xprtrdma: Use ib_device pointer safely

The connect worker can replace ri_id, but prevents ri_id->device
from changing during the lifetime of a transport instance. The old
ID is kept around until a new ID is created and the ->device is
confirmed to be the same.

Cache a copy of ri_id->device in rpcrdma_ia and in rpcrdma_rep.
The cached copy can be used safely in code that does not serialize
with the connect worker.

Other code can use it to save an extra address generation (one
pointer dereference instead of two).

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Tested-By: Devesh Sharma <devesh.sharma@avagotech.com>
Reviewed-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 32 insertions, 29 deletions

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 8e0bd84c8df8..ddd5b362da35 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -272,7 +272,6 @@ rpcrdma_recvcq_process_wc(struct ib_wc *wc, struct list_head *sched_list)
 {
 	struct rpcrdma_rep *rep =
 			(struct rpcrdma_rep *)(unsigned long)wc->wr_id;
-	struct rpcrdma_ia *ia;
 
 	/* WARNING: Only wr_id and status are reliable at this point */
 	if (wc->status != IB_WC_SUCCESS)
@@ -285,9 +284,8 @@ rpcrdma_recvcq_process_wc(struct ib_wc *wc, struct list_head *sched_list)
 	dprintk("RPC:       %s: rep %p opcode 'recv', length %u: success\n",
 		__func__, rep, wc->byte_len);
 
-	ia = &rep->rr_rxprt->rx_ia;
 	rep->rr_len = wc->byte_len;
-	ib_dma_sync_single_for_cpu(ia->ri_id->device,
+	ib_dma_sync_single_for_cpu(rep->rr_device,
 				   rdmab_addr(rep->rr_rdmabuf),
 				   rep->rr_len, DMA_FROM_DEVICE);
 	prefetch(rdmab_to_msg(rep->rr_rdmabuf));
@@ -483,7 +481,7 @@ connected:
 
 		pr_info("rpcrdma: connection to %pIS:%u on %s, memreg '%s', %d credits, %d responders%s\n",
 			sap, rpc_get_port(sap),
-			ia->ri_id->device->name,
+			ia->ri_device->name,
 			ia->ri_ops->ro_displayname,
 			xprt->rx_buf.rb_max_requests,
 			ird, ird < 4 && ird < tird / 2 ? " (low!)" : "");
@@ -584,8 +582,9 @@ rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr, int memreg)
 		rc = PTR_ERR(ia->ri_id);
 		goto out1;
 	}
+	ia->ri_device = ia->ri_id->device;
 
-	ia->ri_pd = ib_alloc_pd(ia->ri_id->device);
+	ia->ri_pd = ib_alloc_pd(ia->ri_device);
 	if (IS_ERR(ia->ri_pd)) {
 		rc = PTR_ERR(ia->ri_pd);
 		dprintk("RPC:       %s: ib_alloc_pd() failed %i\n",
@@ -593,7 +592,7 @@ rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr, int memreg)
 		goto out2;
 	}
 
-	rc = ib_query_device(ia->ri_id->device, devattr);
+	rc = ib_query_device(ia->ri_device, devattr);
 	if (rc) {
 		dprintk("RPC:       %s: ib_query_device failed %d\n",
 			__func__, rc);
@@ -602,7 +601,7 @@ rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr, int memreg)
 
 	if (devattr->device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY) {
 		ia->ri_have_dma_lkey = 1;
-		ia->ri_dma_lkey = ia->ri_id->device->local_dma_lkey;
+		ia->ri_dma_lkey = ia->ri_device->local_dma_lkey;
 	}
 
 	if (memreg == RPCRDMA_FRMR) {
@@ -617,7 +616,7 @@ rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr, int memreg)
 		}
 	}
 	if (memreg == RPCRDMA_MTHCAFMR) {
-		if (!ia->ri_id->device->alloc_fmr) {
+		if (!ia->ri_device->alloc_fmr) {
 			dprintk("RPC:       %s: MTHCAFMR registration "
 				"not supported by HCA\n", __func__);
 			memreg = RPCRDMA_ALLPHYSICAL;
@@ -767,9 +766,9 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
 	init_waitqueue_head(&ep->rep_connect_wait);
 	INIT_DELAYED_WORK(&ep->rep_connect_worker, rpcrdma_connect_worker);
 
-	sendcq = ib_create_cq(ia->ri_id->device, rpcrdma_sendcq_upcall,
-				  rpcrdma_cq_async_error_upcall, ep,
-				  ep->rep_attr.cap.max_send_wr + 1, 0);
+	sendcq = ib_create_cq(ia->ri_device, rpcrdma_sendcq_upcall,
+			      rpcrdma_cq_async_error_upcall, ep,
+			      ep->rep_attr.cap.max_send_wr + 1, 0);
 	if (IS_ERR(sendcq)) {
 		rc = PTR_ERR(sendcq);
 		dprintk("RPC:       %s: failed to create send CQ: %i\n",
@@ -784,9 +783,9 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
 		goto out2;
 	}
 
