[amir73il:user_path_file 2/2] fs/overlayfs/file.c:51:69: warning: passing argument 1 of 'file_user_cred' discards 'const' qualifier from pointer target type

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

tree:   https://github.com/amir73il/linux user_path_file
head:   e01a54da66bb15db70e9c68e9c4fcfd458fab424
commit: e01a54da66bb15db70e9c68e9c4fcfd458fab424 [2/2] backing_file: store user_path_file
config: x86_64-rhel-9.4-ltp (https://download.01.org/0day-ci/archive/20260109/202601091014.yhnPpyCU-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260109/202601091014.yhnPpyCU-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/202601091014.yhnPpyCU-lkp@intel.com/

All warnings (new ones prefixed by >>):

   fs/overlayfs/file.c: In function 'ovl_open_realfile':
>> fs/overlayfs/file.c:51:69: warning: passing argument 1 of 'file_user_cred' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
      51 |                                                      file_user_cred(file),
         |                                                                     ^~~~
   In file included from fs/overlayfs/file.c:14:
   include/linux/backing-file.h:32:62: note: expected 'struct file *' but argument is of type 'const struct file *'
      32 | static inline const struct cred *file_user_cred(struct file *f)
         |                                                 ~~~~~~~~~~~~~^


vim +51 fs/overlayfs/file.c

    26	
    27	static struct file *ovl_open_realfile(const struct file *file,
    28					      const struct path *realpath)
    29	{
    30		struct inode *realinode = d_inode(realpath->dentry);
    31		struct inode *inode = file_inode(file);
    32		struct mnt_idmap *real_idmap;
    33		struct file *realfile;
    34		int flags = file->f_flags | OVL_OPEN_FLAGS;
    35		int acc_mode = ACC_MODE(flags);
    36		int err;
    37	
    38		if (flags & O_APPEND)
    39			acc_mode |= MAY_APPEND;
    40	
    41		with_ovl_creds(inode->i_sb) {
    42			real_idmap = mnt_idmap(realpath->mnt);
    43			err = inode_permission(real_idmap, realinode, MAY_OPEN | acc_mode);
    44			if (err) {
    45				realfile = ERR_PTR(err);
    46			} else {
    47				if (!inode_owner_or_capable(real_idmap, realinode))
    48					flags &= ~O_NOATIME;
    49	
    50				realfile = backing_file_open(file_user_path(file),
  > 51							     file_user_cred(file),
    52							     flags, realpath, current_cred());
    53			}
    54		}
    55	
    56		pr_debug("open(%p[%pD2/%c], 0%o) -> (%p, 0%o)\n",
    57			 file, file, ovl_whatisit(inode, realinode), file->f_flags,
    58			 realfile, IS_ERR(realfile) ? 0 : realfile->f_flags);
    59	
    60		return realfile;
    61	}
    62	

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