* [PATCH 0/2] locking/lockdep: A few cleanups
@ 2018-12-28 5:01 Frederic Weisbecker
2018-12-28 5:02 ` [PATCH 1/2] locking/lockdep: Simplify mark_held_locks() Frederic Weisbecker
2018-12-28 5:02 ` [PATCH 2/2] locking/lockdep: Provide enum lock_usage_bit mask names Frederic Weisbecker
0 siblings, 2 replies; 5+ messages in thread
From: Frederic Weisbecker @ 2018-12-28 5:01 UTC (permalink / raw)
To: LKML; +Cc: Frederic Weisbecker, Ingo Molnar, Peter Zijlstra
Just a few simplification and code cleanup.
Frederic Weisbecker (2):
locking/lockdep: Simplify mark_held_locks()
locking/lockdep: Provide enum lock_usage_bit mask names
kernel/locking/lockdep.c | 54 +++++++++++++-------------------------
kernel/locking/lockdep_internals.h | 4 +++
2 files changed, 22 insertions(+), 36 deletions(-)
--
2.7.4
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 1/2] locking/lockdep: Simplify mark_held_locks()
2018-12-28 5:01 [PATCH 0/2] locking/lockdep: A few cleanups Frederic Weisbecker
@ 2018-12-28 5:02 ` Frederic Weisbecker
2019-01-21 11:31 ` [tip:locking/core] " tip-bot for Frederic Weisbecker
2018-12-28 5:02 ` [PATCH 2/2] locking/lockdep: Provide enum lock_usage_bit mask names Frederic Weisbecker
1 sibling, 1 reply; 5+ messages in thread
From: Frederic Weisbecker @ 2018-12-28 5:02 UTC (permalink / raw)
To: LKML; +Cc: Frederic Weisbecker, Ingo Molnar, Peter Zijlstra
The enum mark_type appears a bit artificial here. We can directly pass
the base enum lock_usage_bit value to mark_held_locks(). All we need
then is to add the read index for each lock if necessary. It makes the
code clearer.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
---
kernel/locking/lockdep.c | 23 ++++++++---------------
1 file changed, 8 insertions(+), 15 deletions(-)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 5c837a5..118a554 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2709,35 +2709,28 @@ mark_lock_irq(struct task_struct *curr, struct held_lock *this,
return 1;
}
-enum mark_type {
-#define LOCKDEP_STATE(__STATE) __STATE,
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
-};
-
/*
* Mark all held locks with a usage bit:
*/
static int
-mark_held_locks(struct task_struct *curr, enum mark_type mark)
+mark_held_locks(struct task_struct *curr, enum lock_usage_bit base_bit)
{
- enum lock_usage_bit usage_bit;
struct held_lock *hlock;
int i;
for (i = 0; i < curr->lockdep_depth; i++) {
+ enum lock_usage_bit hlock_bit = base_bit;
hlock = curr->held_locks + i;
- usage_bit = 2 + (mark << 2); /* ENABLED */
if (hlock->read)
- usage_bit += 1; /* READ */
+ hlock_bit += 1; /* READ */
- BUG_ON(usage_bit >= LOCK_USAGE_STATES);
+ BUG_ON(hlock_bit >= LOCK_USAGE_STATES);
if (!hlock->check)
continue;
- if (!mark_lock(curr, hlock, usage_bit))
+ if (!mark_lock(curr, hlock, hlock_bit))
return 0;
}
@@ -2758,7 +2751,7 @@ static void __trace_hardirqs_on_caller(unsigned long ip)
* We are going to turn hardirqs on, so set the
* usage bit for all held locks:
*/
- if (!mark_held_locks(curr, HARDIRQ))
+ if (!mark_held_locks(curr, LOCK_ENABLED_HARDIRQ))
return;
/*
* If we have softirqs enabled, then set the usage
@@ -2766,7 +2759,7 @@ static void __trace_hardirqs_on_caller(unsigned long ip)
* this bit from being set before)
*/
if (curr->softirqs_enabled)
- if (!mark_held_locks(curr, SOFTIRQ))
+ if (!mark_held_locks(curr, LOCK_ENABLED_SOFTIRQ))
return;
curr->hardirq_enable_ip = ip;
@@ -2880,7 +2873,7 @@ void trace_softirqs_on(unsigned long ip)
* enabled too:
*/
if (curr->hardirqs_enabled)
- mark_held_locks(curr, SOFTIRQ);
+ mark_held_locks(curr, LOCK_ENABLED_SOFTIRQ);
current->lockdep_recursion = 0;
}
--
2.7.4
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 2/2] locking/lockdep: Provide enum lock_usage_bit mask names
2018-12-28 5:01 [PATCH 0/2] locking/lockdep: A few cleanups Frederic Weisbecker
2018-12-28 5:02 ` [PATCH 1/2] locking/lockdep: Simplify mark_held_locks() Frederic Weisbecker
@ 2018-12-28 5:02 ` Frederic Weisbecker
2019-01-21 11:31 ` [tip:locking/core] " tip-bot for Frederic Weisbecker
1 sibling, 1 reply; 5+ messages in thread
From: Frederic Weisbecker @ 2018-12-28 5:02 UTC (permalink / raw)
To: LKML; +Cc: Frederic Weisbecker, Ingo Molnar, Peter Zijlstra
It makes the code more self-explanatory and tells throughout the code
what magic number refers to:
* state (Hardirq/Softirq)
* direction (used in or enabled above state)
* read or write
We can even remove some comments that were compensating for the lack of
those constant names.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
---
kernel/locking/lockdep.c | 33 +++++++++++----------------------
kernel/locking/lockdep_internals.h | 4 ++++
2 files changed, 15 insertions(+), 22 deletions(-)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 118a554..115d43e 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -1624,29 +1624,18 @@ static const char *state_rnames[] = {
static inline const char *state_name(enum lock_usage_bit bit)
{
- return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2];
+ return (bit & LOCK_USAGE_READ_MASK) ? state_rnames[bit >> 2] : state_names[bit >> 2];
}
static int exclusive_bit(int new_bit)
{
- /*
- * USED_IN
- * USED_IN_READ
- * ENABLED
- * ENABLED_READ
- *
- * bit 0 - write/read
- * bit 1 - used_in/enabled
- * bit 2+ state
- */
-
- int state = new_bit & ~3;
- int dir = new_bit & 2;
+ int state = new_bit & LOCK_USAGE_STATE_MASK;
+ int dir = new_bit & LOCK_USAGE_DIR_MASK;
/*
* keep state, bit flip the direction and strip read.
*/
- return state | (dir ^ 2);
+ return state | (dir ^ LOCK_USAGE_DIR_MASK);
}
static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
@@ -2662,8 +2651,8 @@ mark_lock_irq(struct task_struct *curr, struct held_lock *this,
enum lock_usage_bit new_bit)
{
int excl_bit = exclusive_bit(new_bit);
- int read = new_bit & 1;
- int dir = new_bit & 2;
+ int read = new_bit & LOCK_USAGE_READ_MASK;
+ int dir = new_bit & LOCK_USAGE_DIR_MASK;
/*
* mark USED_IN has to look forwards -- to ensure no dependency
@@ -2687,19 +2676,19 @@ mark_lock_irq(struct task_struct *curr, struct held_lock *this,
* states.
*/
if ((!read || !dir || STRICT_READ_CHECKS) &&
- !usage(curr, this, excl_bit, state_name(new_bit & ~1)))
+ !usage(curr, this, excl_bit, state_name(new_bit & ~LOCK_USAGE_READ_MASK)))
return 0;
/*
* Check for read in write conflicts
*/
if (!read) {
- if (!valid_state(curr, this, new_bit, excl_bit + 1))
+ if (!valid_state(curr, this, new_bit, excl_bit + LOCK_USAGE_READ_MASK))
return 0;
if (STRICT_READ_CHECKS &&
- !usage(curr, this, excl_bit + 1,
- state_name(new_bit + 1)))
+ !usage(curr, this, excl_bit + LOCK_USAGE_READ_MASK,
+ state_name(new_bit + LOCK_USAGE_READ_MASK)))
return 0;
}
@@ -2723,7 +2712,7 @@ mark_held_locks(struct task_struct *curr, enum lock_usage_bit base_bit)
hlock = curr->held_locks + i;
if (hlock->read)
- hlock_bit += 1; /* READ */
+ hlock_bit += LOCK_USAGE_READ_MASK;
BUG_ON(hlock_bit >= LOCK_USAGE_STATES);
diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h
index 88c847a..2ebb9d0 100644
--- a/kernel/locking/lockdep_internals.h
+++ b/kernel/locking/lockdep_internals.h
@@ -22,6 +22,10 @@ enum lock_usage_bit {
LOCK_USAGE_STATES
};
+#define LOCK_USAGE_READ_MASK 1
+#define LOCK_USAGE_DIR_MASK 2
+#define LOCK_USAGE_STATE_MASK (~(LOCK_USAGE_READ_MASK | LOCK_USAGE_DIR_MASK))
+
/*
* Usage-state bitmasks:
*/
--
2.7.4
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [tip:locking/core] locking/lockdep: Simplify mark_held_locks()
2018-12-28 5:02 ` [PATCH 1/2] locking/lockdep: Simplify mark_held_locks() Frederic Weisbecker
