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

2019-02-18 Thread Eric Blake
On 2/18/19 10:18 AM, Kevin Wolf wrote:
> 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 
> ---
>  block.c | 4 
>  1 file changed, 4 deletions(-)

Reviewed-by: Eric Blake 

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.   +1-919-301-3226
Virtualization:  qemu.org | libvirt.org



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

2019-02-18 Thread Kevin Wolf
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 
---
 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