btrfs-progs: raid56: Introduce new function to calculate raid5 parity or data stripe

Introduce new function raid5_gen_result() to calculate parity or data
stripe.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/disk-io.h b/disk-io.h
index d4a0e7fc..1c8387e7 100644
--- a/disk-io.h
+++ b/disk-io.h
@@ -199,5 +199,6 @@ int write_and_map_eb(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 
 /* raid56.c */
 void raid6_gen_syndrome(int disks, size_t bytes, void **ptrs);
+int raid5_gen_result(int nr_devs, size_t stripe_len, int dest, void **data);
 
 #endif