Merge tag 'nfs-rdma-for-3.20' of git://git.linux-nfs.org/projects/anna/nfs-rdma

NFS: Client side changes for RDMA

These patches improve the scalability of the NFSoRDMA client and take large
variables off of the stack. Additionally, the GFP_* flags are updated to
match what TCP uses.

Signed-off-by: Anna Schumaker <[e-mail]>

* tag 'nfs-rdma-for-3.20' of git://git.linux-nfs.org/projects/anna/nfs-rdma: (21 commits)
xprtrdma: Update the GFP flags used in xprt_rdma_allocate()
xprtrdma: Clean up after adding regbuf management
xprtrdma: Allocate zero pad separately from rpcrdma_buffer
xprtrdma: Allocate RPC/RDMA receive buffer separately from struct rpcrdma_rep
xprtrdma: Allocate RPC/RDMA send buffer separately from struct rpcrdma_req
xprtrdma: Allocate RPC send buffer separately from struct rpcrdma_req
xprtrdma: Add struct rpcrdma_regbuf and helpers
xprtrdma: Refactor rpcrdma_buffer_create() and rpcrdma_buffer_destroy()
xprtrdma: Simplify synopsis of rpcrdma_buffer_create()
xprtrdma: Take struct ib_qp_attr and ib_qp_init_attr off the stack
xprtrdma: Take struct ib_device_attr off the stack
xprtrdma: Free the pd if ib_query_qp() fails
xprtrdma: Remove rpcrdma_ep::rep_func and ::rep_xprt
xprtrdma: Move credit update to RPC reply handler
xprtrdma: Remove rl_mr field, and the mr_chunk union
xprtrdma: Remove rpcrdma_ep::rep_ia
xprtrdma: Rename "xprt" and "rdma_connect" fields in struct rpcrdma_xprt
xprtrdma: Clean up hdrlen
xprtrdma: Display XIDs in host byte order
xprtrdma: Modernize htonl and ntohl
...

include/linux/sunrpc/rpc_rdma.h

···
 
 #include <linux/types.h>
 
+#define RPCRDMA_VERSION		1
+#define rpcrdma_version		cpu_to_be32(RPCRDMA_VERSION)
+
 struct rpcrdma_segment {
 	__be32 rs_handle;	/* Registered memory handle */
 	__be32 rs_length;	/* Length of the chunk in bytes */
···
 	} rm_body;
 };
 
-#define RPCRDMA_HDRLEN_MIN	28
+/*
+ * Smallest RPC/RDMA header: rm_xid through rm_type, then rm_nochunks
+ */
+#define RPCRDMA_HDRLEN_MIN	(sizeof(__be32) * 7)
 
 enum rpcrdma_errcode {
 	ERR_VERS = 1,
···
 	RDMA_DONE = 3,		/* Client signals reply completion */
 	RDMA_ERROR = 4		/* An RPC RDMA encoding error */
 };
+
+#define rdma_msg	cpu_to_be32(RDMA_MSG)
+#define rdma_nomsg	cpu_to_be32(RDMA_NOMSG)
+#define rdma_msgp	cpu_to_be32(RDMA_MSGP)
+#define rdma_done	cpu_to_be32(RDMA_DONE)
+#define rdma_error	cpu_to_be32(RDMA_ERROR)
 
 #endif				/* _LINUX_SUNRPC_RPC_RDMA_H */

include/linux/sunrpc/svc_rdma.h

···
 extern atomic_t rdma_stat_sq_poll;
 extern atomic_t rdma_stat_sq_prod;
 
-#define RPCRDMA_VERSION 1
-
 /*
  * Contexts are built when an RDMA request is created and are a
  * record of the resources that can be recovered when the request

net/sunrpc/xprtrdma/rpc_rdma.c

···
 		if (cur_rchunk) {	/* read */
 			cur_rchunk->rc_discrim = xdr_one;
 			/* all read chunks have the same "position" */
-			cur_rchunk->rc_position = htonl(pos);
-			cur_rchunk->rc_target.rs_handle = htonl(seg->mr_rkey);
-			cur_rchunk->rc_target.rs_length = htonl(seg->mr_len);
+			cur_rchunk->rc_position = cpu_to_be32(pos);
+			cur_rchunk->rc_target.rs_handle =
+						cpu_to_be32(seg->mr_rkey);
+			cur_rchunk->rc_target.rs_length =
+						cpu_to_be32(seg->mr_len);
 			xdr_encode_hyper(
 					(__be32 *)&cur_rchunk->rc_target.rs_offset,
 					seg->mr_base);
···
 			cur_rchunk++;
 			r_xprt->rx_stats.read_chunk_count++;
 		} else {		/* write/reply */
-			cur_wchunk->wc_target.rs_handle = htonl(seg->mr_rkey);
-			cur_wchunk->wc_target.rs_length = htonl(seg->mr_len);
+			cur_wchunk->wc_target.rs_handle =
+						cpu_to_be32(seg->mr_rkey);
+			cur_wchunk->wc_target.rs_length =
+						cpu_to_be32(seg->mr_len);
 			xdr_encode_hyper(
 					(__be32 *)&cur_wchunk->wc_target.rs_offset,
 					seg->mr_base);
···
 		*iptr++ = xdr_zero;	/* encode a NULL reply chunk */
 	} else {
 		warray->wc_discrim = xdr_one;
-		warray->wc_nchunks = htonl(nchunks);
+		warray->wc_nchunks = cpu_to_be32(nchunks);
 		iptr = (__be32 *) cur_wchunk;
 		if (type == rpcrdma_writech) {
 			*iptr++ = xdr_zero; /* finish the write chunk list */
···
 rpcrdma_marshal_chunks(struct rpc_rqst *rqst, ssize_t result)
 {
 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
-	struct rpcrdma_msg *headerp = (struct rpcrdma_msg *)req->rl_base;
+	struct rpcrdma_msg *headerp = rdmab_to_msg(req->rl_rdmabuf);
 
 	if (req->rl_rtype != rpcrdma_noch)
 		result = rpcrdma_create_chunks(rqst, &rqst->rq_snd_buf,
···
 	base = rqst->rq_svec[0].iov_base;
 	rpclen = rqst->rq_svec[0].iov_len;
 
-	/* build RDMA header in private area at front */
-	headerp = (struct rpcrdma_msg *) req->rl_base;
-	/* don't htonl XID, it's already done in request */
+	headerp = rdmab_to_msg(req->rl_rdmabuf);
+	/* don't byte-swap XID, it's already done in request */
 	headerp->rm_xid = rqst->rq_xid;
-	headerp->rm_vers = xdr_one;
-	headerp->rm_credit = htonl(r_xprt->rx_buf.rb_max_requests);
-	headerp->rm_type = htonl(RDMA_MSG);
+	headerp->rm_vers = rpcrdma_version;
+	headerp->rm_credit = cpu_to_be32(r_xprt->rx_buf.rb_max_requests);
+	headerp->rm_type = rdma_msg;
 
 	/*
 	 * Chunks needed for results?
···
 		return -EIO;
 	}
 
-	hdrlen = 28; /*sizeof *headerp;*/
+	hdrlen = RPCRDMA_HDRLEN_MIN;
 	padlen = 0;
 
 	/*
···
 						RPCRDMA_INLINE_PAD_VALUE(rqst));
 
 		if (padlen) {
-			headerp->rm_type = htonl(RDMA_MSGP);
+			headerp->rm_type = rdma_msgp;
 			headerp->rm_body.rm_padded.rm_align =
-				htonl(RPCRDMA_INLINE_PAD_VALUE(rqst));
+				cpu_to_be32(RPCRDMA_INLINE_PAD_VALUE(rqst));
 			headerp->rm_body.rm_padded.rm_thresh =
-				htonl(RPCRDMA_INLINE_PAD_THRESH);
+				cpu_to_be32(RPCRDMA_INLINE_PAD_THRESH);
 			headerp->rm_body.rm_padded.rm_pempty[0] = xdr_zero;
 			headerp->rm_body.rm_padded.rm_pempty[1] = xdr_zero;
 			headerp->rm_body.rm_padded.rm_pempty[2] = xdr_zero;
···
 	dprintk("RPC:       %s: %s: hdrlen %zd rpclen %zd padlen %zd"
 		" headerp 0x%p base 0x%p lkey 0x%x\n",
 		__func__, transfertypes[req->rl_wtype], hdrlen, rpclen, padlen,
-		headerp, base, req->rl_iov.lkey);
+		headerp, base, rdmab_lkey(req->rl_rdmabuf));
 
 	/*
 	 * initialize send_iov's - normally only two: rdma chunk header and
···
 	 * header and any write data. In all non-rdma cases, any following
 	 * data has been copied into the RPC header buffer.
 	 */
-	req->rl_send_iov[0].addr = req->rl_iov.addr;
+	req->rl_send_iov[0].addr = rdmab_addr(req->rl_rdmabuf);
 	req->rl_send_iov[0].length = hdrlen;
-	req->rl_send_iov[0].lkey = req->rl_iov.lkey;
+	req->rl_send_iov[0].lkey = rdmab_lkey(req->rl_rdmabuf);
 
-	req->rl_send_iov[1].addr = req->rl_iov.addr + (base - req->rl_base);
+	req->rl_send_iov[1].addr = rdmab_addr(req->rl_sendbuf);
 	req->rl_send_iov[1].length = rpclen;
-	req->rl_send_iov[1].lkey = req->rl_iov.lkey;
+	req->rl_send_iov[1].lkey = rdmab_lkey(req->rl_sendbuf);
 
 	req->rl_niovs = 2;
 
 	if (padlen) {
 		struct rpcrdma_ep *ep = &r_xprt->rx_ep;
 
-		req->rl_send_iov[2].addr = ep->rep_pad.addr;
+		req->rl_send_iov[2].addr = rdmab_addr(ep->rep_padbuf);
 		req->rl_send_iov[2].length = padlen;
-		req->rl_send_iov[2].lkey = ep->rep_pad.lkey;
+		req->rl_send_iov[2].lkey = rdmab_lkey(ep->rep_padbuf);
 
 		req->rl_send_iov[3].addr = req->rl_send_iov[1].addr + rpclen;
 		req->rl_send_iov[3].length = rqst->rq_slen - rpclen;
-		req->rl_send_iov[3].lkey = req->rl_iov.lkey;
+		req->rl_send_iov[3].lkey = rdmab_lkey(req->rl_sendbuf);
 
 		req->rl_niovs = 4;
 	}
···
 {
 	unsigned int i, total_len;
 	struct rpcrdma_write_chunk *cur_wchunk;
+	char *base = (char *)rdmab_to_msg(rep->rr_rdmabuf);
 
-	i = ntohl(**iptrp);	/* get array count */
+	i = be32_to_cpu(**iptrp);
 	if (i > max)
 		return -1;
 	cur_wchunk = (struct rpcrdma_write_chunk *) (*iptrp + 1);
···
 			xdr_decode_hyper((__be32 *)&seg->rs_offset, &off);
 			dprintk("RPC:       %s: chunk %d@0x%llx:0x%x\n",
 				__func__,
-				ntohl(seg->rs_length),
+				be32_to_cpu(seg->rs_length),
 				(unsigned long long)off,
-				ntohl(seg->rs_handle));
+				be32_to_cpu(seg->rs_handle));
 		}
-		total_len += ntohl(seg->rs_length);
+		total_len += be32_to_cpu(seg->rs_length);
 		++cur_wchunk;
 	}
 	/* check and adjust for properly terminated write chunk */
···
 			return -1;
 		cur_wchunk = (struct rpcrdma_write_chunk *) w;
 	}
-	if ((char *) cur_wchunk > rep->rr_base + rep->rr_len)
+	if ((char *)cur_wchunk > base + rep->rr_len)
 		return -1;
 
 	*iptrp = (__be32 *) cur_wchunk;
···
 {
 	struct rpcrdma_ep *ep =
 		container_of(work, struct rpcrdma_ep, rep_connect_worker.work);
-	struct rpc_xprt *xprt = ep->rep_xprt;
+	struct rpcrdma_xprt *r_xprt =
+		container_of(ep, struct rpcrdma_xprt, rx_ep);
+	struct rpc_xprt *xprt = &r_xprt->rx_xprt;
 
 	spin_lock_bh(&xprt->transport_lock);
 	if (++xprt->connect_cookie == 0)	/* maintain a reserved value */
···
 	struct rpc_xprt *xprt = rep->rr_xprt;
 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
 	__be32 *iptr;
-	int rdmalen, status;
+	int credits, rdmalen, status;
 	unsigned long cwnd;
 
 	/* Check status. If bad, signal disconnect and return rep to pool */
···
 		}
 		return;
 	}
-	if (rep->rr_len < 28) {
+	if (rep->rr_len < RPCRDMA_HDRLEN_MIN) {
 		dprintk("RPC:       %s: short/invalid reply\n", __func__);
 		goto repost;
 	}
-	headerp = (struct rpcrdma_msg *) rep->rr_base;
-	if (headerp->rm_vers != xdr_one) {
+	headerp = rdmab_to_msg(rep->rr_rdmabuf);
+	if (headerp->rm_vers != rpcrdma_version) {
 		dprintk("RPC:       %s: invalid version %d\n",
-			__func__, ntohl(headerp->rm_vers));
+			__func__, be32_to_cpu(headerp->rm_vers));
 		goto repost;
 	}
 
···
 		spin_unlock(&xprt->transport_lock);
 		dprintk("RPC:       %s: reply 0x%p failed "
 			"to match any request xid 0x%08x len %d\n",
-			__func__, rep, headerp->rm_xid, rep->rr_len);
+			__func__, rep, be32_to_cpu(headerp->rm_xid),
+			rep->rr_len);
 repost:
 		r_xprt->rx_stats.bad_reply_count++;
 		rep->rr_func = rpcrdma_reply_handler;
···
 		spin_unlock(&xprt->transport_lock);
 		dprintk("RPC:       %s: duplicate reply 0x%p to RPC "
 			"request 0x%p: xid 0x%08x\n", __func__, rep, req,
-			headerp->rm_xid);
+			be32_to_cpu(headerp->rm_xid));
 		goto repost;
 	}
 
 	dprintk("RPC:       %s: reply 0x%p completes request 0x%p\n"
 		"                   RPC request 0x%p xid 0x%08x\n",
-			__func__, rep, req, rqst, headerp->rm_xid);
+			__func__, rep, req, rqst,
+			be32_to_cpu(headerp->rm_xid));
 
 	/* from here on, the reply is no longer an orphan */
 	req->rl_reply = rep;
···
 	/* check for expected message types */
 	/* The order of some of these tests is important. */
 	switch (headerp->rm_type) {
-	case htonl(RDMA_MSG):
+	case rdma_msg:
 		/* never expect read chunks */
 		/* never expect reply chunks (two ways to check) */
 		/* never expect write chunks without having offered RDMA */
···
 		} else {
 			/* else ordinary inline */
 			rdmalen = 0;
-			iptr = (__be32 *)((unsigned char *)headerp + 28);
-			rep->rr_len -= 28; /*sizeof *headerp;*/
+			iptr = (__be32 *)((unsigned char *)headerp +
+							RPCRDMA_HDRLEN_MIN);
+			rep->rr_len -= RPCRDMA_HDRLEN_MIN;
 			status = rep->rr_len;
 		}
 		/* Fix up the rpc results for upper layer */
 		rpcrdma_inline_fixup(rqst, (char *)iptr, rep->rr_len, rdmalen);
 		break;
 
-	case htonl(RDMA_NOMSG):
+	case rdma_nomsg:
 		/* never expect read or write chunks, always reply chunks */
 		if (headerp->rm_body.rm_chunks[0] != xdr_zero ||
 		    headerp->rm_body.rm_chunks[1] != xdr_zero ||
 		    headerp->rm_body.rm_chunks[2] != xdr_one ||
 		    req->rl_nchunks == 0)
 			goto badheader;
-		iptr = (__be32 *)((unsigned char *)headerp + 28);
+		iptr = (__be32 *)((unsigned char *)headerp +
+							RPCRDMA_HDRLEN_MIN);
 		rdmalen = rpcrdma_count_chunks(rep, req->rl_nchunks, 0, &iptr);
 		if (rdmalen < 0)
 			goto badheader;
···
 		dprintk("%s: invalid rpcrdma reply header (type %d):"
 				" chunks[012] == %d %d %d"
 				" expected chunks <= %d\n",
-				__func__, ntohl(headerp->rm_type),
+				__func__, be32_to_cpu(headerp->rm_type),
 				headerp->rm_body.rm_chunks[0],
 				headerp->rm_body.rm_chunks[1],
 				headerp->rm_body.rm_chunks[2],
···
 		break;
 	}
 
