Merge tag 'nfs-rdma-for-5.5-1' of git://git.linux-nfs.org/projects/anna/linux-nfs

NFSoRDMA Client Updates for Linux 5.5

New Features:
- New tracepoints for congestion control and Local Invalidate WRs

Bugfixes and Cleanups:
- Eliminate log noise in call_reserveresult
- Fix unstable connections after a reconnect
- Clean up some code duplication
- Close race between waking a sender and posting a receive
- Fix MR list corruption, and clean up MR usage
- Remove unused rpcrdma_sendctx fields
- Try to avoid DMA mapping pages if it is too costly
- Wake pending tasks if connection fails
- Replace some dprintk()s with tracepoints

8 files changed, 421 insertions, 328 deletions

diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 5baf9b9be2e8..a3379765605d 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -1679,8 +1679,6 @@ call_reserveresult(struct rpc_task *task)
 			return;
 		}
 
-		printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
-				__func__, status);
 		rpc_call_rpcerror(task, -EIO);
 		return;
 	}
@@ -1689,11 +1687,8 @@ call_reserveresult(struct rpc_task *task)
 	 * Even though there was an error, we may have acquired
 	 * a request slot somehow.  Make sure not to leak it.
 	 */
-	if (task->tk_rqstp) {
-		printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
-				__func__, status);
+	if (task->tk_rqstp)
 		xprt_release(task);
-	}
 
 	switch (status) {
 	case -ENOMEM:
@@ -1702,14 +1697,9 @@ call_reserveresult(struct rpc_task *task)
 	case -EAGAIN:	/* woken up; retry */
 		task->tk_action = call_retry_reserve;
 		return;
-	case -EIO:	/* probably a shutdown */
-		break;
 	default:
-		printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
-				__func__, status);
-		break;
+		rpc_call_rpcerror(task, status);
 	}
-	rpc_call_rpcerror(task, status);
 }
 
 /*
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 41df4c507193..1aafe8d3f3f4 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -205,20 +205,20 @@ int xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
 
 	if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
 		if (task == xprt->snd_task)
-			return 1;
+			goto out_locked;
 		goto out_sleep;
 	}
 	if (test_bit(XPRT_WRITE_SPACE, &xprt->state))
 		goto out_unlock;
 	xprt->snd_task = task;
 
+out_locked:
+	trace_xprt_reserve_xprt(xprt, task);
 	return 1;
 
 out_unlock:
 	xprt_clear_locked(xprt);
 out_sleep:
-	dprintk("RPC: %5u failed to lock transport %p\n",
-			task->tk_pid, xprt);
 	task->tk_status = -EAGAIN;
 	if  (RPC_IS_SOFT(task))
 		rpc_sleep_on_timeout(&xprt->sending, task, NULL,
@@ -269,23 +269,22 @@ int xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task)
 
 	if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
 		if (task == xprt->snd_task)
-			return 1;
+			goto out_locked;
 		goto out_sleep;
 	}
 	if (req == NULL) {
 		xprt->snd_task = task;
-		return 1;
+		goto out_locked;
 	}
 	if (test_bit(XPRT_WRITE_SPACE, &xprt->state))
 		goto out_unlock;
 	if (!xprt_need_congestion_window_wait(xprt)) {
 		xprt->snd_task = task;
-		return 1;
+		goto out_locked;
 	}
 out_unlock:
 	xprt_clear_locked(xprt);
 out_sleep:
-	dprintk("RPC: %5u failed to lock transport %p\n", task->tk_pid, xprt);
 	task->tk_status = -EAGAIN;
 	if (RPC_IS_SOFT(task))
 		rpc_sleep_on_timeout(&xprt->sending, task, NULL,
@@ -293,6 +292,9 @@ out_sleep:
 	else
 		rpc_sleep_on(&xprt->sending, task, NULL);
 	return 0;
+out_locked:
+	trace_xprt_reserve_cong(xprt, task);
+	return 1;
 }
 EXPORT_SYMBOL_GPL(xprt_reserve_xprt_cong);
 
@@ -357,6 +359,7 @@ void xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
 		xprt_clear_locked(xprt);
 		__xprt_lock_write_next(xprt);
 	}
+	trace_xprt_release_xprt(xprt, task);
 }
 EXPORT_SYMBOL_GPL(xprt_release_xprt);
 
@@ -374,6 +377,7 @@ void xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task)
 		xprt_clear_locked(xprt);
 		__xprt_lock_write_next_cong(xprt);
 	}
+	trace_xprt_release_cong(xprt, task);
 }
 EXPORT_SYMBOL_GPL(xprt_release_xprt_cong);
 
@@ -395,8 +399,7 @@ __xprt_get_cong(struct rpc_xprt *xprt, struct rpc_rqst *req)
 {
 	if (req->rq_cong)
 		return 1;
-	dprintk("RPC: %5u xprt_cwnd_limited cong = %lu cwnd = %lu\n",
-			req->rq_task->tk_pid, xprt->cong, xprt->cwnd);
+	trace_xprt_get_cong(xprt, req->rq_task);
 	if (RPCXPRT_CONGESTED(xprt)) {
 		xprt_set_congestion_window_wait(xprt);
 		return 0;
@@ -418,6 +421,7 @@ __xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req)
 	req->rq_cong = 0;
 	xprt->cong -= RPC_CWNDSCALE;
 	xprt_test_and_clear_congestion_window_wait(xprt);
+	trace_xprt_put_cong(xprt, req->rq_task);
 	__xprt_lock_write_next_cong(xprt);
 }
 
diff --git a/net/sunrpc/xprtrdma/backchannel.c b/net/sunrpc/xprtrdma/backchannel.c
index b458bf53ca69..9d02eae353c6 100644
--- a/net/sunrpc/xprtrdma/backchannel.c
+++ b/net/sunrpc/xprtrdma/backchannel.c
@@ -79,7 +79,7 @@ static int rpcrdma_bc_marshal_reply(struct rpc_rqst *rqst)
 	*p = xdr_zero;
 
 	if (rpcrdma_prepare_send_sges(r_xprt, req, RPCRDMA_HDRLEN_MIN,
-				      &rqst->rq_snd_buf, rpcrdma_noch))
+				      &rqst->rq_snd_buf, rpcrdma_noch_pullup))
 		return -EIO;
 
 	trace_xprtrdma_cb_reply(rqst);
diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c
index 30065a28628c..523722be6a16 100644
--- a/net/sunrpc/xprtrdma/frwr_ops.c
+++ b/net/sunrpc/xprtrdma/frwr_ops.c
@@ -36,8 +36,8 @@
  * connect worker from running concurrently.
  *
  * When the underlying transport disconnects, MRs that are in flight
- * are flushed and are likely unusable. Thus all flushed MRs are
- * destroyed. New MRs are created on demand.
+ * are flushed and are likely unusable. Thus all MRs are destroyed.
+ * New MRs are created on demand.
  */
 
 #include <linux/sunrpc/rpc_rdma.h>
@@ -88,8 +88,10 @@ void frwr_release_mr(struct rpcrdma_mr *mr)
 	kfree(mr);
 }
 
-static void frwr_mr_recycle(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr *mr)
+static void frwr_mr_recycle(struct rpcrdma_mr *mr)
 {
+	struct rpcrdma_xprt *r_xprt = mr->mr_xprt;
+
 	trace_xprtrdma_mr_recycle(mr);
 
 	if (mr->mr_dir != DMA_NONE) {
@@ -107,32 +109,6 @@ static void frwr_mr_recycle(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr *mr)
 	frwr_release_mr(mr);
 }
 
-/* MRs are dynamically allocated, so simply clean up and release the MR.
- * A replacement MR will subsequently be allocated on demand.
- */
-static void
-frwr_mr_recycle_worker(struct work_struct *work)
-{
-	struct rpcrdma_mr *mr = container_of(work, struct rpcrdma_mr,
-					     mr_recycle);
-
-	frwr_mr_recycle(mr->mr_xprt, mr);
-}
-
-/* frwr_recycle - Discard MRs
- * @req: request to reset
- *
- * Used after a reconnect. These MRs could be in flight, we can't
- * tell. Safe thing to do is release them.
- */
-void frwr_recycle(struct rpcrdma_req *req)
-{
-	struct rpcrdma_mr *mr;
-
-	while ((mr = rpcrdma_mr_pop(&req->rl_registered)))
-		frwr_mr_recycle(mr->mr_xprt, mr);
-}
-
 /* frwr_reset - Place MRs back on the free list
  * @req: request to reset
  *
@@ -166,9 +142,6 @@ int frwr_init_mr(struct rpcrdma_ia *ia, struct rpcrdma_mr *mr)
 	struct ib_mr *frmr;
 	int rc;
 
