1 files changed, 198 insertions, 183 deletions

diff --git a/net/rds/ib_recv.c b/net/rds/ib_recv.c
index 8eb9501e3d60..4248dfa816eb 100644
--- a/net/rds/ib_recv.c
+++ b/net/rds/ib_recv.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2006 Oracle.  All rights reserved.
+ * Copyright (c) 2006, 2019 Oracle and/or its affiliates. All rights reserved.
  *
  * This software is available to you under a choice of one of two
  * licenses.  You may choose to be licensed under the terms of the GNU
@@ -31,11 +31,13 @@
  *
  */
 #include <linux/kernel.h>
+#include <linux/sched/clock.h>
 #include <linux/slab.h>
 #include <linux/pci.h>
 #include <linux/dma-mapping.h>
 #include <rdma/rdma_cm.h>
 
+#include "rds_single_path.h"
 #include "rds.h"
 #include "ib.h"
 
@@ -60,14 +62,14 @@ void rds_ib_recv_init_ring(struct rds_ib_connection *ic)
 		recv->r_wr.num_sge = RDS_IB_RECV_SGE;
 
 		sge = &recv->r_sge[0];
-		sge->addr = ic->i_recv_hdrs_dma + (i * sizeof(struct rds_header));
+		sge->addr = ic->i_recv_hdrs_dma[i];
 		sge->length = sizeof(struct rds_header);
-		sge->lkey = ic->i_mr->lkey;
+		sge->lkey = ic->i_pd->local_dma_lkey;
 
 		sge = &recv->r_sge[1];
 		sge->addr = 0;
 		sge->length = RDS_FRAG_SIZE;
-		sge->lkey = ic->i_mr->lkey;
+		sge->lkey = ic->i_pd->local_dma_lkey;
 	}
 }
 
@@ -97,12 +99,12 @@ static void rds_ib_cache_xfer_to_ready(struct rds_ib_refill_cache *cache)
 	}
 }
 
-static int rds_ib_recv_alloc_cache(struct rds_ib_refill_cache *cache)
+static int rds_ib_recv_alloc_cache(struct rds_ib_refill_cache *cache, gfp_t gfp)
 {
 	struct rds_ib_cache_head *head;
 	int cpu;
 
-	cache->percpu = alloc_percpu(struct rds_ib_cache_head);
+	cache->percpu = alloc_percpu_gfp(struct rds_ib_cache_head, gfp);
 	if (!cache->percpu)
 	       return -ENOMEM;
 
@@ -117,13 +119,13 @@ static int rds_ib_recv_alloc_cache(struct rds_ib_refill_cache *cache)
 	return 0;
 }
 
-int rds_ib_recv_alloc_caches(struct rds_ib_connection *ic)
+int rds_ib_recv_alloc_caches(struct rds_ib_connection *ic, gfp_t gfp)
 {
 	int ret;
 
-	ret = rds_ib_recv_alloc_cache(&ic->i_cache_incs);
+	ret = rds_ib_recv_alloc_cache(&ic->i_cache_incs, gfp);
 	if (!ret) {
-		ret = rds_ib_recv_alloc_cache(&ic->i_cache_frags);
+		ret = rds_ib_recv_alloc_cache(&ic->i_cache_frags, gfp);
 		if (ret)
 			free_percpu(ic->i_cache_incs.percpu);
 	}
@@ -167,6 +169,7 @@ void rds_ib_recv_free_caches(struct rds_ib_connection *ic)
 		list_del(&inc->ii_cache_entry);
 		WARN_ON(!list_empty(&inc->ii_frags));
 		kmem_cache_free(rds_ib_incoming_slab, inc);
+		atomic_dec(&rds_ib_allocation);
 	}
 
 	rds_ib_cache_xfer_to_ready(&ic->i_cache_frags);
@@ -193,6 +196,8 @@ static void rds_ib_frag_free(struct rds_ib_connection *ic,
 	rdsdebug("frag %p page %p\n", frag, sg_page(&frag->f_sg));
 
 	rds_ib_recv_cache_put(&frag->f_cache_entry, &ic->i_cache_frags);
+	atomic_add(RDS_FRAG_SIZE / SZ_1K, &ic->i_cache_allocs);
+	rds_ib_stats_add(s_ib_recv_added_to_cache, RDS_FRAG_SIZE);
 }
 
