[tip: x86/misc] selftests/fpu: Fix debugfs_simple_attr.cocci warning

From: tip-bot2 for kernel test robot
Date: Mon Jan 18 2021 - 07:16:15 EST


The following commit has been merged into the x86/misc branch of tip:

Commit-ID: 443121b3ebb9025fd99ff11851d3537cb756d456
Gitweb: https://git.kernel.org/tip/443121b3ebb9025fd99ff11851d3537cb756d456
Author: kernel test robot <lkp@xxxxxxxxx>
AuthorDate: Sun, 25 Oct 2020 11:20:04 +01:00
Committer: Borislav Petkov <bp@xxxxxxx>
CommitterDate: Mon, 18 Jan 2021 11:03:26 +01:00

selftests/fpu: Fix debugfs_simple_attr.cocci warning

lib/test_fpu.c:66:0-23: WARNING: test_fpu_fops should be defined with DEFINE_DEBUGFS_ATTRIBUTE

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().

In order to protect against file removal races, debugfs files created
via debugfs_create_file() now get wrapped by a struct file_operations
at their opening.

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().

In order to help debugfs users who use the common
DEFINE_SIMPLE_ATTRIBUTE() + debugfs_create_file() idiom to
transition to removal safe struct file_operations, the helper macro
DEFINE_DEBUGFS_ATTRIBUTE() has been introduced.

Thus, the preferred strategy is to use
DEFINE_DEBUGFS_ATTRIBUTE() + debugfs_create_file_unsafe()
now.

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

Fixes: 4185b3b92792 ("selftests/fpu: Add an FPU selftest")
Signed-off-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Julia Lawall <julia.lawall@xxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Link: https://lkml.kernel.org/r/alpine.DEB.2.22.394.2010251117180.2714@hadrien
---
lib/test_fpu.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/test_fpu.c b/lib/test_fpu.c
index c33764a..e82db19 100644
--- a/lib/test_fpu.c
+++ b/lib/test_fpu.c
@@ -63,7 +63,7 @@ static int test_fpu_get(void *data, u64 *val)
return status;
}

-DEFINE_SIMPLE_ATTRIBUTE(test_fpu_fops, test_fpu_get, NULL, "%lld\n");
+DEFINE_DEBUGFS_ATTRIBUTE(test_fpu_fops, test_fpu_get, NULL, "%lld\n");
static struct dentry *selftest_dir;

static int __init test_fpu_init(void)
@@ -72,8 +72,8 @@ static int __init test_fpu_init(void)
if (!selftest_dir)
return -ENOMEM;

- debugfs_create_file("test_fpu", 0444, selftest_dir, NULL,
- &test_fpu_fops);
+ debugfs_create_file_unsafe("test_fpu", 0444, selftest_dir, NULL,
+ &test_fpu_fops);

return 0;
}