@ 2019-01-21 11:31 ` tip-bot for Frederic Weisbecker
0 siblings, 0 replies; 5+ messages in thread
From: tip-bot for Frederic Weisbecker @ 2019-01-21 11:31 UTC (permalink / raw)
To: linux-tip-commits
Cc: peterz, frederic, akpm, torvalds, hpa, linux-kernel, tglx,
will.deacon, mingo, paulmck
Commit-ID: 436a49ae7b693161c4fdf98b575ef16243dc2dfa
Gitweb: https://git.kernel.org/tip/436a49ae7b693161c4fdf98b575ef16243dc2dfa
Author: Frederic Weisbecker <frederic@kernel.org>
AuthorDate: Fri, 28 Dec 2018 06:02:00 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 21 Jan 2019 11:18:54 +0100
locking/lockdep: Simplify mark_held_locks()
The enum mark_type appears a bit artificial here. We can directly pass
the base enum lock_usage_bit value to mark_held_locks(). All we need
then is to add the read index for each lock if necessary. It makes the
code clearer.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: https://lkml.kernel.org/r/1545973321-24422-2-git-send-email-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/locking/lockdep.c | 23 ++++++++---------------
1 file changed, 8 insertions(+), 15 deletions(-)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index e805fe3bf87f..1dcd8341e35b 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2709,35 +2709,28 @@ mark_lock_irq(struct task_struct *curr, struct held_lock *this,
return 1;
}
-enum mark_type {
-#define LOCKDEP_STATE(__STATE) __STATE,
-#include "lockdep_states.h"
-#undef LOCKDEP_STATE
-};
-
/*
* Mark all held locks with a usage bit:
*/
static int
-mark_held_locks(struct task_struct *curr, enum mark_type mark)
+mark_held_locks(struct task_struct *curr, enum lock_usage_bit base_bit)
{
- enum lock_usage_bit usage_bit;
struct held_lock *hlock;
int i;
for (i = 0; i < curr->lockdep_depth; i++) {
+ enum lock_usage_bit hlock_bit = base_bit;
hlock = curr->held_locks + i;
- usage_bit = 2 + (mark << 2); /* ENABLED */
if (hlock->read)
- usage_bit += 1; /* READ */
+ hlock_bit += 1; /* READ */
- BUG_ON(usage_bit >= LOCK_USAGE_STATES);
+ BUG_ON(hlock_bit >= LOCK_USAGE_STATES);
if (!hlock->check)
continue;
- if (!mark_lock(curr, hlock, usage_bit))
+ if (!mark_lock(curr, hlock, hlock_bit))
return 0;
}
@@ -2758,7 +2751,7 @@ static void __trace_hardirqs_on_caller(unsigned long ip)
* We are going to turn hardirqs on, so set the
* usage bit for all held locks:
*/
- if (!mark_held_locks(curr, HARDIRQ))
+ if (!mark_held_locks(curr, LOCK_ENABLED_HARDIRQ))
return;
/*
* If we have softirqs enabled, then set the usage
@@ -2766,7 +2759,7 @@ static void __trace_hardirqs_on_caller(unsigned long ip)
* this bit from being set before)
*/
if (curr->softirqs_enabled)
- if (!mark_held_locks(curr, SOFTIRQ))
+ if (!mark_held_locks(curr, LOCK_ENABLED_SOFTIRQ))
return;
curr->hardirq_enable_ip = ip;
@@ -2880,7 +2873,7 @@ void trace_softirqs_on(unsigned long ip)
* enabled too:
*/
if (curr->hardirqs_enabled)
- mark_held_locks(curr, SOFTIRQ);
+ mark_held_locks(curr, LOCK_ENABLED_SOFTIRQ);
current->lockdep_recursion = 0;
}
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [tip:locking/core] locking/lockdep: Provide enum lock_usage_bit mask names
2018-12-28 5:02 ` [PATCH 2/2] locking/lockdep: Provide enum lock_usage_bit mask names Frederic Weisbecker
@ 2019-01-21 11:31 ` tip-bot for Frederic Weisbecker
0 siblings, 0 replies; 5+ messages in thread
From: tip-bot for Frederic Weisbecker @ 2019-01-21 11:31 UTC (permalink / raw)
To: linux-tip-commits
Cc: mingo, will.deacon, paulmck, tglx, peterz, torvalds,
linux-kernel, hpa, frederic, akpm
Commit-ID: bba2a8f1f974a45ca6ceaf688b2be7bc1c418a2f
Gitweb: https://git.kernel.org/tip/bba2a8f1f974a45ca6ceaf688b2be7bc1c418a2f
Author: Frederic Weisbecker <frederic@kernel.org>
