svcrdma: Make RDMA_ERROR messages work

Fix several issues with svc_rdma_send_error():

 - Post a receive buffer to replace the one that was consumed by
   the incoming request
 - Posting a send should use DMA_TO_DEVICE, not DMA_FROM_DEVICE
 - No need to put_page _and_ free pages in svc_rdma_put_context
 - Make sure the sge is set up completely in case the error
   path goes through svc_rdma_unmap_dma()
 - Replace the use of ENOSYS, which has a reserved meaning

Related fixes in svc_rdma_recvfrom():

 - Don't leak the ctxt associated with the incoming request
 - Don't close the connection after sending an error reply
 - Let svc_rdma_send_error() figure out the right header error code

As a last clean up, move svc_rdma_send_error() to svc_rdma_sendto.c
with other similar functions. There is some common logic in these
functions that could someday be combined to reduce code duplication.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Devesh Sharma <devesh.sharma@broadcom.com>
Tested-by: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 9 insertions, 10 deletions

diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index acf15b8bca70..0f09052110a7 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -612,7 +612,6 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
 	struct svc_rdma_op_ctxt *ctxt = NULL;
 	struct rpcrdma_msg *rmsgp;
 	int ret = 0;
-	int len;
 
 	dprintk("svcrdma: rqstp=%p\n", rqstp);
 
@@ -654,15 +653,10 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
 	rdma_build_arg_xdr(rqstp, ctxt, ctxt->byte_len);
 
 	/* Decode the RDMA header. */
-	len = svc_rdma_xdr_decode_req(&rmsgp, rqstp);
-	rqstp->rq_xprt_hlen = len;
-
-	/* If the request is invalid, reply with an error */
-	if (len < 0) {
-		if (len == -ENOSYS)
-			svc_rdma_send_error(rdma_xprt, rmsgp, ERR_VERS);
-		goto close_out;
-	}
+	ret = svc_rdma_xdr_decode_req(&rmsgp, rqstp);
+	if (ret < 0)
+		goto out_err;
+	rqstp->rq_xprt_hlen = ret;
 
 	if (svc_rdma_is_backchannel_reply(xprt, rmsgp)) {
 		ret = svc_rdma_handle_bc_reply(xprt->xpt_bc_xprt, rmsgp,
@@ -698,6 +692,11 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
 	svc_xprt_copy_addrs(rqstp, xprt);
 	return ret;
 
+out_err:
+	svc_rdma_send_error(rdma_xprt, rmsgp, ret);
+	svc_rdma_put_context(ctxt, 0);
+	return 0;
+
  close_out:
 	if (ctxt)
 		svc_rdma_put_context(ctxt, 1);