Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1653 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/hfi1/user_sdma.c b/drivers/infiniband/hw/hfi1/user_sdma.c
new file mode 100644
index 000000000..02bd62b85
--- /dev/null
+++ b/drivers/infiniband/hw/hfi1/user_sdma.c
@@ -0,0 +1,1653 @@
+// SPDX-License-Identifier: GPL-2.0 or BSD-3-Clause
+/*
+ * Copyright(c) 2020 - Cornelis Networks, Inc.
+ * Copyright(c) 2015 - 2018 Intel Corporation.
+ */
+
+#include <linux/mm.h>
+#include <linux/types.h>
+#include <linux/device.h>
+#include <linux/dmapool.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/highmem.h>
+#include <linux/io.h>
+#include <linux/uio.h>
+#include <linux/rbtree.h>
+#include <linux/spinlock.h>
+#include <linux/delay.h>
+#include <linux/kthread.h>
+#include <linux/mmu_context.h>
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/string.h>
+
+#include "hfi.h"
+#include "sdma.h"
+#include "user_sdma.h"
+#include "verbs.h"  /* for the headers */
+#include "common.h" /* for struct hfi1_tid_info */
+#include "trace.h"
+
+static uint hfi1_sdma_comp_ring_size = 128;
+module_param_named(sdma_comp_size, hfi1_sdma_comp_ring_size, uint, S_IRUGO);
+MODULE_PARM_DESC(sdma_comp_size, "Size of User SDMA completion ring. Default: 128");
+
+static unsigned initial_pkt_count = 8;
+
+static int user_sdma_send_pkts(struct user_sdma_request *req, u16 maxpkts);
+static void user_sdma_txreq_cb(struct sdma_txreq *txreq, int status);
+static inline void pq_update(struct hfi1_user_sdma_pkt_q *pq);
+static void user_sdma_free_request(struct user_sdma_request *req);
+static int check_header_template(struct user_sdma_request *req,
+				 struct hfi1_pkt_header *hdr, u32 lrhlen,
+				 u32 datalen);
+static int set_txreq_header(struct user_sdma_request *req,
+			    struct user_sdma_txreq *tx, u32 datalen);
+static int set_txreq_header_ahg(struct user_sdma_request *req,
+				struct user_sdma_txreq *tx, u32 len);
+static inline void set_comp_state(struct hfi1_user_sdma_pkt_q *pq,
+				  struct hfi1_user_sdma_comp_q *cq,
+				  u16 idx, enum hfi1_sdma_comp_state state,
+				  int ret);
+static inline u32 set_pkt_bth_psn(__be32 bthpsn, u8 expct, u32 frags);
+static inline u32 get_lrh_len(struct hfi1_pkt_header, u32 len);
+
+static int defer_packet_queue(
+	struct sdma_engine *sde,
+	struct iowait_work *wait,
+	struct sdma_txreq *txreq,
+	uint seq,
+	bool pkts_sent);
+static void activate_packet_queue(struct iowait *wait, int reason);
+static bool sdma_rb_filter(struct mmu_rb_node *node, unsigned long addr,
+			   unsigned long len);
+static int sdma_rb_evict(void *arg, struct mmu_rb_node *mnode,
+			 void *arg2, bool *stop);
+static void sdma_rb_remove(void *arg, struct mmu_rb_node *mnode);
+
+static struct mmu_rb_ops sdma_rb_ops = {
+	.filter = sdma_rb_filter,
+	.evict = sdma_rb_evict,
+	.remove = sdma_rb_remove,
+};
+
+static int add_system_pages_to_sdma_packet(struct user_sdma_request *req,
+					   struct user_sdma_txreq *tx,
+					   struct user_sdma_iovec *iovec,
+					   u32 *pkt_remaining);
+
+static int defer_packet_queue(
+	struct sdma_engine *sde,
+	struct iowait_work *wait,
+	struct sdma_txreq *txreq,
+	uint seq,
+	bool pkts_sent)
+{
+	struct hfi1_user_sdma_pkt_q *pq =
+		container_of(wait->iow, struct hfi1_user_sdma_pkt_q, busy);
+
+	write_seqlock(&sde->waitlock);
+	trace_hfi1_usdma_defer(pq, sde, &pq->busy);
+	if (sdma_progress(sde, seq, txreq))
+		goto eagain;
+	/*
+	 * We are assuming that if the list is enqueued somewhere, it
+	 * is to the dmawait list since that is the only place where
+	 * it is supposed to be enqueued.