-	/* NB: ib_alloc_mr and device drivers typically allocate
-	 *     memory with GFP_KERNEL.
-	 */
 	frmr = ib_alloc_mr(ia->ri_pd, ia->ri_mrtype, depth);
 	if (IS_ERR(frmr))
 		goto out_mr_err;
@@ -180,7 +153,6 @@ int frwr_init_mr(struct rpcrdma_ia *ia, struct rpcrdma_mr *mr)
 	mr->frwr.fr_mr = frmr;
 	mr->mr_dir = DMA_NONE;
 	INIT_LIST_HEAD(&mr->mr_list);
-	INIT_WORK(&mr->mr_recycle, frwr_mr_recycle_worker);
 	init_completion(&mr->frwr.fr_linv_done);
 
 	sg_init_table(sg, depth);
@@ -424,7 +396,7 @@ int frwr_send(struct rpcrdma_ia *ia, struct rpcrdma_req *req)
 	struct ib_send_wr *post_wr;
 	struct rpcrdma_mr *mr;
 
-	post_wr = &req->rl_sendctx->sc_wr;
+	post_wr = &req->rl_wr;
 	list_for_each_entry(mr, &req->rl_registered, mr_list) {
 		struct rpcrdma_frwr *frwr;
 
@@ -440,9 +412,6 @@ int frwr_send(struct rpcrdma_ia *ia, struct rpcrdma_req *req)
 		post_wr = &frwr->fr_regwr.wr;
 	}
 
-	/* If ib_post_send fails, the next ->send_request for
-	 * @req will queue these MRs for recovery.
-	 */
 	return ib_post_send(ia->ri_id->qp, post_wr, NULL);
 }
 
@@ -468,7 +437,7 @@ void frwr_reminv(struct rpcrdma_rep *rep, struct list_head *mrs)
 static void __frwr_release_mr(struct ib_wc *wc, struct rpcrdma_mr *mr)
 {
 	if (wc->status != IB_WC_SUCCESS)
-		rpcrdma_mr_recycle(mr);
+		frwr_mr_recycle(mr);
 	else
 		rpcrdma_mr_put(mr);
 }
@@ -570,7 +539,6 @@ void frwr_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
 	 */
 	bad_wr = NULL;
 	rc = ib_post_send(r_xprt->rx_ia.ri_id->qp, first, &bad_wr);
-	trace_xprtrdma_post_send(req, rc);
 
 	/* The final LOCAL_INV WR in the chain is supposed to
 	 * do the wake. If it was never posted, the wake will
@@ -583,6 +551,7 @@ void frwr_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
 
 	/* Recycle MRs in the LOCAL_INV chain that did not get posted.
 	 */
+	trace_xprtrdma_post_linv(req, rc);
 	while (bad_wr) {
 		frwr = container_of(bad_wr, struct rpcrdma_frwr,
 				    fr_invwr);
@@ -590,7 +559,7 @@ void frwr_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
 		bad_wr = bad_wr->next;
 
 		list_del_init(&mr->mr_list);
-		rpcrdma_mr_recycle(mr);
+		frwr_mr_recycle(mr);
 	}
 }
 
@@ -673,18 +642,18 @@ void frwr_unmap_async(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
 	 */
 	bad_wr = NULL;
 	rc = ib_post_send(r_xprt->rx_ia.ri_id->qp, first, &bad_wr);
-	trace_xprtrdma_post_send(req, rc);
 	if (!rc)
 		return;
 
 	/* Recycle MRs in the LOCAL_INV chain that did not get posted.
 	 */
+	trace_xprtrdma_post_linv(req, rc);
 	while (bad_wr) {
 		frwr = container_of(bad_wr, struct rpcrdma_frwr, fr_invwr);
 		mr = container_of(frwr, struct rpcrdma_mr, frwr);
 		bad_wr = bad_wr->next;
 
-		rpcrdma_mr_recycle(mr);
+		frwr_mr_recycle(mr);
 	}
 
 	/* The final LOCAL_INV WR in the chain is supposed to
diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index b86b5fd62d9f..aec3beb93b25 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -78,8 +78,6 @@ static unsigned int rpcrdma_max_call_header_size(unsigned int maxsegs)
 	size += rpcrdma_segment_maxsz * sizeof(__be32);
 	size += sizeof(__be32);	/* list discriminator */
 
-	dprintk("RPC:       %s: max call header size = %u\n",
-		__func__, size);
 	return size;
 }
 
@@ -100,8 +98,6 @@ static unsigned int rpcrdma_max_reply_header_size(unsigned int maxsegs)
 	size += maxsegs * rpcrdma_segment_maxsz * sizeof(__be32);
 	size += sizeof(__be32);	/* list discriminator */
 
-	dprintk("RPC:       %s: max reply header size = %u\n",
-		__func__, size);
 	return size;
 }
 
@@ -363,8 +359,7 @@ static struct rpcrdma_mr_seg *rpcrdma_mr_prepare(struct rpcrdma_xprt *r_xprt,
 out_getmr_err:
 	trace_xprtrdma_nomrs(req);
 	xprt_wait_for_buffer_space(&r_xprt->rx_xprt);
-	if (r_xprt->rx_ep.rep_connected != -ENODEV)
-		schedule_work(&r_xprt->rx_buf.rb_refresh_worker);
+	rpcrdma_mrs_refresh(r_xprt);
 	return ERR_PTR(-EAGAIN);
 }
 
@@ -393,7 +388,7 @@ static int rpcrdma_encode_read_list(struct rpcrdma_xprt *r_xprt,
 	unsigned int pos;
 	int nsegs;
 
-	if (rtype == rpcrdma_noch)
+	if (rtype == rpcrdma_noch_pullup || rtype == rpcrdma_noch_mapped)
 		goto done;
 
 	pos = rqst->rq_snd_buf.head[0].iov_len;
@@ -565,6 +560,7 @@ static void rpcrdma_sendctx_done(struct kref *kref)
  */
 void rpcrdma_sendctx_unmap(struct rpcrdma_sendctx *sc)
 {
+	struct rpcrdma_regbuf *rb = sc->sc_req->rl_sendbuf;
 	struct ib_sge *sge;
 
 	if (!sc->sc_unmap_count)
@@ -576,7 +572,7 @@ void rpcrdma_sendctx_unmap(struct rpcrdma_sendctx *sc)
 	 */
 	for (sge = &sc->sc_sges[2]; sc->sc_unmap_count;
 	     ++sge, --sc->sc_unmap_count)
-		ib_dma_unmap_page(sc->sc_device, sge->addr, sge->length,
+		ib_dma_unmap_page(rdmab_device(rb), sge->addr, sge->length,
 				  DMA_TO_DEVICE);
 
 	kref_put(&sc->sc_req->rl_kref, rpcrdma_sendctx_done);
@@ -589,149 +585,228 @@ static bool rpcrdma_prepare_hdr_sge(struct rpcrdma_xprt *r_xprt,
 {
 	struct rpcrdma_sendctx *sc = req->rl_sendctx;
 	struct rpcrdma_regbuf *rb = req->rl_rdmabuf;
-	struct ib_sge *sge = sc->sc_sges;
+	struct ib_sge *sge = &sc->sc_sges[req->rl_wr.num_sge++];
 
 	if (!rpcrdma_regbuf_dma_map(r_xprt, rb))
-		goto out_regbuf;
+		return false;
 	sge->addr = rdmab_addr(rb);
 	sge->length = len;
 	sge->lkey = rdmab_lkey(rb);
 
 	ib_dma_sync_single_for_device(rdmab_device(rb), sge->addr, sge->length,
 				      DMA_TO_DEVICE);
-	sc->sc_wr.num_sge++;
 	return true;
-
-out_regbuf:
-	pr_err("rpcrdma: failed to DMA map a Send buffer\n");
-	return false;
 }
 