AuthorDate: Fri, 28 Dec 2018 06:02:01 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 21 Jan 2019 11:18:56 +0100
locking/lockdep: Provide enum lock_usage_bit mask names
It makes the code more self-explanatory and tells throughout the code
what magic number refers to:
- state (Hardirq/Softirq)
- direction (used in or enabled above state)
- read or write
We can even remove some comments that were compensating for the lack of
those constant names.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: https://lkml.kernel.org/r/1545973321-24422-3-git-send-email-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/locking/lockdep.c | 33 +++++++++++----------------------
kernel/locking/lockdep_internals.h | 4 ++++
2 files changed, 15 insertions(+), 22 deletions(-)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 1dcd8341e35b..608f74ed8bb9 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -1624,29 +1624,18 @@ static const char *state_rnames[] = {
static inline const char *state_name(enum lock_usage_bit bit)
{
- return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2];
+ return (bit & LOCK_USAGE_READ_MASK) ? state_rnames[bit >> 2] : state_names[bit >> 2];
}
static int exclusive_bit(int new_bit)
{
- /*
- * USED_IN
- * USED_IN_READ
- * ENABLED
- * ENABLED_READ
- *
- * bit 0 - write/read
- * bit 1 - used_in/enabled
- * bit 2+ state
- */
-
- int state = new_bit & ~3;
- int dir = new_bit & 2;
+ int state = new_bit & LOCK_USAGE_STATE_MASK;
+ int dir = new_bit & LOCK_USAGE_DIR_MASK;
/*
* keep state, bit flip the direction and strip read.
*/
- return state | (dir ^ 2);
+ return state | (dir ^ LOCK_USAGE_DIR_MASK);
}
static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
@@ -2662,8 +2651,8 @@ mark_lock_irq(struct task_struct *curr, struct held_lock *this,
enum lock_usage_bit new_bit)
{
int excl_bit = exclusive_bit(new_bit);
- int read = new_bit & 1;
- int dir = new_bit & 2;
+ int read = new_bit & LOCK_USAGE_READ_MASK;
+ int dir = new_bit & LOCK_USAGE_DIR_MASK;
/*
* mark USED_IN has to look forwards -- to ensure no dependency
@@ -2687,19 +2676,19 @@ mark_lock_irq(struct task_struct *curr, struct held_lock *this,
* states.
*/
if ((!read || !dir || STRICT_READ_CHECKS) &&
- !usage(curr, this, excl_bit, state_name(new_bit & ~1)))
+ !usage(curr, this, excl_bit, state_name(new_bit & ~LOCK_USAGE_READ_MASK)))
return 0;
/*
* Check for read in write conflicts
*/
if (!read) {
- if (!valid_state(curr, this, new_bit, excl_bit + 1))
+ if (!valid_state(curr, this, new_bit, excl_bit + LOCK_USAGE_READ_MASK))
return 0;
if (STRICT_READ_CHECKS &&
- !usage(curr, this, excl_bit + 1,
- state_name(new_bit + 1)))
+ !usage(curr, this, excl_bit + LOCK_USAGE_READ_MASK,
+ state_name(new_bit + LOCK_USAGE_READ_MASK)))
return 0;
}
@@ -2723,7 +2712,7 @@ mark_held_locks(struct task_struct *curr, enum lock_usage_bit base_bit)
hlock = curr->held_locks + i;
if (hlock->read)
- hlock_bit += 1; /* READ */
+ hlock_bit += LOCK_USAGE_READ_MASK;
BUG_ON(hlock_bit >= LOCK_USAGE_STATES);
diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h
index 88c847a41c8a..2ebb9d0ea91c 100644
--- a/kernel/locking/lockdep_internals.h
+++ b/kernel/locking/lockdep_internals.h
@@ -22,6 +22,10 @@ enum lock_usage_bit {
LOCK_USAGE_STATES
};
+#define LOCK_USAGE_READ_MASK 1
+#define LOCK_USAGE_DIR_MASK 2
+#define LOCK_USAGE_STATE_MASK (~(LOCK_USAGE_READ_MASK | LOCK_USAGE_DIR_MASK))
+
/*
* Usage-state bitmasks:
*/
^ permalink raw reply related [flat|nested] 5+ messages in thread
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2018-12-28 5:01 [PATCH 0/2] locking/lockdep: A few cleanups Frederic Weisbecker
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2019-01-21 11:31 ` [tip:locking/core] " tip-bot for Frederic Weisbecker
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