 /* Recycle inc after freeing attached frags */
@@ -260,9 +265,10 @@ static struct rds_ib_incoming *rds_ib_refill_one_inc(struct rds_ib_connection *i
 			atomic_dec(&rds_ib_allocation);
 			return NULL;
 		}
+		rds_ib_stats_inc(s_ib_rx_total_incs);
 	}
 	INIT_LIST_HEAD(&ibinc->ii_frags);
-	rds_inc_init(&ibinc->ii_inc, ic->conn, ic->conn->c_faddr);
+	rds_inc_init(&ibinc->ii_inc, ic->conn, &ic->conn->c_faddr);
 
 	return ibinc;
 }
@@ -277,6 +283,8 @@ static struct rds_page_frag *rds_ib_refill_one_frag(struct rds_ib_connection *ic
 	cache_item = rds_ib_recv_cache_get(&ic->i_cache_frags);
 	if (cache_item) {
 		frag = container_of(cache_item, struct rds_page_frag, f_cache_entry);
+		atomic_sub(RDS_FRAG_SIZE / SZ_1K, &ic->i_cache_allocs);
+		rds_ib_stats_add(s_ib_recv_added_to_cache, RDS_FRAG_SIZE);
 	} else {
 		frag = kmem_cache_alloc(rds_ib_frag_slab, slab_mask);
 		if (!frag)
@@ -289,6 +297,7 @@ static struct rds_page_frag *rds_ib_refill_one_frag(struct rds_ib_connection *ic
 			kmem_cache_free(rds_ib_frag_slab, frag);
 			return NULL;
 		}
+		rds_ib_stats_inc(s_ib_rx_total_frags);
 	}
 
 	INIT_LIST_HEAD(&frag->f_item);
@@ -297,15 +306,15 @@ static struct rds_page_frag *rds_ib_refill_one_frag(struct rds_ib_connection *ic
 }
 
 static int rds_ib_recv_refill_one(struct rds_connection *conn,
-				  struct rds_ib_recv_work *recv, int prefill)
+				  struct rds_ib_recv_work *recv, gfp_t gfp)
 {
 	struct rds_ib_connection *ic = conn->c_transport_data;
 	struct ib_sge *sge;
 	int ret = -ENOMEM;
-	gfp_t slab_mask = GFP_NOWAIT;
-	gfp_t page_mask = GFP_NOWAIT;
+	gfp_t slab_mask = gfp;
+	gfp_t page_mask = gfp;
 
-	if (prefill) {
+	if (gfp & __GFP_DIRECT_RECLAIM) {
 		slab_mask = GFP_KERNEL;
 		page_mask = GFP_HIGHUSER;
 	}
@@ -335,34 +344,59 @@ static int rds_ib_recv_refill_one(struct rds_connection *conn,
 	WARN_ON(ret != 1);
 
 	sge = &recv->r_sge[0];
-	sge->addr = ic->i_recv_hdrs_dma + (recv - ic->i_recvs) * sizeof(struct rds_header);
+	sge->addr = ic->i_recv_hdrs_dma[recv - ic->i_recvs];
 	sge->length = sizeof(struct rds_header);
 
 	sge = &recv->r_sge[1];
-	sge->addr = ib_sg_dma_address(ic->i_cm_id->device, &recv->r_frag->f_sg);
-	sge->length = ib_sg_dma_len(ic->i_cm_id->device, &recv->r_frag->f_sg);
+	sge->addr = sg_dma_address(&recv->r_frag->f_sg);
+	sge->length = sg_dma_len(&recv->r_frag->f_sg);
 
 	ret = 0;
 out:
 	return ret;
 }
 
+static int acquire_refill(struct rds_connection *conn)
+{
+	return test_and_set_bit(RDS_RECV_REFILL, &conn->c_flags) == 0;
+}
+
+static void release_refill(struct rds_connection *conn)
+{
+	clear_bit(RDS_RECV_REFILL, &conn->c_flags);
+	smp_mb__after_atomic();
+
+	/* We don't use wait_on_bit()/wake_up_bit() because our waking is in a
+	 * hot path and finding waiters is very rare.  We don't want to walk
+	 * the system-wide hashed waitqueue buckets in the fast path only to
+	 * almost never find waiters.
+	 */
+	if (waitqueue_active(&conn->c_waitq))
+		wake_up_all(&conn->c_waitq);
+}
+
 /*
  * This tries to allocate and post unused work requests after making sure that
  * they have all the allocations they need to queue received fragments into
  * sockets.
- *
- * -1 is returned if posting fails due to temporary resource exhaustion.
  */
-void rds_ib_recv_refill(struct rds_connection *conn, int prefill)
+void rds_ib_recv_refill(struct rds_connection *conn, int prefill, gfp_t gfp)
 {
 	struct rds_ib_connection *ic = conn->c_transport_data;
 	struct rds_ib_recv_work *recv;
-	struct ib_recv_wr *failed_wr;
 	unsigned int posted = 0;
 	int ret = 0;
+	bool can_wait = !!(gfp & __GFP_DIRECT_RECLAIM);
+	bool must_wake = false;
 	u32 pos;
 
+	/* the goal here is to just make sure that someone, somewhere
+	 * is posting buffers.  If we can't get the refill lock,
+	 * let them do their thing
+	 */
+	if (!acquire_refill(conn))
+		return;
+
 	while ((prefill || rds_conn_up(conn)) &&
 	       rds_ib_ring_alloc(&ic->i_recv_ring, 1, &pos)) {
 		if (pos >= ic->i_recv_ring.w_nr) {
@@ -372,28 +406,32 @@ void rds_ib_recv_refill(struct rds_connection *conn, int prefill)
 		}
 
 		recv = &ic->i_recvs[pos];
-		ret = rds_ib_recv_refill_one(conn, recv, prefill);
+		ret = rds_ib_recv_refill_one(conn, recv, gfp);
 		if (ret) {
+			must_wake = true;
 			break;
 		}
 
-		/* XXX when can this fail? */
-		ret = ib_post_recv(ic->i_cm_id->qp, &recv->r_wr, &failed_wr);
-		rdsdebug("recv %p ibinc %p page %p addr %lu ret %d\n", recv,
+		rdsdebug("recv %p ibinc %p page %p addr %lu\n", recv,
 			 recv->r_ibinc, sg_page(&recv->r_frag->f_sg),
-			 (long) ib_sg_dma_address(
-				ic->i_cm_id->device,
-				&recv->r_frag->f_sg),
-			ret);
+			 (long)sg_dma_address(&recv->r_frag->f_sg));
+
+		/* XXX when can this fail? */
+		ret = ib_post_recv(ic->i_cm_id->qp, &recv->r_wr, NULL);
 		if (ret) {
 			rds_ib_conn_error(conn, "recv post on "
-			       "%pI4 returned %d, disconnecting and "
+			       "%pI6c returned %d, disconnecting and "
 			       "reconnecting\n", &conn->c_faddr,
 			       ret);
 			break;
 		}
 
 		posted++;
+
+		if ((posted > 128 && need_resched()) || posted > 8192) {
+			must_wake = true;
+			break;
+		}
 	}
 
 	/* We're doing flow control - update the window. */
@@ -402,6 +440,27 @@ void rds_ib_recv_refill(struct rds_connection *conn, int prefill)
 
 	if (ret)
 		rds_ib_ring_unalloc(&ic->i_recv_ring, 1);
+
+	release_refill(conn);
+
+	/* if we're called from the softirq handler, we'll be GFP_NOWAIT.
+	 * in this case the ring being low is going to lead to more interrupts
+	 * and we can safely let the softirq code take care of it unless the
+	 * ring is completely empty.
+	 *
+	 * if we're called from krdsd, we'll be GFP_KERNEL.  In this case
+	 * we might have raced with the softirq code while we had the refill
+	 * lock held.  Use rds_ib_ring_low() instead of ring_empty to decide
+	 * if we should requeue.
+	 */
+	if (rds_conn_up(conn) &&
+	    (must_wake ||
+	    (can_wait && rds_ib_ring_low(&ic->i_recv_ring)) ||
+	    rds_ib_ring_empty(&ic->i_recv_ring))) {
+		queue_delayed_work(rds_wq, &conn->c_recv_w, 1);
+	}
+	if (can_wait)
+		cond_resched();
 }
 
 /*
@@ -421,8 +480,7 @@ static void rds_ib_recv_cache_put(struct list_head *new_item,
 				 struct rds_ib_refill_cache *cache)
 {
 	unsigned long flags;
-	struct list_head *old;
-	struct list_head __percpu *chpfirst;
+	struct list_head *old, *chpfirst;
 
 	local_irq_save(flags);
 
@@ -432,7 +490,7 @@ static void rds_ib_recv_cache_put(struct list_head *new_item,
 	else /* put on front */
 		list_add_tail(new_item, chpfirst);
 
-	__this_cpu_write(chpfirst, new_item);
+	__this_cpu_write(cache->percpu->first, new_item);
 	__this_cpu_inc(cache->percpu->count);
 
 	if (__this_cpu_read(cache->percpu->count) < RDS_IB_RECYCLE_BATCH_COUNT)
@@ -452,7 +510,7 @@ static void rds_ib_recv_cache_put(struct list_head *new_item,
 	} while (old);
 
 
-	__this_cpu_write(chpfirst, NULL);
+	__this_cpu_write(cache->percpu->first, NULL);
 	__this_cpu_write(cache->percpu->count, 0);
 end:
 	local_irq_restore(flags);
@@ -473,15 +531,12 @@ static struct list_head *rds_ib_recv_cache_get(struct rds_ib_refill_cache *cache
 	return head;
 }
 
-int rds_ib_inc_copy_to_user(struct rds_incoming *inc, struct iovec *first_iov,
-			    size_t size)
+int rds_ib_inc_copy_to_user(struct rds_incoming *inc, struct iov_iter *to)
 {
 	struct rds_ib_incoming *ibinc;
 	struct rds_page_frag *frag;
-	struct iovec *iov = first_iov;
 	unsigned long to_copy;
 	unsigned long frag_off = 0;
-	unsigned long iov_off = 0;
 	int copied = 0;
 	int ret;
 	u32 len;
@@ -490,37 +545,25 @@ int rds_ib_inc_copy_to_user(struct rds_incoming *inc, struct iovec *first_iov,
 	frag = list_entry(ibinc->ii_frags.next, struct rds_page_frag, f_item);
 	len = be32_to_cpu(inc->i_hdr.h_len);
 
-	while (copied < size && copied < len) {
+	while (iov_iter_count(to) && copied < len) {
 		if (frag_off == RDS_FRAG_SIZE) {
 			frag = list_entry(frag->f_item.next,
 					  struct rds_page_frag, f_item);
 			frag_off = 0;
 		}
-		while (iov_off == iov->iov_len) {
-			iov_off = 0;
-			iov++;
-		}
-
-		to_copy = min(iov->iov_len - iov_off, RDS_FRAG_SIZE - frag_off);
-		to_copy = min_t(size_t, to_copy, size - copied);
+		to_copy = min_t(unsigned long, iov_iter_count(to),
+				RDS_FRAG_SIZE - frag_off);
 		to_copy = min_t(unsigned long, to_copy, len - copied);
 
-		rdsdebug("%lu bytes to user [%p, %zu] + %lu from frag "
-			 "[%p, %u] + %lu\n",
-			 to_copy, iov->iov_base, iov->iov_len, iov_off,
-			 sg_page(&frag->f_sg), frag->f_sg.offset, frag_off);
-
 		/* XXX needs + offset for multiple recvs per page */
-		ret = rds_page_copy_to_user(sg_page(&frag->f_sg),
-					    frag->f_sg.offset + frag_off,
-					    iov->iov_base + iov_off,
-					    to_copy);
-		if (ret) {
-			copied = ret;
-			break;
-		}
+		rds_stats_add(s_copy_to_user, to_copy);
+		ret = copy_page_to_iter(sg_page(&frag->f_sg),
+					frag->f_sg.offset + frag_off,
+					to_copy,
+					to);
+		if (ret != to_copy)
+			return -EFAULT;
 
-		iov_off += to_copy;
 		frag_off += to_copy;
 		copied += to_copy;
 	}
@@ -536,7 +579,7 @@ void rds_ib_recv_init_ack(struct rds_ib_connection *ic)
 
 	sge->addr = ic->i_ack_dma;
 	sge->length = sizeof(struct rds_header);
-	sge->lkey = ic->i_mr->lkey;
+	sge->lkey = ic->i_pd->local_dma_lkey;
 
 	wr->sg_list = sge;
 	wr->num_sge = 1;
@@ -568,8 +611,7 @@ void rds_ib_recv_init_ack(struct rds_ib_connection *ic)
  * wr_id and avoids working with the ring in that case.
  */
 #ifndef KERNEL_HAS_ATOMIC64
-static void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq,
-				int ack_required)
+void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, int ack_required)
 {
 	unsigned long flags;
 
