Re: [PATCH] media: qcom: camss: avoid format string warning

[Bryan O'Donoghue]

On 20/03/2026 15:18, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@xxxxxxxx>
>
> clang-22 warns about csiphy_match_clock_name() taking a variable format
> string that is not checked against the 'int index' argument:
>
> drivers/media/platform/qcom/camss/camss-csiphy.c:566:44: error: diagnostic behavior may be improved by
>        adding the 'format(printf, 2, 3)' attribute to the declaration of 'csiphy_match_clock_name'
>        [-Werror,-Wmissing-format-attribute]
>    561 | static bool csiphy_match_clock_name(const char *clock_name, const char *format,
>        | __attribute__((format(printf, 2, 3)))
>    562 |                                     int index)
>    563 | {
>    564 |         char name[16]; /* csiphyXXX_timer\0 */
>    565 |
>    566 |         snprintf(name, sizeof(name), format, index);
>        |                                                   ^
> drivers/media/platform/qcom/camss/camss-csiphy.c:561:13: note: 'csiphy_match_clock_name' declared here
>    561 | static bool csiphy_match_clock_name(const char *clock_name, const char *format,
>        |             ^
>
> Change the function to use a snprintf() style format string that allows this
> to be checked at the call site.
>
> Fixes: 0727615fb975 ("media: qcom: camss: Functionally decompose CSIPHY clock lookups")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
>   drivers/media/platform/qcom/camss/camss-csiphy.c | 10 +++++++---
>   1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/media/platform/qcom/camss/camss-csiphy.c b/drivers/media/platform/qcom/camss/camss-csiphy.c
> index 62623393f414..78a1b568dbae 100644
> --- a/drivers/media/platform/qcom/camss/camss-csiphy.c
> +++ b/drivers/media/platform/qcom/camss/camss-csiphy.c
> @@ -558,12 +558,16 @@ static int csiphy_init_formats(struct v4l2_subdev *sd,
>   	return csiphy_set_format(sd, fh ? fh->state : NULL, &format);
>   }
>   
> -static bool csiphy_match_clock_name(const char *clock_name, const char *format,
> -				    int index)
> +static bool __printf(2, 3)
> +csiphy_match_clock_name(const char *clock_name, const char *format, ...)
>   {
>   	char name[16]; /* csiphyXXX_timer\0 */
> +	va_list args;
> +
> +	va_start(args, format);
> +	vsnprintf(name, sizeof(name), format, args);
> +	va_end(args);
>   
> -	snprintf(name, sizeof(name), format, index);
>   	return !strcmp(clock_name, name);
>   }
>   
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>