re: Btrfs: split up __extent_writepage to lower stack usage

2014-06-09 Thread Dan Carpenter 
Hello Chris Mason,

The patch 263524b4ac6b: Btrfs: split up __extent_writepage to lower
stack usage from May 21, 2014, leads to the following static checker
warning:

fs/btrfs/extent_io.c:4071 try_release_extent_state()
warn: use 'mask' here instead of GFP_XXX?

fs/btrfs/extent_io.c
  4053  static int try_release_extent_state(struct extent_map_tree *map,
  4054  struct extent_io_tree *tree,
  4055  struct page *page, gfp_t mask)
  4056  {
  4057  u64 start = page_offset(page);
  4058  u64 end = start + PAGE_CACHE_SIZE - 1;
  4059  int ret = 1;
  4060  
  4061  if (test_range_bit(tree, start, end,
  4062 EXTENT_IOBITS, 0, NULL))
  4063  ret = 0;
  4064  else {
  4065  if ((mask  GFP_NOFS) == GFP_NOFS)
  4066  mask = GFP_NOFS;
  4067  /*
  4068   * at this point we can safely clear everything except 
the
  4069   * locked bit and the nodatasum bit
  4070   */
  4071  ret = clear_extent_bit(tree, start, end,
  4072   ~(EXTENT_LOCKED | EXTENT_NODATASUM),
  4073   0, 0, NULL, GFP_ATOMIC);
 ^^
It upsets the static checkers to keep mask around when we don't use it
anymore.

  4074  
  4075  /* if clear_extent_bit failed for enomem reasons,
  4076   * we can't allow the release to continue.
  4077   */
  4078  if (ret  0)
  4079  ret = 0;
  4080  else
  4081  ret = 1;
  4082  }
  4083  return ret;
  4084  }

regards,
dan carpenter
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Re: Btrfs: split up __extent_writepage to lower stack usage

2014-06-09 Thread Chris Mason 
On 06/09/2014 10:40 AM, Dan Carpenter wrote:
 Hello Chris Mason,
 
 The patch 263524b4ac6b: Btrfs: split up __extent_writepage to lower
 stack usage from May 21, 2014, leads to the following static checker
 warning:
 
   fs/btrfs/extent_io.c:4071 try_release_extent_state()
   warn: use 'mask' here instead of GFP_XXX?
 
 fs/btrfs/extent_io.c
   4053  static int try_release_extent_state(struct extent_map_tree *map,
   4054  struct extent_io_tree *tree,
   4055  struct page *page, gfp_t mask)
   4056  {
   4057  u64 start = page_offset(page);
   4058  u64 end = start + PAGE_CACHE_SIZE - 1;
   4059  int ret = 1;
   4060  
   4061  if (test_range_bit(tree, start, end,
   4062 EXTENT_IOBITS, 0, NULL))
   4063  ret = 0;
   4064  else {
   4065  if ((mask  GFP_NOFS) == GFP_NOFS)
   4066  mask = GFP_NOFS;
   4067  /*
   4068   * at this point we can safely clear everything 
 except the
   4069   * locked bit and the nodatasum bit
   4070   */
   4071  ret = clear_extent_bit(tree, start, end,
   4072   ~(EXTENT_LOCKED | EXTENT_NODATASUM),
   4073   0, 0, NULL, GFP_ATOMIC);
  ^^
 It upsets the static checkers to keep mask around when we don't use it
 anymore.

Thanks Dan, I'll switch this around to make it more clear.

-chris
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