block: access io_limits_disabled with atomic ops

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20170605123908.18777-4-pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
This commit is contained in:
Paolo Bonzini 2017-06-05 14:38:52 +02:00 committed by Fam Zheng
parent 414c2ec358
commit d993b85804
3 changed files with 5 additions and 4 deletions

View File

@ -1953,7 +1953,7 @@ static void blk_root_drained_begin(BdrvChild *child)
/* Note that blk->root may not be accessible here yet if we are just
* attaching to a BlockDriverState that is drained. Use child instead. */
if (blk->public.io_limits_disabled++ == 0) {
if (atomic_fetch_inc(&blk->public.io_limits_disabled) == 0) {
throttle_group_restart_blk(blk);
}
}
@ -1964,7 +1964,7 @@ static void blk_root_drained_end(BdrvChild *child)
assert(blk->quiesce_counter);
assert(blk->public.io_limits_disabled);
--blk->public.io_limits_disabled;
atomic_dec(&blk->public.io_limits_disabled);
if (--blk->quiesce_counter == 0) {
if (blk->dev_ops && blk->dev_ops->drained_end) {

View File

@ -240,7 +240,7 @@ static bool throttle_group_schedule_timer(BlockBackend *blk, bool is_write)
ThrottleGroup *tg = container_of(ts, ThrottleGroup, ts);
bool must_wait;
if (blkp->io_limits_disabled) {
if (atomic_read(&blkp->io_limits_disabled)) {
return false;
}

View File

@ -80,7 +80,8 @@ typedef struct BlockBackendPublic {
CoQueue throttled_reqs[2];
/* Nonzero if the I/O limits are currently being ignored; generally
* it is zero. */
* it is zero. Accessed with atomic operations.
*/
unsigned int io_limits_disabled;
/* The following fields are protected by the ThrottleGroup lock.