SUNRPC: New xdr_streams XDR decoder API

Now that all client-side XDR decoder routines use xdr_streams, there
should be no need to support the legacy calling sequence [rpc_rqst *,
__be32 *, RPC res *] anywhere.  We can construct an xdr_stream in the
generic RPC code, instead of in each decoder function.

This is a refactoring change.  It should not cause different behavior.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

8 files changed, 468 insertions, 530 deletions

diff --git a/fs/lockd/clnt4xdr.c b/fs/lockd/clnt4xdr.c
index 974f1d9cd32..f848b52c67b 100644
--- a/fs/lockd/clnt4xdr.c
+++ b/fs/lockd/clnt4xdr.c
@@ -529,17 +529,16 @@ out:
 	return error;
 }
 
-static int nlm4_xdr_dec_testres(struct rpc_rqst *req, __be32 *p,
+static int nlm4_xdr_dec_testres(struct rpc_rqst *req,
+				struct xdr_stream *xdr,
 				struct nlm_res *result)
 {
-	struct xdr_stream xdr;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_cookie(&xdr, &result->cookie);
+	error = decode_cookie(xdr, &result->cookie);
 	if (unlikely(error))
 		goto out;
-	error = decode_nlm4_testrply(&xdr, result);
+	error = decode_nlm4_testrply(xdr, result);
 out:
 	return error;
 }
@@ -550,17 +549,16 @@ out:
  *		nlm4_stat stat;
  *	};
  */
-static int nlm4_xdr_dec_res(struct rpc_rqst *req, __be32 *p,
+static int nlm4_xdr_dec_res(struct rpc_rqst *req,
+			    struct xdr_stream *xdr,
 			    struct nlm_res *result)
 {
-	struct xdr_stream xdr;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_cookie(&xdr, &result->cookie);
+	error = decode_cookie(xdr, &result->cookie);
 	if (unlikely(error))
 		goto out;
-	error = decode_nlm4_stat(&xdr, &result->status);
+	error = decode_nlm4_stat(xdr, &result->status);
 out:
 	return error;
 }
@@ -575,7 +573,7 @@ out:
 [NLMPROC_##proc] = {							\
 	.p_proc      = NLMPROC_##proc,					\
 	.p_encode    = (kxdreproc_t)nlm4_xdr_enc_##argtype,		\
-	.p_decode    = (kxdrproc_t)nlm4_xdr_dec_##restype,		\
+	.p_decode    = (kxdrdproc_t)nlm4_xdr_dec_##restype,		\
 	.p_arglen    = NLM4_##argtype##_sz,				\
 	.p_replen    = NLM4_##restype##_sz,				\
 	.p_statidx   = NLMPROC_##proc,					\
diff --git a/fs/lockd/clntxdr.c b/fs/lockd/clntxdr.c
index c6fda8fb1c5..180ac34feb9 100644
--- a/fs/lockd/clntxdr.c
+++ b/fs/lockd/clntxdr.c
@@ -527,17 +527,16 @@ out:
 	return error;
 }
 
-static int nlm_xdr_dec_testres(struct rpc_rqst *req, __be32 *p,
+static int nlm_xdr_dec_testres(struct rpc_rqst *req,
+			       struct xdr_stream *xdr,
 			       struct nlm_res *result)
 {
-	struct xdr_stream xdr;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_cookie(&xdr, &result->cookie);
+	error = decode_cookie(xdr, &result->cookie);
 	if (unlikely(error))
 		goto out;
-	error = decode_nlm_testrply(&xdr, result);
+	error = decode_nlm_testrply(xdr, result);
 out:
 	return error;
 }
@@ -548,17 +547,16 @@ out:
  *		nlm_stat stat;
  *	};
  */
-static int nlm_xdr_dec_res(struct rpc_rqst *req, __be32 *p,
+static int nlm_xdr_dec_res(struct rpc_rqst *req,
+			   struct xdr_stream *xdr,
 			   struct nlm_res *result)
 {
-	struct xdr_stream xdr;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_cookie(&xdr, &result->cookie);
+	error = decode_cookie(xdr, &result->cookie);
 	if (unlikely(error))
 		goto out;
-	error = decode_nlm_stat(&xdr, &result->status);
+	error = decode_nlm_stat(xdr, &result->status);
 out:
 	return error;
 }
@@ -573,7 +571,7 @@ out:
 [NLMPROC_##proc] = {							\
 	.p_proc      = NLMPROC_##proc,					\
 	.p_encode    = (kxdreproc_t)nlm_xdr_enc_##argtype,		\
-	.p_decode    = (kxdrproc_t)nlm_xdr_dec_##restype,		\
+	.p_decode    = (kxdrdproc_t)nlm_xdr_dec_##restype,		\
 	.p_arglen    = NLM_##argtype##_sz,				\
 	.p_replen    = NLM_##restype##_sz,				\
 	.p_statidx   = NLMPROC_##proc,					\
diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
index baa77bc9d82..23d7451b293 100644
--- a/fs/lockd/mon.c
+++ b/fs/lockd/mon.c
@@ -472,35 +472,35 @@ static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr,
 	encode_mon_id(xdr, argp);
 }
 