-/* Prepare the Send SGEs. The head and tail iovec, and each entry
- * in the page list, gets its own SGE.
+/* The head iovec is straightforward, as it is usually already
+ * DMA-mapped. Sync the content that has changed.
  */
-static bool rpcrdma_prepare_msg_sges(struct rpcrdma_xprt *r_xprt,
-				     struct rpcrdma_req *req,
-				     struct xdr_buf *xdr,
-				     enum rpcrdma_chunktype rtype)
+static bool rpcrdma_prepare_head_iov(struct rpcrdma_xprt *r_xprt,
+				     struct rpcrdma_req *req, unsigned int len)
 {
 	struct rpcrdma_sendctx *sc = req->rl_sendctx;
-	unsigned int sge_no, page_base, len, remaining;
+	struct ib_sge *sge = &sc->sc_sges[req->rl_wr.num_sge++];
 	struct rpcrdma_regbuf *rb = req->rl_sendbuf;
-	struct ib_sge *sge = sc->sc_sges;
-	struct page *page, **ppages;
 
-	/* The head iovec is straightforward, as it is already
-	 * DMA-mapped. Sync the content that has changed.
-	 */
 	if (!rpcrdma_regbuf_dma_map(r_xprt, rb))
-		goto out_regbuf;
-	sc->sc_device = rdmab_device(rb);
-	sge_no = 1;
-	sge[sge_no].addr = rdmab_addr(rb);
-	sge[sge_no].length = xdr->head[0].iov_len;
-	sge[sge_no].lkey = rdmab_lkey(rb);
-	ib_dma_sync_single_for_device(rdmab_device(rb), sge[sge_no].addr,
-				      sge[sge_no].length, DMA_TO_DEVICE);
-
-	/* If there is a Read chunk, the page list is being handled
-	 * via explicit RDMA, and thus is skipped here. However, the
-	 * tail iovec may include an XDR pad for the page list, as
-	 * well as additional content, and may not reside in the
-	 * same page as the head iovec.
-	 */
-	if (rtype == rpcrdma_readch) {
-		len = xdr->tail[0].iov_len;
+		return false;
 
-		/* Do not include the tail if it is only an XDR pad */
-		if (len < 4)
-			goto out;
+	sge->addr = rdmab_addr(rb);
+	sge->length = len;
+	sge->lkey = rdmab_lkey(rb);
 
-		page = virt_to_page(xdr->tail[0].iov_base);
-		page_base = offset_in_page(xdr->tail[0].iov_base);
+	ib_dma_sync_single_for_device(rdmab_device(rb), sge->addr, sge->length,
+				      DMA_TO_DEVICE);
+	return true;
+}
 
-		/* If the content in the page list is an odd length,
-		 * xdr_write_pages() has added a pad at the beginning
-		 * of the tail iovec. Force the tail's non-pad content
-		 * to land at the next XDR position in the Send message.
-		 */
-		page_base += len & 3;
-		len -= len & 3;
-		goto map_tail;
-	}
+/* If there is a page list present, DMA map and prepare an
+ * SGE for each page to be sent.
+ */
+static bool rpcrdma_prepare_pagelist(struct rpcrdma_req *req,
+				     struct xdr_buf *xdr)
+{
+	struct rpcrdma_sendctx *sc = req->rl_sendctx;
+	struct rpcrdma_regbuf *rb = req->rl_sendbuf;
+	unsigned int page_base, len, remaining;
+	struct page **ppages;
+	struct ib_sge *sge;
 
-	/* If there is a page list present, temporarily DMA map
-	 * and prepare an SGE for each page to be sent.
-	 */
-	if (xdr->page_len) {
-		ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
-		page_base = offset_in_page(xdr->page_base);
-		remaining = xdr->page_len;
-		while (remaining) {
-			sge_no++;
-			if (sge_no > RPCRDMA_MAX_SEND_SGES - 2)
-				goto out_mapping_overflow;
-
-			len = min_t(u32, PAGE_SIZE - page_base, remaining);
-			sge[sge_no].addr =
-				ib_dma_map_page(rdmab_device(rb), *ppages,
-						page_base, len, DMA_TO_DEVICE);
-			if (ib_dma_mapping_error(rdmab_device(rb),
-						 sge[sge_no].addr))
-				goto out_mapping_err;
-			sge[sge_no].length = len;
-			sge[sge_no].lkey = rdmab_lkey(rb);
-
-			sc->sc_unmap_count++;
-			ppages++;
-			remaining -= len;
-			page_base = 0;
-		}
-	}
+	ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
+	page_base = offset_in_page(xdr->page_base);
+	remaining = xdr->page_len;
+	while (remaining) {
+		sge = &sc->sc_sges[req->rl_wr.num_sge++];
+		len = min_t(unsigned int, PAGE_SIZE - page_base, remaining);
+		sge->addr = ib_dma_map_page(rdmab_device(rb), *ppages,
+					    page_base, len, DMA_TO_DEVICE);
+		if (ib_dma_mapping_error(rdmab_device(rb), sge->addr))
+			goto out_mapping_err;
 
-	/* The tail iovec is not always constructed in the same
-	 * page where the head iovec resides (see, for example,
-	 * gss_wrap_req_priv). To neatly accommodate that case,
-	 * DMA map it separately.
-	 */
-	if (xdr->tail[0].iov_len) {
-		page = virt_to_page(xdr->tail[0].iov_base);
-		page_base = offset_in_page(xdr->tail[0].iov_base);
-		len = xdr->tail[0].iov_len;
+		sge->length = len;
+		sge->lkey = rdmab_lkey(rb);
 
-map_tail:
-		sge_no++;
-		sge[sge_no].addr =
-			ib_dma_map_page(rdmab_device(rb), page, page_base, len,
-					DMA_TO_DEVICE);
-		if (ib_dma_mapping_error(rdmab_device(rb), sge[sge_no].addr))
-			goto out_mapping_err;
-		sge[sge_no].length = len;
-		sge[sge_no].lkey = rdmab_lkey(rb);
 		sc->sc_unmap_count++;
+		ppages++;
+		remaining -= len;
+		page_base = 0;
 	}
 
-out:
-	sc->sc_wr.num_sge += sge_no;
-	if (sc->sc_unmap_count)
-		kref_get(&req->rl_kref);
 	return true;
 
-out_regbuf:
-	pr_err("rpcrdma: failed to DMA map a Send buffer\n");
+out_mapping_err:
+	trace_xprtrdma_dma_maperr(sge->addr);
 	return false;
+}
 
-out_mapping_overflow:
-	rpcrdma_sendctx_unmap(sc);
-	pr_err("rpcrdma: too many Send SGEs (%u)\n", sge_no);
-	return false;
+/* The tail iovec may include an XDR pad for the page list,
+ * as well as additional content, and may not reside in the
+ * same page as the head iovec.
+ */
+static bool rpcrdma_prepare_tail_iov(struct rpcrdma_req *req,
+				     struct xdr_buf *xdr,
+				     unsigned int page_base, unsigned int len)
+{
+	struct rpcrdma_sendctx *sc = req->rl_sendctx;
+	struct ib_sge *sge = &sc->sc_sges[req->rl_wr.num_sge++];
+	struct rpcrdma_regbuf *rb = req->rl_sendbuf;
+	struct page *page = virt_to_page(xdr->tail[0].iov_base);
+
+	sge->addr = ib_dma_map_page(rdmab_device(rb), page, page_base, len,
+				    DMA_TO_DEVICE);
+	if (ib_dma_mapping_error(rdmab_device(rb), sge->addr))
+		goto out_mapping_err;
+
+	sge->length = len;
+	sge->lkey = rdmab_lkey(rb);
+	++sc->sc_unmap_count;
+	return true;
 
 out_mapping_err:
-	rpcrdma_sendctx_unmap(sc);
-	trace_xprtrdma_dma_maperr(sge[sge_no].addr);
+	trace_xprtrdma_dma_maperr(sge->addr);
 	return false;
 }
 
