* [PATCH 2/5] bio: fix improper use of smp_mb__before_atomic() [not found] <1556568902-12464-1-git-send-email-andrea.parri@amarulasolutions.com> @ 2019-04-29 20:14 ` Andrea Parri 2019-04-30 8:21 ` Peter Zijlstra ` (2 more replies) 2019-04-29 20:14 ` [PATCH 3/5] sbitmap: " Andrea Parri 1 sibling, 3 replies; 8+ messages in thread From: Andrea Parri @ 2019-04-29 20:14 UTC (permalink / raw) To: linux-kernel; +Cc: Andrea Parri, stable, Jens Axboe, linux-block 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: dac56212e8127 ("bio: skip atomic inc/dec of ->bi_cnt for most use cases") 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: linux-block@vger.kernel.org --- include/linux/bio.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/bio.h b/include/linux/bio.h index e584673c18814..5becbafb84e8a 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -224,7 +224,7 @@ static inline void bio_cnt_set(struct bio *bio, unsigned int count) { if (count != 1) { bio->bi_flags |= (1 << BIO_REFFED); - smp_mb__before_atomic(); + smp_mb(); } atomic_set(&bio->__bi_cnt, count); } -- 2.7.4 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH 2/5] bio: fix improper use of smp_mb__before_atomic() 2019-04-29 20:14 ` [PATCH 2/5] bio: fix improper use of smp_mb__before_atomic() Andrea Parri @ 2019-04-30 8:21 ` Peter Zijlstra 2019-05-09 20:23 ` Andrea Parri 2019-05-10 3:40 ` Ming Lei 2 siblings, 0 replies; 8+ messages in thread From: Peter Zijlstra @ 2019-04-30 8:21 UTC (permalink / raw) To: Andrea Parri; +Cc: linux-kernel, stable, Jens Axboe, linux-block On Mon, Apr 29, 2019 at 10:14:58PM +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(). > @@ -224,7 +224,7 @@ static inline void bio_cnt_set(struct bio *bio, unsigned int count) > { > if (count != 1) { > bio->bi_flags |= (1 << BIO_REFFED); > - smp_mb__before_atomic(); Maybe also add: /* * XXX the comment that explain this barrier goes here */ > + smp_mb(); > } > atomic_set(&bio->__bi_cnt, count); > } ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 2/5] bio: fix improper use of smp_mb__before_atomic() 2019-04-29 20:14 ` [PATCH 2/5] bio: fix improper use of smp_mb__before_atomic() Andrea Parri 2019-04-30 8:21 ` Peter Zijlstra @ 2019-05-09 20:23 ` Andrea Parri 2019-05-10 3:40 ` Ming Lei 2 siblings, 0 replies; 8+ messages in thread From: Andrea Parri @ 2019-05-09 20:23 UTC (permalink / raw) To: linux-kernel; +Cc: Jens Axboe, linux-block, Paul E. McKenney, Peter Zijlstra On Mon, Apr 29, 2019 at 10:14:58PM +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: dac56212e8127 ("bio: skip atomic inc/dec of ->bi_cnt for most use cases") > 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: linux-block@vger.kernel.org Jens: any suggestions to move this patch forward? Thanx, Andrea > --- > include/linux/bio.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/bio.h b/include/linux/bio.h > index e584673c18814..5becbafb84e8a 100644 > --- a/include/linux/bio.h > +++ b/include/linux/bio.h > @@ -224,7 +224,7 @@ static inline void bio_cnt_set(struct bio *bio, unsigned int count) > { > if (count != 1) { > bio->bi_flags |= (1 << BIO_REFFED); > - smp_mb__before_atomic(); > + smp_mb(); > } > atomic_set(&bio->__bi_cnt, count); > } > -- > 2.7.4 > ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 2/5] bio: fix improper use of smp_mb__before_atomic() 2019-04-29 20:14 ` [PATCH 2/5] bio: fix improper use of smp_mb__before_atomic() Andrea Parri 2019-04-30 8:21 ` Peter Zijlstra 2019-05-09 20:23 ` Andrea Parri @ 2019-05-10 3:40 ` Ming Lei 2 siblings, 0 replies; 8+ messages in thread From: Ming Lei @ 2019-05-10 3:40 UTC (permalink / raw) To: Andrea Parri; +Cc: linux-kernel, stable, Jens Axboe, linux-block On Mon, Apr 29, 2019 at 10:14:58PM +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: dac56212e8127 ("bio: skip atomic inc/dec of ->bi_cnt for most use cases") > 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: linux-block@vger.kernel.org > --- > include/linux/bio.