-static int xdr_dec_stat_res(struct rpc_rqst *rqstp, __be32 *p,
-			    struct nsm_res *resp)
+static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp,
+				struct xdr_stream *xdr,
+				struct nsm_res *resp)
 {
-	struct xdr_stream xdr;
+	__be32 *p;
 
-	xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
-	p = xdr_inline_decode(&xdr, 4 + 4);
+	p = xdr_inline_decode(xdr, 4 + 4);
 	if (unlikely(p == NULL))
 		return -EIO;
 	resp->status = be32_to_cpup(p++);
 	resp->state = be32_to_cpup(p);
 
-	dprintk("lockd: xdr_dec_stat_res status %d state %d\n",
-			resp->status, resp->state);
+	dprintk("lockd: %s status %d state %d\n",
+		__func__, resp->status, resp->state);
 	return 0;
 }
 
-static int xdr_dec_stat(struct rpc_rqst *rqstp, __be32 *p,
-			struct nsm_res *resp)
+static int nsm_xdr_dec_stat(struct rpc_rqst *rqstp,
+			    struct xdr_stream *xdr,
+			    struct nsm_res *resp)
 {
-	struct xdr_stream xdr;
+	__be32 *p;
 
-	xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
-	p = xdr_inline_decode(&xdr, 4);
+	p = xdr_inline_decode(xdr, 4);
 	if (unlikely(p == NULL))
 		return -EIO;
 	resp->state = be32_to_cpup(p);
 
-	dprintk("lockd: xdr_dec_stat state %d\n", resp->state);
+	dprintk("lockd: %s state %d\n", __func__, resp->state);
 	return 0;
 }
 
@@ -517,7 +517,7 @@ static struct rpc_procinfo	nsm_procedures[] = {
 [NSMPROC_MON] = {
 		.p_proc		= NSMPROC_MON,
 		.p_encode	= (kxdreproc_t)nsm_xdr_enc_mon,
-		.p_decode	= (kxdrproc_t)xdr_dec_stat_res,
+		.p_decode	= (kxdrdproc_t)nsm_xdr_dec_stat_res,
 		.p_arglen	= SM_mon_sz,
 		.p_replen	= SM_monres_sz,
 		.p_statidx	= NSMPROC_MON,
@@ -526,7 +526,7 @@ static struct rpc_procinfo	nsm_procedures[] = {
 [NSMPROC_UNMON] = {
 		.p_proc		= NSMPROC_UNMON,
 		.p_encode	= (kxdreproc_t)nsm_xdr_enc_unmon,
-		.p_decode	= (kxdrproc_t)xdr_dec_stat,
+		.p_decode	= (kxdrdproc_t)nsm_xdr_dec_stat,
 		.p_arglen	= SM_mon_id_sz,
 		.p_replen	= SM_unmonres_sz,
 		.p_statidx	= NSMPROC_UNMON,
diff --git a/fs/nfs/mount_clnt.c b/fs/nfs/mount_clnt.c
index 979ebd7af3c..697e07235f3 100644
--- a/fs/nfs/mount_clnt.c
+++ b/fs/nfs/mount_clnt.c
@@ -340,18 +340,16 @@ static int decode_fhandle(struct xdr_stream *xdr, struct mountres *res)
 	return 0;
 }
 
-static int mnt_dec_mountres(struct rpc_rqst *req, __be32 *p,
-			    struct mountres *res)
+static int mnt_xdr_dec_mountres(struct rpc_rqst *req,
+				struct xdr_stream *xdr,
+				struct mountres *res)
 {
-	struct xdr_stream xdr;
 	int status;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-
-	status = decode_status(&xdr, res);
+	status = decode_status(xdr, res);
 	if (unlikely(status != 0 || res->errno != 0))
 		return status;
-	return decode_fhandle(&xdr, res);
+	return decode_fhandle(xdr, res);
 }
 
 static int decode_fhs_status(struct xdr_stream *xdr, struct mountres *res)
@@ -434,30 +432,28 @@ static int decode_auth_flavors(struct xdr_stream *xdr, struct mountres *res)
 	return 0;
 }
 
