| Message ID | 20170411122632.14050-11-famz@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 11 April 2017 at 13:26, Fam Zheng <famz@redhat.com> wrote: > bdrv_inc_in_flight and bdrv_dec_in_flight are mandatory for > BDRV_POLL_WHILE to work, even for the shortcut case where flush is > unnecessary. Move the if block to below bdrv_dec_in_flight, and BTW fix > the variable declaration position. > > Signed-off-by: Fam Zheng <famz@redhat.com> > Acked-by: Stefan Hajnoczi <stefanha@redhat.com> > Reviewed-by: Kevin Wolf <kwolf@redhat.com> > Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> > --- > block/io.c | 16 +++++++++------- > 1 file changed, 9 insertions(+), 7 deletions(-) > > diff --git a/block/io.c b/block/io.c > index 00e45ca..bae6947 100644 > --- a/block/io.c > +++ b/block/io.c > @@ -2278,16 +2278,17 @@ static void coroutine_fn bdrv_flush_co_entry(void *opaque) > > int coroutine_fn bdrv_co_flush(BlockDriverState *bs) > { > - int ret; > - > - if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs) || > - bdrv_is_sg(bs)) { > - return 0; > - } > + int current_gen; > + int ret = 0; > > bdrv_inc_in_flight(bs); > > - int current_gen = bs->write_gen; > + if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs) || > + bdrv_is_sg(bs)) { > + goto early_exit; > + } Coverity points out that there's a problem here -- we call bdrv_inc_in_flight(bs), which assumes bs is not NULL, before we do the test for whether bs is NULL. Presumably the NULL check needs to be pulled up earlier in the function? thanks -- PMM
On Tue, 04/25 16:00, Peter Maydell wrote: > > Coverity points out that there's a problem here -- we call > bdrv_inc_in_flight(bs), which assumes bs is not NULL, before > we do the test for whether bs is NULL. > > Presumably the NULL check needs to be pulled up earlier in > the function? > Yes, will take care of this one. Fam
diff --git a/block/io.c b/block/io.c index 00e45ca..bae6947 100644 --- a/block/io.c +++ b/block/io.c @@ -2278,16 +2278,17 @@ static void coroutine_fn bdrv_flush_co_entry(void *opaque) int coroutine_fn bdrv_co_flush(BlockDriverState *bs) { - int ret; - - if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs) || - bdrv_is_sg(bs)) { - return 0; - } + int current_gen; + int ret = 0; bdrv_inc_in_flight(bs); - int current_gen = bs->write_gen; + if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs) || + bdrv_is_sg(bs)) { + goto early_exit; + } + + current_gen = bs->write_gen; /* Wait until any previous flushes are completed */ while (bs->active_flush_req) { @@ -2370,6 +2371,7 @@ out: /* Return value is ignored - it's ok if wait queue is empty */ qemu_co_queue_next(&bs->flush_queue); +early_exit: bdrv_dec_in_flight(bs); return ret; }