diff mbox series

ceph: Replace DEFINE_SIMPLE_ATTRIBUTE with DEFINE_DEBUGFS_ATTRIBUTE

Message ID 1612165930-110076-1-git-send-email-jiapeng.chong@linux.alibaba.com (mailing list archive)
State New, archived
Headers show
Series ceph: Replace DEFINE_SIMPLE_ATTRIBUTE with DEFINE_DEBUGFS_ATTRIBUTE | expand

Commit Message

Jiapeng Chong Feb. 1, 2021, 7:52 a.m. UTC
Fix the following coccicheck warning:

./fs/ceph/debugfs.c:347:0-23: WARNING: congestion_kb_fops should be
defined with DEFINE_DEBUGFS_ATTRIBUTE.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
---
 fs/ceph/debugfs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Jeff Layton Feb. 1, 2021, 7:01 p.m. UTC | #1
On Mon, 2021-02-01 at 15:52 +0800, Jiapeng Chong wrote:
> Fix the following coccicheck warning:
> 
> ./fs/ceph/debugfs.c:347:0-23: WARNING: congestion_kb_fops should be
> defined with DEFINE_DEBUGFS_ATTRIBUTE.
> 
> Reported-by: Abaci Robot <abaci@linux.alibaba.com>
> Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
> ---
>  fs/ceph/debugfs.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
> index 66989c8..617327e 100644
> --- a/fs/ceph/debugfs.c
> +++ b/fs/ceph/debugfs.c
> @@ -344,8 +344,8 @@ static int congestion_kb_get(void *data, u64 *val)
>  	return 0;
>  }
>  
> 
> -DEFINE_SIMPLE_ATTRIBUTE(congestion_kb_fops, congestion_kb_get,
> -			congestion_kb_set, "%llu\n");
> +DEFINE_DEBUGFS_ATTRIBUTE(congestion_kb_fops, congestion_kb_get,
> +			  congestion_kb_set, "%llu\n");
>  
> 
>  
> 
>  void ceph_fs_debugfs_cleanup(struct ceph_fs_client *fsc)

Looks reasonable. Merged into ceph-client/testing branch.

Thanks!
Ilya Dryomov Feb. 2, 2021, 12:07 p.m. UTC | #2
On Mon, Feb 1, 2021 at 8:52 AM Jiapeng Chong
<jiapeng.chong@linux.alibaba.com> wrote:
>
> Fix the following coccicheck warning:
>
> ./fs/ceph/debugfs.c:347:0-23: WARNING: congestion_kb_fops should be
> defined with DEFINE_DEBUGFS_ATTRIBUTE.
>
> Reported-by: Abaci Robot <abaci@linux.alibaba.com>
> Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
> ---
>  fs/ceph/debugfs.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
> index 66989c8..617327e 100644
> --- a/fs/ceph/debugfs.c
> +++ b/fs/ceph/debugfs.c
> @@ -344,8 +344,8 @@ static int congestion_kb_get(void *data, u64 *val)
>         return 0;
>  }
>
> -DEFINE_SIMPLE_ATTRIBUTE(congestion_kb_fops, congestion_kb_get,
> -                       congestion_kb_set, "%llu\n");
> +DEFINE_DEBUGFS_ATTRIBUTE(congestion_kb_fops, congestion_kb_get,
> +                         congestion_kb_set, "%llu\n");
>
>
>  void ceph_fs_debugfs_cleanup(struct ceph_fs_client *fsc)

Hi Jiapeng,

What is the benefit of this conversion?

From a quick look, with DEFINE_DEBUGFS_ATTRIBUTE writeback_congestion_kb
file would no longer be seekable.  It may not matter much, but something
that should have been mentioned.

Futher, debugfs_create_file() creates a full proxy for fops, protecting
against removal races.  DEFINE_DEBUGFS_ATTRIBUTE adds its own protection
but just for ->read() and ->write().  I don't think we need both.

