From 0d83708a1d2effc5d905cd1d61d0ef47d310ad88 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Mon, 6 May 2019 19:17:58 +0200 Subject: [PATCH] block: Move recursion to bdrv_set_aio_context() Instead of having two recursions, in bdrv_attach_aio_context() and in bdrv_detach_aio_context(), just having one recursion is enough. Said functions are only about a single node now. It is important that the recursion doesn't happen between detaching and attaching a context to the current node because the nested call will drain the node, and draining with a NULL context would segfault. Signed-off-by: Kevin Wolf --- block.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/block.c b/block.c index b2f71142a5..0ace673925 100644 --- a/block.c +++ b/block.c @@ -5679,7 +5679,6 @@ static void bdrv_do_remove_aio_context_notifier(BdrvAioNotifier *ban) static void bdrv_detach_aio_context(BlockDriverState *bs) { BdrvAioNotifier *baf, *baf_tmp; - BdrvChild *child; assert(!bs->walking_aio_notifiers); bs->walking_aio_notifiers = true; @@ -5698,9 +5697,6 @@ static void bdrv_detach_aio_context(BlockDriverState *bs) if (bs->drv && bs->drv->bdrv_detach_aio_context) { bs->drv->bdrv_detach_aio_context(bs); } - QLIST_FOREACH(child, &bs->children, next) { - bdrv_detach_aio_context(child->bs); - } if (bs->quiesce_counter) { aio_enable_external(bs->aio_context); @@ -5712,7 +5708,6 @@ static void bdrv_attach_aio_context(BlockDriverState *bs, AioContext *new_context) { BdrvAioNotifier *ban, *ban_tmp; - BdrvChild *child; if (bs->quiesce_counter) { aio_disable_external(new_context); @@ -5720,9 +5715,6 @@ static void bdrv_attach_aio_context(BlockDriverState *bs, bs->aio_context = new_context; - QLIST_FOREACH(child, &bs->children, next) { - bdrv_attach_aio_context(child->bs, new_context); - } if (bs->drv && bs->drv->bdrv_attach_aio_context) { bs->drv->bdrv_attach_aio_context(bs, new_context); } @@ -5744,11 +5736,18 @@ static void bdrv_attach_aio_context(BlockDriverState *bs, * the same as the current context of bs). */ void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context) { + BdrvChild *child; + if (bdrv_get_aio_context(bs) == new_context) { return; } bdrv_drained_begin(bs); + + QLIST_FOREACH(child, &bs->children, next) { + bdrv_set_aio_context(child->bs, new_context); + } + bdrv_detach_aio_context(bs); /* This function executes in the old AioContext so acquire the new one in -- 2.30.2