+/* Copy the tail to the end of the head buffer.
+ */
+static void rpcrdma_pullup_tail_iov(struct rpcrdma_xprt *r_xprt,
+				    struct rpcrdma_req *req,
+				    struct xdr_buf *xdr)
+{
+	unsigned char *dst;
+
+	dst = (unsigned char *)xdr->head[0].iov_base;
+	dst += xdr->head[0].iov_len + xdr->page_len;
+	memmove(dst, xdr->tail[0].iov_base, xdr->tail[0].iov_len);
+	r_xprt->rx_stats.pullup_copy_count += xdr->tail[0].iov_len;
+}
+
+/* Copy pagelist content into the head buffer.
+ */
+static void rpcrdma_pullup_pagelist(struct rpcrdma_xprt *r_xprt,
+				    struct rpcrdma_req *req,
+				    struct xdr_buf *xdr)
+{
+	unsigned int len, page_base, remaining;
+	struct page **ppages;
+	unsigned char *src, *dst;
+
+	dst = (unsigned char *)xdr->head[0].iov_base;
+	dst += xdr->head[0].iov_len;
+	ppages = xdr->pages + (xdr->page_base >> PAGE_SHIFT);
+	page_base = offset_in_page(xdr->page_base);
+	remaining = xdr->page_len;
+	while (remaining) {
+		src = page_address(*ppages);
+		src += page_base;
+		len = min_t(unsigned int, PAGE_SIZE - page_base, remaining);
+		memcpy(dst, src, len);
+		r_xprt->rx_stats.pullup_copy_count += len;
+
+		ppages++;
+		dst += len;
+		remaining -= len;
+		page_base = 0;
+	}
+}
+
+/* Copy the contents of @xdr into @rl_sendbuf and DMA sync it.
+ * When the head, pagelist, and tail are small, a pull-up copy
+ * is considerably less costly than DMA mapping the components
+ * of @xdr.
+ *
+ * Assumptions:
+ *  - the caller has already verified that the total length
+ *    of the RPC Call body will fit into @rl_sendbuf.
+ */
+static bool rpcrdma_prepare_noch_pullup(struct rpcrdma_xprt *r_xprt,
+					struct rpcrdma_req *req,
+					struct xdr_buf *xdr)
+{
+	if (unlikely(xdr->tail[0].iov_len))
+		rpcrdma_pullup_tail_iov(r_xprt, req, xdr);
+
+	if (unlikely(xdr->page_len))
+		rpcrdma_pullup_pagelist(r_xprt, req, xdr);
+
+	/* The whole RPC message resides in the head iovec now */
+	return rpcrdma_prepare_head_iov(r_xprt, req, xdr->len);
+}
+
+static bool rpcrdma_prepare_noch_mapped(struct rpcrdma_xprt *r_xprt,
+					struct rpcrdma_req *req,
+					struct xdr_buf *xdr)
+{
+	struct kvec *tail = &xdr->tail[0];
+
+	if (!rpcrdma_prepare_head_iov(r_xprt, req, xdr->head[0].iov_len))
+		return false;
+	if (xdr->page_len)
+		if (!rpcrdma_prepare_pagelist(req, xdr))
+			return false;
+	if (tail->iov_len)
+		if (!rpcrdma_prepare_tail_iov(req, xdr,
+					      offset_in_page(tail->iov_base),
+					      tail->iov_len))
+			return false;
+
+	if (req->rl_sendctx->sc_unmap_count)
+		kref_get(&req->rl_kref);
+	return true;
+}
+
+static bool rpcrdma_prepare_readch(struct rpcrdma_xprt *r_xprt,
+				   struct rpcrdma_req *req,
+				   struct xdr_buf *xdr)
+{
+	if (!rpcrdma_prepare_head_iov(r_xprt, req, xdr->head[0].iov_len))
+		return false;
+
+	/* If there is a Read chunk, the page list is being handled
+	 * via explicit RDMA, and thus is skipped here.
+	 */
+
+	/* Do not include the tail if it is only an XDR pad */
+	if (xdr->tail[0].iov_len > 3) {
+		unsigned int page_base, len;
+
+		/* If the content in the page list is an odd length,
+		 * xdr_write_pages() adds a pad at the beginning of
+		 * the tail iovec. Force the tail's non-pad content to
+		 * land at the next XDR position in the Send message.
+		 */
+		page_base = offset_in_page(xdr->tail[0].iov_base);
+		len = xdr->tail[0].iov_len;
+		page_base += len & 3;
+		len -= len & 3;
+		if (!rpcrdma_prepare_tail_iov(req, xdr, page_base, len))
+			return false;
+		kref_get(&req->rl_kref);
+	}
+
+	return true;
+}
+
 /**
  * rpcrdma_prepare_send_sges - Construct SGEs for a Send WR
  * @r_xprt: controlling transport
@@ -742,31 +817,53 @@ out_mapping_err:
  *
  * Returns 0 on success; otherwise a negative errno is returned.
  */
-int
-rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt,
-			  struct rpcrdma_req *req, u32 hdrlen,
-			  struct xdr_buf *xdr, enum rpcrdma_chunktype rtype)
+inline int rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt,
+				     struct rpcrdma_req *req, u32 hdrlen,
+				     struct xdr_buf *xdr,
+				     enum rpcrdma_chunktype rtype)
 {
 	int ret;
 
 	ret = -EAGAIN;
 	req->rl_sendctx = rpcrdma_sendctx_get_locked(r_xprt);
 	if (!req->rl_sendctx)
-		goto err;
-	req->rl_sendctx->sc_wr.num_sge = 0;
+		goto out_nosc;
 	req->rl_sendctx->sc_unmap_count = 0;
 	req->rl_sendctx->sc_req = req;
 	kref_init(&req->rl_kref);
+	req->rl_wr.wr_cqe = &req->rl_sendctx->sc_cqe;
+	req->rl_wr.sg_list = req->rl_sendctx->sc_sges;
+	req->rl_wr.num_sge = 0;
+	req->rl_wr.opcode = IB_WR_SEND;
 
 	ret = -EIO;
 	if (!rpcrdma_prepare_hdr_sge(r_xprt, req, hdrlen))
-		goto err;
-	if (rtype != rpcrdma_areadch)
-		if (!rpcrdma_prepare_msg_sges(r_xprt, req, xdr, rtype))
-			goto err;
+		goto out_unmap;
+
+	switch (rtype) {
+	case rpcrdma_noch_pullup:
+		if (!rpcrdma_prepare_noch_pullup(r_xprt, req, xdr))
+			goto out_unmap;
+		break;
+	case rpcrdma_noch_mapped:
+		if (!rpcrdma_prepare_noch_mapped(r_xprt, req, xdr))
+			goto out_unmap;
+		break;
+	case rpcrdma_readch:
+		if (!rpcrdma_prepare_readch(r_xprt, req, xdr))
+			goto out_unmap;
+		break;
+	case rpcrdma_areadch:
+		break;
+	default:
+		goto out_unmap;
+	}
+
 	return 0;
 
-err:
+out_unmap:
+	rpcrdma_sendctx_unmap(req->rl_sendctx);
+out_nosc:
 	trace_xprtrdma_prepsend_failed(&req->rl_slot, ret);
 	return ret;
 }
@@ -796,6 +893,7 @@ rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst)
 	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
 	struct xdr_stream *xdr = &req->rl_stream;
 	enum rpcrdma_chunktype rtype, wtype;
+	struct xdr_buf *buf = &rqst->rq_snd_buf;
 	bool ddp_allowed;
 	__be32 *p;
 	int ret;
@@ -853,8 +951,9 @@ rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst)
 	 */
 	if (rpcrdma_args_inline(r_xprt, rqst)) {
 		*p++ = rdma_msg;
-		rtype = rpcrdma_noch;
-	} else if (ddp_allowed && rqst->rq_snd_buf.flags & XDRBUF_WRITE) {
+		rtype = buf->len < rdmab_length(req->rl_sendbuf) ?
+			rpcrdma_noch_pullup : rpcrdma_noch_mapped;
+	} else if (ddp_allowed && buf->flags & XDRBUF_WRITE) {
 		*p++ = rdma_msg;
 		rtype = rpcrdma_readch;
 	} else {
@@ -863,12 +962,6 @@ rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst)
 		rtype = rpcrdma_areadch;
 	}
 