@@ -594,12 +636,11 @@ static u64 rds_ib_get_ack(struct rds_ib_connection *ic)
 	return seq;
 }
 #else
-static void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq,
-				int ack_required)
+void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq, int ack_required)
 {
 	atomic64_set(&ic->i_ack_next, seq);
 	if (ack_required) {
-		smp_mb__before_clear_bit();
+		smp_mb__before_atomic();
 		set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
 	}
 }
@@ -607,7 +648,7 @@ static void rds_ib_set_ack(struct rds_ib_connection *ic, u64 seq,
 static u64 rds_ib_get_ack(struct rds_ib_connection *ic)
 {
 	clear_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
-	smp_mb__after_clear_bit();
+	smp_mb__after_atomic();
 
 	return atomic64_read(&ic->i_ack_next);
 }
@@ -617,20 +658,25 @@ static u64 rds_ib_get_ack(struct rds_ib_connection *ic)
 static void rds_ib_send_ack(struct rds_ib_connection *ic, unsigned int adv_credits)
 {
 	struct rds_header *hdr = ic->i_ack;
-	struct ib_send_wr *failed_wr;
 	u64 seq;
 	int ret;
 
 	seq = rds_ib_get_ack(ic);
 
 	rdsdebug("send_ack: ic %p ack %llu\n", ic, (unsigned long long) seq);
+
+	ib_dma_sync_single_for_cpu(ic->rds_ibdev->dev, ic->i_ack_dma,
+				   sizeof(*hdr), DMA_TO_DEVICE);
 	rds_message_populate_header(hdr, 0, 0, 0);
 	hdr->h_ack = cpu_to_be64(seq);
 	hdr->h_credit = adv_credits;
 	rds_message_make_checksum(hdr);
+	ib_dma_sync_single_for_device(ic->rds_ibdev->dev, ic->i_ack_dma,
+				      sizeof(*hdr), DMA_TO_DEVICE);
+
 	ic->i_ack_queued = jiffies;
 
-	ret = ib_post_send(ic->i_cm_id->qp, &ic->i_ack_wr, &failed_wr);
+	ret = ib_post_send(ic->i_cm_id->qp, &ic->i_ack_wr, NULL);
 	if (unlikely(ret)) {
 		/* Failed to send. Release the WR, and
 		 * force another ACK.
@@ -745,7 +791,7 @@ static void rds_ib_cong_recv(struct rds_connection *conn,
 	unsigned long frag_off;
 	unsigned long to_copy;
 	unsigned long copied;
-	uint64_t uncongested = 0;
+	__le64 uncongested = 0;
 	void *addr;
 
 	/* catch completely corrupt packets */
@@ -762,7 +808,7 @@ static void rds_ib_cong_recv(struct rds_connection *conn,
 	copied = 0;
 
 	while (copied < RDS_CONG_MAP_BYTES) {
-		uint64_t *src, *dst;
+		__le64 *src, *dst;
 		unsigned int k;
 
 		to_copy = min(RDS_FRAG_SIZE - frag_off, PAGE_SIZE - map_off);
@@ -770,7 +816,7 @@ static void rds_ib_cong_recv(struct rds_connection *conn,
 
 		addr = kmap_atomic(sg_page(&frag->f_sg));
 
-		src = addr + frag_off;
+		src = addr + frag->f_sg.offset + frag_off;
 		dst = (void *)map->m_page_addrs[map_page] + map_off;
 		for (k = 0; k < to_copy; k += 8) {
 			/* Record ports that became uncongested, ie
@@ -797,25 +843,9 @@ static void rds_ib_cong_recv(struct rds_connection *conn,
 	}
 
 	/* the congestion map is in little endian order */
-	uncongested = le64_to_cpu(uncongested);
-
-	rds_cong_map_updated(map, uncongested);
+	rds_cong_map_updated(map, le64_to_cpu(uncongested));
 }
 
-/*
- * Rings are posted with all the allocations they'll need to queue the
- * incoming message to the receiving socket so this can't fail.
- * All fragments start with a header, so we can make sure we're not receiving
- * garbage, and we can tell a small 8 byte fragment from an ACK frame.
- */
-struct rds_ib_ack_state {
-	u64		ack_next;
-	u64		ack_recv;
-	unsigned int	ack_required:1;
-	unsigned int	ack_next_valid:1;
-	unsigned int	ack_recv_valid:1;
-};
-
 static void rds_ib_process_recv(struct rds_connection *conn,
 				struct rds_ib_recv_work *recv, u32 data_len,
 				struct rds_ib_ack_state *state)
@@ -823,6 +853,7 @@ static void rds_ib_process_recv(struct rds_connection *conn,
 	struct rds_ib_connection *ic = conn->c_transport_data;
 	struct rds_ib_incoming *ibinc = ic->i_ibinc;
 	struct rds_header *ihdr, *hdr;
+	dma_addr_t dma_addr = ic->i_recv_hdrs_dma[recv - ic->i_recvs];
 
