ShuriZma
/
xemu
mirror of https://github.com/xemu-project/xemu.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

block/io: split out bdrv_find_conflicting_request 

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>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2020-10-21 17:58:41 +03:00 committed by Max Reitz
parent 2e36da62cf
commit 3183937ff9
1 changed files with 40 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
block/io.c
View File

@ -754,43 +754,54 @@ static bool tracked_request_overlaps(BdrvTrackedRequest *req,
return true; return true;
} }
static bool coroutine_fn /* Called with self->bs->reqs_lock held */
bdrv_wait_serialising_requests_locked(BlockDriverState *bs, static BdrvTrackedRequest *
BdrvTrackedRequest *self) bdrv_find_conflicting_request(BdrvTrackedRequest *self)
{ {
BdrvTrackedRequest *req; BdrvTrackedRequest *req;
bool retry;
bool waited = false;
do { QLIST_FOREACH(req, &self->bs->tracked_requests, list) {
retry = false;
QLIST_FOREACH(req, &bs->tracked_requests, list) {
if (req == self || (!req->serialising && !self->serialising)) { if (req == self || (!req->serialising && !self->serialising)) {
continue; continue;
} }
if (tracked_request_overlaps(req, self->overlap_offset, if (tracked_request_overlaps(req, self->overlap_offset,
self->overlap_bytes)) self->overlap_bytes))
{ {
/* Hitting this means there was a reentrant request, for /*
* Hitting this means there was a reentrant request, for
* example, a block driver issuing nested requests. This must * example, a block driver issuing nested requests. This must
* never happen since it means deadlock. * never happen since it means deadlock.
*/ */
assert(qemu_coroutine_self() != req->co); assert(qemu_coroutine_self() != req->co);
/* If the request is already (indirectly) waiting for us, or /*
* If the request is already (indirectly) waiting for us, or
* will wait for us as soon as it wakes up, then just go on * will wait for us as soon as it wakes up, then just go on
* (instead of producing a deadlock in the former case). */ * (instead of producing a deadlock in the former case).
*/
if (!req->waiting_for) { if (!req->waiting_for) {
return req;
}
}
}
return NULL;
}
static bool coroutine_fn
bdrv_wait_serialising_requests_locked(BlockDriverState *bs,
BdrvTrackedRequest *self)
{
BdrvTrackedRequest *req;
bool waited = false;
while ((req = bdrv_find_conflicting_request(self))) {
self->waiting_for = req; self->waiting_for = req;
qemu_co_queue_wait(&req->wait_queue, &bs->reqs_lock); qemu_co_queue_wait(&req->wait_queue, &bs->reqs_lock);
self->waiting_for = NULL; self->waiting_for = NULL;
retry = true;
waited = true; waited = true;
break;
} }
}
}
} while (retry);
return waited; return waited;
} }