[PATCH] bcache: replace snprintf in show functions with sysfs_emit

[PATCH] bcache: replace snprintf in show functions with sysfs_emit

[Qing Wang]

coccicheck complains about the use of snprintf() in sysfs show functions.

Fix the coccicheck warning:
WARNING: use scnprintf or sprintf.

Use sysfs_emit instead of scnprintf or sprintf makes more sense.

Signed-off-by: Qing Wang <wangqing@vivo.com>
---
 drivers/md/bcache/sysfs.c | 2 +-
 drivers/md/bcache/sysfs.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index 05ac1d6..e146c9e 100644
--- a/drivers/md/bcache/sysfs.c
+++ b/drivers/md/bcache/sysfs.c
@@ -639,7 +639,7 @@ static int bch_bset_print_stats(struct cache_set *c, char *buf)
 	if (ret < 0)
 		return ret;
 
-	return snprintf(buf, PAGE_SIZE,
+	return sysfs_emit(buf,
 			"btree nodes:		%zu\n"
 			"written sets:		%zu\n"
 			"unwritten sets:		%zu\n"
diff --git a/drivers/md/bcache/sysfs.h b/drivers/md/bcache/sysfs.h
index 215df32..8bec32d 100644
--- a/drivers/md/bcache/sysfs.h
+++ b/drivers/md/bcache/sysfs.h
@@ -51,7 +51,7 @@ 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)						\
-- 
2.7.4

Re: [PATCH] bcache: replace snprintf in show functions with sysfs_emit

[Coly Li]

On 10/13/21 11:27 AM, Qing Wang wrote:
> coccicheck complains about the use of snprintf() in sysfs show functions.
>
> Fix the coccicheck warning:
> WARNING: use scnprintf or sprintf.
>
> Use sysfs_emit instead of scnprintf or sprintf makes more sense.
>
> Signed-off-by: Qing Wang <wangqing@vivo.com>
> ---
>   drivers/md/bcache/sysfs.c | 2 +-
>   drivers/md/bcache/sysfs.h | 2 +-
>   2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
> index 05ac1d6..e146c9e 100644
> --- a/drivers/md/bcache/sysfs.c
> +++ b/drivers/md/bcache/sysfs.c
> @@ -639,7 +639,7 @@ static int bch_bset_print_stats(struct cache_set *c, char *buf)
>   	if (ret < 0)
>   		return ret;
>   
> -	return snprintf(buf, PAGE_SIZE,
> +	return sysfs_emit(buf,
>   			"btree nodes:		%zu\n"
>   			"written sets:		%zu\n"
>   			"unwritten sets:		%zu\n"

Let's keep this location as snprintf(), to make code style be consistent.


> diff --git a/drivers/md/bcache/sysfs.h b/drivers/md/bcache/sysfs.h
> index 215df32..8bec32d 100644
> --- a/drivers/md/bcache/sysfs.h
> +++ b/drivers/md/bcache/sysfs.h
> @@ -51,7 +51,7 @@ 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)						\

IMHO I like this change :-) BTW, for snprint() from util.h, it seems 
only to be used by sysfs_print() in syfs.h, would you like to change it 
to use sysfs_emit too ?

Thanks for the patch.

Coly Li

回复: [PATCH] bcache: replace snprintf in show functions with sysfs_emit

[王擎]

>>
>> diff --git a/drivers/md/bcache/sysfs.h b/drivers/md/bcache/sysfs.h
>> index 215df32..8bec32d 100644
>> --- a/drivers/md/bcache/sysfs.h
>> +++ b/drivers/md/bcache/sysfs.h
>> @@ -51,7 +51,7 @@ 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)                                              \
> 
> IMHO I like this change :-) BTW, for snprint() from util.h, it seems 
> only to be used by sysfs_print() in syfs.h, would you like to change it 
> to use sysfs_emit too ?
> 
> Thanks for the patch.
> 
> Coly Li
> 

sysfs_print() should also be modified if size is a fixed value PAGE_SIZE, 
but here is param, it would be appreciate if you have better method.

Thanks,

Qing

Re: 回复: [PATCH] bcache: replace snprintf in show functions with sysfs_emit

[Coly Li]

On 10/13/21 3:39 PM, 王擎 wrote:
>>> diff --git a/drivers/md/bcache/sysfs.h b/drivers/md/bcache/sysfs.h
>>> index 215df32..8bec32d 100644
>>> --- a/drivers/md/bcache/sysfs.h
>>> +++ b/drivers/md/bcache/sysfs.h
>>> @@ -51,7 +51,7 @@ 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)                                              \
>> IMHO I like this change :-) BTW, for snprint() from util.h, it seems
>> only to be used by sysfs_print() in syfs.h, would you like to change it
>> to use sysfs_emit too ?
>>
>> Thanks for the patch.
>>
>> Coly Li
>>
> sysfs_print() should also be modified if size is a fixed value PAGE_SIZE,
> but here is param, it would be appreciate if you have better method.

Yes, I meant you may implement sysfs_print() by sysfs_emit() directly in 
the way as snprint() does. Then you may remove snprint() since no one 
uses it any more.

Coly Li