btrfs: simplify data stripe calculation helpers

There are two helpers doing the same calculations based on nparity and
ncopies. calc_data_stripes can be simplified into one expression, so far
we don't have profile with both copies and parity, so there's no
effective change. calc_stripe_length should reuse the helper and not
repeat the same calculation.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 23159bd..c7339f1 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3568,10 +3568,7 @@ static u64 calc_data_stripes(u64 type, int num_stripes)
        const int ncopies = btrfs_raid_array[index].ncopies;
        const int nparity = btrfs_raid_array[index].nparity;
 
-       if (nparity)
-               return num_stripes - nparity;
-       else
-               return num_stripes / ncopies;
+       return (num_stripes - nparity) / ncopies;
 }
 
 /* [pstart, pend) */
@@ -6879,15 +6876,7 @@ static void btrfs_report_missing_device(struct btrfs_fs_info *fs_info,
 
 static u64 calc_stripe_length(u64 type, u64 chunk_len, int num_stripes)
 {
-       int index = btrfs_bg_flags_to_raid_index(type);
-       int ncopies = btrfs_raid_array[index].ncopies;
-       const int nparity = btrfs_raid_array[index].nparity;
-       int data_stripes;
-
-       if (nparity)
-               data_stripes = num_stripes - nparity;
-       else
-               data_stripes = num_stripes / ncopies;
+       const int data_stripes = calc_data_stripes(type, num_stripes);
 
        return div_u64(chunk_len, data_stripes);
 }