* [PATCH 4/5] ceph: fix improper use of smp_mb__before_atomic()
[not found] <1556568902-12464-1-git-send-email-andrea.parri@amarulasolutions.com>
@ 2019-04-29 20:15 ` Andrea Parri
2019-04-30 8:23 ` Peter Zijlstra
0 siblings, 1 reply; 6+ messages in thread
From: Andrea Parri @ 2019-04-29 20:15 UTC (permalink / raw)
To: linux-kernel
Cc: Andrea Parri, stable, Yan, Zheng, Sage Weil, Ilya Dryomov,
ceph-devel
This barrier only applies to the read-modify-write operations; in
particular, it does not apply to the atomic64_set() primitive.
Replace the barrier with an smp_mb().
Fixes: fdd4e15838e59 ("ceph: rework dcache readdir")
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: "Yan, Zheng" <zyan@redhat.com>
Cc: Sage Weil <sage@redhat.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: ceph-devel@vger.kernel.org
---
fs/ceph/super.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 16c03188578ea..b5c782e6d62f1 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -541,7 +541,7 @@ static inline void __ceph_dir_set_complete(struct ceph_inode_info *ci,
long long release_count,
long long ordered_count)
{
- smp_mb__before_atomic();
+ smp_mb();
atomic64_set(&ci->i_complete_seq[0], release_count);
atomic64_set(&ci->i_complete_seq[1], ordered_count);
}
--
2.7.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 4/5] ceph: fix improper use of smp_mb__before_atomic()
2019-04-29 20:15 ` [PATCH 4/5] ceph: fix improper use of smp_mb__before_atomic() Andrea Parri
@ 2019-04-30 8:23 ` Peter Zijlstra
2019-04-30 9:08 ` Yan, Zheng
0 siblings, 1 reply; 6+ messages in thread
From: Peter Zijlstra @ 2019-04-30 8:23 UTC (permalink / raw)
To: Andrea Parri
Cc: linux-kernel, stable, Yan, Zheng, Sage Weil, Ilya Dryomov,
ceph-devel
On Mon, Apr 29, 2019 at 10:15:00PM +0200, Andrea Parri wrote:
> This barrier only applies to the read-modify-write operations; in
> particular, it does not apply to the atomic64_set() primitive.
>
> Replace the barrier with an smp_mb().
>
> @@ -541,7 +541,7 @@ static inline void __ceph_dir_set_complete(struct ceph_inode_info *ci,
> long long release_count,
> long long ordered_count)
> {
> - smp_mb__before_atomic();
same
/*
* XXX: the comment that explain this barrier goes here.
*/
> + smp_mb();
> atomic64_set(&ci->i_complete_seq[0], release_count);
> atomic64_set(&ci->i_complete_seq[1], ordered_count);
> }
> --
> 2.7.4
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 4/5] ceph: fix improper use of smp_mb__before_atomic()
2019-04-30 8:23 ` Peter Zijlstra
@ 2019-04-30 9:08 ` Yan, Zheng
2019-05-09 20:55 ` Andrea Parri
0 siblings, 1 reply; 6+ messages in thread
From: Yan, Zheng @ 2019-04-30 9:08 UTC (permalink / raw)
To: Peter Zijlstra
Cc: Andrea Parri, Linux Kernel Mailing List, stable, Yan, Zheng,
Sage Weil, Ilya Dryomov, ceph-devel
On Tue, Apr 30, 2019 at 4:26 PM Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Mon, Apr 29, 2019 at 10:15:00PM +0200, Andrea Parri wrote:
> > This barrier only applies to the read-modify-write operations; in
> > particular, it does not apply to the atomic64_set() primitive.
> >
> > Replace the barrier with an smp_mb().
> >
>
> > @@ -541,7 +541,7 @@ static inline void __ceph_dir_set_complete(struct ceph_inode_info *ci,
> > long long release_count,
> > long long ordered_count)
> > {
> > - smp_mb__before_atomic();
>
> same
> /*
> * XXX: the comment that explain this barrier goes here.
> */
>
makes sure operations that setup readdir cache (update page cache and
i_size) are strongly ordered with following atomic64_set.
> > + smp_mb();
>
> > atomic64_set(&ci->i_complete_seq[0], release_count);
> > atomic64_set(&ci->i_complete_seq[1], ordered_count);
> > }
> > --
> > 2.7.4
> >
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 4/5] ceph: fix improper use of smp_mb__before_atomic()
2019-04-30 9:08 ` Yan, Zheng
@ 2019-05-09 20:55 ` Andrea Parri
2019-05-13 13:04 ` Yan, Zheng
0 siblings, 1 reply; 6+ messages in thread
From: Andrea Parri @ 2019-05-09 20:55 UTC (permalink / raw)
To: Yan, Zheng
Cc: Linux Kernel Mailing List, Yan, Zheng, Sage Weil, Ilya Dryomov,
ceph-devel, Paul E. McKenney, Peter Zijlstra
On Tue, Apr 30, 2019 at 05:08:43PM +0800, Yan, Zheng wrote:
> On Tue, Apr 30, 2019 at 4:26 PM Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > On Mon, Apr 29, 2019 at 10:15:00PM +0200, Andrea Parri wrote:
> > > This barrier only applies to the read-modify-write operations; in
> > > particular, it does not apply to the atomic64_set() primitive.
