[Qemu-devel] [PATCH 08/12] block: Don't poll in bdrv_set_aio_context()

From: Kevin Wolf <kwolf@redhat.com>
To: qemu-block@nongnu.org
Cc: kwolf@redhat.com, mreitz@redhat.com, eblake@redhat.com,
	stefanha@redhat.com, berrange@redhat.com, pbonzini@redhat.com,
	qemu-devel@nongnu.org
Subject: [Qemu-devel] [PATCH 08/12] block: Don't poll in bdrv_set_aio_context()
Date: Mon, 18 Feb 2019 17:18:18 +0100	[thread overview]
Message-ID: <20190218161822.3573-9-kwolf@redhat.com> (raw)
In-Reply-To: <20190218161822.3573-1-kwolf@redhat.com>

The explicit aio_poll() call in bdrv_set_aio_context() was added in
commit c2b6428d388 as a workaround for bdrv_drain() failing to achieve
to actually quiesce everything (specifically the NBD client code to
switch AioContext).

Now that the NBD client has been fixed to complete this operation during
bdrv_drain(), we don't need the workaround any more.

It was wrong anyway: aio_poll() must always be run in the home thread of
the AioContext.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/block.c b/block.c
index 0c12632661..17bc1d3dca 100644
--- a/block.c
+++ b/block.c
@@ -5273,10 +5273,6 @@ void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)
     bdrv_parent_drained_begin(bs, NULL, false);
     bdrv_drain(bs); /* ensure there are no in-flight requests */
 
-    while (aio_poll(ctx, false)) {
-        /* wait for all bottom halves to execute */
-    }
-
     bdrv_detach_aio_context(bs);
 
     /* This function executes in the old AioContext so acquire the new one in
-- 
2.20.1