-static int mnt_dec_mountres3(struct rpc_rqst *req, __be32 *p,
-			     struct mountres *res)
+static int mnt_xdr_dec_mountres3(struct rpc_rqst *req,
+				 struct xdr_stream *xdr,
+				 struct mountres *res)
 {
-	struct xdr_stream xdr;
 	int status;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-
-	status = decode_fhs_status(&xdr, res);
+	status = decode_fhs_status(xdr, res);
 	if (unlikely(status != 0 || res->errno != 0))
 		return status;
-	status = decode_fhandle3(&xdr, res);
+	status = decode_fhandle3(xdr, res);
 	if (unlikely(status != 0)) {
 		res->errno = -EBADHANDLE;
 		return 0;
 	}
-	return decode_auth_flavors(&xdr, res);
+	return decode_auth_flavors(xdr, res);
 }
 
 static struct rpc_procinfo mnt_procedures[] = {
 	[MOUNTPROC_MNT] = {
 		.p_proc		= MOUNTPROC_MNT,
 		.p_encode	= (kxdreproc_t)mnt_xdr_enc_dirpath,
-		.p_decode	= (kxdrproc_t)mnt_dec_mountres,
+		.p_decode	= (kxdrdproc_t)mnt_xdr_dec_mountres,
 		.p_arglen	= MNT_enc_dirpath_sz,
 		.p_replen	= MNT_dec_mountres_sz,
 		.p_statidx	= MOUNTPROC_MNT,
@@ -476,7 +472,7 @@ static struct rpc_procinfo mnt3_procedures[] = {
 	[MOUNTPROC3_MNT] = {
 		.p_proc		= MOUNTPROC3_MNT,
 		.p_encode	= (kxdreproc_t)mnt_xdr_enc_dirpath,
-		.p_decode	= (kxdrproc_t)mnt_dec_mountres3,
+		.p_decode	= (kxdrdproc_t)mnt_xdr_dec_mountres3,
 		.p_arglen	= MNT_enc_dirpath_sz,
 		.p_replen	= MNT_dec_mountres3_sz,
 		.p_statidx	= MOUNTPROC3_MNT,
diff --git a/fs/nfs/nfs2xdr.c b/fs/nfs/nfs2xdr.c
index 8f3acbec761..51f1cfa04d2 100644
--- a/fs/nfs/nfs2xdr.c
+++ b/fs/nfs/nfs2xdr.c
@@ -783,15 +783,13 @@ static void nfs2_xdr_enc_readdirargs(struct rpc_rqst *req,
  * "NFS: Network File System Protocol Specification".
  */
 
-static int nfs2_xdr_dec_stat(struct rpc_rqst *req, __be32 *p,
+static int nfs2_xdr_dec_stat(struct rpc_rqst *req, struct xdr_stream *xdr,
 			     void *__unused)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_stat(&xdr, &status);
+	error = decode_stat(xdr, &status);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS_OK)
@@ -802,22 +800,16 @@ out_default:
 	return nfs_stat_to_errno(status);
 }
 
-static int nfs2_xdr_dec_attrstat(struct rpc_rqst *req, __be32 *p,
+static int nfs2_xdr_dec_attrstat(struct rpc_rqst *req, struct xdr_stream *xdr,
 				 struct nfs_fattr *result)
 {
-	struct xdr_stream xdr;
-
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	return decode_attrstat(&xdr, result);
+	return decode_attrstat(xdr, result);
 }
 
-static int nfs2_xdr_dec_diropres(struct rpc_rqst *req, __be32 *p,
+static int nfs2_xdr_dec_diropres(struct rpc_rqst *req, struct xdr_stream *xdr,
 				 struct nfs_diropok *result)
 {
-	struct xdr_stream xdr;
-
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	return decode_diropres(&xdr, result);
+	return decode_diropres(xdr, result);
 }
 
 /*
@@ -830,20 +822,18 @@ static int nfs2_xdr_dec_diropres(struct rpc_rqst *req, __be32 *p,
  *		void;
  *	};
  */
-static int nfs2_xdr_dec_readlinkres(struct rpc_rqst *req, __be32 *p,
-				    void *__unused)
+static int nfs2_xdr_dec_readlinkres(struct rpc_rqst *req,
+				    struct xdr_stream *xdr, void *__unused)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_stat(&xdr, &status);
+	error = decode_stat(xdr, &status);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS_OK)
 		goto out_default;
-	error = decode_path(&xdr);
+	error = decode_path(xdr);
 out:
 	return error;
 out_default:
@@ -861,39 +851,33 @@ out_default:
  *		void;
  *	};
  */
-static int nfs2_xdr_dec_readres(struct rpc_rqst *req, __be32 *p,
+static int nfs2_xdr_dec_readres(struct rpc_rqst *req, struct xdr_stream *xdr,
 				struct nfs_readres *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_stat(&xdr, &status);
+	error = decode_stat(xdr, &status);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS_OK)
 		goto out_default;
-	error = decode_fattr(&xdr, result->fattr);
+	error = decode_fattr(xdr, result->fattr);
 	if (unlikely(error))
 		goto out;
-	error = decode_nfsdata(&xdr, result);
+	error = decode_nfsdata(xdr, result);
 out:
 	return error;
 out_default:
 	return nfs_stat_to_errno(status);
 }
 