+	 */
+	xchg(&pq->state, SDMA_PKT_Q_DEFERRED);
+	if (list_empty(&pq->busy.list)) {
+		pq->busy.lock = &sde->waitlock;
+		iowait_get_priority(&pq->busy);
+		iowait_queue(pkts_sent, &pq->busy, &sde->dmawait);
+	}
+	write_sequnlock(&sde->waitlock);
+	return -EBUSY;
+eagain:
+	write_sequnlock(&sde->waitlock);
+	return -EAGAIN;
+}
+
+static void activate_packet_queue(struct iowait *wait, int reason)
+{
+	struct hfi1_user_sdma_pkt_q *pq =
+		container_of(wait, struct hfi1_user_sdma_pkt_q, busy);
+
+	trace_hfi1_usdma_activate(pq, wait, reason);
+	xchg(&pq->state, SDMA_PKT_Q_ACTIVE);
+	wake_up(&wait->wait_dma);
+};
+
+int hfi1_user_sdma_alloc_queues(struct hfi1_ctxtdata *uctxt,
+				struct hfi1_filedata *fd)
+{
+	int ret = -ENOMEM;
+	char buf[64];
+	struct hfi1_devdata *dd;
+	struct hfi1_user_sdma_comp_q *cq;
+	struct hfi1_user_sdma_pkt_q *pq;
+
+	if (!uctxt || !fd)
+		return -EBADF;
+
+	if (!hfi1_sdma_comp_ring_size)
+		return -EINVAL;
+
+	dd = uctxt->dd;
+
+	pq = kzalloc(sizeof(*pq), GFP_KERNEL);
+	if (!pq)
+		return -ENOMEM;
+	pq->dd = dd;
+	pq->ctxt = uctxt->ctxt;
+	pq->subctxt = fd->subctxt;
+	pq->n_max_reqs = hfi1_sdma_comp_ring_size;
+	atomic_set(&pq->n_reqs, 0);
+	init_waitqueue_head(&pq->wait);
+	atomic_set(&pq->n_locked, 0);
+
+	iowait_init(&pq->busy, 0, NULL, NULL, defer_packet_queue,
+		    activate_packet_queue, NULL, NULL);
+	pq->reqidx = 0;
+
+	pq->reqs = kcalloc(hfi1_sdma_comp_ring_size,
+			   sizeof(*pq->reqs),
+			   GFP_KERNEL);
+	if (!pq->reqs)
+		goto pq_reqs_nomem;
+
+	pq->req_in_use = bitmap_zalloc(hfi1_sdma_comp_ring_size, GFP_KERNEL);
+	if (!pq->req_in_use)
+		goto pq_reqs_no_in_use;
+
+	snprintf(buf, 64, "txreq-kmem-cache-%u-%u-%u", dd->unit, uctxt->ctxt,
+		 fd->subctxt);
+	pq->txreq_cache = kmem_cache_create(buf,
+					    sizeof(struct user_sdma_txreq),
+					    L1_CACHE_BYTES,
+					    SLAB_HWCACHE_ALIGN,
+					    NULL);
+	if (!pq->txreq_cache) {
+		dd_dev_err(dd, "[%u] Failed to allocate TxReq cache\n",
+			   uctxt->ctxt);
+		goto pq_txreq_nomem;
+	}
+
+	cq = kzalloc(sizeof(*cq), GFP_KERNEL);
+	if (!cq)
+		goto cq_nomem;
+
+	cq->comps = vmalloc_user(PAGE_ALIGN(sizeof(*cq->comps)
+				 * hfi1_sdma_comp_ring_size));
+	if (!cq->comps)
+		goto cq_comps_nomem;
+
+	cq->nentries = hfi1_sdma_comp_ring_size;
+
+	ret = hfi1_mmu_rb_register(pq, &sdma_rb_ops, dd->pport->hfi1_wq,
+				   &pq->handler);
+	if (ret) {
+		dd_dev_err(dd, "Failed to register with MMU %d", ret);
+		goto pq_mmu_fail;
+	}
+
+	rcu_assign_pointer(fd->pq, pq);
+	fd->cq = cq;
+
+	return 0;
+
+pq_mmu_fail:
+	vfree(cq->comps);
+cq_comps_nomem:
+	kfree(cq);
+cq_nomem:
+	kmem_cache_destroy(pq->txreq_cache);
+pq_txreq_nomem:
+	bitmap_free(pq->req_in_use);
+pq_reqs_no_in_use:
+	kfree(pq->reqs);
+pq_reqs_nomem:
+	kfree(pq);
+
+	return ret;
+}
+
+static void flush_pq_iowait(struct hfi1_user_sdma_pkt_q *pq)
+{
+	unsigned long flags;
+	seqlock_t *lock = pq->busy.lock;
+
+	if (!lock)
+		return;
+	write_seqlock_irqsave(lock, flags);
+	if (!list_empty(&pq->busy.list)) {
+		list_del_init(&pq->busy.list);
+		pq->busy.lock = NULL;
+	}
+	write_sequnlock_irqrestore(lock, flags);
+}
+
+int hfi1_user_sdma_free_queues(struct hfi1_filedata *fd,
+			       struct hfi1_ctxtdata *uctxt)
+{
+	struct hfi1_user_sdma_pkt_q *pq;
+
+	trace_hfi1_sdma_user_free_queues(uctxt->dd, uctxt->ctxt, fd->subctxt);
+
+	spin_lock(&fd->pq_rcu_lock);
+	pq = srcu_dereference_check(fd->pq, &fd->pq_srcu,
+				    lockdep_is_held(&fd->pq_rcu_lock));
+	if (pq) {
+		rcu_assign_pointer(fd->pq, NULL);
+		spin_unlock(&fd->pq_rcu_lock);
+		synchronize_srcu(&fd->pq_srcu);
+		/* at this point there can be no more new requests */
+		iowait_sdma_drain(&pq->busy);
+		/* Wait until all requests have been freed. */
+		wait_event_interruptible(
+			pq->wait,
+			!atomic_read(&pq->n_reqs));
+		kfree(pq->reqs);
+		if (pq->handler)
+			hfi1_mmu_rb_unregister(pq->handler);
+		bitmap_free(pq->req_in_use);
+		kmem_cache_destroy(pq->txreq_cache);
+		flush_pq_iowait(pq);
+		kfree(pq);
+	} else {
+		spin_unlock(&fd->pq_rcu_lock);
+	}
+	if (fd->cq) {
+		vfree(fd->cq->comps);
+		kfree(fd->cq);
+		fd->cq = NULL;
+	}
+	return 0;
+}
+
+static u8 dlid_to_selector(u16 dlid)
+{
+	static u8 mapping[256];
+	static int initialized;
+	static u8 next;
+	int hash;
+
+	if (!initialized) {
+		memset(mapping, 0xFF, 256);
+		initialized = 1;
+	}
+
+	hash = ((dlid >> 8) ^ dlid) & 0xFF;
+	if (mapping[hash] == 0xFF) {
+		mapping[hash] = next;
+		next = (next + 1) & 0x7F;
