[PATCH -next] EDAC: Fix debugfs_simple_attr.cocci warnings

[PATCH -next] EDAC: Fix debugfs_simple_attr.cocci warnings

[YueHaibing]

Use DEFINE_DEBUGFS_ATTRIBUTE rather than DEFINE_SIMPLE_ATTRIBUTE
for debugfs files.

Semantic patch information:
Rationale: DEFINE_SIMPLE_ATTRIBUTE + debugfs_create_file()
imposes some significant overhead as compared to
DEFINE_DEBUGFS_ATTRIBUTE + debugfs_create_file_unsafe().

Generated by: scripts/coccinelle/api/debugfs/debugfs_simple_attr.cocci

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
---
 drivers/edac/skx_edac.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/edac/skx_edac.c b/drivers/edac/skx_edac.c
index e840412..a9a32b3 100644
--- a/drivers/edac/skx_edac.c
+++ b/drivers/edac/skx_edac.c
@@ -913,12 +913,13 @@ static int debugfs_u64_set(void *data, u64 val)
 	return 0;
 }
 
-DEFINE_SIMPLE_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
+DEFINE_DEBUGFS_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
 
 static struct dentry *mydebugfs_create(const char *name, umode_t mode,
 				       struct dentry *parent, u64 *value)
 {
-	return debugfs_create_file(name, mode, parent, value, &fops_u64_wo);
+	return debugfs_create_file_unsafe(name, mode, parent, value,
+					  &fops_u64_wo);
 }
 
 static void setup_skx_debug(void)

Re: [PATCH -next] EDAC: Fix debugfs_simple_attr.cocci warnings

[Borislav Petkov]

On Fri, Oct 05, 2018 at 10:52:40AM +0000, YueHaibing wrote:
> Use DEFINE_DEBUGFS_ATTRIBUTE rather than DEFINE_SIMPLE_ATTRIBUTE
> for debugfs files.
> 
> Semantic patch information:
> Rationale: DEFINE_SIMPLE_ATTRIBUTE + debugfs_create_file()
> imposes some significant overhead as compared to

What significant overhead? This commit message needs to explain what is
wrong with the use of DEFINE_DEBUGFS_ATTRIBUTE first.

> DEFINE_DEBUGFS_ATTRIBUTE + debugfs_create_file_unsafe().

Reading the comment over this function:

 * It is your responsibility to protect your struct file_operation
 * methods against file removals by means of debugfs_use_file_start()
 * and debugfs_use_file_finish(). ->open() is still protected by
 * debugfs though.

doesn't sound like something I'd want to additionally pay attention to.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.