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Subject: [PATCH RFC 6/7] NFS: Extract the xdr_init_encode/decode() calls from
 decode_compound
From:   Chuck Lever <chuck.lever@oracle.com>
To:     linux-nfs@vger.kernel.org
Date:   Mon, 12 Jul 2021 10:52:52 -0400
Message-ID: <162610157208.2466.16225800632391871908.stgit@klimt.1015granger.net>
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References: <162610122257.2466.7452891285800059767.stgit@klimt.1015granger.net>
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Precedence: bulk

Clean up: Move the xdr_init_encode() and xdr_init_decode() calls
into the dispatcher, just like the NFSD and lockd dispatchers.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/nfs/callback_xdr.c |   22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index c72f46e2857a..19bbe8fc6cc2 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -916,22 +916,15 @@ static __be32 nfs4_callback_compound(struct svc_rqst *rqstp)
 {
 	struct cb_compound_hdr_arg hdr_arg = { 0 };
 	struct cb_compound_hdr_res hdr_res = { NULL };
-	struct xdr_stream xdr_in, xdr_out;
-	__be32 *p, status;
 	struct cb_process_state cps = {
 		.drc_status = 0,
 		.clp = NULL,
 		.net = SVC_NET(rqstp),
 	};
 	unsigned int nops = 0;
+	__be32 status;
 
-	xdr_init_decode(&xdr_in, &rqstp->rq_arg,
-			rqstp->rq_arg.head[0].iov_base, NULL);
-
-	p = (__be32*)((char *)rqstp->rq_res.head[0].iov_base + rqstp->rq_res.head[0].iov_len);
-	xdr_init_encode(&xdr_out, &rqstp->rq_res, p, NULL);
-
-	status = decode_compound_hdr_arg(&xdr_in, &hdr_arg);
+	status = decode_compound_hdr_arg(&rqstp->rq_arg_stream, &hdr_arg);
 	if (status == htonl(NFS4ERR_RESOURCE))
 		return rpc_garbage_args;
 
@@ -951,15 +944,15 @@ static __be32 nfs4_callback_compound(struct svc_rqst *rqstp)
 	cps.minorversion = hdr_arg.minorversion;
 	hdr_res.taglen = hdr_arg.taglen;
 	hdr_res.tag = hdr_arg.tag;
-	if (encode_compound_hdr_res(&xdr_out, &hdr_res) != 0) {
+	if (encode_compound_hdr_res(&rqstp->rq_res_stream, &hdr_res) != 0) {
 		if (cps.clp)
 			nfs_put_client(cps.clp);
 		return rpc_system_err;
 	}
 	while (status == 0 && nops != hdr_arg.nops) {
-		status = process_op(nops, rqstp, &xdr_in,
-				    rqstp->rq_argp, &xdr_out, rqstp->rq_resp,
-				    &cps);
+		status = process_op(nops, rqstp, &rqstp->rq_arg_stream,
+				    rqstp->rq_argp,&rqstp->rq_res_stream,
+				    rqstp->rq_resp, &cps);
 		nops++;
 	}
 
@@ -987,6 +980,9 @@ nfs_callback_dispatch(struct svc_rqst *rqstp, __be32 *statp)
 {
 	const struct svc_procedure *procp = rqstp->rq_procinfo;
 
+	svcxdr_init_decode(rqstp);
+	svcxdr_init_encode(rqstp);
+
 	*statp = procp->pc_func(rqstp);
 	return !test_bit(RQ_DROPME, &rqstp->rq_flags);
 }