[PATCH] dm snapshot: remove unneeded variable

[PATCH] dm snapshot: remove unneeded variable

[cgel.zte]

From: ran jianping <ran.jianping@zte.com.cn>

Fix the following coccicheck review:
./drivers/md/dm-snap-transient.c:91:10-12: Unneeded variable

Remove unneeded variable used to store return value.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: ran jianping <ran.jianping@zte.com.cn>
---
 drivers/md/dm-snap-transient.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/md/dm-snap-transient.c b/drivers/md/dm-snap-transient.c
index 0e0ae4c36b37..d95b59855da0 100644
--- a/drivers/md/dm-snap-transient.c
+++ b/drivers/md/dm-snap-transient.c
@@ -88,7 +88,6 @@ static unsigned transient_status(struct dm_exception_store *store,
 				 status_type_t status, char *result,
 				 unsigned maxlen)
 {
-	unsigned sz = 0;
 
 	switch (status) {
 	case STATUSTYPE_INFO:
@@ -101,7 +100,7 @@ static unsigned transient_status(struct dm_exception_store *store,
 		break;
 	}
 
-	return sz;
+	return 0;
 }
 
 static struct dm_exception_store_type _transient_type = {
-- 
2.25.1

Re: [PATCH] dm snapshot: remove unneeded variable

[kernel test robot]

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Hi,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on device-mapper-dm/for-next]
[also build test ERROR on v5.15 next-20211111]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/cgel-zte-gmail-com/dm-snapshot-remove-unneeded-variable/20211111-155800
base:   https://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm.git for-next
config: ia64-defconfig (attached as .config)
compiler: ia64-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/f69a0e783035cffc39b44a355d0e0470d5d63a0b
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review cgel-zte-gmail-com/dm-snapshot-remove-unneeded-variable/20211111-155800
        git checkout f69a0e783035cffc39b44a355d0e0470d5d63a0b
        # save the attached .config to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=ia64 SHELL=/bin/bash drivers/md/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from drivers/md/dm-exception-store.h:15,
                    from drivers/md/dm-snap-transient.c:8:
   drivers/md/dm-snap-transient.c: In function 'transient_status':
>> include/linux/device-mapper.h:602:22: error: 'sz' undeclared (first use in this function); did you mean 's8'?
     602 | #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
         |                      ^~
   drivers/md/dm-snap-transient.c:96:17: note: in expansion of macro 'DMEMIT'
      96 |                 DMEMIT(" N %llu", (unsigned long long)store->chunk_size);
         |                 ^~~~~~
   include/linux/device-mapper.h:602:22: note: each undeclared identifier is reported only once for each function it appears in
     602 | #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
         |                      ^~
   drivers/md/dm-snap-transient.c:96:17: note: in expansion of macro 'DMEMIT'
      96 |                 DMEMIT(" N %llu", (unsigned long long)store->chunk_size);
         |                 ^~~~~~


vim +602 include/linux/device-mapper.h

0da336e5fab75c Alasdair G Kergon 2008-04-24  601  
0da336e5fab75c Alasdair G Kergon 2008-04-24 @602  #define DMEMIT(x...) sz += ((sz >= maxlen) ? \
0da336e5fab75c Alasdair G Kergon 2008-04-24  603  			  0 : scnprintf(result + sz, maxlen - sz, x))
0da336e5fab75c Alasdair G Kergon 2008-04-24  604  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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Re: dm snapshot: remove unneeded variable

[Mike Snitzer]

On Thu, Nov 11 2021 at  2:56P -0500,
cgel.zte@gmail.com <cgel.zte@gmail.com> wrote:

> From: ran jianping <ran.jianping@zte.com.cn>
> 
> Fix the following coccicheck review:
> ./drivers/md/dm-snap-transient.c:91:10-12: Unneeded variable
> 
> Remove unneeded variable used to store return value.
> 
> Reported-by: Zeal Robot <zealci@zte.com.cn>
> Signed-off-by: ran jianping <ran.jianping@zte.com.cn>
> ---
>  drivers/md/dm-snap-transient.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/md/dm-snap-transient.c b/drivers/md/dm-snap-transient.c
> index 0e0ae4c36b37..d95b59855da0 100644
> --- a/drivers/md/dm-snap-transient.c
> +++ b/drivers/md/dm-snap-transient.c
> @@ -88,7 +88,6 @@ static unsigned transient_status(struct dm_exception_store *store,
>  				 status_type_t status, char *result,
>  				 unsigned maxlen)
>  {
> -	unsigned sz = 0;
>  
>  	switch (status) {
>  	case STATUSTYPE_INFO:
> @@ -101,7 +100,7 @@ static unsigned transient_status(struct dm_exception_store *store,
>  		break;
>  	}
>  
> -	return sz;
> +	return 0;
>  }
>  
>  static struct dm_exception_store_type _transient_type = {
> -- 
> 2.25.1
> 

You clearly didn't even compile test this.

Nacked-by: Mike Snitzer <snitzer@redhat.com>