Re: [PATCH 12/12] block: remove outdated AioContext locking comments

[Eric Blake]

On Wed, Nov 29, 2023 at 02:55:53PM -0500, Stefan Hajnoczi wrote:
> The AioContext lock no longer exists.
> 
> There is one noteworthy change:
> 
>   - * More specifically, these functions use BDRV_POLL_WHILE(bs), which
>   - * requires the caller to be either in the main thread and hold
>   - * the BlockdriverState (bs) AioContext lock, or directly in the
>   - * home thread that runs the bs AioContext. Calling them from
>   - * another thread in another AioContext would cause deadlocks.
>   + * More specifically, these functions use BDRV_POLL_WHILE(bs), which 
> requires
>   + * the caller to be either in the main thread or directly in the home 
> thread
>   + * that runs the bs AioContext. Calling them from another thread in another
>   + * AioContext would cause deadlocks.
> 
> I am not sure whether deadlocks are still possible. Maybe they have just
> moved to the fine-grained locks that have replaced the AioContext. Since
> I am not sure if the deadlocks are gone, I have kept the substance
> unchanged and just removed mention of the AioContext.

I'd rather text that may be overly conservative than an omission that
could lead to a bug; so I'm okay with your action there.

> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.
Virtualization:  qemu.org | libguestfs.org