+	}
+
+	return mapping[hash];
+}
+
+/**
+ * hfi1_user_sdma_process_request() - Process and start a user sdma request
+ * @fd: valid file descriptor
+ * @iovec: array of io vectors to process
+ * @dim: overall iovec array size
+ * @count: number of io vector array entries processed
+ */
+int hfi1_user_sdma_process_request(struct hfi1_filedata *fd,
+				   struct iovec *iovec, unsigned long dim,
+				   unsigned long *count)
+{
+	int ret = 0, i;
+	struct hfi1_ctxtdata *uctxt = fd->uctxt;
+	struct hfi1_user_sdma_pkt_q *pq =
+		srcu_dereference(fd->pq, &fd->pq_srcu);
+	struct hfi1_user_sdma_comp_q *cq = fd->cq;
+	struct hfi1_devdata *dd = pq->dd;
+	unsigned long idx = 0;
+	u8 pcount = initial_pkt_count;
+	struct sdma_req_info info;
+	struct user_sdma_request *req;
+	u8 opcode, sc, vl;
+	u16 pkey;
+	u32 slid;
+	u16 dlid;
+	u32 selector;
+
+	if (iovec[idx].iov_len < sizeof(info) + sizeof(req->hdr)) {
+		hfi1_cdbg(
+		   SDMA,
+		   "[%u:%u:%u] First vector not big enough for header %lu/%lu",
+		   dd->unit, uctxt->ctxt, fd->subctxt,
+		   iovec[idx].iov_len, sizeof(info) + sizeof(req->hdr));
+		return -EINVAL;
+	}
+	ret = copy_from_user(&info, iovec[idx].iov_base, sizeof(info));
+	if (ret) {
+		hfi1_cdbg(SDMA, "[%u:%u:%u] Failed to copy info QW (%d)",
+			  dd->unit, uctxt->ctxt, fd->subctxt, ret);
+		return -EFAULT;
+	}
+
+	trace_hfi1_sdma_user_reqinfo(dd, uctxt->ctxt, fd->subctxt,
+				     (u16 *)&info);
+	if (info.comp_idx >= hfi1_sdma_comp_ring_size) {
+		hfi1_cdbg(SDMA,
+			  "[%u:%u:%u:%u] Invalid comp index",
+			  dd->unit, uctxt->ctxt, fd->subctxt, info.comp_idx);
+		return -EINVAL;
+	}
+
+	/*
+	 * Sanity check the header io vector count.  Need at least 1 vector
+	 * (header) and cannot be larger than the actual io vector count.
+	 */
+	if (req_iovcnt(info.ctrl) < 1 || req_iovcnt(info.ctrl) > dim) {
+		hfi1_cdbg(SDMA,
+			  "[%u:%u:%u:%u] Invalid iov count %d, dim %ld",
+			  dd->unit, uctxt->ctxt, fd->subctxt, info.comp_idx,
+			  req_iovcnt(info.ctrl), dim);
+		return -EINVAL;
+	}
+
+	if (!info.fragsize) {
+		hfi1_cdbg(SDMA,
+			  "[%u:%u:%u:%u] Request does not specify fragsize",
+			  dd->unit, uctxt->ctxt, fd->subctxt, info.comp_idx);
+		return -EINVAL;
+	}
+
+	/* Try to claim the request. */
+	if (test_and_set_bit(info.comp_idx, pq->req_in_use)) {
+		hfi1_cdbg(SDMA, "[%u:%u:%u] Entry %u is in use",
+			  dd->unit, uctxt->ctxt, fd->subctxt,
+			  info.comp_idx);
+		return -EBADSLT;
+	}
+	/*
+	 * All safety checks have been done and this request has been claimed.
+	 */
+	trace_hfi1_sdma_user_process_request(dd, uctxt->ctxt, fd->subctxt,
+					     info.comp_idx);
+	req = pq->reqs + info.comp_idx;
+	req->data_iovs = req_iovcnt(info.ctrl) - 1; /* subtract header vector */
+	req->data_len  = 0;
+	req->pq = pq;
+	req->cq = cq;
+	req->ahg_idx = -1;
+	req->iov_idx = 0;
+	req->sent = 0;
+	req->seqnum = 0;
+	req->seqcomp = 0;
+	req->seqsubmitted = 0;
+	req->tids = NULL;
+	req->has_error = 0;
+	INIT_LIST_HEAD(&req->txps);
+
+	memcpy(&req->info, &info, sizeof(info));
+
+	/* The request is initialized, count it */
+	atomic_inc(&pq->n_reqs);
+
+	if (req_opcode(info.ctrl) == EXPECTED) {
+		/* expected must have a TID info and at least one data vector */
+		if (req->data_iovs < 2) {
+			SDMA_DBG(req,
+				 "Not enough vectors for expected request");
+			ret = -EINVAL;
+			goto free_req;
+		}
+		req->data_iovs--;
+	}
+
+	if (!info.npkts || req->data_iovs > MAX_VECTORS_PER_REQ) {
+		SDMA_DBG(req, "Too many vectors (%u/%u)", req->data_iovs,
+			 MAX_VECTORS_PER_REQ);
+		ret = -EINVAL;
+		goto free_req;
+	}
+
+	/* Copy the header from the user buffer */
+	ret = copy_from_user(&req->hdr, iovec[idx].iov_base + sizeof(info),
+			     sizeof(req->hdr));
+	if (ret) {
+		SDMA_DBG(req, "Failed to copy header template (%d)", ret);
+		ret = -EFAULT;
+		goto free_req;
+	}
+
+	/* If Static rate control is not enabled, sanitize the header. */
+	if (!HFI1_CAP_IS_USET(STATIC_RATE_CTRL))
+		req->hdr.pbc[2] = 0;
+
+	/* Validate the opcode. Do not trust packets from user space blindly. */
+	opcode = (be32_to_cpu(req->hdr.bth[0]) >> 24) & 0xff;
+	if ((opcode & USER_OPCODE_CHECK_MASK) !=
+	     USER_OPCODE_CHECK_VAL) {
+		SDMA_DBG(req, "Invalid opcode (%d)", opcode);
+		ret = -EINVAL;
+		goto free_req;
+	}
+	/*
+	 * Validate the vl. Do not trust packets from user space blindly.
+	 * VL comes from PBC, SC comes from LRH, and the VL needs to
+	 * match the SC look up.
