xprtrdma: Chunk list encoders must not return zero

Clean up, based on code audit: Remove the possibility that the
chunk list XDR encoders can return zero, which would be interpreted
as a NULL.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

3 files changed, 7 insertions, 3 deletions

diff --git a/net/sunrpc/xprtrdma/fmr_ops.c b/net/sunrpc/xprtrdma/fmr_ops.c
index aae4c372a40f..bc5f4a1e3122 100644
--- a/net/sunrpc/xprtrdma/fmr_ops.c
+++ b/net/sunrpc/xprtrdma/fmr_ops.c
@@ -246,6 +246,8 @@ fmr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
         }
         mw->mw_nents = i;
         mw->mw_dir = rpcrdma_data_dir(writing);
+        if (i == 0)
+                goto out_dmamap_err;
 
         if (!ib_dma_map_sg(r_xprt->rx_ia.ri_device,
                            mw->mw_sg, mw->mw_nents, mw->mw_dir))
diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c
index d7613db9185d..f3a06faf0a18 100644
--- a/net/sunrpc/xprtrdma/frwr_ops.c
+++ b/net/sunrpc/xprtrdma/frwr_ops.c
@@ -411,6 +411,8 @@ frwr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
         }
         mw->mw_nents = i;
         mw->mw_dir = rpcrdma_data_dir(writing);
+        if (i == 0)
+                goto out_dmamap_err;
 
         dma_nents = ib_dma_map_sg(ia->ri_device,
                                   mw->mw_sg, mw->mw_nents, mw->mw_dir);
diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index 77e002f4d005..8fde0ab3b695 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -329,7 +329,7 @@ rpcrdma_encode_read_list(struct rpcrdma_xprt *r_xprt,
 
         do {
                 n = r_xprt->rx_ia.ri_ops->ro_map(r_xprt, seg, nsegs, false);
-                if (n <= 0)
+                if (n < 0)
                         return ERR_PTR(n);
 
                 *iptr++ = xdr_one;      /* item present */
@@ -397,7 +397,7 @@ rpcrdma_encode_write_list(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req,
         nchunks = 0;
         do {
                 n = r_xprt->rx_ia.ri_ops->ro_map(r_xprt, seg, nsegs, true);
-                if (n <= 0)
+                if (n < 0)
                         return ERR_PTR(n);
 
                 iptr = xdr_encode_rdma_segment(iptr, seg);
@@ -462,7 +462,7 @@ rpcrdma_encode_reply_chunk(struct rpcrdma_xprt *r_xprt,
         nchunks = 0;
         do {
                 n = r_xprt->rx_ia.ri_ops->ro_map(r_xprt, seg, nsegs, true);
-                if (n <= 0)
+                if (n < 0)
                         return ERR_PTR(n);
 
                 iptr = xdr_encode_rdma_segment(iptr, seg);