: use of job helpers in drivers to avoid TOC/TOU Emanuele Giuseppe Esposito
2022-07-11 13:15 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 11/21] jobs: group together API calls under the same job lock Emanuele Giuseppe Esposito
2022-07-11 13:26 ` Vladimir Sementsov-Ogievskiy
2022-07-19 12:40 ` Emanuele Giuseppe Esposito
2022-07-20 13:10 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 12/21] commit and mirror: create new nodes using bdrv_get_aio_context, and not the job aiocontext Emanuele Giuseppe Esposito
2022-07-11 13:32 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 13/21] job: detect change of aiocontext within job coroutine Emanuele Giuseppe Esposito
2022-07-11 13:59 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 14/21] jobs: protect job.aio_context with BQL and job_mutex Emanuele Giuseppe Esposito
2022-07-11 14:19 ` Vladimir Sementsov-Ogievskiy
2022-07-19 12:48 ` Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 15/21] job.c: enable job lock/unlock and remove Aiocontext locks Emanuele Giuseppe Esposito
2022-07-11 14:33 ` Vladimir Sementsov-Ogievskiy
2022-07-19 12:51 ` Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 16/21] block_job_query: remove atomic read Emanuele Giuseppe Esposito
2022-07-11 14:37 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 17/21] blockjob.h: categorize fields in struct BlockJob Emanuele Giuseppe Esposito
2022-07-11 14:44 ` Vladimir Sementsov-Ogievskiy
2022-07-19 12:53 ` Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 18/21] blockjob: rename notifier callbacks as _locked Emanuele Giuseppe Esposito
2022-07-11 14:47 ` Vladimir Sementsov-Ogievskiy
2022-07-06 20:15 ` [PATCH v9 19/21] blockjob: protect iostatus field in BlockJob struct Emanuele Giuseppe Esposito
2022-07-11 14:51 ` Vladimir Sementsov-Ogievskiy
2022-07-19 13:07 ` Emanuele Giuseppe Esposito
2022-07-20 13:15 ` Vladimir Sementsov-Ogievskiy
2022-07-20 14:06 ` Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 20/21] blockjob: remove unused functions Emanuele Giuseppe Esposito
2022-07-06 20:15 ` [PATCH v9 21/21] job: " Emanuele Giuseppe Esposito
2022-07-11 15:57 ` [PATCH v9 00/21] job: replace AioContext lock with job_mutex Vladimir Sementsov-Ogievskiy
2022-07-19 13:13 ` Emanuele Giuseppe Esposito
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