linux-kernel - fs/splice.c:53:19: sparse: sparse: cast from restricted fmode

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Date: Thu, 4 Jan 2024 07:03:03 +0800
From: kernel test robot <lkp@...el.com>
To: Jens Axboe <axboe@...nel.dk>
Cc: oe-kbuild-all@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: fs/splice.c:53:19: sparse: sparse: cast from restricted fmode_t

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   610a9b8f49fbcf1100716370d3b5f6f884a2835a
commit: 0f99fc513ddd28de155c58547824a9fd63daacea splice: clear FMODE_NOWAIT on file if splice/vmsplice is used
date:   8 months ago
config: arm64-buildonly-randconfig-r004-20230608 (https://download.01.org/0day-ci/archive/20240104/202401040601.Ju49YpNa-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 12.3.0
reproduce: (https://download.01.org/0day-ci/archive/20240104/202401040601.Ju49YpNa-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@...el.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202401040601.Ju49YpNa-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/irqflags.h, include/linux/spinlock.h, include/linux/wait.h, ...):
   arch/arm64/include/asm/percpu.h:127:1: sparse: sparse: cast truncates bits from constant value (ffffffff becomes ff)
   arch/arm64/include/asm/percpu.h:127:1: sparse: sparse: cast truncates bits from constant value (ffffffff becomes ffff)
   arch/arm64/include/asm/percpu.h:127:1: sparse: sparse: cast truncates bits from constant value (ffffffff becomes ff)
   arch/arm64/include/asm/percpu.h:127:1: sparse: sparse: cast truncates bits from constant value (ffffffff becomes ffff)

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	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki