pnfs: Refactor the *_layout_mark_request_commit to use pnfs_layout_mark_request_commit

The File Layout's filelayout_mark_request_commit() is almost the
Flex File Layout's ff_layout_mark_request_commit(). And that can
be reduced by calling into nfs_request_add_commit_list().

Signed-off-by: Tom Haynes <loghyr@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index 797cd62..635f086 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -344,6 +344,10 @@
 struct nfs4_pnfs_ds_addr *nfs4_decode_mp_ds_addr(struct net *net,
 						 struct xdr_stream *xdr,
 						 gfp_t gfp_flags);
+void pnfs_layout_mark_request_commit(struct nfs_page *req,
+				     struct pnfs_layout_segment *lseg,
+				     struct nfs_commit_info *cinfo,
+				     u32 ds_commit_idx);
 
 static inline bool nfs_have_layout(struct inode *inode)
 {