Re: [PATCH] proc: align mnt_id in /proc/pid/fdinfo and /proc/pid/mountinfo

[kbuild test robot]

Hi Hu",

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v5.4-rc8 next-20191121]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Chen-Hu/proc-align-mnt_id-in-proc-pid-fdinfo-and-proc-pid-mountinfo/20191122-093927
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 81429eb8d9ca40b0c65bb739d29fa856c5d5e958
config: parisc-c3000_defconfig (attached as .config)
compiler: hppa-linux-gcc (GCC) 7.4.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.4.0 make.cross ARCH=parisc 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

   fs/namespace.c: In function 'lookup_mirror_mnt':
>> fs/namespace.c:698:10: warning: return discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
      return mnt;
             ^~~

vim +/const +698 fs/namespace.c

   685	
   686	/*
   687	 * lookup_mirror_mnt - Return @mnt's mirror mount in the current/local mount
   688	 * namespace. If mirror isn't found, just return NULL.
   689	 */
   690	struct mount *lookup_mirror_mnt(const struct mount *mnt)
   691	{
   692		struct mnt_namespace *ns = current->nsproxy->mnt_ns;
   693		struct mount *mnt_local;
   694		bool is_matched = false;
   695	
   696		/* mnt belongs to current namesapce */
   697		if (mnt->mnt_ns == ns)
 > 698			return mnt;
   699	
   700		down_read(&namespace_sem);
   701		list_for_each_entry(mnt_local, &ns->list, mnt_list) {
   702			struct super_block *sb = mnt->mnt.mnt_sb;
   703			struct super_block *sb_local = mnt_local->mnt.mnt_sb;
   704	
   705			if (MAJOR(sb->s_dev) == MAJOR(sb_local->s_dev) &&
   706			    MINOR(sb->s_dev) == MINOR(sb_local->s_dev)) {
   707				is_matched = true;
   708				break;
   709			}
   710		}
   711		up_read(&namespace_sem);
   712	
   713		return is_matched ? mnt_local : NULL;
   714	}
   715	

---
0-DAY kernel test infrastructure                 Open Source Technology Center
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