From d993b85804b7ec099d4e1d377161ac8af398d855 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Mon, 5 Jun 2017 14:38:52 +0200 Subject: [PATCH] block: access io_limits_disabled with atomic ops Reviewed-by: Stefan Hajnoczi Reviewed-by: Alberto Garcia Signed-off-by: Paolo Bonzini Message-Id: <20170605123908.18777-4-pbonzini@redhat.com> Signed-off-by: Fam Zheng --- block/block-backend.c | 4 ++-- block/throttle-groups.c | 2 +- include/sysemu/block-backend.h | 3 ++- 3 files changed, 5 insertions(+), 4 deletions(-) diff --git a/block/block-backend.c b/block/block-backend.c index 7d7f3697d1..69d0e11466 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -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) { diff --git a/block/throttle-groups.c b/block/throttle-groups.c index b73e7a800b..69bfbd44d9 100644 --- a/block/throttle-groups.c +++ b/block/throttle-groups.c @@ -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; } diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h index 840ad6134c..24b63d6b03 100644 --- a/include/sysemu/block-backend.h +++ b/include/sysemu/block-backend.h @@ -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. -- GitLab