From: Max Reitz <mreitz@redhat.com>
To: qemu-block@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>,
Peter Maydell <peter.maydell@linaro.org>,
qemu-devel@nongnu.org, Max Reitz <mreitz@redhat.com>
Subject: [PULL 07/30] block/io: split out bdrv_find_conflicting_request
Date: Fri, 18 Dec 2020 16:12:26 +0100 [thread overview]
Message-ID: <20201218151249.715731-8-mreitz@redhat.com> (raw)
In-Reply-To: <20201218151249.715731-1-mreitz@redhat.com>
From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
To be reused in separate.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20201021145859.11201-4-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
block/io.c | 71 +++++++++++++++++++++++++++++++-----------------------
1 file changed, 41 insertions(+), 30 deletions(-)
diff --git a/block/io.c b/block/io.c
index 27370107b2..640136b8bc 100644
--- a/block/io.c
+++ b/block/io.c
@@ -754,43 +754,54 @@ static bool tracked_request_overlaps(BdrvTrackedRequest *req,
return true;
}
+/* Called with self->bs->reqs_lock held */
+static BdrvTrackedRequest *
+bdrv_find_conflicting_request(BdrvTrackedRequest *self)
+{
+ BdrvTrackedRequest *req;
+
+ QLIST_FOREACH(req, &self->bs->tracked_requests, list) {
+ if (req == self || (!req->serialising && !self->serialising)) {
+ continue;
+ }
+ if (tracked_request_overlaps(req, self->overlap_offset,
+ self->overlap_bytes))
+ {
+ /*
+ * Hitting this means there was a reentrant request, for
+ * example, a block driver issuing nested requests. This must
+ * never happen since it means deadlock.
+ */
+ assert(qemu_coroutine_self() != req->co);
+
+ /*
+ * If the request is already (indirectly) waiting for us, or
+ * will wait for us as soon as it wakes up, then just go on
+ * (instead of producing a deadlock in the former case).
+ */
+ if (!req->waiting_for) {
+ return req;
+ }
+ }
+ }
+
+ return NULL;
+}
+
static bool coroutine_fn
bdrv_wait_serialising_requests_locked(BlockDriverState *bs,
BdrvTrackedRequest *self)
{
BdrvTrackedRequest *req;
- bool retry;
bool waited = false;
- do {
- retry = false;
- QLIST_FOREACH(req, &bs->tracked_requests, list) {
- if (req == self || (!req->serialising && !self->serialising)) {
- continue;
- }
- if (tracked_request_overlaps(req, self->overlap_offset,
- self->overlap_bytes))
- {
- /* Hitting this means there was a reentrant request, for
- * example, a block driver issuing nested requests. This must
- * never happen since it means deadlock.
- */
- assert(qemu_coroutine_self() != req->co);
-
- /* If the request is already (indirectly) waiting for us, or
- * will wait for us as soon as it wakes up, then just go on
- * (instead of producing a deadlock in the former case). */
- if (!req->waiting_for) {
- self->waiting_for = req;
- qemu_co_queue_wait(&req->wait_queue, &bs->reqs_lock);
- self->waiting_for = NULL;
- retry = true;
- waited = true;
- break;
- }
- }
- }
- } while (retry);
+ while ((req = bdrv_find_conflicting_request(self))) {
+ self->waiting_for = req;
+ qemu_co_queue_wait(&req->wait_queue, &bs->reqs_lock);
+ self->waiting_for = NULL;
+ waited = true;
+ }
+
return waited;
}
--
2.29.2
next prev parent reply other threads:[~2020-12-18 15:15 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-18 15:12 [PULL 00/30] Block patches Max Reitz
2020-12-18 15:12 ` [PULL 01/30] block: add bdrv_refresh_perms() helper Max Reitz
2020-12-18 15:12 ` [PULL 02/30] block: bdrv_set_perm() drop redundant parameters Max Reitz
2020-12-18 15:12 ` [PULL 03/30] block: bdrv_child_set_perm() " Max Reitz
2020-12-18 15:12 ` [PULL 04/30] block: drop tighten_restrictions Max Reitz
2020-12-18 15:12 ` [PULL 05/30] block: simplify comment to BDRV_REQ_SERIALISING Max Reitz
2020-12-18 15:12 ` [PULL 06/30] block/io.c: drop assertion on double waiting for request serialisation Max Reitz
2020-12-18 15:12 ` Max Reitz [this message]
2020-12-18 15:12 ` [PULL 08/30] block/io: bdrv_wait_serialising_requests_locked: drop extra bs arg Max Reitz
2020-12-18 15:12 ` [PULL 09/30] block: bdrv_mark_request_serialising: split non-waiting function Max Reitz
2020-12-18 15:12 ` [PULL 10/30] block: introduce BDRV_REQ_NO_WAIT flag Max Reitz
2020-12-18 15:12 ` [PULL 11/30] block: bdrv_check_perm(): process children anyway Max Reitz
2020-12-18 15:12 ` [PULL 12/30] block: introduce preallocate filter Max Reitz
2020-12-18 15:12 ` [PULL 13/30] qemu-io: add preallocate mode parameter for truncate command Max Reitz
2020-12-18 15:12 ` [PULL 14/30] iotests: qemu_io_silent: support --image-opts Max Reitz
2020-12-18 15:12 ` [PULL 15/30] iotests.py: execute_setup_common(): add required_fmts argument Max Reitz
2020-12-18 15:12 ` [PULL 16/30] iotests: add 298 to test new preallocate filter driver Max Reitz
2020-12-18 15:12 ` [PULL 17/30] scripts/simplebench: fix grammar: s/successed/succeeded/ Max Reitz
2020-12-18 15:12 ` [PULL 18/30] scripts/simplebench: support iops Max Reitz
2020-12-18 15:12 ` [PULL 19/30] scripts/simplebench: use standard deviation for +- error Max Reitz
2020-12-18 15:12 ` [PULL 20/30] simplebench: rename ascii() to results_to_text() Max Reitz
2020-12-18 15:12 ` [PULL 21/30] simplebench: move results_to_text() into separate file Max Reitz
2020-12-18 15:12 ` [PULL 22/30] simplebench/results_to_text: improve view of the table Max Reitz
2020-12-18 15:12 ` [PULL 23/30] simplebench/results_to_text: add difference line to " Max Reitz
2020-12-18 15:12 ` [PULL 24/30] simplebench/results_to_text: make executable Max Reitz
2020-12-18 15:12 ` [PULL 25/30] scripts/simplebench: add bench_prealloc.py Max Reitz
2020-12-18 15:12 ` [PULL 26/30] quorum: Implement bdrv_co_block_status() Max Reitz
2020-12-18 15:12 ` [PULL 27/30] quorum: Implement bdrv_co_pwrite_zeroes() Max Reitz
2020-12-18 15:12 ` [PULL 28/30] block/nvme: Implement fake truncate() coroutine Max Reitz
2020-12-18 15:12 ` [PULL 29/30] iotests/102: Pass $QEMU_HANDLE to _send_qemu_cmd Max Reitz
2020-12-18 15:12 ` [PULL 30/30] iotests: Fix _send_qemu_cmd with bash 5.1 Max Reitz
2021-01-01 12:53 ` [PULL 00/30] Block patches Peter Maydell
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