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/bio.h b/include/linux/bio.h > index e584673c18814..5becbafb84e8a 100644 > --- a/include/linux/bio.h > +++ b/include/linux/bio.h > @@ -224,7 +224,7 @@ static inline void bio_cnt_set(struct bio *bio, unsigned int count) > { > if (count != 1) { > bio->bi_flags |= (1 << BIO_REFFED); > - smp_mb__before_atomic(); > + smp_mb(); > } > atomic_set(&bio->__bi_cnt, count); > } > -- > 2.7.4 > Looks fine, Reviewed-by: Ming Lei <ming.lei@redhat.com> Thanks, Ming ^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH 3/5] sbitmap: fix improper use of smp_mb__before_atomic() [not found] <1556568902-12464-1-git-send-email-andrea.parri@amarulasolutions.com> 2019-04-29 20:14 ` [PATCH 2/5] bio: fix improper use of smp_mb__before_atomic() Andrea Parri @ 2019-04-29 20:14 ` Andrea Parri 2019-05-09 20:26 ` Andrea Parri 2019-05-10 3:41 ` Ming Lei 1 sibling, 2 replies; 8+ messages in thread From: Andrea Parri @ 2019-04-29 20:14 UTC (permalink / raw) To: linux-kernel; +Cc: Andrea Parri, stable, Jens Axboe, Omar Sandoval, linux-block 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 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH 3/5] sbitmap: fix improper use of smp_mb__before_atomic() 2019-04-29 20:14 ` [PATCH 3/5] sbitmap: " Andrea Parri @ 2019-05-09 20:26 ` Andrea Parri 2019-05-10 3:41 ` Ming Lei 1 sibling, 0 replies; 8+ messages in thread From: Andrea Parri @ 2019-05-09 20:26 UTC (permalink / raw) To: linux-kernel Cc: Jens Axboe, Omar Sandoval, linux-block, Paul E. McKenney, Peter Zijlstra 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 > ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 3/5] sbitmap: fix improper use of smp_mb__before_atomic() 2019-04-29 20:14 ` [PATCH 3/5] sbitmap: " Andrea Parri 2019-05-09 20:26 ` Andrea Parri @ 2019-05-10 3:41 ` Ming Lei 2019-05-10 6:27 ` Andrea Parri 1 sibling, 1 reply; 8+ messages in thread From: Ming Lei @ 2019-05-10 3:41 UTC (permalink / raw) To: Andrea Parri; +Cc: linux-kernel, stable, Jens Axboe, Omar Sandoval, linux-block 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 ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 3/5] sbitmap: fix improper use of smp_mb__before_atomic() 2019-05-10 3:41 ` Ming Lei @ 2019-05-10 6:27 ` Andrea Parri 0 siblings, 0 replies; 8+ messages in thread From: Andrea Parri @ 2019-05-10 6:27 UTC (permalink / raw) To: Ming Lei; +Cc: linux-kernel, Jens Axboe, Omar Sandoval, linux-block 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 ^ permalink raw reply [flat|nested] 8+ messages in thread
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2019-04-29 20:14 ` [PATCH 2/5] bio: fix improper use of smp_mb__before_atomic() Andrea Parri
2019-04-30 8:21 ` Peter Zijlstra
2019-05-09 20:23 ` Andrea Parri
2019-05-10 3:40 ` Ming Lei
2019-04-29 20:14 ` [PATCH 3/5] sbitmap: " Andrea Parri
2019-05-09 20:26 ` Andrea Parri
2019-05-10 3:41 ` Ming Lei
2019-05-10 6:27 ` Andrea Parri
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