 	/* XXX shut down the connection if port 0,0 are seen? */
 
@@ -831,7 +862,7 @@ static void rds_ib_process_recv(struct rds_connection *conn,
 
 	if (data_len < sizeof(struct rds_header)) {
 		rds_ib_conn_error(conn, "incoming message "
-		       "from %pI4 didn't include a "
+		       "from %pI6c didn't include a "
 		       "header, disconnecting and "
 		       "reconnecting\n",
 		       &conn->c_faddr);
@@ -839,16 +870,18 @@ static void rds_ib_process_recv(struct rds_connection *conn,
 	}
 	data_len -= sizeof(struct rds_header);
 
-	ihdr = &ic->i_recv_hdrs[recv - ic->i_recvs];
+	ihdr = ic->i_recv_hdrs[recv - ic->i_recvs];
 
+	ib_dma_sync_single_for_cpu(ic->rds_ibdev->dev, dma_addr,
+				   sizeof(*ihdr), DMA_FROM_DEVICE);
 	/* Validate the checksum. */
 	if (!rds_message_verify_checksum(ihdr)) {
 		rds_ib_conn_error(conn, "incoming message "
-		       "from %pI4 has corrupted header - "
+		       "from %pI6c has corrupted header - "
 		       "forcing a reconnect\n",
 		       &conn->c_faddr);
 		rds_stats_inc(s_recv_drop_bad_checksum);
-		return;
+		goto done;
 	}
 
 	/* Process the ACK sequence which comes with every packet */
@@ -877,7 +910,7 @@ static void rds_ib_process_recv(struct rds_connection *conn,
 		 */
 		rds_ib_frag_free(ic, recv->r_frag);
 		recv->r_frag = NULL;
-		return;
+		goto done;
 	}
 
 	/*
@@ -892,8 +925,12 @@ static void rds_ib_process_recv(struct rds_connection *conn,
 		ic->i_ibinc = ibinc;
 
 		hdr = &ibinc->ii_inc.i_hdr;
+		ibinc->ii_inc.i_rx_lat_trace[RDS_MSG_RX_HDR] =
+				local_clock();
 		memcpy(hdr, ihdr, sizeof(*hdr));
 		ic->i_recv_data_rem = be32_to_cpu(hdr->h_len);
+		ibinc->ii_inc.i_rx_lat_trace[RDS_MSG_RX_START] =
+				local_clock();
 
 		rdsdebug("ic %p ibinc %p rem %u flag 0x%x\n", ic, ibinc,
 			 ic->i_recv_data_rem, hdr->h_flags);
@@ -907,7 +944,7 @@ static void rds_ib_process_recv(struct rds_connection *conn,
 		    hdr->h_dport != ihdr->h_dport) {
 			rds_ib_conn_error(conn,
 				"fragment header mismatch; forcing reconnect\n");
-			return;
+			goto done;
 		}
 	}
 
@@ -920,10 +957,10 @@ static void rds_ib_process_recv(struct rds_connection *conn,
 		ic->i_recv_data_rem = 0;
 		ic->i_ibinc = NULL;
 
-		if (ibinc->ii_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP)
+		if (ibinc->ii_inc.i_hdr.h_flags == RDS_FLAG_CONG_BITMAP) {
 			rds_ib_cong_recv(conn, ibinc);
-		else {
-			rds_recv_incoming(conn, conn->c_faddr, conn->c_laddr,
+		} else {
+			rds_recv_incoming(conn, &conn->c_faddr, &conn->c_laddr,
 					  &ibinc->ii_inc, GFP_ATOMIC);
 			state->ack_next = be64_to_cpu(hdr->h_sequence);
 			state->ack_next_valid = 1;
@@ -939,91 +976,56 @@ static void rds_ib_process_recv(struct rds_connection *conn,
 
 		rds_inc_put(&ibinc->ii_inc);
 	}
+done:
+	ib_dma_sync_single_for_device(ic->rds_ibdev->dev, dma_addr,
+				      sizeof(*ihdr), DMA_FROM_DEVICE);
 }
 
