Am 18.02.2019 um 21:57 hat Eric Blake geschrieben:
> On 2/18/19 10:18 AM, Kevin Wolf wrote:
> > Now that bdrv_set_aio_context() works inside drained sections, it can
> > also use the real drain function instead of open coding something
> > similar.
> >
> > Signed-off-by: Kevin Wolf <[email protected]>
> > ---
> > block.c | 14 +++++---------
> > 1 file changed, 5 insertions(+), 9 deletions(-)
> >
> > diff --git a/block.c b/block.c
> > index aefb5701f5..7024172db8 100644
> > --- a/block.c
> > +++ b/block.c
> > @@ -5268,18 +5268,15 @@ void bdrv_attach_aio_context(BlockDriverState *bs,
> > bs->walking_aio_notifiers = false;
> > }
> >
> > +/* The caller must own the AioContext lock for the old AioContext of bs,
> > but it
> > + * must not own the AioContext lock for new_context. */
>
> Is this comment still accurate, given
>
> > void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context)
> > {
> > - AioContext *ctx = bdrv_get_aio_context(bs);
> > -
> > - if (ctx == new_context) {
> > + if (bdrv_get_aio_context(bs) == new_context) {
> > return;
> > }
>
> the short-circuiting when the old context is the new context?
Hm, yes, old == new is an exception where you quite obviously can't have
old locked and new unlocked at the same time.
So is adding this enough?
(unless new_context is the same as the current context of bs)
Kevin
