linux-kernel - Re: [PATCH V2] bcache: replace snprintf in show functions with sysfs

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Message-ID: <f63d7139-8843-793a-dfb8-b368e57ce425@suse.de>
Date:   Mon, 18 Oct 2021 22:47:00 +0800
From:   Coly Li <colyli@...e.de>
To:     Qing Wang <wangqing@...o.com>
Cc:     Kent Overstreet <kent.overstreet@...il.com>,
        linux-bcache@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V2] bcache: replace snprintf in show functions with
 sysfs_emit

On 10/13/21 7:58 PM, Qing Wang wrote:
> coccicheck complains about the use of snprintf() in sysfs show functions.
>
> Fix the following coccicheck warning:
> drivers/md/bcache/sysfs.h:54:12-20: WARNING: use scnprintf or sprintf.
>
> Implement sysfs_print() by sysfs_emit() and remove snprint() since no one
> uses it any more.
>
> Suggested-by: Coly Li <colyli@...e.de>
> Signed-off-by: Qing Wang <wangqing@...o.com>

It looks fine to me. Let me add it into my for-test directory.

Thanks for the fix up.

Coly Li

> ---
>   drivers/md/bcache/sysfs.h | 18 ++++++++++++++++--
>   drivers/md/bcache/util.h  | 17 -----------------
>   2 files changed, 16 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/md/bcache/sysfs.h b/drivers/md/bcache/sysfs.h
> index 215df32..c1752ba
> --- a/drivers/md/bcache/sysfs.h
> +++ b/drivers/md/bcache/sysfs.h
> @@ -51,13 +51,27 @@ STORE(fn)								\
>   #define sysfs_printf(file, fmt, ...)					\
>   do {									\
>   	if (attr == &sysfs_ ## file)					\
> -		return snprintf(buf, PAGE_SIZE, fmt "\n", __VA_ARGS__);	\
> +		return sysfs_emit(buf, fmt "\n", __VA_ARGS__);	\
>   } while (0)
>   
>   #define sysfs_print(file, var)						\
>   do {									\
>   	if (attr == &sysfs_ ## file)					\
> -		return snprint(buf, PAGE_SIZE, var);			\
> +		return sysfs_emit(buf,						\
> +				__builtin_types_compatible_p(typeof(var), int)		\
> +					 ? "%i\n" :				\
> +				__builtin_types_compatible_p(typeof(var), unsigned int)	\
> +					 ? "%u\n" :				\
> +				__builtin_types_compatible_p(typeof(var), long)		\
> +					 ? "%li\n" :			\
> +				__builtin_types_compatible_p(typeof(var), unsigned long)\
> +					 ? "%lu\n" :			\
> +				__builtin_types_compatible_p(typeof(var), int64_t)	\
> +					 ? "%lli\n" :			\
> +				__builtin_types_compatible_p(typeof(var), uint64_t)	\
> +					 ? "%llu\n" :			\
> +				__builtin_types_compatible_p(typeof(var), const char *)	\
> +					 ? "%s\n" : "%i\n", var);	\
>   } while (0)
>   
>   #define sysfs_hprint(file, val)						\
> diff --git a/drivers/md/bcache/util.h b/drivers/md/bcache/util.h
> index b64460a..fecdea1
> --- a/drivers/md/bcache/util.h
> +++ b/drivers/md/bcache/util.h
> @@ -340,23 +340,6 @@ static inline int bch_strtoul_h(const char *cp, long *res)
>   	_r;								\
>   })
>   
> -#define snprint(buf, size, var)						\
> -	snprintf(buf, size,						\
> -		__builtin_types_compatible_p(typeof(var), int)		\
> -		     ? "%i\n" :						\
> -		__builtin_types_compatible_p(typeof(var), unsigned int)	\
> -		     ? "%u\n" :						\
> -		__builtin_types_compatible_p(typeof(var), long)		\
> -		     ? "%li\n" :					\
> -		__builtin_types_compatible_p(typeof(var), unsigned long)\
> -		     ? "%lu\n" :					\
> -		__builtin_types_compatible_p(typeof(var), int64_t)	\
> -		     ? "%lli\n" :					\
> -		__builtin_types_compatible_p(typeof(var), uint64_t)	\
> -		     ? "%llu\n" :					\
> -		__builtin_types_compatible_p(typeof(var), const char *)	\
> -		     ? "%s\n" : "%i\n", var)
> -
>   ssize_t bch_hprint(char *buf, int64_t v);
>   
>   bool bch_is_zero(const char *p, size_t n);