+	credits = be32_to_cpu(headerp->rm_credit);
+	if (credits == 0)
+		credits = 1;	/* don't deadlock */
+	else if (credits > r_xprt->rx_buf.rb_max_requests)
+		credits = r_xprt->rx_buf.rb_max_requests;
+
 	cwnd = xprt->cwnd;
-	xprt->cwnd = atomic_read(&r_xprt->rx_buf.rb_credits) << RPC_CWNDSHIFT;
+	xprt->cwnd = credits << RPC_CWNDSHIFT;
 	if (xprt->cwnd > cwnd)
 		xprt_release_rqst_cong(rqst->rq_task);
 

net/sunrpc/xprtrdma/transport.c

···
 static void
 xprt_rdma_connect_worker(struct work_struct *work)
 {
-	struct rpcrdma_xprt *r_xprt =
-		container_of(work, struct rpcrdma_xprt, rdma_connect.work);
-	struct rpc_xprt *xprt = &r_xprt->xprt;
+	struct rpcrdma_xprt *r_xprt = container_of(work, struct rpcrdma_xprt,
+						   rx_connect_worker.work);
+	struct rpc_xprt *xprt = &r_xprt->rx_xprt;
 	int rc = 0;
 
 	xprt_clear_connected(xprt);
···
 
 	dprintk("RPC:       %s: called\n", __func__);
 
-	cancel_delayed_work_sync(&r_xprt->rdma_connect);
+	cancel_delayed_work_sync(&r_xprt->rx_connect_worker);
 
 	xprt_clear_connected(xprt);
 
···
 	 * any inline data. Also specify any padding which will be provided
 	 * from a preregistered zero buffer.
 	 */
-	rc = rpcrdma_buffer_create(&new_xprt->rx_buf, new_ep, &new_xprt->rx_ia,
-				&new_xprt->rx_data);
+	rc = rpcrdma_buffer_create(new_xprt);
 	if (rc)
 		goto out3;
 
···
 	 * connection loss notification is async. We also catch connection loss
 	 * when reaping receives.
 	 */
-	INIT_DELAYED_WORK(&new_xprt->rdma_connect, xprt_rdma_connect_worker);
-	new_ep->rep_func = rpcrdma_conn_func;
-	new_ep->rep_xprt = xprt;
+	INIT_DELAYED_WORK(&new_xprt->rx_connect_worker,
+			  xprt_rdma_connect_worker);
 
 	xprt_rdma_format_addresses(xprt);
 	xprt->max_payload = rpcrdma_max_payload(new_xprt);
···
 
 	if (r_xprt->rx_ep.rep_connected != 0) {
 		/* Reconnect */
-		schedule_delayed_work(&r_xprt->rdma_connect,
-			xprt->reestablish_timeout);
+		schedule_delayed_work(&r_xprt->rx_connect_worker,
+				      xprt->reestablish_timeout);
 		xprt->reestablish_timeout <<= 1;
 		if (xprt->reestablish_timeout > RPCRDMA_MAX_REEST_TO)
 			xprt->reestablish_timeout = RPCRDMA_MAX_REEST_TO;
 		else if (xprt->reestablish_timeout < RPCRDMA_INIT_REEST_TO)
 			xprt->reestablish_timeout = RPCRDMA_INIT_REEST_TO;
 	} else {
-		schedule_delayed_work(&r_xprt->rdma_connect, 0);
+		schedule_delayed_work(&r_xprt->rx_connect_worker, 0);
 		if (!RPC_IS_ASYNC(task))
-			flush_delayed_work(&r_xprt->rdma_connect);
+			flush_delayed_work(&r_xprt->rx_connect_worker);
 	}
 }
 
 /*
  * The RDMA allocate/free functions need the task structure as a place
  * to hide the struct rpcrdma_req, which is necessary for the actual send/recv
- * sequence. For this reason, the recv buffers are attached to send
- * buffers for portions of the RPC. Note that the RPC layer allocates
- * both send and receive buffers in the same call. We may register
- * the receive buffer portion when using reply chunks.
+ * sequence.
+ *
+ * The RPC layer allocates both send and receive buffers in the same call
+ * (rq_send_buf and rq_rcv_buf are both part of a single contiguous buffer).
+ * We may register rq_rcv_buf when using reply chunks.
  */
 static void *
 xprt_rdma_allocate(struct rpc_task *task, size_t size)
 {
 	struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
-	struct rpcrdma_req *req, *nreq;
+	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
+	struct rpcrdma_regbuf *rb;
+	struct rpcrdma_req *req;
+	size_t min_size;
+	gfp_t flags;
 
-	req = rpcrdma_buffer_get(&rpcx_to_rdmax(xprt)->rx_buf);
+	req = rpcrdma_buffer_get(&r_xprt->rx_buf);
 	if (req == NULL)
 		return NULL;
 
-	if (size > req->rl_size) {
-		dprintk("RPC:       %s: size %zd too large for buffer[%zd]: "
-			"prog %d vers %d proc %d\n",
-			__func__, size, req->rl_size,
-			task->tk_client->cl_prog, task->tk_client->cl_vers,
-			task->tk_msg.rpc_proc->p_proc);
-		/*
-		 * Outgoing length shortage. Our inline write max must have
-		 * been configured to perform direct i/o.
-		 *
-		 * This is therefore a large metadata operation, and the
-		 * allocate call was made on the maximum possible message,
-		 * e.g. containing long filename(s) or symlink data. In
-		 * fact, while these metadata operations *might* carry
-		 * large outgoing payloads, they rarely *do*. However, we
-		 * have to commit to the request here, so reallocate and
-		 * register it now. The data path will never require this
-		 * reallocation.
-		 *
-		 * If the allocation or registration fails, the RPC framework
-		 * will (doggedly) retry.
-		 */
-		if (task->tk_flags & RPC_TASK_SWAPPER)
-			nreq = kmalloc(sizeof *req + size, GFP_ATOMIC);
-		else
-			nreq = kmalloc(sizeof *req + size, GFP_NOFS);
-		if (nreq == NULL)
-			goto outfail;
+	flags = GFP_NOIO | __GFP_NOWARN;
+	if (RPC_IS_SWAPPER(task))
+		flags = __GFP_MEMALLOC | GFP_NOWAIT | __GFP_NOWARN;
 
-		if (rpcrdma_register_internal(&rpcx_to_rdmax(xprt)->rx_ia,
-				nreq->rl_base, size + sizeof(struct rpcrdma_req)
-				- offsetof(struct rpcrdma_req, rl_base),
-				&nreq->rl_handle, &nreq->rl_iov)) {
-			kfree(nreq);
-			goto outfail;
-		}
-		rpcx_to_rdmax(xprt)->rx_stats.hardway_register_count += size;
-		nreq->rl_size = size;
-		nreq->rl_niovs = 0;
-		nreq->rl_nchunks = 0;
-		nreq->rl_buffer = (struct rpcrdma_buffer *)req;
-		nreq->rl_reply = req->rl_reply;
-		memcpy(nreq->rl_segments,
-			req->rl_segments, sizeof nreq->rl_segments);
-		/* flag the swap with an unused field */
-		nreq->rl_iov.length = 0;
-		req->rl_reply = NULL;
-		req = nreq;
-	}
+	if (req->rl_rdmabuf == NULL)
+		goto out_rdmabuf;
+	if (req->rl_sendbuf == NULL)
+		goto out_sendbuf;
+	if (size > req->rl_sendbuf->rg_size)
+		goto out_sendbuf;
+
+out:
 	dprintk("RPC:       %s: size %zd, request 0x%p\n", __func__, size, req);
 	req->rl_connect_cookie = 0;	/* our reserved value */
-	return req->rl_xdr_buf;
+	return req->rl_sendbuf->rg_base;
 
-outfail:
+out_rdmabuf:
+	min_size = RPCRDMA_INLINE_WRITE_THRESHOLD(task->tk_rqstp);
+	rb = rpcrdma_alloc_regbuf(&r_xprt->rx_ia, min_size, flags);
+	if (IS_ERR(rb))
+		goto out_fail;
+	req->rl_rdmabuf = rb;
+
+out_sendbuf:
+	/* XDR encoding and RPC/RDMA marshaling of this request has not
+	 * yet occurred. Thus a lower bound is needed to prevent buffer
+	 * overrun during marshaling.
+	 *
+	 * RPC/RDMA marshaling may choose to send payload bearing ops
+	 * inline, if the result is smaller than the inline threshold.
+	 * The value of the "size" argument accounts for header
+	 * requirements but not for the payload in these cases.
+	 *
+	 * Likewise, allocate enough space to receive a reply up to the
+	 * size of the inline threshold.
+	 *
+	 * It's unlikely that both the send header and the received
+	 * reply will be large, but slush is provided here to allow
+	 * flexibility when marshaling.
+	 */
+	min_size = RPCRDMA_INLINE_READ_THRESHOLD(task->tk_rqstp);
+	min_size += RPCRDMA_INLINE_WRITE_THRESHOLD(task->tk_rqstp);
+	if (size < min_size)
+		size = min_size;
+
+	rb = rpcrdma_alloc_regbuf(&r_xprt->rx_ia, size, flags);
+	if (IS_ERR(rb))
+		goto out_fail;
+	rb->rg_owner = req;
+
+	r_xprt->rx_stats.hardway_register_count += size;
+	rpcrdma_free_regbuf(&r_xprt->rx_ia, req->rl_sendbuf);
+	req->rl_sendbuf = rb;
+	goto out;
+
+out_fail:
 	rpcrdma_buffer_put(req);
-	rpcx_to_rdmax(xprt)->rx_stats.failed_marshal_count++;
+	r_xprt->rx_stats.failed_marshal_count++;
 	return NULL;
 }
 
···
 {
 	struct rpcrdma_req *req;
 	struct rpcrdma_xprt *r_xprt;
-	struct rpcrdma_rep *rep;
+	struct rpcrdma_regbuf *rb;
 	int i;
 
 	if (buffer == NULL)
 		return;
 
-	req = container_of(buffer, struct rpcrdma_req, rl_xdr_buf[0]);
-	if (req->rl_iov.length == 0) {	/* see allocate above */
-		r_xprt = container_of(((struct rpcrdma_req *) req->rl_buffer)->rl_buffer,
-				      struct rpcrdma_xprt, rx_buf);
-	} else
-		r_xprt = container_of(req->rl_buffer, struct rpcrdma_xprt, rx_buf);
-	rep = req->rl_reply;
+	rb = container_of(buffer, struct rpcrdma_regbuf, rg_base[0]);
+	req = rb->rg_owner;
+	r_xprt = container_of(req->rl_buffer, struct rpcrdma_xprt, rx_buf);
 
-	dprintk("RPC:       %s: called on 0x%p%s\n",
-		__func__, rep, (rep && rep->rr_func) ? " (with waiter)" : "");
+	dprintk("RPC:       %s: called on 0x%p\n", __func__, req->rl_reply);
 
-	/*
-	 * Finish the deregistration.  The process is considered
-	 * complete when the rr_func vector becomes NULL - this
-	 * was put in place during rpcrdma_reply_handler() - the wait
-	 * call below will not block if the dereg is "done". If
-	 * interrupted, our framework will clean up.
-	 */
 	for (i = 0; req->rl_nchunks;) {
 		--req->rl_nchunks;
 		i += rpcrdma_deregister_external(
 			&req->rl_segments[i], r_xprt);
 	}
 
-	if (req->rl_iov.length == 0) {	/* see allocate above */
-		struct rpcrdma_req *oreq = (struct rpcrdma_req *)req->rl_buffer;
-		oreq->rl_reply = req->rl_reply;
-		(void) rpcrdma_deregister_internal(&r_xprt->rx_ia,
-						   req->rl_handle,
-						   &req->rl_iov);
-		kfree(req);
-		req = oreq;
-	}
-
-	/* Put back request+reply buffers */
 	rpcrdma_buffer_put(req);
 }
 

net/sunrpc/xprtrdma/verbs.c

···
 
 #include <linux/interrupt.h>
 #include <linux/slab.h>
+#include <linux/prefetch.h>
 #include <asm/bitops.h>
 
 #include "xprt_rdma.h"
···
 		event->device->name, context);
 	if (ep->rep_connected == 1) {
 		ep->rep_connected = -EIO;
-		ep->rep_func(ep);
+		rpcrdma_conn_func(ep);
 		wake_up_all(&ep->rep_connect_wait);
 	}
 }
···
 		event->device->name, context);
 	if (ep->rep_connected == 1) {
 		ep->rep_connected = -EIO;
-		ep->rep_func(ep);
+		rpcrdma_conn_func(ep);
 		wake_up_all(&ep->rep_connect_wait);
 	}
 }
 
+static const char * const wc_status[] = {
+	"success",
+	"local length error",
+	"local QP operation error",
+	"local EE context operation error",
+	"local protection error",
+	"WR flushed",
+	"memory management operation error",
+	"bad response error",
+	"local access error",
+	"remote invalid request error",
+	"remote access error",
+	"remote operation error",
+	"transport retry counter exceeded",
+	"RNR retrycounter exceeded",
+	"local RDD violation error",
+	"remove invalid RD request",
+	"operation aborted",
+	"invalid EE context number",
+	"invalid EE context state",
+	"fatal error",
+	"response timeout error",
+	"general error",
+};
+
+#define COMPLETION_MSG(status)					\
+	((status) < ARRAY_SIZE(wc_status) ?			\
+		wc_status[(status)] : "unexpected completion error")
+
 static void
 rpcrdma_sendcq_process_wc(struct ib_wc *wc)
 {
-	struct rpcrdma_mw *frmr = (struct rpcrdma_mw *)(unsigned long)wc->wr_id;
-
-	dprintk("RPC:       %s: frmr %p status %X opcode %d\n",
-		__func__, frmr, wc->status, wc->opcode);
-
-	if (wc->wr_id == 0ULL)
+	if (likely(wc->status == IB_WC_SUCCESS))
 		return;
-	if (wc->status != IB_WC_SUCCESS)
-		frmr->r.frmr.fr_state = FRMR_IS_STALE;
+
+	/* WARNING: Only wr_id and status are reliable at this point */
+	if (wc->wr_id == 0ULL) {
+		if (wc->status != IB_WC_WR_FLUSH_ERR)
+			pr_err("RPC:       %s: SEND: %s\n",
+			       __func__, COMPLETION_MSG(wc->status));
+	} else {
+		struct rpcrdma_mw *r;
+
+		r = (struct rpcrdma_mw *)(unsigned long)wc->wr_id;
+		r->r.frmr.fr_state = FRMR_IS_STALE;
+		pr_err("RPC:       %s: frmr %p (stale): %s\n",
+		       __func__, r, COMPLETION_MSG(wc->status));
+	}
 }
 
 static int
···
 	struct rpcrdma_rep *rep =
 			(struct rpcrdma_rep *)(unsigned long)wc->wr_id;
 
-	dprintk("RPC:       %s: rep %p status %X opcode %X length %u\n",
-		__func__, rep, wc->status, wc->opcode, wc->byte_len);
+	/* WARNING: Only wr_id and status are reliable at this point */
+	if (wc->status != IB_WC_SUCCESS)
+		goto out_fail;
 
-	if (wc->status != IB_WC_SUCCESS) {
-		rep->rr_len = ~0U;
-		goto out_schedule;
-	}
+	/* status == SUCCESS means all fields in wc are trustworthy */
 	if (wc->opcode != IB_WC_RECV)
 		return;
 
+	dprintk("RPC:       %s: rep %p opcode 'recv', length %u: success\n",
+		__func__, rep, wc->byte_len);
+
 	rep->rr_len = wc->byte_len;
 	ib_dma_sync_single_for_cpu(rdmab_to_ia(rep->rr_buffer)->ri_id->device,
-			rep->rr_iov.addr, rep->rr_len, DMA_FROM_DEVICE);
-
-	if (rep->rr_len >= 16) {
-		struct rpcrdma_msg *p = (struct rpcrdma_msg *)rep->rr_base;
-		unsigned int credits = ntohl(p->rm_credit);
-
-		if (credits == 0)
-			credits = 1;	/* don't deadlock */
-		else if (credits > rep->rr_buffer->rb_max_requests)
-			credits = rep->rr_buffer->rb_max_requests;
-		atomic_set(&rep->rr_buffer->rb_credits, credits);
-	}
+				   rdmab_addr(rep->rr_rdmabuf),
+				   rep->rr_len, DMA_FROM_DEVICE);
+	prefetch(rdmab_to_msg(rep->rr_rdmabuf));
 
 out_schedule:
 	list_add_tail(&rep->rr_list, sched_list);
+	return;
+out_fail:
+	if (wc->status != IB_WC_WR_FLUSH_ERR)
+		pr_err("RPC:       %s: rep %p: %s\n",
+		       __func__, rep, COMPLETION_MSG(wc->status));
+	rep->rr_len = ~0U;
+	goto out_schedule;
 }
 
 static int
···
 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 	struct sockaddr_in *addr = (struct sockaddr_in *) &ep->rep_remote_addr;
 #endif
-	struct ib_qp_attr attr;
-	struct ib_qp_init_attr iattr;
+	struct ib_qp_attr *attr = &ia->ri_qp_attr;
+	struct ib_qp_init_attr *iattr = &ia->ri_qp_init_attr;
 	int connstate = 0;
 
 	switch (event->event) {
···
 		break;
 	case RDMA_CM_EVENT_ESTABLISHED:
 		connstate = 1;
-		ib_query_qp(ia->ri_id->qp, &attr,
-			IB_QP_MAX_QP_RD_ATOMIC | IB_QP_MAX_DEST_RD_ATOMIC,
-			&iattr);
+		ib_query_qp(ia->ri_id->qp, attr,
+			    IB_QP_MAX_QP_RD_ATOMIC | IB_QP_MAX_DEST_RD_ATOMIC,
+			    iattr);
 		dprintk("RPC:       %s: %d responder resources"
 			" (%d initiator)\n",
-			__func__, attr.max_dest_rd_atomic, attr.max_rd_atomic);
+			__func__, attr->max_dest_rd_atomic,
+			attr->max_rd_atomic);
 		goto connected;
 	case RDMA_CM_EVENT_CONNECT_ERROR:
 		connstate = -ENOTCONN;
···
 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
 		connstate = -ENODEV;
 connected:
-		atomic_set(&rpcx_to_rdmax(ep->rep_xprt)->rx_buf.rb_credits, 1);
 		dprintk("RPC:       %s: %sconnected\n",
 					__func__, connstate > 0 ? "" : "dis");
 		ep->rep_connected = connstate;
-		ep->rep_func(ep);
+		rpcrdma_conn_func(ep);
 		wake_up_all(&ep->rep_connect_wait);
 		/*FALLTHROUGH*/
 	default:
···
 
 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 	if (connstate == 1) {
-		int ird = attr.max_dest_rd_atomic;
+		int ird = attr->max_dest_rd_atomic;
 		int tird = ep->rep_remote_cma.responder_resources;
 		printk(KERN_INFO "rpcrdma: connection to %pI4:%u "
 			"on %s, memreg %d slots %d ird %d%s\n",
···
 rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr, int memreg)
 {
 	int rc, mem_priv;
-	struct ib_device_attr devattr;
 	struct rpcrdma_ia *ia = &xprt->rx_ia;
+	struct ib_device_attr *devattr = &ia->ri_devattr;
 
 	ia->ri_id = rpcrdma_create_id(xprt, ia, addr);
 	if (IS_ERR(ia->ri_id)) {
···
 		goto out2;
 	}
 
-	/*
-	 * Query the device to determine if the requested memory
-	 * registration strategy is supported. If it isn't, set the
-	 * strategy to a globally supported model.
-	 */
-	rc = ib_query_device(ia->ri_id->device, &devattr);
+	rc = ib_query_device(ia->ri_id->device, devattr);
 	if (rc) {
 		dprintk("RPC:       %s: ib_query_device failed %d\n",
 			__func__, rc);
-		goto out2;
+		goto out3;
 	}
 
-	if (devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY) {
+	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;
 	}
 
 	if (memreg == RPCRDMA_FRMR) {
 		/* Requires both frmr reg and local dma lkey */
-		if ((devattr.device_cap_flags &
+		if ((devattr->device_cap_flags &
 		     (IB_DEVICE_MEM_MGT_EXTENSIONS|IB_DEVICE_LOCAL_DMA_LKEY)) !=
 		    (IB_DEVICE_MEM_MGT_EXTENSIONS|IB_DEVICE_LOCAL_DMA_LKEY)) {
 			dprintk("RPC:       %s: FRMR registration "
···
 			/* Mind the ia limit on FRMR page list depth */
 			ia->ri_max_frmr_depth = min_t(unsigned int,
 				RPCRDMA_MAX_DATA_SEGS,
-				devattr.max_fast_reg_page_list_len);
+				devattr->max_fast_reg_page_list_len);
 		}
 	}
 	if (memreg == RPCRDMA_MTHCAFMR) {
···
 				"phys register failed with %lX\n",
 				__func__, PTR_ERR(ia->ri_bind_mem));
 			rc = -ENOMEM;
-			goto out2;
+			goto out3;
 		}
 		break;
 	default:
 		printk(KERN_ERR "RPC: Unsupported memory "
 				"registration mode: %d\n", memreg);
 		rc = -ENOMEM;
-		goto out2;
+		goto out3;
 	}
 	dprintk("RPC:       %s: memory registration strategy is %d\n",
 		__func__, memreg);
···
 
 	rwlock_init(&ia->ri_qplock);
 	return 0;
+
+out3:
+	ib_dealloc_pd(ia->ri_pd);
+	ia->ri_pd = NULL;
 out2:
 	rdma_destroy_id(ia->ri_id);
 	ia->ri_id = NULL;
···
 rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
 				struct rpcrdma_create_data_internal *cdata)
 {
-	struct ib_device_attr devattr;
+	struct ib_device_attr *devattr = &ia->ri_devattr;
 	struct ib_cq *sendcq, *recvcq;
 	int rc, err;
 
-	rc = ib_query_device(ia->ri_id->device, &devattr);
-	if (rc) {
-		dprintk("RPC:       %s: ib_query_device failed %d\n",
-			__func__, rc);
-		return rc;
-	}
-
 	/* check provider's send/recv wr limits */
-	if (cdata->max_requests > devattr.max_qp_wr)
-		cdata->max_requests = devattr.max_qp_wr;
+	if (cdata->max_requests > devattr->max_qp_wr)
+		cdata->max_requests = devattr->max_qp_wr;
 
 	ep->rep_attr.event_handler = rpcrdma_qp_async_error_upcall;
 	ep->rep_attr.qp_context = ep;
···
 
 		}
 		ep->rep_attr.cap.max_send_wr *= depth;
-		if (ep->rep_attr.cap.max_send_wr > devattr.max_qp_wr) {
-			cdata->max_requests = devattr.max_qp_wr / depth;
+		if (ep->rep_attr.cap.max_send_wr > devattr->max_qp_wr) {
+			cdata->max_requests = devattr->max_qp_wr / depth;
 			if (!cdata->max_requests)
 				return -EINVAL;
 			ep->rep_attr.cap.max_send_wr = cdata->max_requests *
···
 	ep->rep_attr.qp_type = IB_QPT_RC;
 	ep->rep_attr.port_num = ~0;
 
+	if (cdata->padding) {
+		ep->rep_padbuf = rpcrdma_alloc_regbuf(ia, cdata->padding,
+						      GFP_KERNEL);
+		if (IS_ERR(ep->rep_padbuf))
+			return PTR_ERR(ep->rep_padbuf);
+	} else
+		ep->rep_padbuf = NULL;
+
 	dprintk("RPC:       %s: requested max: dtos: send %d recv %d; "
 		"iovs: send %d recv %d\n",
 		__func__,
···
 	else if (ep->rep_cqinit <= 2)
 		ep->rep_cqinit = 0;
 	INIT_CQCOUNT(ep);
-	ep->rep_ia = ia;
 	init_waitqueue_head(&ep->rep_connect_wait);
 	INIT_DELAYED_WORK(&ep->rep_connect_worker, rpcrdma_connect_worker);
 
···
 
 	/* Client offers RDMA Read but does not initiate */
 	ep->rep_remote_cma.initiator_depth = 0;
-	if (devattr.max_qp_rd_atom > 32)	/* arbitrary but <= 255 */
+	if (devattr->max_qp_rd_atom > 32)	/* arbitrary but <= 255 */
 		ep->rep_remote_cma.responder_resources = 32;
 	else
-		ep->rep_remote_cma.responder_resources = devattr.max_qp_rd_atom;
+		ep->rep_remote_cma.responder_resources =
+						devattr->max_qp_rd_atom;
 
 	ep->rep_remote_cma.retry_count = 7;
 	ep->rep_remote_cma.flow_control = 0;
···
 		dprintk("RPC:       %s: ib_destroy_cq returned %i\n",
 			__func__, err);
 out1:
+	rpcrdma_free_regbuf(ia, ep->rep_padbuf);
 	return rc;
 }
 
···
 		ia->ri_id->qp = NULL;
 	}
 
-	/* padding - could be done in rpcrdma_buffer_destroy... */
-	if (ep->rep_pad_mr) {
-		rpcrdma_deregister_internal(ia, ep->rep_pad_mr, &ep->rep_pad);
-		ep->rep_pad_mr = NULL;
-	}
+	rpcrdma_free_regbuf(ia, ep->rep_padbuf);
 
 	rpcrdma_clean_cq(ep->rep_attr.recv_cq);
 	rc = ib_destroy_cq(ep->rep_attr.recv_cq);
···
 	}
 }
 