-	/* If this is a retransmit, discard previously registered
-	 * chunks. Very likely the connection has been replaced,
-	 * so these registrations are invalid and unusable.
-	 */
-	frwr_recycle(req);
-
 	/* This implementation supports the following combinations
 	 * of chunk lists in one RPC-over-RDMA Call message:
 	 *
@@ -902,7 +995,7 @@ rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst)
 		goto out_err;
 
 	ret = rpcrdma_prepare_send_sges(r_xprt, req, req->rl_hdrbuf.len,
-					&rqst->rq_snd_buf, rtype);
+					buf, rtype);
 	if (ret)
 		goto out_err;
 
@@ -916,6 +1009,40 @@ out_err:
 	return ret;
 }
 
+static void __rpcrdma_update_cwnd_locked(struct rpc_xprt *xprt,
+					 struct rpcrdma_buffer *buf,
+					 u32 grant)
+{
+	buf->rb_credits = grant;
+	xprt->cwnd = grant << RPC_CWNDSHIFT;
+}
+
+static void rpcrdma_update_cwnd(struct rpcrdma_xprt *r_xprt, u32 grant)
+{
+	struct rpc_xprt *xprt = &r_xprt->rx_xprt;
+
+	spin_lock(&xprt->transport_lock);
+	__rpcrdma_update_cwnd_locked(xprt, &r_xprt->rx_buf, grant);
+	spin_unlock(&xprt->transport_lock);
+}
+
+/**
+ * rpcrdma_reset_cwnd - Reset the xprt's congestion window
+ * @r_xprt: controlling transport instance
+ *
+ * Prepare @r_xprt for the next connection by reinitializing
+ * its credit grant to one (see RFC 8166, Section 3.3.3).
+ */
+void rpcrdma_reset_cwnd(struct rpcrdma_xprt *r_xprt)
+{
+	struct rpc_xprt *xprt = &r_xprt->rx_xprt;
+
+	spin_lock(&xprt->transport_lock);
+	xprt->cong = 0;
+	__rpcrdma_update_cwnd_locked(xprt, &r_xprt->rx_buf, 1);
+	spin_unlock(&xprt->transport_lock);
+}
+
 /**
  * rpcrdma_inline_fixup - Scatter inline received data into rqst's iovecs
  * @rqst: controlling RPC request
@@ -955,7 +1082,6 @@ rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad)
 	curlen = rqst->rq_rcv_buf.head[0].iov_len;
 	if (curlen > copy_len)
 		curlen = copy_len;
-	trace_xprtrdma_fixup(rqst, copy_len, curlen);
 	srcp += curlen;
 	copy_len -= curlen;
 
@@ -975,8 +1101,6 @@ rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad)
 			if (curlen > pagelist_len)
 				curlen = pagelist_len;
 
-			trace_xprtrdma_fixup_pg(rqst, i, srcp,
-						copy_len, curlen);
 			destp = kmap_atomic(ppages[i]);
 			memcpy(destp + page_base, srcp, curlen);
 			flush_dcache_page(ppages[i]);
@@ -1008,6 +1132,8 @@ rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad)
 		rqst->rq_private_buf.tail[0].iov_base = srcp;
 	}
 
+	if (fixup_copy_count)
+		trace_xprtrdma_fixup(rqst, fixup_copy_count);
 	return fixup_copy_count;
 }
 
@@ -1356,12 +1482,9 @@ void rpcrdma_reply_handler(struct rpcrdma_rep *rep)
 		credits = 1;	/* don't deadlock */
 	else if (credits > buf->rb_max_requests)
 		credits = buf->rb_max_requests;
-	if (buf->rb_credits != credits) {
-		spin_lock(&xprt->transport_lock);
-		buf->rb_credits = credits;
-		xprt->cwnd = credits << RPC_CWNDSHIFT;
-		spin_unlock(&xprt->transport_lock);
-	}
+	if (buf->rb_credits != credits)
+		rpcrdma_update_cwnd(r_xprt, credits);
+	rpcrdma_post_recvs(r_xprt, false);
 
 	req = rpcr_to_rdmar(rqst);
 	if (req->rl_reply) {
diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
index 160558b4135e..7395eb2cfdeb 100644
--- a/net/sunrpc/xprtrdma/transport.c
+++ b/net/sunrpc/xprtrdma/transport.c
@@ -243,16 +243,13 @@ xprt_rdma_connect_worker(struct work_struct *work)
 	rc = rpcrdma_ep_connect(&r_xprt->rx_ep, &r_xprt->rx_ia);
 	xprt_clear_connecting(xprt);
 	if (r_xprt->rx_ep.rep_connected > 0) {
-		if (!xprt_test_and_set_connected(xprt)) {
-			xprt->stat.connect_count++;
-			xprt->stat.connect_time += (long)jiffies -
-						   xprt->stat.connect_start;
-			xprt_wake_pending_tasks(xprt, -EAGAIN);
-		}
-	} else {
-		if (xprt_test_and_clear_connected(xprt))
-			xprt_wake_pending_tasks(xprt, rc);
+		xprt->stat.connect_count++;
+		xprt->stat.connect_time += (long)jiffies -
+					   xprt->stat.connect_start;
+		xprt_set_connected(xprt);
+		rc = -EAGAIN;
 	}
+	xprt_wake_pending_tasks(xprt, rc);
 }
 
 /**
@@ -425,12 +422,6 @@ void xprt_rdma_close(struct rpc_xprt *xprt)
 		return;
 	rpcrdma_ep_disconnect(ep, ia);
 
-	/* Prepare @xprt for the next connection by reinitializing
-	 * its credit grant to one (see RFC 8166, Section 3.3.3).
-	 */
-	r_xprt->rx_buf.rb_credits = 1;
-	xprt->cwnd = RPC_CWNDSHIFT;
-
 out:
 	xprt->reestablish_timeout = 0;
 	++xprt->connect_cookie;
@@ -450,12 +441,6 @@ xprt_rdma_set_port(struct rpc_xprt *xprt, u16 port)
 	struct sockaddr *sap = (struct sockaddr *)&xprt->addr;
 	char buf[8];
 
-	dprintk("RPC:       %s: setting port for xprt %p (%s:%s) to %u\n",
-		__func__, xprt,
-		xprt->address_strings[RPC_DISPLAY_ADDR],
-		xprt->address_strings[RPC_DISPLAY_PORT],
-		port);
-
 	rpc_set_port(sap, port);
 
 	kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
@@ -465,6 +450,9 @@ xprt_rdma_set_port(struct rpc_xprt *xprt, u16 port)
 	kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
 	snprintf(buf, sizeof(buf), "%4hx", port);
 	xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
+
+	trace_xprtrdma_op_setport(container_of(xprt, struct rpcrdma_xprt,
+					       rx_xprt));
 }
 
 /**
@@ -536,13 +524,12 @@ xprt_rdma_connect(struct rpc_xprt *xprt, struct rpc_task *task)
 	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
 	unsigned long delay;
 
-	trace_xprtrdma_op_connect(r_xprt);
-
 	delay = 0;
 	if (r_xprt->rx_ep.rep_connected != 0) {
 		delay = xprt_reconnect_delay(xprt);
 		xprt_reconnect_backoff(xprt, RPCRDMA_INIT_REEST_TO);
 	}
+	trace_xprtrdma_op_connect(r_xprt, delay);
 	queue_delayed_work(xprtiod_workqueue, &r_xprt->rx_connect_worker,
 			   delay);
 }
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 3a907537e2cf..77c7dd7f05e8 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -74,17 +74,17 @@
 /*
  * internal functions
  */
-static void rpcrdma_sendctx_put_locked(struct rpcrdma_sendctx *sc);
+static void rpcrdma_sendctx_put_locked(struct rpcrdma_xprt *r_xprt,
+				       struct rpcrdma_sendctx *sc);
+static void rpcrdma_reqs_reset(struct rpcrdma_xprt *r_xprt);
 static void rpcrdma_reps_destroy(struct rpcrdma_buffer *buf);
 static void rpcrdma_mrs_create(struct rpcrdma_xprt *r_xprt);
-static void rpcrdma_mrs_destroy(struct rpcrdma_buffer *buf);
-static void rpcrdma_mr_free(struct rpcrdma_mr *mr);
+static void rpcrdma_mrs_destroy(struct rpcrdma_xprt *r_xprt);
 static struct rpcrdma_regbuf *
 rpcrdma_regbuf_alloc(size_t size, enum dma_data_direction direction,
 		     gfp_t flags);
 static void rpcrdma_regbuf_dma_unmap(struct rpcrdma_regbuf *rb);
 static void rpcrdma_regbuf_free(struct rpcrdma_regbuf *rb);
-static void rpcrdma_post_recvs(struct rpcrdma_xprt *r_xprt, bool temp);
 
 /* Wait for outstanding transport work to finish. ib_drain_qp
  * handles the drains in the wrong order for us, so open code
@@ -125,7 +125,7 @@ rpcrdma_qp_event_handler(struct ib_event *event, void *context)
 
 /**
  * rpcrdma_wc_send - Invoked by RDMA provider for each polled Send WC
- * @cq:	completion queue (ignored)
+ * @cq:	completion queue
  * @wc:	completed WR
  *
  */
@@ -138,7 +138,7 @@ rpcrdma_wc_send(struct ib_cq *cq, struct ib_wc *wc)
 
 	/* WARNING: Only wr_cqe and status are reliable at this point */
 	trace_xprtrdma_wc_send(sc, wc);
-	rpcrdma_sendctx_put_locked(sc);
+	rpcrdma_sendctx_put_locked((struct rpcrdma_xprt *)cq->cq_context, sc);
 }
 
 /**
@@ -170,7 +170,6 @@ rpcrdma_wc_receive(struct ib_cq *cq, struct ib_wc *wc)
 				   rdmab_addr(rep->rr_rdmabuf),
 				   wc->byte_len, DMA_FROM_DEVICE);
 
-	rpcrdma_post_recvs(r_xprt, false);
 	rpcrdma_reply_handler(rep);
 	return;
 
@@ -178,11 +177,11 @@ out_flushed:
 	rpcrdma_recv_buffer_put(rep);
 }
 
-static void
-rpcrdma_update_connect_private(struct rpcrdma_xprt *r_xprt,
-			       struct rdma_conn_param *param)
+static void rpcrdma_update_cm_private(struct rpcrdma_xprt *r_xprt,
+				      struct rdma_conn_param *param)
 {
 	const struct rpcrdma_connect_private *pmsg = param->private_data;
+	struct rpcrdma_ep *ep = &r_xprt->rx_ep;
 	unsigned int rsize, wsize;
 
 	/* Default settings for RPC-over-RDMA Version One */
@@ -198,13 +197,11 @@ rpcrdma_update_connect_private(struct rpcrdma_xprt *r_xprt,
 		wsize = rpcrdma_decode_buffer_size(pmsg->cp_recv_size);
 	}
 
-	if (rsize < r_xprt->rx_ep.rep_inline_recv)
-		r_xprt->rx_ep.rep_inline_recv = rsize;
-	if (wsize < r_xprt->rx_ep.rep_inline_send)
-		r_xprt->rx_ep.rep_inline_send = wsize;
-	dprintk("RPC:       %s: max send %u, max recv %u\n", __func__,
-		r_xprt->rx_ep.rep_inline_send,
-		r_xprt->rx_ep.rep_inline_recv);
+	if (rsize < ep->rep_inline_recv)
+		ep->rep_inline_recv = rsize;
+	if (wsize < ep->rep_inline_send)
+		ep->rep_inline_send = wsize;
+
 	rpcrdma_set_max_header_sizes(r_xprt);
 }
 
@@ -258,7 +255,8 @@ rpcrdma_cm_event_handler(struct rdma_cm_id *id, struct rdma_cm_event *event)
 	case RDMA_CM_EVENT_ESTABLISHED:
 		++xprt->connect_cookie;
 		ep->rep_connected = 1;
-		rpcrdma_update_connect_private(r_xprt, &event->param.conn);
+		rpcrdma_update_cm_private(r_xprt, &event->param.conn);
+		trace_xprtrdma_inline_thresh(r_xprt);
 		wake_up_all(&ep->rep_connect_wait);
 		break;
 	case RDMA_CM_EVENT_CONNECT_ERROR:
@@ -298,8 +296,6 @@ rpcrdma_create_id(struct rpcrdma_xprt *xprt, struct rpcrdma_ia *ia)
 	struct rdma_cm_id *id;
 	int rc;
 
-	trace_xprtrdma_conn_start(xprt);
-
 	init_completion(&ia->ri_done);
 	init_completion(&ia->ri_remove_done);
 
@@ -315,10 +311,8 @@ rpcrdma_create_id(struct rpcrdma_xprt *xprt, struct rpcrdma_ia *ia)
 	if (rc)
 		goto out;
 	rc = wait_for_completion_interruptible_timeout(&ia->ri_done, wtimeout);
-	if (rc < 0) {
-		trace_xprtrdma_conn_tout(xprt);
+	if (rc < 0)
 		goto out;
-	}
 
 	rc = ia->ri_async_rc;
 	if (rc)
@@ -329,10 +323,8 @@ rpcrdma_create_id(struct rpcrdma_xprt *xprt, struct rpcrdma_ia *ia)
 	if (rc)
 		goto out;
 	rc = wait_for_completion_interruptible_timeout(&ia->ri_done, wtimeout);
-	if (rc < 0) {
-		trace_xprtrdma_conn_tout(xprt);
+	if (rc < 0)
 		goto out;
-	}
 	rc = ia->ri_async_rc;
 	if (rc)
 		goto out;
@@ -409,8 +401,6 @@ rpcrdma_ia_remove(struct rpcrdma_ia *ia)
 	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
 	struct rpcrdma_req *req;
 
-	cancel_work_sync(&buf->rb_refresh_worker);
-
 	/* This is similar to rpcrdma_ep_destroy, but:
 	 * - Don't cancel the connect worker.
 	 * - Don't call rpcrdma_ep_disconnect, which waits
@@ -437,7 +427,7 @@ rpcrdma_ia_remove(struct rpcrdma_ia *ia)
 		rpcrdma_regbuf_dma_unmap(req->rl_sendbuf);
 		rpcrdma_regbuf_dma_unmap(req->rl_recvbuf);
 	}
-	rpcrdma_mrs_destroy(buf);
+	rpcrdma_mrs_destroy(r_xprt);
 	ib_dealloc_pd(ia->ri_pd);
 	ia->ri_pd = NULL;
 
@@ -522,7 +512,7 @@ int rpcrdma_ep_create(struct rpcrdma_xprt *r_xprt)
 	init_waitqueue_head(&ep->rep_connect_wait);
 	ep->rep_receive_count = 0;
 
-	sendcq = ib_alloc_cq_any(ia->ri_id->device, NULL,
+	sendcq = ib_alloc_cq_any(ia->ri_id->device, r_xprt,
 				 ep->rep_attr.cap.max_send_wr + 1,
 				 IB_POLL_WORKQUEUE);
 	if (IS_ERR(sendcq)) {
@@ -630,8 +620,6 @@ static int rpcrdma_ep_recreate_xprt(struct rpcrdma_xprt *r_xprt,
 		pr_err("rpcrdma: rdma_create_qp returned %d\n", err);
 		goto out3;
 	}
-
-	rpcrdma_mrs_create(r_xprt);
 	return 0;
 
 out3:
@@ -649,8 +637,6 @@ static int rpcrdma_ep_reconnect(struct rpcrdma_xprt *r_xprt,
 	struct rdma_cm_id *id, *old;
 	int err, rc;
 
-	trace_xprtrdma_reconnect(r_xprt);
-
 	rpcrdma_ep_disconnect(&r_xprt->rx_ep, ia);
 
 	rc = -EHOSTUNREACH;
@@ -705,7 +691,6 @@ retry:
 	memcpy(&qp_init_attr, &ep->rep_attr, sizeof(qp_init_attr));
 	switch (ep->rep_connected) {
 	case 0:
-		dprintk("RPC:       %s: connecting...\n", __func__);
 		rc = rdma_create_qp(ia->ri_id, ia->ri_pd, &qp_init_attr);
 		if (rc) {
 			rc = -ENETUNREACH;
@@ -726,6 +711,7 @@ retry:
 	ep->rep_connected = 0;
 	xprt_clear_connected(xprt);
 