-	recvcq = ib_create_cq(ia->ri_id->device, rpcrdma_recvcq_upcall,
-				  rpcrdma_cq_async_error_upcall, ep,
-				  ep->rep_attr.cap.max_recv_wr + 1, 0);
+	recvcq = ib_create_cq(ia->ri_device, rpcrdma_recvcq_upcall,
+			      rpcrdma_cq_async_error_upcall, ep,
+			      ep->rep_attr.cap.max_recv_wr + 1, 0);
 	if (IS_ERR(recvcq)) {
 		rc = PTR_ERR(recvcq);
 		dprintk("RPC:       %s: failed to create recv CQ: %i\n",
@@ -907,7 +906,7 @@ retry:
 		 * More stuff I haven't thought of!
 		 * Rrrgh!
 		 */
-		if (ia->ri_id->device != id->device) {
+		if (ia->ri_device != id->device) {
 			printk("RPC:       %s: can't reconnect on "
 				"different device!\n", __func__);
 			rdma_destroy_id(id);
@@ -1049,6 +1048,7 @@ rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt)
 		goto out_free;
 	}
 
+	rep->rr_device = ia->ri_device;
 	rep->rr_rxprt = r_xprt;
 	return rep;
 
@@ -1449,9 +1449,9 @@ rpcrdma_register_internal(struct rpcrdma_ia *ia, void *va, int len,
 	/*
 	 * All memory passed here was kmalloc'ed, therefore phys-contiguous.
 	 */
-	iov->addr = ib_dma_map_single(ia->ri_id->device,
+	iov->addr = ib_dma_map_single(ia->ri_device,
 			va, len, DMA_BIDIRECTIONAL);
-	if (ib_dma_mapping_error(ia->ri_id->device, iov->addr))
+	if (ib_dma_mapping_error(ia->ri_device, iov->addr))
 		return -ENOMEM;
 
 	iov->length = len;
@@ -1495,8 +1495,8 @@ rpcrdma_deregister_internal(struct rpcrdma_ia *ia,
 {
 	int rc;
 
-	ib_dma_unmap_single(ia->ri_id->device,
-			iov->addr, iov->length, DMA_BIDIRECTIONAL);
+	ib_dma_unmap_single(ia->ri_device,
+			    iov->addr, iov->length, DMA_BIDIRECTIONAL);
 
 	if (NULL == mr)
 		return 0;
@@ -1589,15 +1589,18 @@ rpcrdma_ep_post(struct rpcrdma_ia *ia,
 	send_wr.num_sge = req->rl_niovs;
 	send_wr.opcode = IB_WR_SEND;
 	if (send_wr.num_sge == 4)	/* no need to sync any pad (constant) */
-		ib_dma_sync_single_for_device(ia->ri_id->device,
-			req->rl_send_iov[3].addr, req->rl_send_iov[3].length,
-			DMA_TO_DEVICE);
-	ib_dma_sync_single_for_device(ia->ri_id->device,
-		req->rl_send_iov[1].addr, req->rl_send_iov[1].length,
-		DMA_TO_DEVICE);
-	ib_dma_sync_single_for_device(ia->ri_id->device,
-		req->rl_send_iov[0].addr, req->rl_send_iov[0].length,
-		DMA_TO_DEVICE);
+		ib_dma_sync_single_for_device(ia->ri_device,
+					      req->rl_send_iov[3].addr,
+					      req->rl_send_iov[3].length,
+					      DMA_TO_DEVICE);
+	ib_dma_sync_single_for_device(ia->ri_device,
+				      req->rl_send_iov[1].addr,
+				      req->rl_send_iov[1].length,
+				      DMA_TO_DEVICE);
+	ib_dma_sync_single_for_device(ia->ri_device,
+				      req->rl_send_iov[0].addr,
+				      req->rl_send_iov[0].length,
+				      DMA_TO_DEVICE);
 
 	if (DECR_CQCOUNT(ep) > 0)
 		send_wr.send_flags = 0;
@@ -1630,7 +1633,7 @@ rpcrdma_ep_post_recv(struct rpcrdma_ia *ia,
 	recv_wr.sg_list = &rep->rr_rdmabuf->rg_iov;
 	recv_wr.num_sge = 1;
 
-	ib_dma_sync_single_for_cpu(ia->ri_id->device,
+	ib_dma_sync_single_for_cpu(ia->ri_device,
 				   rdmab_addr(rep->rr_rdmabuf),
 				   rdmab_length(rep->rr_rdmabuf),
 				   DMA_BIDIRECTIONAL);