fs/splice.c:53:19: sparse: sparse: cast from restricted fmode_t

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

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   ac865f00af293d081356bec56eea90815094a60e
commit: 0f99fc513ddd28de155c58547824a9fd63daacea splice: clear FMODE_NOWAIT on file if splice/vmsplice is used
date:   8 months ago
config: csky-randconfig-r013-20230825 (https://download.01.org/0day-ci/archive/20240104/202401041120.Cr5feSew-lkp@intel.com/config)
compiler: csky-linux-gcc (GCC) 12.3.0
reproduce: (https://download.01.org/0day-ci/archive/20240104/202401041120.Cr5feSew-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/202401041120.Cr5feSew-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> fs/splice.c:53:19: sparse: sparse: cast from restricted fmode_t
>> fs/splice.c:53:19: sparse: sparse: cast from restricted fmode_t
>> fs/splice.c:53:19: sparse: sparse: cast to restricted fmode_t
   fs/splice.c: note: in included file (through include/linux/mmzone.h, include/linux/gfp.h, include/linux/xarray.h, ...):
   include/linux/page-flags.h:246:46: sparse: sparse: self-comparison always evaluates to false

vim +53 fs/splice.c

    39	
    40	/*
    41	 * Splice doesn't support FMODE_NOWAIT. Since pipes may set this flag to
    42	 * indicate they support non-blocking reads or writes, we must clear it
    43	 * here if set to avoid blocking other users of this pipe if splice is
    44	 * being done on it.
    45	 */
    46	static noinline void noinline pipe_clear_nowait(struct file *file)
    47	{
    48		fmode_t fmode = READ_ONCE(file->f_mode);
    49	
    50		do {
    51			if (!(fmode & FMODE_NOWAIT))
    52				break;
  > 53		} while (!try_cmpxchg(&file->f_mode, &fmode, fmode & ~FMODE_NOWAIT));
    54	}
    55	

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