NFS/flexfiles: Simplify ff_layout_get_ds_cred()

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

fs/nfs/flexfilelayout/flexfilelayout.c

@@ -1783,7 +1783,7 @@ ff_layout_read_pagelist(struct nfs_pgio_header *hdr)
 	if (IS_ERR(ds_clnt))
 		goto out_failed;
 
-	ds_cred = ff_layout_get_ds_cred(lseg, idx, hdr->cred);
+	ds_cred = ff_layout_get_ds_cred(mirror, &lseg->pls_range, hdr->cred);
 	if (!ds_cred)
 		goto out_failed;
 
@@ -1848,7 +1848,7 @@ ff_layout_write_pagelist(struct nfs_pgio_header *hdr, int sync)
 	if (IS_ERR(ds_clnt))
 		goto out_failed;
 
-	ds_cred = ff_layout_get_ds_cred(lseg, idx, hdr->cred);
+	ds_cred = ff_layout_get_ds_cred(mirror, &lseg->pls_range, hdr->cred);
 	if (!ds_cred)
 		goto out_failed;
 
@@ -1933,7 +1933,7 @@ static int ff_layout_initiate_commit(struct nfs_commit_data *data, int how)
 	if (IS_ERR(ds_clnt))
 		goto out_err;
 
-	ds_cred = ff_layout_get_ds_cred(lseg, idx, data->cred);
+	ds_cred = ff_layout_get_ds_cred(mirror, &lseg->pls_range, data->cred);
 	if (!ds_cred)
 		goto out_err;
 

fs/nfs/flexfilelayout/flexfilelayout.h

@@ -218,8 +218,9 @@ struct rpc_clnt *
 nfs4_ff_find_or_create_ds_client(struct nfs4_ff_layout_mirror *mirror,
 				 struct nfs_client *ds_clp,
 				 struct inode *inode);
-const struct cred *ff_layout_get_ds_cred(struct pnfs_layout_segment *lseg,
-				       u32 ds_idx, const struct cred *mdscred);
+const struct cred *ff_layout_get_ds_cred(struct nfs4_ff_layout_mirror *mirror,
+					 const struct pnfs_layout_range *range,
+					 const struct cred *mdscred);
 bool ff_layout_avoid_mds_available_ds(struct pnfs_layout_segment *lseg);
 bool ff_layout_avoid_read_on_rw(struct pnfs_layout_segment *lseg);
 

fs/nfs/flexfilelayout/flexfilelayoutdev.c

@@ -446,14 +446,14 @@ nfs4_ff_layout_prepare_ds(struct pnfs_layout_segment *lseg,
 }
 
 const struct cred *
-ff_layout_get_ds_cred(struct pnfs_layout_segment *lseg, u32 ds_idx,
+ff_layout_get_ds_cred(struct nfs4_ff_layout_mirror *mirror,
+		      const struct pnfs_layout_range *range,
 		      const struct cred *mdscred)
 {
-	struct nfs4_ff_layout_mirror *mirror = FF_LAYOUT_COMP(lseg, ds_idx);
 	const struct cred *cred;
 
 	if (mirror && !mirror->mirror_ds->ds_versions[0].tightly_coupled) {
-		cred = ff_layout_get_mirror_cred(mirror, lseg->pls_range.iomode);
+		cred = ff_layout_get_mirror_cred(mirror, range->iomode);
 		if (!cred)
 			cred = get_cred(mdscred);
 	} else {