* [PATCH -next] nfsd: use DEFINE_SPINLOCK() for spinlock
@ 2020-07-25 8:56 Qinglang Miao
2020-07-31 12:30 ` Chuck Lever
0 siblings, 1 reply; 6+ messages in thread
From: Qinglang Miao @ 2020-07-25 8:56 UTC (permalink / raw)
To: J. Bruce Fields, Chuck Lever, Greg Kroah-Hartman; +Cc: linux-nfs, linux-kernel
nfsd_drc_lock can be initialized automatically with
DEFINE_SPINLOCK() rather than explicitly calling spin_lock_init().
Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
---
fs/nfsd/nfssvc.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index b603dfcdd..20f0a27fe 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -88,7 +88,7 @@ DEFINE_MUTEX(nfsd_mutex);
* version 4.1 DRC caches.
* nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage.
*/
-spinlock_t nfsd_drc_lock;
+DEFINE_SPINLOCK(nfsd_drc_lock);
unsigned long nfsd_drc_max_mem;
unsigned long nfsd_drc_mem_used;
@@ -568,7 +568,6 @@ static void set_max_drc(void)
nfsd_drc_max_mem = (nr_free_buffer_pages()
>> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE;
nfsd_drc_mem_used = 0;
- spin_lock_init(&nfsd_drc_lock);
dprintk("%s nfsd_drc_max_mem %lu \n", __func__, nfsd_drc_max_mem);
}
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH -next] nfsd: use DEFINE_SPINLOCK() for spinlock
2020-07-25 8:56 [PATCH -next] nfsd: use DEFINE_SPINLOCK() for spinlock Qinglang Miao
@ 2020-07-31 12:30 ` Chuck Lever
0 siblings, 0 replies; 6+ messages in thread
From: Chuck Lever @ 2020-07-31 12:30 UTC (permalink / raw)
To: Qinglang Miao, Bruce Fields
Cc: Greg Kroah-Hartman, Linux NFS Mailing List, open list
Hello-
> On Jul 25, 2020, at 4:56 AM, Qinglang Miao <miaoqinglang@huawei.com> wrote:
>
> nfsd_drc_lock can be initialized automatically with
> DEFINE_SPINLOCK() rather than explicitly calling spin_lock_init().
>
> Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Thanks for your patch.
I am quite honestly on the fence about this one. It doesn't
seem to make a difference behaviorally or in terms of code
legibility.
A broader clean-up that moves set_max_drc and those global
variables into nfs4state.c might be better, but again, there
isn't much to justify such a change.
Bruce, any thoughts?
> ---
> fs/nfsd/nfssvc.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
> index b603dfcdd..20f0a27fe 100644
> --- a/fs/nfsd/nfssvc.c
> +++ b/fs/nfsd/nfssvc.c
> @@ -88,7 +88,7 @@ DEFINE_MUTEX(nfsd_mutex);
> * version 4.1 DRC caches.
> * nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage.
> */
> -spinlock_t nfsd_drc_lock;
> +DEFINE_SPINLOCK(nfsd_drc_lock);
> unsigned long nfsd_drc_max_mem;
> unsigned long nfsd_drc_mem_used;
>
> @@ -568,7 +568,6 @@ static void set_max_drc(void)
> nfsd_drc_max_mem = (nr_free_buffer_pages()
> >> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE;
> nfsd_drc_mem_used = 0;
> - spin_lock_init(&nfsd_drc_lock);
> dprintk("%s nfsd_drc_max_mem %lu \n", __func__, nfsd_drc_max_mem);
> }
>
> --
> 2.25.1
>
--
Chuck Lever
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH -next] NFSD: Use DEFINE_SPINLOCK() for spinlock
@ 2021-04-06 12:08 Huang Guobin
2021-04-06 15:46 ` Chuck Lever III
2021-04-06 15:58 ` Chuck Lever III
0 siblings, 2 replies; 6+ messages in thread
From: Huang Guobin @ 2021-04-06 12:08 UTC (permalink / raw)
To: huangguobin4, J. Bruce Fields, Chuck Lever, Jeff Layton
Cc: linux-nfs, linux-kernel
From: Guobin Huang <huangguobin4@huawei.com>
spinlock can be initialized automatically with DEFINE_SPINLOCK()
rather than explicitly calling spin_lock_init().
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Guobin Huang <huangguobin4@huawei.com>
---
fs/nfsd/nfssvc.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index b2eef4112bc2..82ba034fa579 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -84,7 +84,7 @@ DEFINE_MUTEX(nfsd_mutex);
* version 4.1 DRC caches.
* nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage.
*/
-spinlock_t nfsd_drc_lock;
+DEFINE_SPINLOCK(nfsd_drc_lock);
unsigned long nfsd_drc_max_mem;
unsigned long nfsd_drc_mem_used;
@@ -563,7 +563,6 @@ static void set_max_drc(void)
nfsd_drc_max_mem = (nr_free_buffer_pages()
>> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE;
nfsd_drc_mem_used = 0;
- spin_lock_init(&nfsd_drc_lock);
dprintk("%s nfsd_drc_max_mem %lu \n", __func__, nfsd_drc_max_mem);
}
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH -next] NFSD: Use DEFINE_SPINLOCK() for spinlock
2021-04-06 12:08 [PATCH -next] NFSD: Use " Huang Guobin
@ 2021-04-06 15:46 ` Chuck Lever III
2021-04-06 15:55 ` Bruce Fields
2021-04-06 15:58 ` Chuck Lever III
1 sibling, 1 reply; 6+ messages in thread
From: Chuck Lever III @ 2021-04-06 15:46 UTC (permalink / raw)
To: Huang Guobin, Bruce Fields; +Cc: Jeff Layton, Linux NFS Mailing List, LKML
> On Apr 6, 2021, at 8:08 AM, Huang Guobin <huangguobin4@huawei.com> wrote:
>
> From: Guobin Huang <huangguobin4@huawei.com>
>
> spinlock can be initialized automatically with DEFINE_SPINLOCK()
> rather than explicitly calling spin_lock_init().
>
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Guobin Huang <huangguobin4@huawei.com>
This same patch was sent last July, without the Reported-by:
https://lore.kernel.org/linux-nfs/1617710898-49064-1-git-send-email-huangguobin4@huawei.com/T/#u
If I'm reading the code correctly, it appears that set_max_drc()
can be called more than once by user space API functions via
nfsd_create_serv().
It seems to me we want to guarantee that nfsd_drc_lock is
initialized exactly once, and using DEFINE_SPINLOCK() would
do just that.
Likewise, re-initializing nfsd_drc_mem_used is probably not good
to do either, but clobbering a spinlock like that might lead to
a crash.
Bruce, any further thoughts?
> ---
> fs/nfsd/nfssvc.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
> index b2eef4112bc2..82ba034fa579 100644
> --- a/fs/nfsd/nfssvc.c
> +++ b/fs/nfsd/nfssvc.c
> @@ -84,7 +84,7 @@ DEFINE_MUTEX(nfsd_mutex);
> * version 4.1 DRC caches.
> * nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage.
> */
> -spinlock_t nfsd_drc_lock;
> +DEFINE_SPINLOCK(nfsd_drc_lock);
> unsigned long nfsd_drc_max_mem;
> unsigned long nfsd_drc_mem_used;
>
> @@ -563,7 +563,6 @@ static void set_max_drc(void)
> nfsd_drc_max_mem = (nr_free_buffer_pages()
> >> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE;
> nfsd_drc_mem_used = 0;
> - spin_lock_init(&nfsd_drc_lock);
> dprintk("%s nfsd_drc_max_mem %lu \n", __func__, nfsd_drc_max_mem);
> }
>
>
--
Chuck Lever
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH -next] NFSD: Use DEFINE_SPINLOCK() for spinlock
2021-04-06 15:46 ` Chuck Lever III
@ 2021-04-06 15:55 ` Bruce Fields
0 siblings, 0 replies; 6+ messages in thread
From: Bruce Fields @ 2021-04-06 15:55 UTC (permalink / raw)
To: Chuck Lever III; +Cc: Huang Guobin, Jeff Layton, Linux NFS Mailing List, LKML
On Tue, Apr 06, 2021 at 03:46:34PM +0000, Chuck Lever III wrote:
>
>
> > On Apr 6, 2021, at 8:08 AM, Huang Guobin <huangguobin4@huawei.com> wrote:
> >
> > From: Guobin Huang <huangguobin4@huawei.com>
> >
> > spinlock can be initialized automatically with DEFINE_SPINLOCK()
> > rather than explicitly calling spin_lock_init().
> >
> > Reported-by: Hulk Robot <hulkci@huawei.com>
> > Signed-off-by: Guobin Huang <huangguobin4@huawei.com>
>
> This same patch was sent last July, without the Reported-by:
>
> https://lore.kernel.org/linux-nfs/1617710898-49064-1-git-send-email-huangguobin4@huawei.com/T/#u
>
> If I'm reading the code correctly, it appears that set_max_drc()
> can be called more than once by user space API functions via
> nfsd_create_serv().
>
> It seems to me we want to guarantee that nfsd_drc_lock is
> initialized exactly once, and using DEFINE_SPINLOCK() would
> do just that.
>
> Likewise, re-initializing nfsd_drc_mem_used is probably not good
> to do either, but clobbering a spinlock like that might lead to
> a crash.
>
> Bruce, any further thoughts?
The other nfsd_drc_lock users run in nfsd threads, which shouldn't be
running yet at the point we call set_max_drc.
Reinitializing the lock each time is pretty weird, though, ACK to the
patch even if it's just cleanup.
--b.
>
>
> > ---
> > fs/nfsd/nfssvc.c | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
> > index b2eef4112bc2..82ba034fa579 100644
> > --- a/fs/nfsd/nfssvc.c
> > +++ b/fs/nfsd/nfssvc.c
> > @@ -84,7 +84,7 @@ DEFINE_MUTEX(nfsd_mutex);
> > * version 4.1 DRC caches.
> > * nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage.
> > */
> > -spinlock_t nfsd_drc_lock;
> > +DEFINE_SPINLOCK(nfsd_drc_lock);
> > unsigned long nfsd_drc_max_mem;
> > unsigned long nfsd_drc_mem_used;
> >
> > @@ -563,7 +563,6 @@ static void set_max_drc(void)
> > nfsd_drc_max_mem = (nr_free_buffer_pages()
> > >> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE;
> > nfsd_drc_mem_used = 0;
> > - spin_lock_init(&nfsd_drc_lock);
> > dprintk("%s nfsd_drc_max_mem %lu \n", __func__, nfsd_drc_max_mem);
> > }
> >
> >
>
> --
> Chuck Lever
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH -next] NFSD: Use DEFINE_SPINLOCK() for spinlock
2021-04-06 12:08 [PATCH -next] NFSD: Use " Huang Guobin
2021-04-06 15:46 ` Chuck Lever III
@ 2021-04-06 15:58 ` Chuck Lever III
1 sibling, 0 replies; 6+ messages in thread
From: Chuck Lever III @ 2021-04-06 15:58 UTC (permalink / raw)
To: Huang Guobin
Cc: Bruce Fields, Jeff Layton, Linux NFS Mailing List, linux-kernel
Hello-
> On Apr 6, 2021, at 8:08 AM, Huang Guobin <huangguobin4@huawei.com> wrote:
>
> From: Guobin Huang <huangguobin4@huawei.com>
>
> spinlock can be initialized automatically with DEFINE_SPINLOCK()
> rather than explicitly calling spin_lock_init().
>
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Guobin Huang <huangguobin4@huawei.com>
This change has been pushed to the for-next topic branch in
git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git
> ---
> fs/nfsd/nfssvc.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
> index b2eef4112bc2..82ba034fa579 100644
> --- a/fs/nfsd/nfssvc.c
> +++ b/fs/nfsd/nfssvc.c
> @@ -84,7 +84,7 @@ DEFINE_MUTEX(nfsd_mutex);
> * version 4.1 DRC caches.
> * nfsd_drc_pages_used tracks the current version 4.1 DRC memory usage.
> */
> -spinlock_t nfsd_drc_lock;
> +DEFINE_SPINLOCK(nfsd_drc_lock);
> unsigned long nfsd_drc_max_mem;
> unsigned long nfsd_drc_mem_used;
>
> @@ -563,7 +563,6 @@ static void set_max_drc(void)
> nfsd_drc_max_mem = (nr_free_buffer_pages()
> >> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE;
> nfsd_drc_mem_used = 0;
> - spin_lock_init(&nfsd_drc_lock);
> dprintk("%s nfsd_drc_max_mem %lu \n", __func__, nfsd_drc_max_mem);
> }
>
>
--
Chuck Lever
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-04-06 15:59 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2020-07-25 8:56 [PATCH -next] nfsd: use DEFINE_SPINLOCK() for spinlock Qinglang Miao
2020-07-31 12:30 ` Chuck Lever
2021-04-06 12:08 [PATCH -next] NFSD: Use " Huang Guobin
2021-04-06 15:46 ` Chuck Lever III
2021-04-06 15:55 ` Bruce Fields
2021-04-06 15:58 ` Chuck Lever III
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