btrfs: Document btrfs_csum_one_bio

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 5a3be16ca93d5f29d7a09d73614b56bbfcb6f999..d431ea8198e411e1ce88937179fc0f5e1e519770 100644 (file)
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -413,6 +413,16 @@ int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
        return ret;
 }
 
+/*
+ * btrfs_csum_one_bio - Calculates checksums of the data contained inside a bio
+ * @inode:      Owner of the data inside the bio
+ * @bio:        Contains the data to be checksummed
+ * @file_start:  offset in file this bio begins to describe
+ * @contig:     Boolean. If true/1 means all bio vecs in this bio are
+ *              contiguous and they begin at @file_start in the file. False/0
+ *              means this bio can contains potentially discontigous bio vecs
+ *              so the logical offset of each should be calculated separately.
+ */
 blk_status_t btrfs_csum_one_bio(struct inode *inode, struct bio *bio,
                       u64 file_start, int contig)
 {