-static int nfs2_xdr_dec_writeres(struct rpc_rqst *req, __be32 *p,
+static int nfs2_xdr_dec_writeres(struct rpc_rqst *req, struct xdr_stream *xdr,
 				 struct nfs_writeres *result)
 {
-	struct xdr_stream xdr;
-
 	/* All NFSv2 writes are "file sync" writes */
 	result->verf->committed = NFS_FILE_SYNC;
-
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	return decode_attrstat(&xdr, result->fattr);
+	return decode_attrstat(xdr, result->fattr);
 }
 
 /**
@@ -1008,20 +992,18 @@ out_cheating:
 	goto out;
 }
 
-static int nfs2_xdr_dec_readdirres(struct rpc_rqst *req, __be32 *p,
-				   void *__unused)
+static int nfs2_xdr_dec_readdirres(struct rpc_rqst *req,
+				   struct xdr_stream *xdr, void *__unused)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_stat(&xdr, &status);
+	error = decode_stat(xdr, &status);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS_OK)
 		goto out_default;
-	error = decode_readdirok(&xdr);
+	error = decode_readdirok(xdr);
 out:
 	return error;
 out_default:
@@ -1062,20 +1044,18 @@ out_overflow:
 	return -EIO;
 }
 
-static int nfs2_xdr_dec_statfsres(struct rpc_rqst *req, __be32 *p,
+static int nfs2_xdr_dec_statfsres(struct rpc_rqst *req, struct xdr_stream *xdr,
 				  struct nfs2_fsstat *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_stat(&xdr, &status);
+	error = decode_stat(xdr, &status);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS_OK)
 		goto out_default;
-	error = decode_info(&xdr, result);
+	error = decode_info(xdr, result);
 out:
 	return error;
 out_default:
@@ -1150,7 +1130,7 @@ int nfs_stat_to_errno(enum nfs_stat status)
 [NFSPROC_##proc] = {							\
 	.p_proc	    =  NFSPROC_##proc,					\
 	.p_encode   =  (kxdreproc_t)nfs2_xdr_enc_##argtype,		\
-	.p_decode   =  (kxdrproc_t)nfs2_xdr_dec_##restype,		\
+	.p_decode   =  (kxdrdproc_t)nfs2_xdr_dec_##restype,		\
 	.p_arglen   =  NFS_##argtype##_sz,				\
 	.p_replen   =  NFS_##restype##_sz,				\
 	.p_timer    =  timer,						\
diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c
index ae1b1a43f05..df30a26cc4f 100644
--- a/fs/nfs/nfs3xdr.c
+++ b/fs/nfs/nfs3xdr.c
@@ -1366,20 +1366,19 @@ static void nfs3_xdr_enc_setacl3args(struct rpc_rqst *req,
  *		void;
  *	};
  */
-static int nfs3_xdr_dec_getattr3res(struct rpc_rqst *req, __be32 *p,
+static int nfs3_xdr_dec_getattr3res(struct rpc_rqst *req,
+				    struct xdr_stream *xdr,
 				    struct nfs_fattr *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_nfsstat3(&xdr, &status);
+	error = decode_nfsstat3(xdr, &status);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS3_OK)
 		goto out_default;
-	error = decode_fattr3(&xdr, result);
+	error = decode_fattr3(xdr, result);
 out:
 	return error;
 out_default:
@@ -1404,18 +1403,17 @@ out_default:
  *		SETATTR3resfail resfail;
  *	};
  */
-static int nfs3_xdr_dec_setattr3res(struct rpc_rqst *req, __be32 *p,
+static int nfs3_xdr_dec_setattr3res(struct rpc_rqst *req,
+				    struct xdr_stream *xdr,
 				    struct nfs_fattr *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_nfsstat3(&xdr, &status);
+	error = decode_nfsstat3(xdr, &status);
 	if (unlikely(error))
 		goto out;
-	error = decode_wcc_data(&xdr, result);
+	error = decode_wcc_data(xdr, result);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS3_OK)
@@ -1446,30 +1444,29 @@ out_status:
  *		LOOKUP3resfail	resfail;
  *	};
  */
-static int nfs3_xdr_dec_lookup3res(struct rpc_rqst *req, __be32 *p,
+static int nfs3_xdr_dec_lookup3res(struct rpc_rqst *req,
+				   struct xdr_stream *xdr,
 				   struct nfs3_diropres *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_nfsstat3(&xdr, &status);
