nfsd/callback: Drop a useless data copy when comparing sessionid

Signed-off-by: NKinglong Mee <kinglongmee@gmail.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4callback.c

@@ -397,13 +397,10 @@ static int decode_cb_sequence4resok(struct xdr_stream *xdr,
 				    struct nfsd4_callback *cb)
 {
 	struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
-	struct nfs4_sessionid id;
-	int status;
+	int status = -ESERVERFAULT;
 	__be32 *p;
 	u32 dummy;
 
-	status = -ESERVERFAULT;
-
 	/*
 	 * If the server returns different values for sessionID, slotID or
 	 * sequence number, the server is looney tunes.
@@ -411,9 +408,8 @@ static int decode_cb_sequence4resok(struct xdr_stream *xdr,
 	p = xdr_inline_decode(xdr, NFS4_MAX_SESSIONID_LEN + 4 + 4 + 4 + 4);
 	if (unlikely(p == NULL))
 		goto out_overflow;
-	memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
-	if (memcmp(id.data, session->se_sessionid.data,
-					NFS4_MAX_SESSIONID_LEN) != 0) {
+
+	if (memcmp(p, session->se_sessionid.data, NFS4_MAX_SESSIONID_LEN)) {
 		dprintk("NFS: %s Invalid session id\n", __func__);
 		goto out;
 	}