+	rpcrdma_reset_cwnd(r_xprt);
 	rpcrdma_post_recvs(r_xprt, true);
 
 	rc = rdma_connect(ia->ri_id, &ep->rep_remote_cma);
@@ -742,13 +728,14 @@ retry:
 		goto out;
 	}
 
-	dprintk("RPC:       %s: connected\n", __func__);
+	rpcrdma_mrs_create(r_xprt);
 
 out:
 	if (rc)
 		ep->rep_connected = rc;
 
 out_noupdate:
+	trace_xprtrdma_connect(r_xprt, rc);
 	return rc;
 }
 
@@ -757,11 +744,8 @@ out_noupdate:
  * @ep: endpoint to disconnect
  * @ia: associated interface adapter
  *
- * This is separate from destroy to facilitate the ability
- * to reconnect without recreating the endpoint.
- *
- * This call is not reentrant, and must not be made in parallel
- * on the same endpoint.
+ * Caller serializes. Either the transport send lock is held,
+ * or we're being called to destroy the transport.
  */
 void
 rpcrdma_ep_disconnect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
@@ -780,6 +764,8 @@ rpcrdma_ep_disconnect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
 	trace_xprtrdma_disconnect(r_xprt, rc);
 
 	rpcrdma_xprt_drain(r_xprt);
+	rpcrdma_reqs_reset(r_xprt);
+	rpcrdma_mrs_destroy(r_xprt);
 }
 
 /* Fixed-size circular FIFO queue. This implementation is wait-free and
@@ -817,9 +803,6 @@ static struct rpcrdma_sendctx *rpcrdma_sendctx_create(struct rpcrdma_ia *ia)
 	if (!sc)
 		return NULL;
 
-	sc->sc_wr.wr_cqe = &sc->sc_cqe;
-	sc->sc_wr.sg_list = sc->sc_sges;
-	sc->sc_wr.opcode = IB_WR_SEND;
 	sc->sc_cqe.done = rpcrdma_wc_send;
 	return sc;
 }
@@ -847,7 +830,6 @@ static int rpcrdma_sendctxs_create(struct rpcrdma_xprt *r_xprt)
 		if (!sc)
 			return -ENOMEM;
 
-		sc->sc_xprt = r_xprt;
 		buf->rb_sc_ctxs[i] = sc;
 	}
 
@@ -910,6 +892,7 @@ out_emptyq:
 
 /**
  * rpcrdma_sendctx_put_locked - Release a send context
+ * @r_xprt: controlling transport instance
  * @sc: send context to release
  *
  * Usage: Called from Send completion to return a sendctxt
@@ -917,10 +900,10 @@ out_emptyq:
  *
  * The caller serializes calls to this function (per transport).
  */
-static void
-rpcrdma_sendctx_put_locked(struct rpcrdma_sendctx *sc)
+static void rpcrdma_sendctx_put_locked(struct rpcrdma_xprt *r_xprt,
+				       struct rpcrdma_sendctx *sc)
 {
-	struct rpcrdma_buffer *buf = &sc->sc_xprt->rx_buf;
+	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
 	unsigned long next_tail;
 
 	/* Unmap SGEs of previously completed but unsignaled
@@ -938,7 +921,7 @@ rpcrdma_sendctx_put_locked(struct rpcrdma_sendctx *sc)
 	/* Paired with READ_ONCE */
 	smp_store_release(&buf->rb_sc_tail, next_tail);
 
-	xprt_write_space(&sc->sc_xprt->rx_xprt);
+	xprt_write_space(&r_xprt->rx_xprt);
 }
 
 static void
@@ -965,7 +948,7 @@ rpcrdma_mrs_create(struct rpcrdma_xprt *r_xprt)
 		mr->mr_xprt = r_xprt;
 
 		spin_lock(&buf->rb_lock);
-		list_add(&mr->mr_list, &buf->rb_mrs);
+		rpcrdma_mr_push(mr, &buf->rb_mrs);
 		list_add(&mr->mr_all, &buf->rb_all_mrs);
 		spin_unlock(&buf->rb_lock);
 	}
@@ -987,6 +970,28 @@ rpcrdma_mr_refresh_worker(struct work_struct *work)
 }
 
 /**
+ * rpcrdma_mrs_refresh - Wake the MR refresh worker
+ * @r_xprt: controlling transport instance
+ *
+ */
+void rpcrdma_mrs_refresh(struct rpcrdma_xprt *r_xprt)
+{
+	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
+	struct rpcrdma_ep *ep = &r_xprt->rx_ep;
+
+	/* If there is no underlying device, it's no use to
+	 * wake the refresh worker.
+	 */
+	if (ep->rep_connected != -ENODEV) {
+		/* The work is scheduled on a WQ_MEM_RECLAIM
+		 * workqueue in order to prevent MR allocation
+		 * from recursing into NFS during direct reclaim.
+		 */
+		queue_work(xprtiod_workqueue, &buf->rb_refresh_worker);
+	}
+}
+
+/**
  * rpcrdma_req_create - Allocate an rpcrdma_req object
  * @r_xprt: controlling r_xprt
  * @size: initial size, in bytes, of send and receive buffers
@@ -1042,6 +1047,26 @@ out1:
 	return NULL;
 }
 
+/**
+ * rpcrdma_reqs_reset - Reset all reqs owned by a transport
+ * @r_xprt: controlling transport instance
+ *
+ * ASSUMPTION: the rb_allreqs list is stable for the duration,
+ * and thus can be walked without holding rb_lock. Eg. the
+ * caller is holding the transport send lock to exclude
+ * device removal or disconnection.
+ */
+static void rpcrdma_reqs_reset(struct rpcrdma_xprt *r_xprt)
+{
+	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
+	struct rpcrdma_req *req;
+
+	list_for_each_entry(req, &buf->rb_allreqs, rl_all) {
+		/* Credits are valid only for one connection */
+		req->rl_slot.rq_cong = 0;
+	}
+}
+
 static struct rpcrdma_rep *rpcrdma_rep_create(struct rpcrdma_xprt *r_xprt,
 					      bool temp)
 {
@@ -1125,8 +1150,6 @@ int rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt)
 	INIT_LIST_HEAD(&buf->rb_all_mrs);
 	INIT_WORK(&buf->rb_refresh_worker, rpcrdma_mr_refresh_worker);
 
-	rpcrdma_mrs_create(r_xprt);
-
 	INIT_LIST_HEAD(&buf->rb_send_bufs);
 	INIT_LIST_HEAD(&buf->rb_allreqs);
 
@@ -1134,14 +1157,13 @@ int rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt)
 	for (i = 0; i < buf->rb_max_requests; i++) {
 		struct rpcrdma_req *req;
 
-		req = rpcrdma_req_create(r_xprt, RPCRDMA_V1_DEF_INLINE_SIZE,
+		req = rpcrdma_req_create(r_xprt, RPCRDMA_V1_DEF_INLINE_SIZE * 2,
 					 GFP_KERNEL);
 		if (!req)
 			goto out;
 		list_add(&req->rl_list, &buf->rb_send_bufs);
 	}
 
-	buf->rb_credits = 1;
 	init_llist_head(&buf->rb_free_reps);
 
 	rc = rpcrdma_sendctxs_create(r_xprt);
@@ -1158,15 +1180,24 @@ out:
  * rpcrdma_req_destroy - Destroy an rpcrdma_req object
  * @req: unused object to be destroyed
  *
- * This function assumes that the caller prevents concurrent device
- * unload and transport tear-down.
+ * Relies on caller holding the transport send lock to protect
+ * removing req->rl_all from buf->rb_all_reqs safely.
  */
 void rpcrdma_req_destroy(struct rpcrdma_req *req)
 {
+	struct rpcrdma_mr *mr;
+
 	list_del(&req->rl_all);
 