+	error = decode_nfsstat3(xdr, &status);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS3_OK)
 		goto out_default;
-	error = decode_nfs_fh3(&xdr, result->fh);
+	error = decode_nfs_fh3(xdr, result->fh);
 	if (unlikely(error))
 		goto out;
-	error = decode_post_op_attr(&xdr, result->fattr);
+	error = decode_post_op_attr(xdr, result->fattr);
 	if (unlikely(error))
 		goto out;
-	error = decode_post_op_attr(&xdr, result->dir_attr);
+	error = decode_post_op_attr(xdr, result->dir_attr);
 out:
 	return error;
 out_default:
-	error = decode_post_op_attr(&xdr, result->dir_attr);
+	error = decode_post_op_attr(xdr, result->dir_attr);
 	if (unlikely(error))
 		goto out;
 	return nfs_stat_to_errno(status);
@@ -1494,23 +1491,22 @@ out_default:
  *		ACCESS3resfail	resfail;
  *	};
  */
-static int nfs3_xdr_dec_access3res(struct rpc_rqst *req, __be32 *p,
+static int nfs3_xdr_dec_access3res(struct rpc_rqst *req,
+				   struct xdr_stream *xdr,
 				   struct nfs3_accessres *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_nfsstat3(&xdr, &status);
+	error = decode_nfsstat3(xdr, &status);
 	if (unlikely(error))
 		goto out;
-	error = decode_post_op_attr(&xdr, result->fattr);
+	error = decode_post_op_attr(xdr, result->fattr);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS3_OK)
 		goto out_default;
-	error = decode_uint32(&xdr, &result->access);
+	error = decode_uint32(xdr, &result->access);
 out:
 	return error;
 out_default:
@@ -1536,23 +1532,22 @@ out_default:
  *		READLINK3resfail resfail;
  *	};
  */
-static int nfs3_xdr_dec_readlink3res(struct rpc_rqst *req, __be32 *p,
+static int nfs3_xdr_dec_readlink3res(struct rpc_rqst *req,
+				     struct xdr_stream *xdr,
 				     struct nfs_fattr *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_nfsstat3(&xdr, &status);
+	error = decode_nfsstat3(xdr, &status);
 	if (unlikely(error))
 		goto out;
-	error = decode_post_op_attr(&xdr, result);
+	error = decode_post_op_attr(xdr, result);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS3_OK)
 		goto out_default;
-	error = decode_nfspath3(&xdr);
+	error = decode_nfspath3(xdr);
 out:
 	return error;
 out_default:
@@ -1620,23 +1615,21 @@ out_overflow:
 	return -EIO;
 }
 
-static int nfs3_xdr_dec_read3res(struct rpc_rqst *req, __be32 *p,
+static int nfs3_xdr_dec_read3res(struct rpc_rqst *req, struct xdr_stream *xdr,
 				 struct nfs_readres *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_nfsstat3(&xdr, &status);
+	error = decode_nfsstat3(xdr, &status);
 	if (unlikely(error))
 		goto out;
-	error = decode_post_op_attr(&xdr, result->fattr);
+	error = decode_post_op_attr(xdr, result->fattr);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS3_OK)
 		goto out_status;
-	error = decode_read3resok(&xdr, result);
+	error = decode_read3resok(xdr, result);
 out:
 	return error;
 out_status:
@@ -1692,23 +1685,21 @@ out_overflow:
 	return -EIO;
 }
 
-static int nfs3_xdr_dec_write3res(struct rpc_rqst *req, __be32 *p,
+static int nfs3_xdr_dec_write3res(struct rpc_rqst *req, struct xdr_stream *xdr,
 				  struct nfs_writeres *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_nfsstat3(&xdr, &status);
+	error = decode_nfsstat3(xdr, &status);
 	if (unlikely(error))
 		goto out;
-	error = decode_wcc_data(&xdr, result->fattr);
+	error = decode_wcc_data(xdr, result->fattr);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS3_OK)
 		goto out_status;
-	error = decode_write3resok(&xdr, result);
+	error = decode_write3resok(xdr, result);
 out:
 	return error;
 out_status:
@@ -1757,24 +1748,23 @@ out:
 	return error;
 }
 