+static struct rpcrdma_req *
+rpcrdma_create_req(struct rpcrdma_xprt *r_xprt)
+{
+	struct rpcrdma_req *req;
+
+	req = kzalloc(sizeof(*req), GFP_KERNEL);
+	if (req == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	req->rl_buffer = &r_xprt->rx_buf;
+	return req;
+}
+
+static struct rpcrdma_rep *
+rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt)
+{
+	struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;
+	struct rpcrdma_ia *ia = &r_xprt->rx_ia;
+	struct rpcrdma_rep *rep;
+	int rc;
+
+	rc = -ENOMEM;
+	rep = kzalloc(sizeof(*rep), GFP_KERNEL);
+	if (rep == NULL)
+		goto out;
+
+	rep->rr_rdmabuf = rpcrdma_alloc_regbuf(ia, cdata->inline_rsize,
+					       GFP_KERNEL);
+	if (IS_ERR(rep->rr_rdmabuf)) {
+		rc = PTR_ERR(rep->rr_rdmabuf);
+		goto out_free;
+	}
+
+	rep->rr_buffer = &r_xprt->rx_buf;
+	return rep;
+
+out_free:
+	kfree(rep);
+out:
+	return ERR_PTR(rc);
+}
+
 static int
 rpcrdma_init_fmrs(struct rpcrdma_ia *ia, struct rpcrdma_buffer *buf)
 {
···
 }
 
 int
-rpcrdma_buffer_create(struct rpcrdma_buffer *buf, struct rpcrdma_ep *ep,
-	struct rpcrdma_ia *ia, struct rpcrdma_create_data_internal *cdata)
+rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt)
 {
+	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
+	struct rpcrdma_ia *ia = &r_xprt->rx_ia;
+	struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;
 	char *p;
-	size_t len, rlen, wlen;
+	size_t len;
 	int i, rc;
 
 	buf->rb_max_requests = cdata->max_requests;
 	spin_lock_init(&buf->rb_lock);
-	atomic_set(&buf->rb_credits, 1);
 
 	/* Need to allocate:
 	 *   1.  arrays for send and recv pointers
 	 *   2.  arrays of struct rpcrdma_req to fill in pointers
 	 *   3.  array of struct rpcrdma_rep for replies
-	 *   4.  padding, if any
 	 * Send/recv buffers in req/rep need to be registered
 	 */
 	len = buf->rb_max_requests *
 		(sizeof(struct rpcrdma_req *) + sizeof(struct rpcrdma_rep *));
-	len += cdata->padding;
 
 	p = kzalloc(len, GFP_KERNEL);
 	if (p == NULL) {
···
 	p = (char *) &buf->rb_send_bufs[buf->rb_max_requests];
 	buf->rb_recv_bufs = (struct rpcrdma_rep **) p;
 	p = (char *) &buf->rb_recv_bufs[buf->rb_max_requests];
-
-	/*
-	 * Register the zeroed pad buffer, if any.
-	 */
-	if (cdata->padding) {
-		rc = rpcrdma_register_internal(ia, p, cdata->padding,
-					    &ep->rep_pad_mr, &ep->rep_pad);
-		if (rc)
-			goto out;
-	}
-	p += cdata->padding;
 
 	INIT_LIST_HEAD(&buf->rb_mws);
 	INIT_LIST_HEAD(&buf->rb_all);
···
 		break;
 	}
 
-	/*
-	 * Allocate/init the request/reply buffers. Doing this
-	 * using kmalloc for now -- one for each buf.
-	 */
-	wlen = 1 << fls(cdata->inline_wsize + sizeof(struct rpcrdma_req));
-	rlen = 1 << fls(cdata->inline_rsize + sizeof(struct rpcrdma_rep));
-	dprintk("RPC:       %s: wlen = %zu, rlen = %zu\n",
-		__func__, wlen, rlen);
-
 	for (i = 0; i < buf->rb_max_requests; i++) {
 		struct rpcrdma_req *req;
 		struct rpcrdma_rep *rep;
 
-		req = kmalloc(wlen, GFP_KERNEL);
-		if (req == NULL) {
+		req = rpcrdma_create_req(r_xprt);
+		if (IS_ERR(req)) {
 			dprintk("RPC:       %s: request buffer %d alloc"
 				" failed\n", __func__, i);
-			rc = -ENOMEM;
+			rc = PTR_ERR(req);
 			goto out;
 		}
-		memset(req, 0, sizeof(struct rpcrdma_req));
 		buf->rb_send_bufs[i] = req;
-		buf->rb_send_bufs[i]->rl_buffer = buf;
 
-		rc = rpcrdma_register_internal(ia, req->rl_base,
-				wlen - offsetof(struct rpcrdma_req, rl_base),
-				&buf->rb_send_bufs[i]->rl_handle,
-				&buf->rb_send_bufs[i]->rl_iov);
-		if (rc)
-			goto out;
-
-		buf->rb_send_bufs[i]->rl_size = wlen -
-						sizeof(struct rpcrdma_req);
-
-		rep = kmalloc(rlen, GFP_KERNEL);
-		if (rep == NULL) {
+		rep = rpcrdma_create_rep(r_xprt);
+		if (IS_ERR(rep)) {
 			dprintk("RPC:       %s: reply buffer %d alloc failed\n",
 				__func__, i);
-			rc = -ENOMEM;
+			rc = PTR_ERR(rep);
 			goto out;
 		}
-		memset(rep, 0, sizeof(struct rpcrdma_rep));
 		buf->rb_recv_bufs[i] = rep;
-		buf->rb_recv_bufs[i]->rr_buffer = buf;
-
-		rc = rpcrdma_register_internal(ia, rep->rr_base,
-				rlen - offsetof(struct rpcrdma_rep, rr_base),
-				&buf->rb_recv_bufs[i]->rr_handle,
-				&buf->rb_recv_bufs[i]->rr_iov);
-		if (rc)
-			goto out;
-
 	}
-	dprintk("RPC:       %s: max_requests %d\n",
-		__func__, buf->rb_max_requests);
-	/* done */
+
 	return 0;
 out:
 	rpcrdma_buffer_destroy(buf);
 	return rc;
+}
+
+static void
+rpcrdma_destroy_rep(struct rpcrdma_ia *ia, struct rpcrdma_rep *rep)
+{
+	if (!rep)
+		return;
+
+	rpcrdma_free_regbuf(ia, rep->rr_rdmabuf);
+	kfree(rep);
+}
+
+static void
+rpcrdma_destroy_req(struct rpcrdma_ia *ia, struct rpcrdma_req *req)
+{
+	if (!req)
+		return;
+
+	rpcrdma_free_regbuf(ia, req->rl_sendbuf);
+	rpcrdma_free_regbuf(ia, req->rl_rdmabuf);
+	kfree(req);
 }
 
 static void
···
 	dprintk("RPC:       %s: entering\n", __func__);
 
 	for (i = 0; i < buf->rb_max_requests; i++) {
-		if (buf->rb_recv_bufs && buf->rb_recv_bufs[i]) {
-			rpcrdma_deregister_internal(ia,
-					buf->rb_recv_bufs[i]->rr_handle,
-					&buf->rb_recv_bufs[i]->rr_iov);
-			kfree(buf->rb_recv_bufs[i]);
-		}
-		if (buf->rb_send_bufs && buf->rb_send_bufs[i]) {
-			rpcrdma_deregister_internal(ia,
-					buf->rb_send_bufs[i]->rl_handle,
-					&buf->rb_send_bufs[i]->rl_iov);
-			kfree(buf->rb_send_bufs[i]);
-		}
+		if (buf->rb_recv_bufs)
+			rpcrdma_destroy_rep(ia, buf->rb_recv_bufs[i]);
+		if (buf->rb_send_bufs)
+			rpcrdma_destroy_req(ia, buf->rb_send_bufs[i]);
 	}
 
 	switch (ia->ri_memreg_strategy) {
···
 	int i;
 
 	for (i = 1, seg++; i < RPCRDMA_MAX_SEGS; seg++, i++)
-		rpcrdma_buffer_put_mr(&seg->mr_chunk.rl_mw, buf);
-	rpcrdma_buffer_put_mr(&seg1->mr_chunk.rl_mw, buf);
+		rpcrdma_buffer_put_mr(&seg->rl_mw, buf);
+	rpcrdma_buffer_put_mr(&seg1->rl_mw, buf);
 }
 
 static void
···
 			list_add(&r->mw_list, stale);
 			continue;
 		}
-		req->rl_segments[i].mr_chunk.rl_mw = r;
+		req->rl_segments[i].rl_mw = r;
 		if (unlikely(i-- == 0))
 			return req;	/* Success */
 	}
···
 		r = list_entry(buf->rb_mws.next,
 			       struct rpcrdma_mw, mw_list);
 		list_del(&r->mw_list);
-		req->rl_segments[i].mr_chunk.rl_mw = r;
+		req->rl_segments[i].rl_mw = r;
 		if (unlikely(i-- == 0))
 			return req;	/* Success */
 	}
···
 	struct rpcrdma_buffer *buffers = req->rl_buffer;
 	unsigned long flags;
 
