svcrdma: Catch another Reply chunk overflow case

When space in the Reply chunk runs out in the middle of a segment,
we end up passing a zero-length SGL to rdma_rw_ctx_init(), and it
oopses.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c
index 80a0c0e8759094899a80430fe6a83884d95feb62..7c50eddb8d3cafb7da3f0b8f278385eeada0e867 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_rw.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c
@@ -460,6 +460,8 @@ svc_rdma_build_writes(struct svc_rdma_write_info *info,
                offset += info->wi_seg_off;
 
                write_len = min(remaining, length - info->wi_seg_off);
+               if (!write_len)
+                       goto out_overflow;
                ctxt = svc_rdma_get_rw_ctxt(rdma,
                                            (write_len >> PAGE_SHIFT) + 2);
                if (!ctxt)