-static int nfs3_xdr_dec_create3res(struct rpc_rqst *req, __be32 *p,
+static int nfs3_xdr_dec_create3res(struct rpc_rqst *req,
+				   struct xdr_stream *xdr,
 				   struct nfs3_diropres *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_nfsstat3(&xdr, &status);
+	error = decode_nfsstat3(xdr, &status);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS3_OK)
 		goto out_default;
-	error = decode_create3resok(&xdr, result);
+	error = decode_create3resok(xdr, result);
 out:
 	return error;
 out_default:
-	error = decode_wcc_data(&xdr, result->dir_attr);
+	error = decode_wcc_data(xdr, result->dir_attr);
 	if (unlikely(error))
 		goto out;
 	return nfs_stat_to_errno(status);
@@ -1798,18 +1788,17 @@ out_default:
  *		REMOVE3resfail resfail;
  *	};
  */
-static int nfs3_xdr_dec_remove3res(struct rpc_rqst *req, __be32 *p,
+static int nfs3_xdr_dec_remove3res(struct rpc_rqst *req,
+				   struct xdr_stream *xdr,
 				   struct nfs_removeres *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_nfsstat3(&xdr, &status);
+	error = decode_nfsstat3(xdr, &status);
 	if (unlikely(error))
 		goto out;
-	error = decode_wcc_data(&xdr, result->dir_attr);
+	error = decode_wcc_data(xdr, result->dir_attr);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS3_OK)
@@ -1840,21 +1829,20 @@ out_status:
  *		RENAME3resfail resfail;
  *	};
  */
-static int nfs3_xdr_dec_rename3res(struct rpc_rqst *req, __be32 *p,
+static int nfs3_xdr_dec_rename3res(struct rpc_rqst *req,
+				   struct xdr_stream *xdr,
 				   struct nfs_renameres *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_nfsstat3(&xdr, &status);
+	error = decode_nfsstat3(xdr, &status);
 	if (unlikely(error))
 		goto out;
-	error = decode_wcc_data(&xdr, result->old_fattr);
+	error = decode_wcc_data(xdr, result->old_fattr);
 	if (unlikely(error))
 		goto out;
-	error = decode_wcc_data(&xdr, result->new_fattr);
+	error = decode_wcc_data(xdr, result->new_fattr);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS3_OK)
@@ -1885,21 +1873,19 @@ out_status:
  *		LINK3resfail	resfail;
  *	};
  */
-static int nfs3_xdr_dec_link3res(struct rpc_rqst *req, __be32 *p,
+static int nfs3_xdr_dec_link3res(struct rpc_rqst *req, struct xdr_stream *xdr,
 				 struct nfs3_linkres *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_nfsstat3(&xdr, &status);
+	error = decode_nfsstat3(xdr, &status);
 	if (unlikely(error))
 		goto out;
-	error = decode_post_op_attr(&xdr, result->fattr);
+	error = decode_post_op_attr(xdr, result->fattr);
 	if (unlikely(error))
 		goto out;
-	error = decode_wcc_data(&xdr, result->dir_attr);
+	error = decode_wcc_data(xdr, result->dir_attr);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS3_OK)
@@ -2085,24 +2071,23 @@ out:
 	return error;
 }
 
-static int nfs3_xdr_dec_readdir3res(struct rpc_rqst *req, __be32 *p,
+static int nfs3_xdr_dec_readdir3res(struct rpc_rqst *req,
+				    struct xdr_stream *xdr,
 				    struct nfs3_readdirres *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_nfsstat3(&xdr, &status);
+	error = decode_nfsstat3(xdr, &status);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS3_OK)
 		goto out_default;
-	error = decode_readdir3resok(&xdr, result);
+	error = decode_readdir3resok(xdr, result);
 out:
 	return error;
 out_default:
-	error = decode_post_op_attr(&xdr, result->dir_attr);
+	error = decode_post_op_attr(xdr, result->dir_attr);
 	if (unlikely(error))
 		goto out;
 	return nfs_stat_to_errno(status);
@@ -2154,23 +2139,22 @@ out_overflow:
 	return -EIO;
 }
 
-static int nfs3_xdr_dec_fsstat3res(struct rpc_rqst *req, __be32 *p,
+static int nfs3_xdr_dec_fsstat3res(struct rpc_rqst *req,
+				   struct xdr_stream *xdr,
 				   struct nfs_fsstat *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_nfsstat3(&xdr, &status);
+	error = decode_nfsstat3(xdr, &status);
 	if (unlikely(error))
 		goto out;
-	error = decode_post_op_attr(&xdr, result->fattr);
+	error = decode_post_op_attr(xdr, result->fattr);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS3_OK)
 		goto out_status;
-	error = decode_fsstat3resok(&xdr, result);
+	error = decode_fsstat3resok(xdr, result);
 out:
 	return error;
 out_status:
@@ -2231,23 +2215,22 @@ out_overflow:
 	return -EIO;
 }
 