-	while (!list_empty(&req->rl_free_mrs))
-		rpcrdma_mr_free(rpcrdma_mr_pop(&req->rl_free_mrs));
+	while ((mr = rpcrdma_mr_pop(&req->rl_free_mrs))) {
+		struct rpcrdma_buffer *buf = &mr->mr_xprt->rx_buf;
+
+		spin_lock(&buf->rb_lock);
+		list_del(&mr->mr_all);
+		spin_unlock(&buf->rb_lock);
+
+		frwr_release_mr(mr);
+	}
 
 	rpcrdma_regbuf_free(req->rl_recvbuf);
 	rpcrdma_regbuf_free(req->rl_sendbuf);
@@ -1174,28 +1205,33 @@ void rpcrdma_req_destroy(struct rpcrdma_req *req)
 	kfree(req);
 }
 
-static void
-rpcrdma_mrs_destroy(struct rpcrdma_buffer *buf)
+/**
+ * rpcrdma_mrs_destroy - Release all of a transport's MRs
+ * @r_xprt: controlling transport instance
+ *
+ * Relies on caller holding the transport send lock to protect
+ * removing mr->mr_list from req->rl_free_mrs safely.
+ */
+static void rpcrdma_mrs_destroy(struct rpcrdma_xprt *r_xprt)
 {
-	struct rpcrdma_xprt *r_xprt = container_of(buf, struct rpcrdma_xprt,
-						   rx_buf);
+	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
 	struct rpcrdma_mr *mr;
-	unsigned int count;
 
-	count = 0;
+	cancel_work_sync(&buf->rb_refresh_worker);
+
 	spin_lock(&buf->rb_lock);
 	while ((mr = list_first_entry_or_null(&buf->rb_all_mrs,
 					      struct rpcrdma_mr,
 					      mr_all)) != NULL) {
+		list_del(&mr->mr_list);
 		list_del(&mr->mr_all);
 		spin_unlock(&buf->rb_lock);
 
 		frwr_release_mr(mr);
-		count++;
+
 		spin_lock(&buf->rb_lock);
 	}
 	spin_unlock(&buf->rb_lock);
-	r_xprt->rx_stats.mrs_allocated = 0;
 }
 
 /**
@@ -1209,8 +1245,6 @@ rpcrdma_mrs_destroy(struct rpcrdma_buffer *buf)
 void
 rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf)
 {
-	cancel_work_sync(&buf->rb_refresh_worker);
-
 	rpcrdma_sendctxs_destroy(buf);
 	rpcrdma_reps_destroy(buf);
 
@@ -1222,8 +1256,6 @@ rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf)
 		list_del(&req->rl_list);
 		rpcrdma_req_destroy(req);
 	}
-
-	rpcrdma_mrs_destroy(buf);
 }
 
 /**
@@ -1264,17 +1296,6 @@ void rpcrdma_mr_put(struct rpcrdma_mr *mr)
 	rpcrdma_mr_push(mr, &mr->mr_req->rl_free_mrs);
 }
 
-static void rpcrdma_mr_free(struct rpcrdma_mr *mr)
-{
-	struct rpcrdma_xprt *r_xprt = mr->mr_xprt;
-	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
-
-	mr->mr_req = NULL;
-	spin_lock(&buf->rb_lock);
-	rpcrdma_mr_push(mr, &buf->rb_mrs);
-	spin_unlock(&buf->rb_lock);
-}
-
 /**
  * rpcrdma_buffer_get - Get a request buffer
  * @buffers: Buffer pool from which to obtain a buffer
@@ -1437,7 +1458,7 @@ rpcrdma_ep_post(struct rpcrdma_ia *ia,
 		struct rpcrdma_ep *ep,
 		struct rpcrdma_req *req)
 {
-	struct ib_send_wr *send_wr = &req->rl_sendctx->sc_wr;
+	struct ib_send_wr *send_wr = &req->rl_wr;
 	int rc;
 
 	if (!ep->rep_send_count || kref_read(&req->rl_kref) > 1) {
@@ -1455,8 +1476,13 @@ rpcrdma_ep_post(struct rpcrdma_ia *ia,
 	return 0;
 }
 
-static void
-rpcrdma_post_recvs(struct rpcrdma_xprt *r_xprt, bool temp)
+/**
+ * rpcrdma_post_recvs - Refill the Receive Queue
+ * @r_xprt: controlling transport instance
+ * @temp: mark Receive buffers to be deleted after use
+ *
+ */
+void rpcrdma_post_recvs(struct rpcrdma_xprt *r_xprt, bool temp)
 {
 	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
 	struct rpcrdma_ep *ep = &r_xprt->rx_ep;
diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index 65e6b0eb862e..5d15140a0266 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -218,12 +218,8 @@ enum {
 /* 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 ib_device	*sc_device;
-	struct rpcrdma_xprt	*sc_xprt;
 	struct rpcrdma_req	*sc_req;
 	unsigned int		sc_unmap_count;
 	struct ib_sge		sc_sges[];
@@ -257,7 +253,6 @@ struct rpcrdma_mr {
 	u32			mr_handle;
 	u32			mr_length;
 	u64			mr_offset;
-	struct work_struct	mr_recycle;
 	struct list_head	mr_all;
 };
 
@@ -318,6 +313,7 @@ struct rpcrdma_req {
 	struct rpcrdma_rep	*rl_reply;
 	struct xdr_stream	rl_stream;
 	struct xdr_buf		rl_hdrbuf;
+	struct ib_send_wr	rl_wr;
 	struct rpcrdma_sendctx	*rl_sendctx;
 	struct rpcrdma_regbuf	*rl_rdmabuf;	/* xprt header */
 	struct rpcrdma_regbuf	*rl_sendbuf;	/* rq_snd_buf */
@@ -474,6 +470,7 @@ void rpcrdma_ep_disconnect(struct rpcrdma_ep *, struct rpcrdma_ia *);
 
 int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *,
 				struct rpcrdma_req *);
+void rpcrdma_post_recvs(struct rpcrdma_xprt *r_xprt, bool temp);
 
 /*
  * Buffer calls - xprtrdma/verbs.c
@@ -487,12 +484,7 @@ struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_xprt *r_xprt);
 
 struct rpcrdma_mr *rpcrdma_mr_get(struct rpcrdma_xprt *r_xprt);
 void rpcrdma_mr_put(struct rpcrdma_mr *mr);
-
-static inline void
-rpcrdma_mr_recycle(struct rpcrdma_mr *mr)
-{
-	schedule_work(&mr->mr_recycle);
-}
+void rpcrdma_mrs_refresh(struct rpcrdma_xprt *r_xprt);
 
 struct rpcrdma_req *rpcrdma_buffer_get(struct rpcrdma_buffer *);
 void rpcrdma_buffer_put(struct rpcrdma_buffer *buffers,
@@ -542,7 +534,6 @@ rpcrdma_data_dir(bool writing)
 /* Memory registration calls xprtrdma/frwr_ops.c
  */
 bool frwr_is_supported(struct ib_device *device);
-void frwr_recycle(struct rpcrdma_req *req);
 void frwr_reset(struct rpcrdma_req *req);
 int frwr_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep);
 int frwr_init_mr(struct rpcrdma_ia *ia, struct rpcrdma_mr *mr);
@@ -563,6 +554,8 @@ void frwr_unmap_async(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req);
 
 enum rpcrdma_chunktype {
 	rpcrdma_noch = 0,
+	rpcrdma_noch_pullup,
+	rpcrdma_noch_mapped,
 	rpcrdma_readch,
 	rpcrdma_areadch,
 	rpcrdma_writech,
@@ -576,6 +569,7 @@ int rpcrdma_prepare_send_sges(struct rpcrdma_xprt *r_xprt,
 void rpcrdma_sendctx_unmap(struct rpcrdma_sendctx *sc);
 int rpcrdma_marshal_req(struct rpcrdma_xprt *r_xprt, struct rpc_rqst *rqst);
 void rpcrdma_set_max_header_sizes(struct rpcrdma_xprt *);
+void rpcrdma_reset_cwnd(struct rpcrdma_xprt *r_xprt);
 void rpcrdma_complete_rqst(struct rpcrdma_rep *rep);
 void rpcrdma_reply_handler(struct rpcrdma_rep *rep);