4 files changed, 34 insertions, 4 deletions

diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index 853dede38900..4fdeaac6ebe6 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -534,6 +534,11 @@ rpcrdma_unmap_sendctx(struct rpcrdma_sendctx *sc)
 	for (count = sc->sc_unmap_count; count; ++sge, --count)
 		ib_dma_unmap_page(ia->ri_device,
 				  sge->addr, sge->length, DMA_TO_DEVICE);
+
+	if (test_and_clear_bit(RPCRDMA_REQ_F_TX_RESOURCES, &sc->sc_req->rl_flags)) {
+		smp_mb__after_atomic();
+		wake_up_bit(&sc->sc_req->rl_flags, RPCRDMA_REQ_F_TX_RESOURCES);
+	}
 }
 
 /* Prepare an SGE for the RPC-over-RDMA transport header.
@@ -667,6 +672,8 @@ map_tail:
 
 out:
 	sc->sc_wr.num_sge += sge_no;
+	if (sc->sc_unmap_count)
+		__set_bit(RPCRDMA_REQ_F_TX_RESOURCES, &req->rl_flags);
 	return true;
 
 out_regbuf:
@@ -704,6 +711,8 @@ rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt,
 		return -ENOBUFS;
 	req->rl_sendctx->sc_wr.num_sge = 0;
 	req->rl_sendctx->sc_unmap_count = 0;
+	req->rl_sendctx->sc_req = req;
+	__clear_bit(RPCRDMA_REQ_F_TX_RESOURCES, &req->rl_flags);
 
 	if (!rpcrdma_prepare_hdr_sge(&r_xprt->rx_ia, req, hdrlen))
 		return -EIO;
@@ -1305,6 +1314,20 @@ void rpcrdma_release_rqst(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
 	if (!list_empty(&req->rl_registered))
 		r_xprt->rx_ia.ri_ops->ro_unmap_sync(r_xprt,
 						    &req->rl_registered);
+
+	/* Ensure that any DMA mapped pages associated with
+	 * the Send of the RPC Call have been unmapped before
+	 * allowing the RPC to complete. This protects argument
+	 * memory not controlled by the RPC client from being
+	 * re-used before we're done with it.
+	 */
+	if (test_bit(RPCRDMA_REQ_F_TX_RESOURCES, &req->rl_flags)) {
+		r_xprt->rx_stats.reply_waits_for_send++;
+		out_of_line_wait_on_bit(&req->rl_flags,
+					RPCRDMA_REQ_F_TX_RESOURCES,
+					bit_wait,
+					TASK_UNINTERRUPTIBLE);
+	}
 }
 
 /* Reply handling runs in the poll worker thread. Anything that
@@ -1384,7 +1407,8 @@ void rpcrdma_reply_handler(struct rpcrdma_rep *rep)
 	dprintk("RPC:       %s: reply %p completes request %p (xid 0x%08x)\n",
 		__func__, rep, req, be32_to_cpu(rep->rr_xid));
 
-	if (list_empty(&req->rl_registered))
+	if (list_empty(&req->rl_registered) &&
+	    !test_bit(RPCRDMA_REQ_F_TX_RESOURCES, &req->rl_flags))
 		rpcrdma_complete_rqst(rep);
 	else
 		queue_work(rpcrdma_receive_wq, &rep->rr_work);
diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
index 35aefe201848..9fdd11e4758c 100644
--- a/net/sunrpc/xprtrdma/transport.c
+++ b/net/sunrpc/xprtrdma/transport.c
@@ -789,12 +789,13 @@ void xprt_rdma_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
 		   r_xprt->rx_stats.failed_marshal_count,
 		   r_xprt->rx_stats.bad_reply_count,
 		   r_xprt->rx_stats.nomsg_call_count);
-	seq_printf(seq, "%lu %lu %lu %lu %lu\n",
+	seq_printf(seq, "%lu %lu %lu %lu %lu %lu\n",
 		   r_xprt->rx_stats.mrs_recovered,
 		   r_xprt->rx_stats.mrs_orphaned,
 		   r_xprt->rx_stats.mrs_allocated,
 		   r_xprt->rx_stats.local_inv_needed,
-		   r_xprt->rx_stats.empty_sendctx_q);
+		   r_xprt->rx_stats.empty_sendctx_q,
+		   r_xprt->rx_stats.reply_waits_for_send);
 }
 
 static int
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index bab63adf070b..9a824fe8ffc2 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -1526,7 +1526,8 @@ rpcrdma_ep_post(struct rpcrdma_ia *ia,
 	dprintk("RPC:       %s: posting %d s/g entries\n",
 		__func__, send_wr->num_sge);
 
-	if (!ep->rep_send_count) {
+	if (!ep->rep_send_count ||
+	    test_bit(RPCRDMA_REQ_F_TX_RESOURCES, &req->rl_flags)) {
 		send_wr->send_flags |= IB_SEND_SIGNALED;
 		ep->rep_send_count = ep->rep_send_batch;
 	} else {
diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index c260475baa36..bccd5d8b9384 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -236,11 +236,13 @@ struct rpcrdma_rep {
 
 /* struct rpcrdma_sendctx - DMA mapped SGEs to unmap after Send completes
  */
+struct rpcrdma_req;
 struct rpcrdma_xprt;
 struct rpcrdma_sendctx {
 	struct ib_send_wr	sc_wr;
 	struct ib_cqe		sc_cqe;
 	struct rpcrdma_xprt	*sc_xprt;
+	struct rpcrdma_req	*sc_req;
 	unsigned int		sc_unmap_count;
 	struct ib_sge		sc_sges[];
 };
@@ -387,6 +389,7 @@ struct rpcrdma_req {
 enum {
 	RPCRDMA_REQ_F_BACKCHANNEL = 0,
 	RPCRDMA_REQ_F_PENDING,
+	RPCRDMA_REQ_F_TX_RESOURCES,
 };
 
 static inline void
@@ -492,6 +495,7 @@ struct rpcrdma_stats {
 	/* accessed when receiving a reply */
 	unsigned long long	total_rdma_reply;
 	unsigned long long	fixup_copy_count;
+	unsigned long		reply_waits_for_send;
 	unsigned long		local_inv_needed;
 	unsigned long		nomsg_call_count;
 	unsigned long		bcall_count;