+	 */
+	vl = (le16_to_cpu(req->hdr.pbc[0]) >> 12) & 0xF;
+	sc = (((be16_to_cpu(req->hdr.lrh[0]) >> 12) & 0xF) |
+	      (((le16_to_cpu(req->hdr.pbc[1]) >> 14) & 0x1) << 4));
+	if (vl >= dd->pport->vls_operational ||
+	    vl != sc_to_vlt(dd, sc)) {
+		SDMA_DBG(req, "Invalid SC(%u)/VL(%u)", sc, vl);
+		ret = -EINVAL;
+		goto free_req;
+	}
+
+	/* Checking P_KEY for requests from user-space */
+	pkey = (u16)be32_to_cpu(req->hdr.bth[0]);
+	slid = be16_to_cpu(req->hdr.lrh[3]);
+	if (egress_pkey_check(dd->pport, slid, pkey, sc, PKEY_CHECK_INVALID)) {
+		ret = -EINVAL;
+		goto free_req;
+	}
+
+	/*
+	 * Also should check the BTH.lnh. If it says the next header is GRH then
+	 * the RXE parsing will be off and will land in the middle of the KDETH
+	 * or miss it entirely.
+	 */
+	if ((be16_to_cpu(req->hdr.lrh[0]) & 0x3) == HFI1_LRH_GRH) {
+		SDMA_DBG(req, "User tried to pass in a GRH");
+		ret = -EINVAL;
+		goto free_req;
+	}
+
+	req->koffset = le32_to_cpu(req->hdr.kdeth.swdata[6]);
+	/*
+	 * Calculate the initial TID offset based on the values of
+	 * KDETH.OFFSET and KDETH.OM that are passed in.
+	 */
+	req->tidoffset = KDETH_GET(req->hdr.kdeth.ver_tid_offset, OFFSET) *
+		(KDETH_GET(req->hdr.kdeth.ver_tid_offset, OM) ?
+		 KDETH_OM_LARGE : KDETH_OM_SMALL);
+	trace_hfi1_sdma_user_initial_tidoffset(dd, uctxt->ctxt, fd->subctxt,
+					       info.comp_idx, req->tidoffset);
+	idx++;
+
+	/* Save all the IO vector structures */
+	for (i = 0; i < req->data_iovs; i++) {
+		req->iovs[i].offset = 0;
+		INIT_LIST_HEAD(&req->iovs[i].list);
+		memcpy(&req->iovs[i].iov,
+		       iovec + idx++,
+		       sizeof(req->iovs[i].iov));
+		if (req->iovs[i].iov.iov_len == 0) {
+			ret = -EINVAL;
+			goto free_req;
+		}
+		req->data_len += req->iovs[i].iov.iov_len;
+	}
+	trace_hfi1_sdma_user_data_length(dd, uctxt->ctxt, fd->subctxt,
+					 info.comp_idx, req->data_len);
+	if (pcount > req->info.npkts)
+		pcount = req->info.npkts;
+	/*
+	 * Copy any TID info
+	 * User space will provide the TID info only when the
+	 * request type is EXPECTED. This is true even if there is
+	 * only one packet in the request and the header is already
+	 * setup. The reason for the singular TID case is that the
+	 * driver needs to perform safety checks.
+	 */
+	if (req_opcode(req->info.ctrl) == EXPECTED) {
+		u16 ntids = iovec[idx].iov_len / sizeof(*req->tids);
+		u32 *tmp;
+
+		if (!ntids || ntids > MAX_TID_PAIR_ENTRIES) {
+			ret = -EINVAL;
+			goto free_req;
+		}
+
+		/*
+		 * We have to copy all of the tids because they may vary
+		 * in size and, therefore, the TID count might not be
+		 * equal to the pkt count. However, there is no way to
+		 * tell at this point.
+		 */
+		tmp = memdup_user(iovec[idx].iov_base,
+				  ntids * sizeof(*req->tids));
+		if (IS_ERR(tmp)) {
+			ret = PTR_ERR(tmp);
+			SDMA_DBG(req, "Failed to copy %d TIDs (%d)",
+				 ntids, ret);
+			goto free_req;
+		}
+		req->tids = tmp;
+		req->n_tids = ntids;
+		req->tididx = 0;
+		idx++;
+	}
+
+	dlid = be16_to_cpu(req->hdr.lrh[1]);
+	selector = dlid_to_selector(dlid);
+	selector += uctxt->ctxt + fd->subctxt;
+	req->sde = sdma_select_user_engine(dd, selector, vl);
+
+	if (!req->sde || !sdma_running(req->sde)) {
+		ret = -ECOMM;
+		goto free_req;
+	}
+
+	/* We don't need an AHG entry if the request contains only one packet */
+	if (req->info.npkts > 1 && HFI1_CAP_IS_USET(SDMA_AHG))
+		req->ahg_idx = sdma_ahg_alloc(req->sde);
+
+	set_comp_state(pq, cq, info.comp_idx, QUEUED, 0);
+	pq->state = SDMA_PKT_Q_ACTIVE;
+
+	/*
+	 * This is a somewhat blocking send implementation.
+	 * The driver will block the caller until all packets of the
+	 * request have been submitted to the SDMA engine. However, it
+	 * will not wait for send completions.
+	 */
+	while (req->seqsubmitted != req->info.npkts) {
+		ret = user_sdma_send_pkts(req, pcount);
+		if (ret < 0) {
+			int we_ret;
+
+			if (ret != -EBUSY)
+				goto free_req;
+			we_ret = wait_event_interruptible_timeout(
+				pq->busy.wait_dma,
+				pq->state == SDMA_PKT_Q_ACTIVE,
+				msecs_to_jiffies(
+					SDMA_IOWAIT_TIMEOUT));
+			trace_hfi1_usdma_we(pq, we_ret);
+			if (we_ret <= 0)
+				flush_pq_iowait(pq);
+		}
+	}
+	*count += idx;
+	return 0;
+free_req:
+	/*
+	 * If the submitted seqsubmitted == npkts, the completion routine
+	 * controls the final state.  If sequbmitted < npkts, wait for any
+	 * outstanding packets to finish before cleaning up.