-	if (req->rl_iov.length == 0)	/* special case xprt_rdma_allocate() */
-		buffers = ((struct rpcrdma_req *) buffers)->rl_buffer;
 	spin_lock_irqsave(&buffers->rb_lock, flags);
 	if (buffers->rb_recv_index < buffers->rb_max_requests) {
 		req->rl_reply = buffers->rb_recv_bufs[buffers->rb_recv_index];
···
  * Wrappers for internal-use kmalloc memory registration, used by buffer code.
  */
 
-int
+static int
 rpcrdma_register_internal(struct rpcrdma_ia *ia, void *va, int len,
 				struct ib_mr **mrp, struct ib_sge *iov)
 {
···
 	return rc;
 }
 
-int
+static int
 rpcrdma_deregister_internal(struct rpcrdma_ia *ia,
 				struct ib_mr *mr, struct ib_sge *iov)
 {
···
 	if (rc)
 		dprintk("RPC:       %s: ib_dereg_mr failed %i\n", __func__, rc);
 	return rc;
+}
+
+/**
+ * rpcrdma_alloc_regbuf - kmalloc and register memory for SEND/RECV buffers
+ * @ia: controlling rpcrdma_ia
+ * @size: size of buffer to be allocated, in bytes
+ * @flags: GFP flags
+ *
+ * Returns pointer to private header of an area of internally
+ * registered memory, or an ERR_PTR. The registered buffer follows
+ * the end of the private header.
+ *
+ * xprtrdma uses a regbuf for posting an outgoing RDMA SEND, or for
+ * receiving the payload of RDMA RECV operations. regbufs are not
+ * used for RDMA READ/WRITE operations, thus are registered only for
+ * LOCAL access.
+ */
+struct rpcrdma_regbuf *
+rpcrdma_alloc_regbuf(struct rpcrdma_ia *ia, size_t size, gfp_t flags)
+{
+	struct rpcrdma_regbuf *rb;
+	int rc;
+
+	rc = -ENOMEM;
+	rb = kmalloc(sizeof(*rb) + size, flags);
+	if (rb == NULL)
+		goto out;
+
+	rb->rg_size = size;
+	rb->rg_owner = NULL;
+	rc = rpcrdma_register_internal(ia, rb->rg_base, size,
+				       &rb->rg_mr, &rb->rg_iov);
+	if (rc)
+		goto out_free;
+
+	return rb;
+
+out_free:
+	kfree(rb);
+out:
+	return ERR_PTR(rc);
+}
+
+/**
+ * rpcrdma_free_regbuf - deregister and free registered buffer
+ * @ia: controlling rpcrdma_ia
+ * @rb: regbuf to be deregistered and freed
+ */
+void
+rpcrdma_free_regbuf(struct rpcrdma_ia *ia, struct rpcrdma_regbuf *rb)
+{
+	if (rb) {
+		rpcrdma_deregister_internal(ia, rb->rg_mr, &rb->rg_iov);
+		kfree(rb);
+	}
 }
 
 /*
···
 			struct rpcrdma_xprt *r_xprt)
 {
 	struct rpcrdma_mr_seg *seg1 = seg;
-	struct rpcrdma_mw *mw = seg1->mr_chunk.rl_mw;
+	struct rpcrdma_mw *mw = seg1->rl_mw;
 	struct rpcrdma_frmr *frmr = &mw->r.frmr;
 	struct ib_mr *mr = frmr->fr_mr;
 	struct ib_send_wr fastreg_wr, *bad_wr;
···
 	struct ib_send_wr invalidate_wr, *bad_wr;
 	int rc;
 
-	seg1->mr_chunk.rl_mw->r.frmr.fr_state = FRMR_IS_INVALID;
+	seg1->rl_mw->r.frmr.fr_state = FRMR_IS_INVALID;
 
 	memset(&invalidate_wr, 0, sizeof invalidate_wr);
-	invalidate_wr.wr_id = (unsigned long)(void *)seg1->mr_chunk.rl_mw;
+	invalidate_wr.wr_id = (unsigned long)(void *)seg1->rl_mw;
 	invalidate_wr.opcode = IB_WR_LOCAL_INV;
-	invalidate_wr.ex.invalidate_rkey = seg1->mr_chunk.rl_mw->r.frmr.fr_mr->rkey;
+	invalidate_wr.ex.invalidate_rkey = seg1->rl_mw->r.frmr.fr_mr->rkey;
 	DECR_CQCOUNT(&r_xprt->rx_ep);
 
 	read_lock(&ia->ri_qplock);
···
 	read_unlock(&ia->ri_qplock);
 	if (rc) {
 		/* Force rpcrdma_buffer_get() to retry */
-		seg1->mr_chunk.rl_mw->r.frmr.fr_state = FRMR_IS_STALE;
+		seg1->rl_mw->r.frmr.fr_state = FRMR_IS_STALE;
 		dprintk("RPC:       %s: failed ib_post_send for invalidate,"
 			" status %i\n", __func__, rc);
 	}
···
 		    offset_in_page((seg-1)->mr_offset + (seg-1)->mr_len))
 			break;
 	}
-	rc = ib_map_phys_fmr(seg1->mr_chunk.rl_mw->r.fmr,
-				physaddrs, i, seg1->mr_dma);
+	rc = ib_map_phys_fmr(seg1->rl_mw->r.fmr, physaddrs, i, seg1->mr_dma);
 	if (rc) {
 		dprintk("RPC:       %s: failed ib_map_phys_fmr "
 			"%u@0x%llx+%i (%d)... status %i\n", __func__,
···
 		while (i--)
 			rpcrdma_unmap_one(ia, --seg);
 	} else {
-		seg1->mr_rkey = seg1->mr_chunk.rl_mw->r.fmr->rkey;
+		seg1->mr_rkey = seg1->rl_mw->r.fmr->rkey;
 		seg1->mr_base = seg1->mr_dma + pageoff;
 		seg1->mr_nsegs = i;
 		seg1->mr_len = len;
···
 	LIST_HEAD(l);
 	int rc;
 
-	list_add(&seg1->mr_chunk.rl_mw->r.fmr->list, &l);
+	list_add(&seg1->rl_mw->r.fmr->list, &l);
 	rc = ib_unmap_fmr(&l);
 	read_lock(&ia->ri_qplock);
 	while (seg1->mr_nsegs--)
···
 
 	recv_wr.next = NULL;
 	recv_wr.wr_id = (u64) (unsigned long) rep;
-	recv_wr.sg_list = &rep->rr_iov;
+	recv_wr.sg_list = &rep->rr_rdmabuf->rg_iov;
 	recv_wr.num_sge = 1;
 
 	ib_dma_sync_single_for_cpu(ia->ri_id->device,
-		rep->rr_iov.addr, rep->rr_iov.length, DMA_BIDIRECTIONAL);
+				   rdmab_addr(rep->rr_rdmabuf),
+				   rdmab_length(rep->rr_rdmabuf),
+				   DMA_BIDIRECTIONAL);
 
 	rc = ib_post_recv(ia->ri_id->qp, &recv_wr, &recv_wr_fail);
 

net/sunrpc/xprtrdma/xprt_rdma.h

···
 	int			ri_async_rc;
 	enum rpcrdma_memreg	ri_memreg_strategy;
 	unsigned int		ri_max_frmr_depth;
+	struct ib_device_attr	ri_devattr;
+	struct ib_qp_attr	ri_qp_attr;
+	struct ib_qp_init_attr	ri_qp_init_attr;
 };
 
