powerpc/cell/axon_msi: replace DEFINE_SIMPLE_ATTRIBUTE with DEFINE_DEBUGFS_ATTRIBUTE

From: zhang songyi <redacted>

Fix the following coccicheck warning:
/arch/powerpc/platforms/cell/axon_msi.c:457:0-23: WARNING:
fops_msic should be defined with DEFINE_DEBUGFS_ATTRIBUTE

Signed-off-by: zhang songyi <redacted>
---
 arch/powerpc/platforms/cell/axon_msi.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/cell/axon_msi.c b/arch/powerpc/platforms/cell/axon_msi.c
index 5b012abca773..ab080b5022ff 100644
--- a/arch/powerpc/platforms/cell/axon_msi.c
+++ b/arch/powerpc/platforms/cell/axon_msi.c

@@ -454,7 +454,7 @@ static int msic_get(void *data, u64 *val)
        return 0;
 }

-DEFINE_SIMPLE_ATTRIBUTE(fops_msic, msic_get, msic_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_msic, msic_get, msic_set, "%llu\n");

 void axon_msi_debug_setup(struct device_node *dn, struct axon_msic *msic)
 {

@@ -475,6 +475,7 @@ void axon_msi_debug_setup(struct device_node *dn, struct axon_msic *msic)

        snprintf(name, sizeof(name), "msic_%d", of_node_to_nid(dn));

-       debugfs_create_file(name, 0600, arch_debugfs_dir, msic, &fops_msic);
+       debugfs_create_file_unsafe(name, 0600, arch_debugfs_dir,
+                                  msic, &fops_msic);
 }
 #endif /* DEBUG */
--

2.15.2

Hi,

Le 23/11/2022 à 10:06, zhang.songyi@zte.com.cn a écrit :

From: zhang songyi <redacted>

Fix the following coccicheck warning:
/arch/powerpc/platforms/cell/axon_msi.c:457:0-23: WARNING:
fops_msic should be defined with DEFINE_DEBUGFS_ATTRIBUTE

What's the difference between this new patch and the one that is already 
awaiting application here : 
https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20211222090655.484551-1-deng.changcheng@zte.com.cn/ 
?

The only difference I see it that the already existing patch has a more 
complete description of the change, so unless I'm missing something it 
would be nice to avoid sending the same changes again and again.

Thanks
Christophe

Christophe Leroy [off-list ref] writes:

Hi,

Le 23/11/2022 à 10:06, zhang.songyi@zte.com.cn a écrit :

quoted

From: zhang songyi <redacted>

Fix the following coccicheck warning:
/arch/powerpc/platforms/cell/axon_msi.c:457:0-23: WARNING:
fops_msic should be defined with DEFINE_DEBUGFS_ATTRIBUTE

What's the difference between this new patch and the one that is already 
awaiting application here : 
https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20211222090655.484551-1-deng.changcheng@zte.com.cn/ 
?

The only difference I see it that the already existing patch has a more 
complete description of the change, so unless I'm missing something it 
would be nice to avoid sending the same changes again and again.

Both patches switch the code to use a function called "unsafe" without
adequately explaining why that is OK.

The commit that added the cocci check script says:

  If the original struct file_operations are known to be safe against removal
  races by themselves already, the proxy creation may be bypassed by creating
  the files through debugfs_create_file_unsafe().

None of these conversion patches ever contain any explanation which
speaks to that.

In this case I *think* the change is OK and there is no race because the
debugfs file is never removed. But I really wish the submitter would
tell me that in the change log.

cheers