-/*
- * Plucking the oldest entry from the ring can be done concurrently with
- * the thread refilling the ring.  Each ring operation is protected by
- * spinlocks and the transient state of refilling doesn't change the
- * recording of which entry is oldest.
- *
- * This relies on IB only calling one cq comp_handler for each cq so that
- * there will only be one caller of rds_recv_incoming() per RDS connection.
- */
-void rds_ib_recv_cq_comp_handler(struct ib_cq *cq, void *context)
-{
-	struct rds_connection *conn = context;
-	struct rds_ib_connection *ic = conn->c_transport_data;
-
-	rdsdebug("conn %p cq %p\n", conn, cq);
-
-	rds_ib_stats_inc(s_ib_rx_cq_call);
-
-	tasklet_schedule(&ic->i_recv_tasklet);
-}
-
-static inline void rds_poll_cq(struct rds_ib_connection *ic,
-			       struct rds_ib_ack_state *state)
+void rds_ib_recv_cqe_handler(struct rds_ib_connection *ic,
+			     struct ib_wc *wc,
+			     struct rds_ib_ack_state *state)
 {
 	struct rds_connection *conn = ic->conn;
-	struct ib_wc wc;
 	struct rds_ib_recv_work *recv;
 
-	while (ib_poll_cq(ic->i_recv_cq, 1, &wc) > 0) {
-		rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n",
-			 (unsigned long long)wc.wr_id, wc.status,
-			 rds_ib_wc_status_str(wc.status), wc.byte_len,
-			 be32_to_cpu(wc.ex.imm_data));
-		rds_ib_stats_inc(s_ib_rx_cq_event);
+	rdsdebug("wc wr_id 0x%llx status %u (%s) byte_len %u imm_data %u\n",
+		 (unsigned long long)wc->wr_id, wc->status,
+		 ib_wc_status_msg(wc->status), wc->byte_len,
+		 be32_to_cpu(wc->ex.imm_data));
 
-		recv = &ic->i_recvs[rds_ib_ring_oldest(&ic->i_recv_ring)];
-
-		ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1, DMA_FROM_DEVICE);
+	rds_ib_stats_inc(s_ib_rx_cq_event);
+	recv = &ic->i_recvs[rds_ib_ring_oldest(&ic->i_recv_ring)];
+	ib_dma_unmap_sg(ic->i_cm_id->device, &recv->r_frag->f_sg, 1,
+			DMA_FROM_DEVICE);
 
-		/*
-		 * Also process recvs in connecting state because it is possible
-		 * to get a recv completion _before_ the rdmacm ESTABLISHED
-		 * event is processed.
-		 */
-		if (wc.status == IB_WC_SUCCESS) {
-			rds_ib_process_recv(conn, recv, wc.byte_len, state);
-		} else {
-			/* We expect errors as the qp is drained during shutdown */
-			if (rds_conn_up(conn) || rds_conn_connecting(conn))
-				rds_ib_conn_error(conn, "recv completion on %pI4 had "
-						  "status %u (%s), disconnecting and "
-						  "reconnecting\n", &conn->c_faddr,
-						  wc.status,
-						  rds_ib_wc_status_str(wc.status));
-		}
-
-		/*
-		 * It's very important that we only free this ring entry if we've truly
-		 * freed the resources allocated to the entry.  The refilling path can
-		 * leak if we don't.
-		 */
-		rds_ib_ring_free(&ic->i_recv_ring, 1);
+	/* Also process recvs in connecting state because it is possible
+	 * to get a recv completion _before_ the rdmacm ESTABLISHED
+	 * event is processed.
+	 */
+	if (wc->status == IB_WC_SUCCESS) {
+		rds_ib_process_recv(conn, recv, wc->byte_len, state);
+	} else {
+		/* We expect errors as the qp is drained during shutdown */
+		if (rds_conn_up(conn) || rds_conn_connecting(conn))
+			rds_ib_conn_error(conn, "recv completion on <%pI6c,%pI6c, %d> had status %u (%s), vendor err 0x%x, disconnecting and reconnecting\n",
+					  &conn->c_laddr, &conn->c_faddr,
+					  conn->c_tos, wc->status,
+					  ib_wc_status_msg(wc->status),
+					  wc->vendor_err);
 	}
-}
-
-void rds_ib_recv_tasklet_fn(unsigned long data)
-{
-	struct rds_ib_connection *ic = (struct rds_ib_connection *) data;
-	struct rds_connection *conn = ic->conn;
-	struct rds_ib_ack_state state = { 0, };
-
-	rds_poll_cq(ic, &state);
-	ib_req_notify_cq(ic->i_recv_cq, IB_CQ_SOLICITED);
-	rds_poll_cq(ic, &state);
 