-static int nfs3_xdr_dec_fsinfo3res(struct rpc_rqst *req, __be32 *p,
+static int nfs3_xdr_dec_fsinfo3res(struct rpc_rqst *req,
+				   struct xdr_stream *xdr,
 				   struct nfs_fsinfo *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_nfsstat3(&xdr, &status);
+	error = decode_nfsstat3(xdr, &status);
 	if (unlikely(error))
 		goto out;
-	error = decode_post_op_attr(&xdr, result->fattr);
+	error = decode_post_op_attr(xdr, result->fattr);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS3_OK)
 		goto out_status;
-	error = decode_fsinfo3resok(&xdr, result);
+	error = decode_fsinfo3resok(xdr, result);
 out:
 	return error;
 out_status:
@@ -2295,23 +2278,22 @@ out_overflow:
 	return -EIO;
 }
 
-static int nfs3_xdr_dec_pathconf3res(struct rpc_rqst *req, __be32 *p,
+static int nfs3_xdr_dec_pathconf3res(struct rpc_rqst *req,
+				     struct xdr_stream *xdr,
 				     struct nfs_pathconf *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_nfsstat3(&xdr, &status);
+	error = decode_nfsstat3(xdr, &status);
 	if (unlikely(error))
 		goto out;
-	error = decode_post_op_attr(&xdr, result->fattr);
+	error = decode_post_op_attr(xdr, result->fattr);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS3_OK)
 		goto out_status;
-	error = decode_pathconf3resok(&xdr, result);
+	error = decode_pathconf3resok(xdr, result);
 out:
 	return error;
 out_status:
@@ -2337,23 +2319,22 @@ out_status:
  *		COMMIT3resfail	resfail;
  *	};
  */
-static int nfs3_xdr_dec_commit3res(struct rpc_rqst *req, __be32 *p,
+static int nfs3_xdr_dec_commit3res(struct rpc_rqst *req,
+				   struct xdr_stream *xdr,
 				   struct nfs_writeres *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_nfsstat3(&xdr, &status);
+	error = decode_nfsstat3(xdr, &status);
 	if (unlikely(error))
 		goto out;
-	error = decode_wcc_data(&xdr, result->fattr);
+	error = decode_wcc_data(xdr, result->fattr);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS3_OK)
 		goto out_status;
-	error = decode_writeverf3(&xdr, result->verf->verifier);
+	error = decode_writeverf3(xdr, result->verf->verifier);
 out:
 	return error;
 out_status:
@@ -2406,40 +2387,38 @@ out:
 	return error;
 }
 
-static int nfs3_xdr_dec_getacl3res(struct rpc_rqst *req, __be32 *p,
+static int nfs3_xdr_dec_getacl3res(struct rpc_rqst *req,
+				   struct xdr_stream *xdr,
 				   struct nfs3_getaclres *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_nfsstat3(&xdr, &status);
+	error = decode_nfsstat3(xdr, &status);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS3_OK)
 		goto out_default;
-	error = decode_getacl3resok(&xdr, result);
+	error = decode_getacl3resok(xdr, result);
 out:
 	return error;
 out_default:
 	return nfs_stat_to_errno(status);
 }
 
-static int nfs3_xdr_dec_setacl3res(struct rpc_rqst *req, __be32 *p,
+static int nfs3_xdr_dec_setacl3res(struct rpc_rqst *req,
+				   struct xdr_stream *xdr,
 				   struct nfs_fattr *result)
 {
-	struct xdr_stream xdr;
 	enum nfs_stat status;
 	int error;
 
