Re: [Qemu-devel] [PATCH] Revert "blockdev: add note that block_job_cb() must be thread-safe"

[Fam Zheng <famz@redhat.com>]

On Tue, 10/13 13:21, Kevin Wolf wrote:
> Am 13.10.2015 um 12:16 hat Fam Zheng geschrieben:
> > This reverts commit 723c5d93c51bdb3adbc238ce90195c0864aa6cd5.
> > 
> > block_job_cb is called by block_job_completed, which is always called in
> > a main loop bottom half in existing block jobs. So we don't need to
> > worry about thread-safety here.
> > 
> > Signed-off-by: Fam Zheng <famz@redhat.com>
> > ---
> >  blockdev.c | 5 -----
> >  1 file changed, 5 deletions(-)
> > 
> > diff --git a/blockdev.c b/blockdev.c
> > index 32b04b4..130b7fb 100644
> > --- a/blockdev.c
> > +++ b/blockdev.c
> > @@ -2248,11 +2248,6 @@ out:
> >  
> >  static void block_job_cb(void *opaque, int ret)
> >  {
> > -    /* Note that this function may be executed from another AioContext besides
> > -     * the QEMU main loop.  If you need to access anything that assumes the
> > -     * QEMU global mutex, use a BH or introduce a mutex.
> > -     */
> > -
> >      BlockDriverState *bs = opaque;
> >      const char *msg = NULL;
> 
> Should we instead add a comment that tells you that you _have_ to use
> that bottom half because block jobs can be running in an I/O thread?

Probably, but this comment is stale anyway.

Fam