NFS/flexfile: Simplify nfs4_ff_layout_ds_version()

Pass in a pointer to the mirror rather than forcing another
array access.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/flexfilelayout/flexfilelayout.c

@@ -1787,7 +1787,7 @@ ff_layout_read_pagelist(struct nfs_pgio_header *hdr)
 	if (!ds_cred)
 		goto out_failed;
 
-	vers = nfs4_ff_layout_ds_version(lseg, idx);
+	vers = nfs4_ff_layout_ds_version(mirror);
 
 	dprintk("%s USE DS: %s cl_count %d vers %d\n", __func__,
 		ds->ds_remotestr, refcount_read(&ds->ds_clp->cl_count), vers);
@@ -1852,7 +1852,7 @@ ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
 	if (!ds_cred)
 		goto out_failed;
 
-	vers = nfs4_ff_layout_ds_version(lseg, idx);
+	vers = nfs4_ff_layout_ds_version(mirror);
 
 	dprintk("%s ino %lu sync %d req %zu@%llu DS: %s cl_count %d vers %d\n",
 		__func__, hdr->inode->i_ino, sync, (size_t) hdr->args.count,
@@ -1937,7 +1937,7 @@ static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
 	if (!ds_cred)
 		goto out_err;
 
-	vers = nfs4_ff_layout_ds_version(lseg, idx);
+	vers = nfs4_ff_layout_ds_version(mirror);
 
 	dprintk("%s ino %lu, how %d cl_count %d vers %d\n", __func__,
 		data->inode->i_ino, how, refcount_read(&ds->ds_clp->cl_count),

fs/nfs/flexfilelayout/flexfilelayout.h

@@ -181,9 +181,9 @@ ff_layout_no_read_on_rw(struct pnfs_layout_segment *lseg)
 }
 
 static inline int
-nfs4_ff_layout_ds_version(struct pnfs_layout_segment *lseg, u32 ds_idx)
+nfs4_ff_layout_ds_version(const struct nfs4_ff_layout_mirror *mirror)
 {
-	return FF_LAYOUT_COMP(lseg, ds_idx)->mirror_ds->ds_versions[0].version;
+	return mirror->mirror_ds->ds_versions[0].version;
 }
 
 struct nfs4_ff_layout_ds *