diff options
| -rw-r--r-- | block/block-backend.c | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/block/block-backend.c b/block/block-backend.c index 209eb07528..9c4de79e6b 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -44,7 +44,7 @@ struct BlockBackend { char *name; int refcnt; BdrvChild *root; - AioContext *ctx; + AioContext *ctx; /* access with atomic operations only */ DriveInfo *legacy_dinfo; /* null unless created by drive_new() */ QTAILQ_ENTRY(BlockBackend) link; /* for block_backends */ QTAILQ_ENTRY(BlockBackend) monitor_link; /* for monitor_block_backends */ @@ -2414,22 +2414,22 @@ void blk_op_unblock_all(BlockBackend *blk, Error *reason) } } +/** + * Return BB's current AioContext. Note that this context may change + * concurrently at any time, with one exception: If the BB has a root node + * attached, its context will only change through bdrv_try_change_aio_context(), + * which creates a drained section. Therefore, incrementing such a BB's + * in-flight counter will prevent its context from changing. + */ AioContext *blk_get_aio_context(BlockBackend *blk) { - BlockDriverState *bs; IO_CODE(); if (!blk) { return qemu_get_aio_context(); } - bs = blk_bs(blk); - if (bs) { - AioContext *ctx = bdrv_get_aio_context(blk_bs(blk)); - assert(ctx == blk->ctx); - } - - return blk->ctx; + return qatomic_read(&blk->ctx); } int blk_set_aio_context(BlockBackend *blk, AioContext *new_context, @@ -2442,7 +2442,7 @@ int blk_set_aio_context(BlockBackend *blk, AioContext *new_context, GLOBAL_STATE_CODE(); if (!bs) { - blk->ctx = new_context; + qatomic_set(&blk->ctx, new_context); return 0; } @@ -2471,7 +2471,7 @@ static void blk_root_set_aio_ctx_commit(void *opaque) AioContext *new_context = s->new_ctx; ThrottleGroupMember *tgm = &blk->public.throttle_group_member; - blk->ctx = new_context; + qatomic_set(&blk->ctx, new_context); if (tgm->throttle_state) { throttle_group_detach_aio_context(tgm); throttle_group_attach_aio_context(tgm, new_context); |