[v1] char: misc: Use IS_ERR() for filp_open() return value

[PATCH] char: misc: Use IS_ERR() for filp_open() return value

Posted by Alper Ak 1 month, 1 week ago

filp_open() never returns NULL, it returns either a valid pointer or an
error pointer. Using IS_ERR_OR_NULL() is unnecessary. Additionally, if
filp were NULL, PTR_ERR(NULL) would return 0, leading to a misleading
error message.

Fixes: 74d8361be344 ("char: misc: add test cases")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202506132058.thWZHlrb-lkp@intel.com/
Signed-off-by: Alper Ak <alperyasinak1@gmail.com>
---
 drivers/char/misc_minor_kunit.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/char/misc_minor_kunit.c b/drivers/char/misc_minor_kunit.c
index 6fc8b05169c5..e930c78e1ef9 100644
--- a/drivers/char/misc_minor_kunit.c
+++ b/drivers/char/misc_minor_kunit.c
@@ -166,7 +166,7 @@ static void __init miscdev_test_can_open(struct kunit *test, struct miscdevice *
 		KUNIT_FAIL(test, "failed to create node\n");
 
 	filp = filp_open(devname, O_RDONLY, 0);
-	if (IS_ERR_OR_NULL(filp))
+	if (IS_ERR(filp))
 		KUNIT_FAIL(test, "failed to open misc device: %ld\n", PTR_ERR(filp));
 	else
 		fput(filp);
-- 
2.43.0

Re: [PATCH] char: misc: Use IS_ERR() for filp_open() return value

Posted by Thadeu Lima de Souza Cascardo 1 month, 1 week ago

On Sat, Dec 27, 2025 at 02:02:48AM +0300, Alper Ak wrote:
> filp_open() never returns NULL, it returns either a valid pointer or an
> error pointer. Using IS_ERR_OR_NULL() is unnecessary. Additionally, if
> filp were NULL, PTR_ERR(NULL) would return 0, leading to a misleading
> error message.
> 
> Fixes: 74d8361be344 ("char: misc: add test cases")
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Closes: https://lore.kernel.org/r/202506132058.thWZHlrb-lkp@intel.com/
> Signed-off-by: Alper Ak <alperyasinak1@gmail.com>
> ---
>  drivers/char/misc_minor_kunit.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/char/misc_minor_kunit.c b/drivers/char/misc_minor_kunit.c
> index 6fc8b05169c5..e930c78e1ef9 100644
> --- a/drivers/char/misc_minor_kunit.c
> +++ b/drivers/char/misc_minor_kunit.c
> @@ -166,7 +166,7 @@ static void __init miscdev_test_can_open(struct kunit *test, struct miscdevice *
>  		KUNIT_FAIL(test, "failed to create node\n");
>  
>  	filp = filp_open(devname, O_RDONLY, 0);
> -	if (IS_ERR_OR_NULL(filp))
> +	if (IS_ERR(filp))
>  		KUNIT_FAIL(test, "failed to open misc device: %ld\n", PTR_ERR(filp));
>  	else
>  		fput(filp);
> -- 
> 2.43.0
> 

Acked-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>