From 42a65f02f9b380bd8074882d5844d4ea033389cc Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 7 May 2019 18:31:38 +0200 Subject: [PATCH] block: Remove bdrv_set_aio_context() All callers of bdrv_set_aio_context() are eliminated now, they have moved to bdrv_try_set_aio_context() and related safe functions. Remove bdrv_set_aio_context(). With this, we can now know that the .set_aio_ctx callback must be present in bdrv_set_aio_context_ignore() because bdrv_can_set_aio_context() would have returned false previously, so instead of checking the condition, we can assert it. Signed-off-by: Kevin Wolf --- block.c | 30 ++++++++++++++---------------- docs/devel/multiple-iothreads.txt | 4 ++-- include/block/block.h | 9 --------- 3 files changed, 16 insertions(+), 27 deletions(-) diff --git a/block.c b/block.c index ddfae15d9b..e3e77feee0 100644 --- a/block.c +++ b/block.c @@ -5789,8 +5789,17 @@ static void bdrv_attach_aio_context(BlockDriverState *bs, bs->walking_aio_notifiers = false; } -/* @ignore will accumulate all visited BdrvChild object. The caller is - * responsible for freeing the list afterwards. */ +/* + * Changes the AioContext used for fd handlers, timers, and BHs by this + * BlockDriverState and all its children and parents. + * + * The caller must own the AioContext lock for the old AioContext of bs, but it + * must not own the AioContext lock for new_context (unless new_context is the + * same as the current context of bs). + * + * @ignore will accumulate all visited BdrvChild object. The caller is + * responsible for freeing the list afterwards. + */ void bdrv_set_aio_context_ignore(BlockDriverState *bs, AioContext *new_context, GSList **ignore) { @@ -5813,10 +5822,9 @@ void bdrv_set_aio_context_ignore(BlockDriverState *bs, if (g_slist_find(*ignore, child)) { continue; } - if (child->role->set_aio_ctx) { - *ignore = g_slist_prepend(*ignore, child); - child->role->set_aio_ctx(child, new_context, ignore); - } + assert(child->role->set_aio_ctx); + *ignore = g_slist_prepend(*ignore, child); + child->role->set_aio_ctx(child, new_context, ignore); } bdrv_detach_aio_context(bs); @@ -5830,16 +5838,6 @@ void bdrv_set_aio_context_ignore(BlockDriverState *bs, aio_context_release(new_context); } -/* The caller must own the AioContext lock for the old AioContext of bs, but it - * must not own the AioContext lock for new_context (unless new_context is - * the same as the current context of bs). */ -void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context) -{ - GSList *ignore_list = NULL; - bdrv_set_aio_context_ignore(bs, new_context, &ignore_list); - g_slist_free(ignore_list); -} - static bool bdrv_parent_can_set_aio_context(BdrvChild *c, AioContext *ctx, GSList **ignore, Error **errp) { diff --git a/docs/devel/multiple-iothreads.txt b/docs/devel/multiple-iothreads.txt index 4f9012d154..aeb997bed5 100644 --- a/docs/devel/multiple-iothreads.txt +++ b/docs/devel/multiple-iothreads.txt @@ -109,7 +109,7 @@ The AioContext originates from the QEMU block layer, even though nowadays AioContext is a generic event loop that can be used by any QEMU subsystem. The block layer has support for AioContext integrated. Each BlockDriverState -is associated with an AioContext using bdrv_set_aio_context() and +is associated with an AioContext using bdrv_try_set_aio_context() and bdrv_get_aio_context(). This allows block layer code to process I/O inside the right AioContext. Other subsystems may wish to follow a similar approach. @@ -134,5 +134,5 @@ Long-running jobs (usually in the form of coroutines) are best scheduled in the BlockDriverState's AioContext to avoid the need to acquire/release around each bdrv_*() call. The functions bdrv_add/remove_aio_context_notifier, or alternatively blk_add/remove_aio_context_notifier if you use BlockBackends, -can be used to get a notification whenever bdrv_set_aio_context() moves a +can be used to get a notification whenever bdrv_try_set_aio_context() moves a BlockDriverState to a different AioContext. diff --git a/include/block/block.h b/include/block/block.h index 531cf595cf..13ea050a5b 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -583,15 +583,6 @@ AioContext *bdrv_get_aio_context(BlockDriverState *bs); */ void bdrv_coroutine_enter(BlockDriverState *bs, Coroutine *co); -/** - * bdrv_set_aio_context: - * - * Changes the #AioContext used for fd handlers, timers, and BHs by this - * BlockDriverState and all its children. - * - * This function must be called with iothread lock held. - */ -void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context); void bdrv_set_aio_context_ignore(BlockDriverState *bs, AioContext *new_context, GSList **ignore); int bdrv_try_set_aio_context(BlockDriverState *bs, AioContext *ctx,