-	if (state.ack_next_valid)
-		rds_ib_set_ack(ic, state.ack_next, state.ack_required);
-	if (state.ack_recv_valid && state.ack_recv > ic->i_ack_recv) {
-		rds_send_drop_acked(conn, state.ack_recv, NULL);
-		ic->i_ack_recv = state.ack_recv;
+	/* rds_ib_process_recv() doesn't always consume the frag, and
+	 * we might not have called it at all if the wc didn't indicate
+	 * success. We already unmapped the frag's pages, though, and
+	 * the following rds_ib_ring_free() call tells the refill path
+	 * that it will not find an allocated frag here. Make sure we
+	 * keep that promise by freeing a frag that's still on the ring.
+	 */
+	if (recv->r_frag) {
+		rds_ib_frag_free(ic, recv->r_frag);
+		recv->r_frag = NULL;
 	}
-	if (rds_conn_up(conn))
-		rds_ib_attempt_ack(ic);
+	rds_ib_ring_free(&ic->i_recv_ring, 1);
 
 	/* If we ever end up with a really empty receive ring, we're
 	 * in deep trouble, as the sender will definitely see RNR
@@ -1031,20 +1033,25 @@ void rds_ib_recv_tasklet_fn(unsigned long data)
 	if (rds_ib_ring_empty(&ic->i_recv_ring))
 		rds_ib_stats_inc(s_ib_rx_ring_empty);
 
-	if (rds_ib_ring_low(&ic->i_recv_ring))
-		rds_ib_recv_refill(conn, 0);
+	if (rds_ib_ring_low(&ic->i_recv_ring)) {
+		rds_ib_recv_refill(conn, 0, GFP_NOWAIT);
+		rds_ib_stats_inc(s_ib_rx_refill_from_cq);
+	}
 }
 
-int rds_ib_recv(struct rds_connection *conn)
+int rds_ib_recv_path(struct rds_conn_path *cp)
 {
+	struct rds_connection *conn = cp->cp_conn;
 	struct rds_ib_connection *ic = conn->c_transport_data;
-	int ret = 0;
 
 	rdsdebug("conn %p\n", conn);
-	if (rds_conn_up(conn))
+	if (rds_conn_up(conn)) {
 		rds_ib_attempt_ack(ic);
+		rds_ib_recv_refill(conn, 0, GFP_KERNEL);
+		rds_ib_stats_inc(s_ib_rx_refill_from_thread);
+	}
 
-	return ret;
+	return 0;
 }
 
 int rds_ib_recv_init(void)
@@ -1056,18 +1063,24 @@ int rds_ib_recv_init(void)
 	si_meminfo(&si);
 	rds_ib_sysctl_max_recv_allocation = si.totalram / 3 * PAGE_SIZE / RDS_FRAG_SIZE;
 
-	rds_ib_incoming_slab = kmem_cache_create("rds_ib_incoming",
-					sizeof(struct rds_ib_incoming),
-					0, SLAB_HWCACHE_ALIGN, NULL);
+	rds_ib_incoming_slab =
+		kmem_cache_create_usercopy("rds_ib_incoming",
+					   sizeof(struct rds_ib_incoming),
+					   0, SLAB_HWCACHE_ALIGN,
+					   offsetof(struct rds_ib_incoming,
+						    ii_inc.i_usercopy),
+					   sizeof(struct rds_inc_usercopy),
+					   NULL);
 	if (!rds_ib_incoming_slab)
 		goto out;
 
 	rds_ib_frag_slab = kmem_cache_create("rds_ib_frag",
 					sizeof(struct rds_page_frag),
 					0, SLAB_HWCACHE_ALIGN, NULL);
-	if (!rds_ib_frag_slab)
+	if (!rds_ib_frag_slab) {
 		kmem_cache_destroy(rds_ib_incoming_slab);
-	else
+		rds_ib_incoming_slab = NULL;
+	} else
 		ret = 0;
 out:
 	return ret;
@@ -1075,6 +1088,8 @@ out:
 
 void rds_ib_recv_exit(void)
 {
+	WARN_ON(atomic_read(&rds_ib_allocation));
+
 	kmem_cache_destroy(rds_ib_incoming_slab);
 	kmem_cache_destroy(rds_ib_frag_slab);
 }