| Message ID | 1556568902-12464-4-git-send-email-andrea.parri@amarulasolutions.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | None | expand |
On Mon, Apr 29, 2019 at 10:14:59PM +0200, Andrea Parri wrote: > This barrier only applies to the read-modify-write operations; in > particular, it does not apply to the atomic_set() primitive. > > Replace the barrier with an smp_mb(). > > Fixes: 6c0ca7ae292ad ("sbitmap: fix wakeup hang after sbq resize") > Cc: stable@vger.kernel.org > Reported-by: "Paul E. McKenney" <paulmck@linux.ibm.com> > Reported-by: Peter Zijlstra <peterz@infradead.org> > Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com> > Cc: Jens Axboe <axboe@kernel.dk> > Cc: Omar Sandoval <osandov@fb.com> > Cc: linux-block@vger.kernel.org Jens, Omar: any suggestions to move this patch forward? Thanx, Andrea > --- > lib/sbitmap.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/lib/sbitmap.c b/lib/sbitmap.c > index 155fe38756ecf..4a7fc4915dfc6 100644 > --- a/lib/sbitmap.c > +++ b/lib/sbitmap.c > @@ -435,7 +435,7 @@ static void sbitmap_queue_update_wake_batch(struct sbitmap_queue *sbq, > * to ensure that the batch size is updated before the wait > * counts. > */ > - smp_mb__before_atomic(); > + smp_mb(); > for (i = 0; i < SBQ_WAIT_QUEUES; i++) > atomic_set(&sbq->ws[i].wait_cnt, 1); > } > -- > 2.7.4 >
On Mon, Apr 29, 2019 at 10:14:59PM +0200, Andrea Parri wrote: > This barrier only applies to the read-modify-write operations; in > particular, it does not apply to the atomic_set() primitive. > > Replace the barrier with an smp_mb(). > > Fixes: 6c0ca7ae292ad ("sbitmap: fix wakeup hang after sbq resize") > Cc: stable@vger.kernel.org > Reported-by: "Paul E. McKenney" <paulmck@linux.ibm.com> > Reported-by: Peter Zijlstra <peterz@infradead.org> > Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com> > Cc: Jens Axboe <axboe@kernel.dk> > Cc: Omar Sandoval <osandov@fb.com> > Cc: linux-block@vger.kernel.org > --- > lib/sbitmap.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/lib/sbitmap.c b/lib/sbitmap.c > index 155fe38756ecf..4a7fc4915dfc6 100644 > --- a/lib/sbitmap.c > +++ b/lib/sbitmap.c > @@ -435,7 +435,7 @@ static void sbitmap_queue_update_wake_batch(struct sbitmap_queue *sbq, > * to ensure that the batch size is updated before the wait > * counts. > */ > - smp_mb__before_atomic(); > + smp_mb(); > for (i = 0; i < SBQ_WAIT_QUEUES; i++) > atomic_set(&sbq->ws[i].wait_cnt, 1); > } > -- > 2.7.4 > sbitmap_queue_update_wake_batch() won't be called in fast path, and the fix is correct too, so: Reviewed-by: Ming Lei <ming.lei@redhat.com> thanks, Ming
Hi Ming, On Fri, May 10, 2019 at 11:41:02AM +0800, Ming Lei wrote: > On Mon, Apr 29, 2019 at 10:14:59PM +0200, Andrea Parri wrote: > > This barrier only applies to the read-modify-write operations; in > > particular, it does not apply to the atomic_set() primitive. > > > > Replace the barrier with an smp_mb(). > > > > Fixes: 6c0ca7ae292ad ("sbitmap: fix wakeup hang after sbq resize") > > Cc: stable@vger.kernel.org > > Reported-by: "Paul E. McKenney" <paulmck@linux.ibm.com> > > Reported-by: Peter Zijlstra <peterz@infradead.org> > > Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com> > > Cc: Jens Axboe <axboe@kernel.dk> > > Cc: Omar Sandoval <osandov@fb.com> > > Cc: linux-block@vger.kernel.org > > --- > > lib/sbitmap.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/lib/sbitmap.c b/lib/sbitmap.c > > index 155fe38756ecf..4a7fc4915dfc6 100644 > > --- a/lib/sbitmap.c > > +++ b/lib/sbitmap.c > > @@ -435,7 +435,7 @@ static void sbitmap_queue_update_wake_batch(struct sbitmap_queue *sbq, > > * to ensure that the batch size is updated before the wait > > * counts. > > */ > > - smp_mb__before_atomic(); > > + smp_mb(); > > for (i = 0; i < SBQ_WAIT_QUEUES; i++) > > atomic_set(&sbq->ws[i].wait_cnt, 1); > > } > > -- > > 2.7.4 > > > > sbitmap_queue_update_wake_batch() won't be called in fast path, and > the fix is correct too, so: > > Reviewed-by: Ming Lei <ming.lei@redhat.com> Thank you for the review(s), Andrea > thanks, > Ming
diff --git a/lib/sbitmap.c b/lib/sbitmap.c index 155fe38756ecf..4a7fc4915dfc6 100644 --- a/lib/sbitmap.c +++ b/lib/sbitmap.c @@ -435,7 +435,7 @@ static void sbitmap_queue_update_wake_batch(struct sbitmap_queue *sbq, * to ensure that the batch size is updated before the wait * counts. */ - smp_mb__before_atomic(); + smp_mb(); for (i = 0; i < SBQ_WAIT_QUEUES; i++) atomic_set(&sbq->ws[i].wait_cnt, 1); }
This barrier only applies to the read-modify-write operations; in particular, it does not apply to the atomic_set() primitive. Replace the barrier with an smp_mb(). Fixes: 6c0ca7ae292ad ("sbitmap: fix wakeup hang after sbq resize") Cc: stable@vger.kernel.org Reported-by: "Paul E. McKenney" <paulmck@linux.ibm.com> Reported-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Omar Sandoval <osandov@fb.com> Cc: linux-block@vger.kernel.org --- lib/sbitmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)