+	 */
+	if (req->seqsubmitted < req->info.npkts) {
+		if (req->seqsubmitted)
+			wait_event(pq->busy.wait_dma,
+				   (req->seqcomp == req->seqsubmitted - 1));
+		user_sdma_free_request(req);
+		pq_update(pq);
+		set_comp_state(pq, cq, info.comp_idx, ERROR, ret);
+	}
+	return ret;
+}
+
+static inline u32 compute_data_length(struct user_sdma_request *req,
+				      struct user_sdma_txreq *tx)
+{
+	/*
+	 * Determine the proper size of the packet data.
+	 * The size of the data of the first packet is in the header
+	 * template. However, it includes the header and ICRC, which need
+	 * to be subtracted.
+	 * The minimum representable packet data length in a header is 4 bytes,
+	 * therefore, when the data length request is less than 4 bytes, there's
+	 * only one packet, and the packet data length is equal to that of the
+	 * request data length.
+	 * The size of the remaining packets is the minimum of the frag
+	 * size (MTU) or remaining data in the request.
+	 */
+	u32 len;
+
+	if (!req->seqnum) {
+		if (req->data_len < sizeof(u32))
+			len = req->data_len;
+		else
+			len = ((be16_to_cpu(req->hdr.lrh[2]) << 2) -
+			       (sizeof(tx->hdr) - 4));
+	} else if (req_opcode(req->info.ctrl) == EXPECTED) {
+		u32 tidlen = EXP_TID_GET(req->tids[req->tididx], LEN) *
+			PAGE_SIZE;
+		/*
+		 * Get the data length based on the remaining space in the
+		 * TID pair.
+		 */
+		len = min(tidlen - req->tidoffset, (u32)req->info.fragsize);
+		/* If we've filled up the TID pair, move to the next one. */
+		if (unlikely(!len) && ++req->tididx < req->n_tids &&
+		    req->tids[req->tididx]) {
+			tidlen = EXP_TID_GET(req->tids[req->tididx],
+					     LEN) * PAGE_SIZE;
+			req->tidoffset = 0;
+			len = min_t(u32, tidlen, req->info.fragsize);
+		}
+		/*
+		 * Since the TID pairs map entire pages, make sure that we
+		 * are not going to try to send more data that we have
+		 * remaining.
+		 */
+		len = min(len, req->data_len - req->sent);
+	} else {
+		len = min(req->data_len - req->sent, (u32)req->info.fragsize);
+	}
+	trace_hfi1_sdma_user_compute_length(req->pq->dd,
+					    req->pq->ctxt,
+					    req->pq->subctxt,
+					    req->info.comp_idx,
+					    len);
+	return len;
+}
+
+static inline u32 pad_len(u32 len)
+{
+	if (len & (sizeof(u32) - 1))
+		len += sizeof(u32) - (len & (sizeof(u32) - 1));
+	return len;
+}
+
+static inline u32 get_lrh_len(struct hfi1_pkt_header hdr, u32 len)
+{
+	/* (Size of complete header - size of PBC) + 4B ICRC + data length */
+	return ((sizeof(hdr) - sizeof(hdr.pbc)) + 4 + len);
+}
+
+static int user_sdma_txadd_ahg(struct user_sdma_request *req,
+			       struct user_sdma_txreq *tx,
+			       u32 datalen)
+{
+	int ret;
+	u16 pbclen = le16_to_cpu(req->hdr.pbc[0]);
+	u32 lrhlen = get_lrh_len(req->hdr, pad_len(datalen));
+	struct hfi1_user_sdma_pkt_q *pq = req->pq;
+
+	/*
+	 * Copy the request header into the tx header
+	 * because the HW needs a cacheline-aligned
+	 * address.
+	 * This copy can be optimized out if the hdr
+	 * member of user_sdma_request were also
+	 * cacheline aligned.
+	 */
+	memcpy(&tx->hdr, &req->hdr, sizeof(tx->hdr));
+	if (PBC2LRH(pbclen) != lrhlen) {
+		pbclen = (pbclen & 0xf000) | LRH2PBC(lrhlen);
+		tx->hdr.pbc[0] = cpu_to_le16(pbclen);
+	}
+	ret = check_header_template(req, &tx->hdr, lrhlen, datalen);
+	if (ret)
+		return ret;
+	ret = sdma_txinit_ahg(&tx->txreq, SDMA_TXREQ_F_AHG_COPY,
+			      sizeof(tx->hdr) + datalen, req->ahg_idx,
+			      0, NULL, 0, user_sdma_txreq_cb);
+	if (ret)
+		return ret;
+	ret = sdma_txadd_kvaddr(pq->dd, &tx->txreq, &tx->hdr, sizeof(tx->hdr));
+	if (ret)
+		sdma_txclean(pq->dd, &tx->txreq);
+	return ret;
+}
+
+static int user_sdma_send_pkts(struct user_sdma_request *req, u16 maxpkts)
+{
+	int ret = 0;
+	u16 count;
+	unsigned npkts = 0;
+	struct user_sdma_txreq *tx = NULL;
+	struct hfi1_user_sdma_pkt_q *pq = NULL;
+	struct user_sdma_iovec *iovec = NULL;
+
+	if (!req->pq)
+		return -EINVAL;
+
+	pq = req->pq;
+
+	/* If tx completion has reported an error, we are done. */
+	if (READ_ONCE(req->has_error))
+		return -EFAULT;
+
+	/*
+	 * Check if we might have sent the entire request already
+	 */
+	if (unlikely(req->seqnum == req->info.npkts)) {
+		if (!list_empty(&req->txps))
+			goto dosend;
+		return ret;
+	}
+
+	if (!maxpkts || maxpkts > req->info.npkts - req->seqnum)
+		maxpkts = req->info.npkts - req->seqnum;
+
+	while (npkts < maxpkts) {
+		u32 datalen = 0;
+
+		/*
+		 * Check whether any of the completions have come back
+		 * with errors. If so, we are not going to process any
+		 * more packets from this request.