 /*
···
 	atomic_t		rep_cqcount;
 	int			rep_cqinit;
 	int			rep_connected;
-	struct rpcrdma_ia	*rep_ia;
 	struct ib_qp_init_attr	rep_attr;
 	wait_queue_head_t 	rep_connect_wait;
-	struct ib_sge		rep_pad;	/* holds zeroed pad */
-	struct ib_mr		*rep_pad_mr;	/* holds zeroed pad */
-	void			(*rep_func)(struct rpcrdma_ep *);
-	struct rpc_xprt		*rep_xprt;	/* for rep_func */
+	struct rpcrdma_regbuf	*rep_padbuf;
 	struct rdma_conn_param	rep_remote_cma;
 	struct sockaddr_storage	rep_remote_addr;
 	struct delayed_work	rep_connect_worker;
···
 
 #define INIT_CQCOUNT(ep) atomic_set(&(ep)->rep_cqcount, (ep)->rep_cqinit)
 #define DECR_CQCOUNT(ep) atomic_sub_return(1, &(ep)->rep_cqcount)
+
+/* Registered buffer -- registered kmalloc'd memory for RDMA SEND/RECV
+ *
+ * The below structure appears at the front of a large region of kmalloc'd
+ * memory, which always starts on a good alignment boundary.
+ */
+
+struct rpcrdma_regbuf {
+	size_t			rg_size;
+	struct rpcrdma_req	*rg_owner;
+	struct ib_mr		*rg_mr;
+	struct ib_sge		rg_iov;
+	__be32			rg_base[0] __attribute__ ((aligned(256)));
+};
+
+static inline u64
+rdmab_addr(struct rpcrdma_regbuf *rb)
+{
+	return rb->rg_iov.addr;
+}
+
+static inline u32
+rdmab_length(struct rpcrdma_regbuf *rb)
+{
+	return rb->rg_iov.length;
+}
+
+static inline u32
+rdmab_lkey(struct rpcrdma_regbuf *rb)
+{
+	return rb->rg_iov.lkey;
+}
+
+static inline struct rpcrdma_msg *
+rdmab_to_msg(struct rpcrdma_regbuf *rb)
+{
+	return (struct rpcrdma_msg *)rb->rg_base;
+}
 
 enum rpcrdma_chunktype {
 	rpcrdma_noch = 0,
···
 /* temporary static scatter/gather max */
 #define RPCRDMA_MAX_DATA_SEGS	(64)	/* max scatter/gather */
 #define RPCRDMA_MAX_SEGS 	(RPCRDMA_MAX_DATA_SEGS + 2) /* head+tail = 2 */
-#define MAX_RPCRDMAHDR	(\
-	/* max supported RPC/RDMA header */ \
-	sizeof(struct rpcrdma_msg) + (2 * sizeof(u32)) + \
-	(sizeof(struct rpcrdma_read_chunk) * RPCRDMA_MAX_SEGS) + sizeof(u32))
 
 struct rpcrdma_buffer;
 
 struct rpcrdma_rep {
-	unsigned int	rr_len;		/* actual received reply length */
-	struct rpcrdma_buffer *rr_buffer; /* home base for this structure */
-	struct rpc_xprt	*rr_xprt;	/* needed for request/reply matching */
-	void (*rr_func)(struct rpcrdma_rep *);/* called by tasklet in softint */
-	struct list_head rr_list;	/* tasklet list */
-	struct ib_sge	rr_iov;		/* for posting */
-	struct ib_mr	*rr_handle;	/* handle for mem in rr_iov */
-	char	rr_base[MAX_RPCRDMAHDR]; /* minimal inline receive buffer */
+	unsigned int		rr_len;
+	struct rpcrdma_buffer	*rr_buffer;
+	struct rpc_xprt		*rr_xprt;
+	void			(*rr_func)(struct rpcrdma_rep *);
+	struct list_head	rr_list;
+	struct rpcrdma_regbuf	*rr_rdmabuf;
 };
 
 /*
···
  */
 
 struct rpcrdma_mr_seg {		/* chunk descriptors */
-	union {				/* chunk memory handles */
-		struct ib_mr	*rl_mr;		/* if registered directly */
-		struct rpcrdma_mw *rl_mw;	/* if registered from region */
-	} mr_chunk;
+	struct rpcrdma_mw *rl_mw;	/* registered MR */
 	u64		mr_base;	/* registration result */
 	u32		mr_rkey;	/* registration result */
 	u32		mr_len;		/* length of chunk or segment */
···
 };
 
 struct rpcrdma_req {
-	size_t 		rl_size;	/* actual length of buffer */
 	unsigned int	rl_niovs;	/* 0, 2 or 4 */
 	unsigned int	rl_nchunks;	/* non-zero if chunks */
 	unsigned int	rl_connect_cookie;	/* retry detection */
 	enum rpcrdma_chunktype	rl_rtype, rl_wtype;
 	struct rpcrdma_buffer *rl_buffer; /* home base for this structure */
 	struct rpcrdma_rep	*rl_reply;/* holder for reply buffer */
-	struct rpcrdma_mr_seg rl_segments[RPCRDMA_MAX_SEGS];/* chunk segments */
 	struct ib_sge	rl_send_iov[4];	/* for active requests */
-	struct ib_sge	rl_iov;		/* for posting */
-	struct ib_mr	*rl_handle;	/* handle for mem in rl_iov */
-	char		rl_base[MAX_RPCRDMAHDR]; /* start of actual buffer */
-	__u32 		rl_xdr_buf[0];	/* start of returned rpc rq_buffer */
+	struct rpcrdma_regbuf *rl_rdmabuf;
+	struct rpcrdma_regbuf *rl_sendbuf;
+	struct rpcrdma_mr_seg rl_segments[RPCRDMA_MAX_SEGS];
 };
-#define rpcr_to_rdmar(r) \
-	container_of((r)->rq_buffer, struct rpcrdma_req, rl_xdr_buf[0])
+
+static inline struct rpcrdma_req *
+rpcr_to_rdmar(struct rpc_rqst *rqst)
+{
+	struct rpcrdma_regbuf *rb = container_of(rqst->rq_buffer,
+						 struct rpcrdma_regbuf,
+						 rg_base[0]);
+	return rb->rg_owner;
+}
 
 /*
  * struct rpcrdma_buffer -- holds list/queue of pre-registered memory for
···
  */
 struct rpcrdma_buffer {
 	spinlock_t	rb_lock;	/* protects indexes */
-	atomic_t	rb_credits;	/* most recent server credits */
 	int		rb_max_requests;/* client max requests */
 	struct list_head rb_mws;	/* optional memory windows/fmrs/frmrs */
 	struct list_head rb_all;
···
  * during unmount.
  */
 struct rpcrdma_xprt {
-	struct rpc_xprt		xprt;
+	struct rpc_xprt		rx_xprt;
 	struct rpcrdma_ia	rx_ia;
 	struct rpcrdma_ep	rx_ep;
 	struct rpcrdma_buffer	rx_buf;
 	struct rpcrdma_create_data_internal rx_data;
-	struct delayed_work	rdma_connect;
+	struct delayed_work	rx_connect_worker;
 	struct rpcrdma_stats	rx_stats;
 };
 
-#define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, xprt)
+#define rpcx_to_rdmax(x) container_of(x, struct rpcrdma_xprt, rx_xprt)
 #define rpcx_to_rdmad(x) (rpcx_to_rdmax(x)->rx_data)
 
 /* Setting this to 0 ensures interoperability with early servers.
···
 /*
  * Buffer calls - xprtrdma/verbs.c
  */
-int rpcrdma_buffer_create(struct rpcrdma_buffer *, struct rpcrdma_ep *,
-				struct rpcrdma_ia *,
-				struct rpcrdma_create_data_internal *);
+int rpcrdma_buffer_create(struct rpcrdma_xprt *);
 void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);
 
 struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *);
···
 void rpcrdma_recv_buffer_get(struct rpcrdma_req *);
 void rpcrdma_recv_buffer_put(struct rpcrdma_rep *);
 
-int rpcrdma_register_internal(struct rpcrdma_ia *, void *, int,
-				struct ib_mr **, struct ib_sge *);
-int rpcrdma_deregister_internal(struct rpcrdma_ia *,
-				struct ib_mr *, struct ib_sge *);
-
 int rpcrdma_register_external(struct rpcrdma_mr_seg *,
 				int, int, struct rpcrdma_xprt *);
 int rpcrdma_deregister_external(struct rpcrdma_mr_seg *,
 				struct rpcrdma_xprt *);
+
+struct rpcrdma_regbuf *rpcrdma_alloc_regbuf(struct rpcrdma_ia *,
+					    size_t, gfp_t);
+void rpcrdma_free_regbuf(struct rpcrdma_ia *,
+			 struct rpcrdma_regbuf *);
 
 /*
  * RPC/RDMA connection management calls - xprtrdma/rpc_rdma.c