sunrpc: potential memory leak in function rdma_read_xdr

In case the check on ch_count fails the cleanup path is skipped and the
previously allocated memory 'rpl_map', 'chl_map' is not freed.

Reported by Coverity.

Signed-off-by: Christian Engelmayer <christian.engelmayer@frequentis.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

net/sunrpc/xprtrdma/svc_rdma_recvfrom.c

@@ -397,14 +397,14 @@ static int rdma_read_xdr(struct svcxprt_rdma *xprt,
 	if (!ch)
 		return 0;
 
-	/* Allocate temporary reply and chunk maps */
-	rpl_map = svc_rdma_get_req_map();
-	chl_map = svc_rdma_get_req_map();
-
 	svc_rdma_rcl_chunk_counts(ch, &ch_count, &byte_count);
 	if (ch_count > RPCSVC_MAXPAGES)
 		return -EINVAL;
 
+	/* Allocate temporary reply and chunk maps */
+	rpl_map = svc_rdma_get_req_map();
+	chl_map = svc_rdma_get_req_map();
+
 	if (!xprt->sc_frmr_pg_list_len)
 		sge_count = map_read_chunks(xprt, rqstp, hdr_ctxt, rmsgp,
 					    rpl_map, chl_map, ch_count,