-	xdr_init_decode(&xdr, &req->rq_rcv_buf, p);
-	error = decode_nfsstat3(&xdr, &status);
+	error = decode_nfsstat3(xdr, &status);
 	if (unlikely(error))
 		goto out;
 	if (status != NFS3_OK)
 		goto out_default;
-	error = decode_post_op_attr(&xdr, result);
+	error = decode_post_op_attr(xdr, result);
 out:
 	return error;
 out_default:
@@ -2452,7 +2431,7 @@ out_default:
 [NFS3PROC_##proc] = {							\
 	.p_proc      = NFS3PROC_##proc,					\
 	.p_encode    = (kxdreproc_t)nfs3_xdr_enc_##argtype##3args,	\
-	.p_decode    = (kxdrproc_t)nfs3_xdr_dec_##restype##3res,	\
+	.p_decode    = (kxdrdproc_t)nfs3_xdr_dec_##restype##3res,	\
 	.p_arglen    = NFS3_##argtype##args_sz,				\
 	.p_replen    = NFS3_##restype##res_sz,				\
 	.p_timer     = timer,						\
@@ -2495,7 +2474,7 @@ static struct rpc_procinfo	nfs3_acl_procedures[] = {
 	[ACLPROC3_GETACL] = {
 		.p_proc = ACLPROC3_GETACL,
 		.p_encode = (kxdreproc_t)nfs3_xdr_enc_getacl3args,
-		.p_decode = (kxdrproc_t)nfs3_xdr_dec_getacl3res,
+		.p_decode = (kxdrdproc_t)nfs3_xdr_dec_getacl3res,
 		.p_arglen = ACL3_getaclargs_sz,
 		.p_replen = ACL3_getaclres_sz,
 		.p_timer = 1,
@@ -2504,7 +2483,7 @@ static struct rpc_procinfo	nfs3_acl_procedures[] = {
 	[ACLPROC3_SETACL] = {
 		.p_proc = ACLPROC3_SETACL,
 		.p_encode = (kxdreproc_t)nfs3_xdr_enc_setacl3args,
-		.p_decode = (kxdrproc_t)nfs3_xdr_dec_setacl3res,
+		.p_decode = (kxdrdproc_t)nfs3_xdr_dec_setacl3res,
 		.p_arglen = ACL3_setaclargs_sz,
 		.p_replen = ACL3_setaclres_sz,
 		.p_timer = 0,
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 6ec38b3e4a3..f3f99156bfc 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -5013,26 +5013,26 @@ out_overflow:
 /*
  * Decode OPEN_DOWNGRADE response
  */
-static int nfs4_xdr_dec_open_downgrade(struct rpc_rqst *rqstp, __be32 *p, struct nfs_closeres *res)
+static int nfs4_xdr_dec_open_downgrade(struct rpc_rqst *rqstp,
+				       struct xdr_stream *xdr,
+				       struct nfs_closeres *res)
 {
-	struct xdr_stream xdr;
 	struct compound_hdr hdr;
 	int status;
 
-	xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
-	status = decode_compound_hdr(&xdr, &hdr);
+	status = decode_compound_hdr(xdr, &hdr);
 	if (status)
 		goto out;
-	status = decode_sequence(&xdr, &res->seq_res, rqstp);
+	status = decode_sequence(xdr, &res->seq_res, rqstp);
 	if (status)
 		goto out;
-	status = decode_putfh(&xdr);
+	status = decode_putfh(xdr);
 	if (status)
 		goto out;
-	status = decode_open_downgrade(&xdr, res);
+	status = decode_open_downgrade(xdr, res);
 	if (status != 0)
 		goto out;
-	decode_getfattr(&xdr, res->fattr, res->server,
+	decode_getfattr(xdr, res->fattr, res->server,
 			!RPC_IS_ASYNC(rqstp->rq_task));
 out:
 	return status;
@@ -5041,26 +5041,25 @@ out:
 /*
  * Decode ACCESS response
  */
-static int nfs4_xdr_dec_access(struct rpc_rqst *rqstp, __be32 *p, struct nfs4_accessres *res)
+static int nfs4_xdr_dec_access(struct rpc_rqst *rqstp, struct xdr_stream *xdr,
+			       struct nfs4_accessres *res)
 {
-	struct xdr_stream xdr;
 	struct compound_hdr hdr;
 	int status;
 
-	xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
-	status = decode_compound_hdr(&xdr, &hdr);
+	status = decode_compound_hdr(xdr, &hdr);
 	if (status)
 		goto out;
-	status = decode_sequence(&xdr, &res->seq_res, rqstp);
+	status = decode_sequence(xdr, &res->seq_res, rqstp);
 	if (status)
 		goto out;
-	status = decode_putfh(&xdr);
+	status = decode_putfh(xdr);
 	if (status != 0)
 		goto out;
-	status = decode_access(&xdr, res);
+	status = decode_access(xdr, res);
 	if (status != 0)
 		goto out;
-	decode_getfattr(&xdr, res->fattr, res->server,
+	decode_getfattr(xdr, res->fattr, res->server,
 			!RPC_IS_ASYNC(rqstp->rq_task));
 out:
 	return status;
@@ -5069,26 +5068,28 @@ out:
 /*
  * Decode LOOKUP response
  */
-static int nfs4_xdr_dec_lookup(struct rpc_rqst *rqstp, __be32 *p, struct nfs4_lookup_res *res