btrfs: replace map_lookup->stripe_len by BTRFS_STRIPE_LEN

Currently btrfs doesn't support stripe lengths other than 64KiB.
This is already set in the tree-checker.

There is really no meaning to record that fixed value in map_lookup for
now, and can all be replaced with BTRFS_STRIPE_LEN.

Furthermore we can use the fix stripe length to do the following
optimization:

- Use BTRFS_STRIPE_LEN_SHIFT to replace some 64bit division
  Now we only need to do a right shift.

  And the value of BTRFS_STRIPE_LEN itself is already too large for bit
  shift, thus if we accidentally use BTRFS_STRIPE_LEN to do bit shift,
  a compiler warning would be triggered.

  Thus this bit shift optimization would be safe.

- Use BTRFS_STRIPE_LEN_MASK to calculate the offset inside a stripe

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 0 insertions, 1 deletions

diff --git a/fs/btrfs/tests/extent-map-tests.c b/fs/btrfs/tests/extent-map-tests.c
index f2f2e11dac4c..ed0f36ae5346 100644
--- a/fs/btrfs/tests/extent-map-tests.c
+++ b/fs/btrfs/tests/extent-map-tests.c
@@ -486,7 +486,6 @@ static int test_rmap_block(struct btrfs_fs_info *fs_info,
 	em->map_lookup = map;
 
 	map->num_stripes = test->num_stripes;
-	map->stripe_len = BTRFS_STRIPE_LEN;
 	map->type = test->raid_type;
 
 	for (i = 0; i < map->num_stripes; i++) {