Thanks,

                Ilya
Jeff Layton Feb. 2, 2021, 12:45 p.m. UTC | #3
On Tue, 2021-02-02 at 13:07 +0100, Ilya Dryomov wrote:
> On Mon, Feb 1, 2021 at 8:52 AM Jiapeng Chong
> <jiapeng.chong@linux.alibaba.com> wrote:
> > 
> > Fix the following coccicheck warning:
> > 
> > ./fs/ceph/debugfs.c:347:0-23: WARNING: congestion_kb_fops should be
> > defined with DEFINE_DEBUGFS_ATTRIBUTE.
> > 
> > Reported-by: Abaci Robot <abaci@linux.alibaba.com>
> > Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
> > ---
> >  fs/ceph/debugfs.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
> > index 66989c8..617327e 100644
> > --- a/fs/ceph/debugfs.c
> > +++ b/fs/ceph/debugfs.c
> > @@ -344,8 +344,8 @@ static int congestion_kb_get(void *data, u64 *val)
> >         return 0;
> >  }
> > 
> > -DEFINE_SIMPLE_ATTRIBUTE(congestion_kb_fops, congestion_kb_get,
> > -                       congestion_kb_set, "%llu\n");
> > +DEFINE_DEBUGFS_ATTRIBUTE(congestion_kb_fops, congestion_kb_get,
> > +                         congestion_kb_set, "%llu\n");
> > 
> > 
> >  void ceph_fs_debugfs_cleanup(struct ceph_fs_client *fsc)
> 
> Hi Jiapeng,
> 
> What is the benefit of this conversion?
> 
> From a quick look, with DEFINE_DEBUGFS_ATTRIBUTE writeback_congestion_kb
> file would no longer be seekable.  It may not matter much, but something
> that should have been mentioned.
> 
> Futher, debugfs_create_file() creates a full proxy for fops, protecting
> against removal races.  DEFINE_DEBUGFS_ATTRIBUTE adds its own protection
> but just for ->read() and ->write().  I don't think we need both.
> 


The coccinelle script clarifies some of this. See the commit log here:

    https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5103068eaca290f890a30aae70085fac44cecaf6

That said, it also mentions that the file should be converted to use
debugfs_create_file_unsafe now as well, and that wasn't done in this
patch. Jiapeng, was that intentional? If so, why?
Jeff Layton Feb. 2, 2021, 4:01 p.m. UTC | #4
On Tue, 2021-02-02 at 07:45 -0500, Jeff Layton wrote:
> On Tue, 2021-02-02 at 13:07 +0100, Ilya Dryomov wrote:
> > On Mon, Feb 1, 2021 at 8:52 AM Jiapeng Chong
> > <jiapeng.chong@linux.alibaba.com> wrote:
> > > 
> > > Fix the following coccicheck warning:
> > > 
> > > ./fs/ceph/debugfs.c:347:0-23: WARNING: congestion_kb_fops should be
> > > defined with DEFINE_DEBUGFS_ATTRIBUTE.
> > > 
> > > Reported-by: Abaci Robot <abaci@linux.alibaba.com>
> > > Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
> > > ---
> > >  fs/ceph/debugfs.c | 4 ++--
> > >  1 file changed, 2 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
> > > index 66989c8..617327e 100644
> > > --- a/fs/ceph/debugfs.c
> > > +++ b/fs/ceph/debugfs.c
> > > @@ -344,8 +344,8 @@ static int congestion_kb_get(void *data, u64 *val)
> > >         return 0;
> > >  }
> > > 
> > > -DEFINE_SIMPLE_ATTRIBUTE(congestion_kb_fops, congestion_kb_get,
> > > -                       congestion_kb_set, "%llu\n");
> > > +DEFINE_DEBUGFS_ATTRIBUTE(congestion_kb_fops, congestion_kb_get,
> > > +                         congestion_kb_set, "%llu\n");
> > > 
> > > 
> > >  void ceph_fs_debugfs_cleanup(struct ceph_fs_client *fsc)
> > 
> > Hi Jiapeng,
> > 
> > What is the benefit of this conversion?
> > 
> > From a quick look, with DEFINE_DEBUGFS_ATTRIBUTE writeback_congestion_kb
> > file would no longer be seekable.  It may not matter much, but something
> > that should have been mentioned.
> > 
> > Futher, debugfs_create_file() creates a full proxy for fops, protecting
> > against removal races.  DEFINE_DEBUGFS_ATTRIBUTE adds its own protection
> > but just for ->read() and ->write().  I don't think we need both.
> > 
> 
> 
> The coccinelle script clarifies some of this. See the commit log here:
> 
>     https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5103068eaca290f890a30aae70085fac44cecaf6
> 
> That said, it also mentions that the file should be converted to use
> debugfs_create_file_unsafe now as well, and that wasn't done in this
> patch. Jiapeng, was that intentional? If so, why?
> 

For now, I've dropped this patch until the situation with
debugfs_create_file_unsafe is clear.
diff mbox series

Patch

diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
index 66989c8..617327e 100644
--- a/fs/ceph/debugfs.c
+++ b/fs/ceph/debugfs.c
@@ -344,8 +344,8 @@  static int congestion_kb_get(void *data, u64 *val)
 	return 0;
 }
 
-DEFINE_SIMPLE_ATTRIBUTE(congestion_kb_fops, congestion_kb_get,
-			congestion_kb_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(congestion_kb_fops, congestion_kb_get,
+			  congestion_kb_set, "%llu\n");
 
 
 void ceph_fs_debugfs_cleanup(struct ceph_fs_client *fsc)