+		 */
+		if (READ_ONCE(req->has_error))
+			return -EFAULT;
+
+		tx = kmem_cache_alloc(pq->txreq_cache, GFP_KERNEL);
+		if (!tx)
+			return -ENOMEM;
+
+		tx->flags = 0;
+		tx->req = req;
+		INIT_LIST_HEAD(&tx->list);
+
+		/*
+		 * For the last packet set the ACK request
+		 * and disable header suppression.
+		 */
+		if (req->seqnum == req->info.npkts - 1)
+			tx->flags |= (TXREQ_FLAGS_REQ_ACK |
+				      TXREQ_FLAGS_REQ_DISABLE_SH);
+
+		/*
+		 * Calculate the payload size - this is min of the fragment
+		 * (MTU) size or the remaining bytes in the request but only
+		 * if we have payload data.
+		 */
+		if (req->data_len) {
+			iovec = &req->iovs[req->iov_idx];
+			if (READ_ONCE(iovec->offset) == iovec->iov.iov_len) {
+				if (++req->iov_idx == req->data_iovs) {
+					ret = -EFAULT;
+					goto free_tx;
+				}
+				iovec = &req->iovs[req->iov_idx];
+				WARN_ON(iovec->offset);
+			}
+
+			datalen = compute_data_length(req, tx);
+
+			/*
+			 * Disable header suppression for the payload <= 8DWS.
+			 * If there is an uncorrectable error in the receive
+			 * data FIFO when the received payload size is less than
+			 * or equal to 8DWS then the RxDmaDataFifoRdUncErr is
+			 * not reported.There is set RHF.EccErr if the header
+			 * is not suppressed.
+			 */
+			if (!datalen) {
+				SDMA_DBG(req,
+					 "Request has data but pkt len is 0");
+				ret = -EFAULT;
+				goto free_tx;
+			} else if (datalen <= 32) {
+				tx->flags |= TXREQ_FLAGS_REQ_DISABLE_SH;
+			}
+		}
+
+		if (req->ahg_idx >= 0) {
+			if (!req->seqnum) {
+				ret = user_sdma_txadd_ahg(req, tx, datalen);
+				if (ret)
+					goto free_tx;
+			} else {
+				int changes;
+
+				changes = set_txreq_header_ahg(req, tx,
+							       datalen);
+				if (changes < 0) {
+					ret = changes;
+					goto free_tx;
+				}
+			}
+		} else {
+			ret = sdma_txinit(&tx->txreq, 0, sizeof(req->hdr) +
+					  datalen, user_sdma_txreq_cb);
+			if (ret)
+				goto free_tx;
+			/*
+			 * Modify the header for this packet. This only needs
+			 * to be done if we are not going to use AHG. Otherwise,
+			 * the HW will do it based on the changes we gave it
+			 * during sdma_txinit_ahg().
+			 */
+			ret = set_txreq_header(req, tx, datalen);
+			if (ret)
+				goto free_txreq;
+		}
+
+		req->koffset += datalen;
+		if (req_opcode(req->info.ctrl) == EXPECTED)
+			req->tidoffset += datalen;
+		req->sent += datalen;
+		while (datalen) {
+			ret = add_system_pages_to_sdma_packet(req, tx, iovec,
+							      &datalen);
+			if (ret)
+				goto free_txreq;
+			iovec = &req->iovs[req->iov_idx];
+		}
+		list_add_tail(&tx->txreq.list, &req->txps);
+		/*
+		 * It is important to increment this here as it is used to
+		 * generate the BTH.PSN and, therefore, can't be bulk-updated
+		 * outside of the loop.
+		 */
+		tx->seqnum = req->seqnum++;
+		npkts++;
+	}
+dosend:
+	ret = sdma_send_txlist(req->sde,
+			       iowait_get_ib_work(&pq->busy),
+			       &req->txps, &count);
+	req->seqsubmitted += count;
+	if (req->seqsubmitted == req->info.npkts) {
+		/*
+		 * The txreq has already been submitted to the HW queue
+		 * so we can free the AHG entry now. Corruption will not
+		 * happen due to the sequential manner in which
+		 * descriptors are processed.
+		 */
+		if (req->ahg_idx >= 0)
+			sdma_ahg_free(req->sde, req->ahg_idx);
+	}
+	return ret;
+
+free_txreq:
+	sdma_txclean(pq->dd, &tx->txreq);
+free_tx:
+	kmem_cache_free(pq->txreq_cache, tx);
+	return ret;
+}
+
+static u32 sdma_cache_evict(struct hfi1_user_sdma_pkt_q *pq, u32 npages)
+{
+	struct evict_data evict_data;
+	struct mmu_rb_handler *handler = pq->handler;
+
+	evict_data.cleared = 0;
+	evict_data.target = npages;
+	hfi1_mmu_rb_evict(handler, &evict_data);
+	return evict_data.cleared;
+}
+
+static int check_header_template(struct user_sdma_request *req,
+				 struct hfi1_pkt_header *hdr, u32 lrhlen,
+				 u32 datalen)
+{
+	/*
+	 * Perform safety checks for any type of packet:
+	 *    - transfer size is multiple of 64bytes
+	 *    - packet length is multiple of 4 bytes
+	 *    - packet length is not larger than MTU size
+	 *
+	 * These checks are only done for the first packet of the
+	 * transfer since the header is "given" to us by user space.
+	 * For the remainder of the packets we compute the values.
+	 */
+	if (req->info.fragsize % PIO_BLOCK_SIZE || lrhlen & 0x3 ||
+	    lrhlen > get_lrh_len(*hdr, req->info.fragsize))
+		return -EINVAL;
+
+	if (req_opcode(req->info.ctrl) == EXPECTED) {
+		/*
+		 * The header is checked only on the first packet. Furthermore,
+		 * we ensure that at least one TID entry is copied when the
+		 * request is submitted. Therefore, we don't have to verify that
+		 * tididx points to something sane.