> > >
> > > Replace the barrier with an smp_mb().
> > >
> >
> > > @@ -541,7 +541,7 @@ static inline void __ceph_dir_set_complete(struct ceph_inode_info *ci,
> > > long long release_count,
> > > long long ordered_count)
> > > {
> > > - smp_mb__before_atomic();
> >
> > same
> > /*
> > * XXX: the comment that explain this barrier goes here.
> > */
> >
>
> makes sure operations that setup readdir cache (update page cache and
> i_size) are strongly ordered with following atomic64_set.
Thanks for the suggestion, Yan.
To be clear: would you like me to integrate your comment and resend?
any other suggestions?
Thanx,
Andrea
>
> > > + smp_mb();
> >
> > > atomic64_set(&ci->i_complete_seq[0], release_count);
> > > atomic64_set(&ci->i_complete_seq[1], ordered_count);
> > > }
> > > --
> > > 2.7.4
> > >
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 4/5] ceph: fix improper use of smp_mb__before_atomic()
2019-05-09 20:55 ` Andrea Parri
@ 2019-05-13 13:04 ` Yan, Zheng
2019-05-13 22:47 ` Andrea Parri
0 siblings, 1 reply; 6+ messages in thread
From: Yan, Zheng @ 2019-05-13 13:04 UTC (permalink / raw)
To: Andrea Parri, Yan, Zheng
Cc: Linux Kernel Mailing List, Sage Weil, Ilya Dryomov, ceph-devel,
Paul E. McKenney, Peter Zijlstra
On 5/10/19 4:55 AM, Andrea Parri wrote:
> On Tue, Apr 30, 2019 at 05:08:43PM +0800, Yan, Zheng wrote:
>> On Tue, Apr 30, 2019 at 4:26 PM Peter Zijlstra <peterz@infradead.org> wrote:
>>>
>>> On Mon, Apr 29, 2019 at 10:15:00PM +0200, Andrea Parri wrote:
>>>> This barrier only applies to the read-modify-write operations; in
>>>> particular, it does not apply to the atomic64_set() primitive.
>>>>
>>>> Replace the barrier with an smp_mb().
>>>>
>>>
>>>> @@ -541,7 +541,7 @@ static inline void __ceph_dir_set_complete(struct ceph_inode_info *ci,
>>>> long long release_count,
>>>> long long ordered_count)
>>>> {
>>>> - smp_mb__before_atomic();
>>>
>>> same
>>> /*
>>> * XXX: the comment that explain this barrier goes here.
>>> */
>>>
>>
>> makes sure operations that setup readdir cache (update page cache and
>> i_size) are strongly ordered with following atomic64_set.
>
> Thanks for the suggestion, Yan.
>
> To be clear: would you like me to integrate your comment and resend?
> any other suggestions?
>
Yes, please
Regards
Yan, Zheng
> Thanx,
> Andrea
>
>
>>
>>>> + smp_mb();
>>>
>>>> atomic64_set(&ci->i_complete_seq[0], release_count);
>>>> atomic64_set(&ci->i_complete_seq[1], ordered_count);
>>>> }
>>>> --
>>>> 2.7.4
>>>>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 4/5] ceph: fix improper use of smp_mb__before_atomic()
2019-05-13 13:04 ` Yan, Zheng
@ 2019-05-13 22:47 ` Andrea Parri
0 siblings, 0 replies; 6+ messages in thread
From: Andrea Parri @ 2019-05-13 22:47 UTC (permalink / raw)
To: Yan, Zheng
Cc: Yan, Zheng, Linux Kernel Mailing List, Sage Weil, Ilya Dryomov,
ceph-devel, Paul E. McKenney, Peter Zijlstra
> >>> /*
> >>> * XXX: the comment that explain this barrier goes here.
> >>> */
> >>>
> >>
> >>makes sure operations that setup readdir cache (update page cache and
> >>i_size) are strongly ordered with following atomic64_set.
> >
> >Thanks for the suggestion, Yan.
> >
> >To be clear: would you like me to integrate your comment and resend?
> >any other suggestions?
> >
>
> Yes, please
Will do: I'll let the merge window close and send v2 on top of -rc1.
Thanks,
Andrea
^ permalink raw reply [flat|nested] 6+ messages in thread
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2019-04-29 20:15 ` [PATCH 4/5] ceph: fix improper use of smp_mb__before_atomic() Andrea Parri
2019-04-30 8:23 ` Peter Zijlstra
2019-04-30 9:08 ` Yan, Zheng
2019-05-09 20:55 ` Andrea Parri
2019-05-13 13:04 ` Yan, Zheng
2019-05-13 22:47 ` Andrea Parri
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