Re: [PATCH] Support lockref reference count if enable LOCK_STAT

[kernel test robot <lkp@intel.com>]

Hi yongli-oc,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]
[also build test WARNING on akpm-mm/mm-nonmm-unstable linus/master v6.12-rc7 next-20241113]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/yongli-oc/Support-lockref-reference-count-if-enable-LOCK_STAT/20241113-171348
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20241113085703.148839-1-yongli-oc%40zhaoxin.com
patch subject: [PATCH] Support lockref reference count if enable LOCK_STAT
config: s390-allmodconfig (https://download.01.org/0day-ci/archive/20241114/202411140548.NBssFC0E-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 592c0fe55f6d9a811028b5f3507be91458ab2713)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241114/202411140548.NBssFC0E-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202411140548.NBssFC0E-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from arch/s390/purgatory/purgatory.c:10:
   In file included from include/linux/kexec.h:18:
   In file included from include/linux/vmcore_info.h:6:
   In file included from include/linux/elfcore.h:11:
   In file included from include/linux/ptrace.h:10:
   In file included from include/linux/pid_namespace.h:7:
   In file included from include/linux/mm.h:1120:
   In file included from include/linux/huge_mm.h:7:
   In file included from include/linux/fs.h:8:
>> include/linux/dcache.h:369:13: warning: taking address of packed member 'lock' of class or structure 'lockref::(anonymous union)::struct (anonymous at include/linux/lockref.h:39:3)' may result in an unaligned pointer value [-Waddress-of-packed-member]
     369 |         spin_lock(&dentry->d_lock);
         |                    ^~~~~~~~~~~~~~
   include/linux/dcache.h:371:15: warning: taking address of packed member 'lock' of class or structure 'lockref::(anonymous union)::struct (anonymous at include/linux/lockref.h:39:3)' may result in an unaligned pointer value [-Waddress-of-packed-member]
     371 |         spin_unlock(&dentry->d_lock);
         |                      ^~~~~~~~~~~~~~
   2 warnings generated.


vim +369 include/linux/dcache.h

d83c49f3e36cec Al Viro 2010-04-30  366  
d83c49f3e36cec Al Viro 2010-04-30  367  static inline void dont_mount(struct dentry *dentry)
d83c49f3e36cec Al Viro 2010-04-30  368  {
d83c49f3e36cec Al Viro 2010-04-30 @369  	spin_lock(&dentry->d_lock);
d83c49f3e36cec Al Viro 2010-04-30  370  	dentry->d_flags |= DCACHE_CANT_MOUNT;
d83c49f3e36cec Al Viro 2010-04-30  371  	spin_unlock(&dentry->d_lock);
d83c49f3e36cec Al Viro 2010-04-30  372  }
d83c49f3e36cec Al Viro 2010-04-30  373  

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