+		 */
+		u32 tidval = req->tids[req->tididx],
+			tidlen = EXP_TID_GET(tidval, LEN) * PAGE_SIZE,
+			tididx = EXP_TID_GET(tidval, IDX),
+			tidctrl = EXP_TID_GET(tidval, CTRL),
+			tidoff;
+		__le32 kval = hdr->kdeth.ver_tid_offset;
+
+		tidoff = KDETH_GET(kval, OFFSET) *
+			  (KDETH_GET(req->hdr.kdeth.ver_tid_offset, OM) ?
+			   KDETH_OM_LARGE : KDETH_OM_SMALL);
+		/*
+		 * Expected receive packets have the following
+		 * additional checks:
+		 *     - offset is not larger than the TID size
+		 *     - TIDCtrl values match between header and TID array
+		 *     - TID indexes match between header and TID array
+		 */
+		if ((tidoff + datalen > tidlen) ||
+		    KDETH_GET(kval, TIDCTRL) != tidctrl ||
+		    KDETH_GET(kval, TID) != tididx)
+			return -EINVAL;
+	}
+	return 0;
+}
+
+/*
+ * Correctly set the BTH.PSN field based on type of
+ * transfer - eager packets can just increment the PSN but
+ * expected packets encode generation and sequence in the
+ * BTH.PSN field so just incrementing will result in errors.
+ */
+static inline u32 set_pkt_bth_psn(__be32 bthpsn, u8 expct, u32 frags)
+{
+	u32 val = be32_to_cpu(bthpsn),
+		mask = (HFI1_CAP_IS_KSET(EXTENDED_PSN) ? 0x7fffffffull :
+			0xffffffull),
+		psn = val & mask;
+	if (expct)
+		psn = (psn & ~HFI1_KDETH_BTH_SEQ_MASK) |
+			((psn + frags) & HFI1_KDETH_BTH_SEQ_MASK);
+	else
+		psn = psn + frags;
+	return psn & mask;
+}
+
+static int set_txreq_header(struct user_sdma_request *req,
+			    struct user_sdma_txreq *tx, u32 datalen)
+{
+	struct hfi1_user_sdma_pkt_q *pq = req->pq;
+	struct hfi1_pkt_header *hdr = &tx->hdr;
+	u8 omfactor; /* KDETH.OM */
+	u16 pbclen;
+	int ret;
+	u32 tidval = 0, lrhlen = get_lrh_len(*hdr, pad_len(datalen));
+
+	/* Copy the header template to the request before modification */
+	memcpy(hdr, &req->hdr, sizeof(*hdr));
+
+	/*
+	 * Check if the PBC and LRH length are mismatched. If so
+	 * adjust both in the header.
+	 */
+	pbclen = le16_to_cpu(hdr->pbc[0]);
+	if (PBC2LRH(pbclen) != lrhlen) {
+		pbclen = (pbclen & 0xf000) | LRH2PBC(lrhlen);
+		hdr->pbc[0] = cpu_to_le16(pbclen);
+		hdr->lrh[2] = cpu_to_be16(lrhlen >> 2);
+		/*
+		 * Third packet
+		 * This is the first packet in the sequence that has
+		 * a "static" size that can be used for the rest of
+		 * the packets (besides the last one).
+		 */
+		if (unlikely(req->seqnum == 2)) {
+			/*
+			 * From this point on the lengths in both the
+			 * PBC and LRH are the same until the last
+			 * packet.
+			 * Adjust the template so we don't have to update
+			 * every packet
+			 */
+			req->hdr.pbc[0] = hdr->pbc[0];
+			req->hdr.lrh[2] = hdr->lrh[2];
+		}
+	}
+	/*
+	 * We only have to modify the header if this is not the
+	 * first packet in the request. Otherwise, we use the
+	 * header given to us.
+	 */
+	if (unlikely(!req->seqnum)) {
+		ret = check_header_template(req, hdr, lrhlen, datalen);
+		if (ret)
+			return ret;
+		goto done;
+	}
+
+	hdr->bth[2] = cpu_to_be32(
+		set_pkt_bth_psn(hdr->bth[2],
+				(req_opcode(req->info.ctrl) == EXPECTED),
+				req->seqnum));
+
+	/* Set ACK request on last packet */
+	if (unlikely(tx->flags & TXREQ_FLAGS_REQ_ACK))
+		hdr->bth[2] |= cpu_to_be32(1UL << 31);
+
+	/* Set the new offset */
+	hdr->kdeth.swdata[6] = cpu_to_le32(req->koffset);
+	/* Expected packets have to fill in the new TID information */
+	if (req_opcode(req->info.ctrl) == EXPECTED) {
+		tidval = req->tids[req->tididx];
+		/*
+		 * If the offset puts us at the end of the current TID,
+		 * advance everything.
+		 */
+		if ((req->tidoffset) == (EXP_TID_GET(tidval, LEN) *
+					 PAGE_SIZE)) {
+			req->tidoffset = 0;
+			/*
+			 * Since we don't copy all the TIDs, all at once,
+			 * we have to check again.
+			 */
+			if (++req->tididx > req->n_tids - 1 ||
+			    !req->tids[req->tididx]) {
+				return -EINVAL;
+			}
+			tidval = req->tids[req->tididx];
+		}
+		omfactor = EXP_TID_GET(tidval, LEN) * PAGE_SIZE >=
+			KDETH_OM_MAX_SIZE ? KDETH_OM_LARGE_SHIFT :
+			KDETH_OM_SMALL_SHIFT;
+		/* Set KDETH.TIDCtrl based on value for this TID. */
+		KDETH_SET(hdr->kdeth.ver_tid_offset, TIDCTRL,
+			  EXP_TID_GET(tidval, CTRL));
+		/* Set KDETH.TID based on value for this TID */
+		KDETH_SET(hdr->kdeth.ver_tid_offset, TID,
+			  EXP_TID_GET(tidval, IDX));
+		/* Clear KDETH.SH when DISABLE_SH flag is set */
+		if (unlikely(tx->flags & TXREQ_FLAGS_REQ_DISABLE_SH))
+			KDETH_SET(hdr->kdeth.ver_tid_offset, SH, 0);
+		/*
+		 * Set the KDETH.OFFSET and KDETH.OM based on size of
+		 * transfer.
+		 */
+		trace_hfi1_sdma_user_tid_info(
+			pq->dd, pq->ctxt, pq->subctxt, req->info.comp_idx,
+			req->tidoffset, req->tidoffset >> omfactor,
+			omfactor != KDETH_OM_SMALL_SHIFT);
+		KDETH_SET(hdr->kdeth.ver_tid_offset, OFFSET,
+			  req->tidoffset >> omfactor);
+		KDETH_SET(hdr->kdeth.ver_tid_offset, OM,
+			  omfactor != KDETH_OM_SMALL_SHIFT);
+	}
+done:
+	trace_hfi1_sdma_user_header(pq->dd, pq->ctxt, pq->subctxt,
+				    req->info.comp_idx, hdr, tidval);
+	return sdma_txadd_kvaddr(pq->dd, &tx->txreq, hdr, sizeof(*hdr));
+}
+
+static int set_txreq_header_ahg(struct user_sdma_request *req,
+				struct user_sdma_txreq *tx, u32 datalen)
+{
+	u32 ahg[AHG_KDETH_ARRAY_SIZE];
+	int idx = 0;
+	u8 omfactor; /* KDETH.OM */
+	struct hfi1_user_sdma_pkt_q *pq = req->pq;
+	struct hfi1_pkt_header *hdr = &req->hdr;
+	u16 pbclen = le16_to_cpu(hdr->pbc[0]);
+	u32 val32, tidval = 0, lrhlen = get_lrh_len(*hdr, pad_len(datalen));
+	size_t array_size = ARRAY_SIZE(ahg);
+
+	if (PBC2LRH(pbclen) != lrhlen) {
+		/* PBC.PbcLengthDWs */
+		idx = ahg_header_set(ahg, idx, array_size, 0, 0, 12,
+				     (__force u16)cpu_to_le16(LRH2PBC(lrhlen)));
+		if (idx < 0)
+			return idx;
+		/* LRH.PktLen (we need the full 16 bits due to byte swap) */
+		idx = ahg_header_set(ahg, idx, array_size, 3, 0, 16,
+				     (__force u16)cpu_to_be16(lrhlen >> 2));
+		if (idx < 0)
+			return idx;
+	}
+
+	/*
+	 * Do the common updates
+	 */
+	/* BTH.PSN and BTH.A */
+	val32 = (be32_to_cpu(hdr->bth[2]) + req->seqnum) &
+		(HFI1_CAP_IS_KSET(EXTENDED_PSN) ? 0x7fffffff : 0xffffff);
+	if (unlikely(tx->flags & TXREQ_FLAGS_REQ_ACK))
+		val32 |= 1UL << 31;
+	idx = ahg_header_set(ahg, idx, array_size, 6, 0, 16,
+			     (__force u16)cpu_to_be16(val32 >> 16));
+	if (idx < 0)
+		return idx;
+	idx = ahg_header_set(ahg, idx, array_size, 6, 16, 16,
+			     (__force u16)cpu_to_be16(val32 & 0xffff));
+	if (idx < 0)
+		return idx;
+	/* KDETH.Offset */
+	idx = ahg_header_set(ahg, idx, array_size, 15, 0, 16,
+			     (__force u16)cpu_to_le16(req->koffset & 0xffff));
+	if (idx < 0)
+		return idx;
+	idx = ahg_header_set(ahg, idx, array_size, 15, 16, 16,
+			     (__force u16)cpu_to_le16(req->koffset >> 16));
+	if (idx < 0)
+		return idx;
+	if (req_opcode(req->info.ctrl) == EXPECTED) {
+		__le16 val;
+
+		tidval = req->tids[req->tididx];
+
+		/*
+		 * If the offset puts us at the end of the current TID,
+		 * advance everything.
+		 */
+		if ((req->tidoffset) == (EXP_TID_GET(tidval, LEN) *
+					 PAGE_SIZE)) {
+			req->tidoffset = 0;
+			/*
+			 * Since we don't copy all the TIDs, all at once,
+			 * we have to check again.
+			 */
+			if (++req->tididx > req->n_tids - 1 ||
+			    !req->tids[req->tididx])
+				return -EINVAL;
+			tidval = req->tids[req->tididx];
+		}
+		omfactor = ((EXP_TID_GET(tidval, LEN) *
+				  PAGE_SIZE) >=
+				 KDETH_OM_MAX_SIZE) ? KDETH_OM_LARGE_SHIFT :
+				 KDETH_OM_SMALL_SHIFT;
+		/* KDETH.OM and KDETH.OFFSET (TID) */
+		idx = ahg_header_set(
+				ahg, idx, array_size, 7, 0, 16,
+				((!!(omfactor - KDETH_OM_SMALL_SHIFT)) << 15 |
+				((req->tidoffset >> omfactor)
+				& 0x7fff)));
+		if (idx < 0)
+			return idx;
+		/* KDETH.TIDCtrl, KDETH.TID, KDETH.Intr, KDETH.SH */
+		val = cpu_to_le16(((EXP_TID_GET(tidval, CTRL) & 0x3) << 10) |
+				   (EXP_TID_GET(tidval, IDX) & 0x3ff));
+
+		if (unlikely(tx->flags & TXREQ_FLAGS_REQ_DISABLE_SH)) {
+			val |= cpu_to_le16((KDETH_GET(hdr->kdeth.ver_tid_offset,
+						      INTR) <<
+					    AHG_KDETH_INTR_SHIFT));
+		} else {
+			val |= KDETH_GET(hdr->kdeth.ver_tid_offset, SH) ?
+			       cpu_to_le16(0x1 << AHG_KDETH_SH_SHIFT) :
+			       cpu_to_le16((KDETH_GET(hdr->kdeth.ver_tid_offset,
+						      INTR) <<
+					     AHG_KDETH_INTR_SHIFT));
+		}
+
+		idx = ahg_header_set(ahg, idx, array_size,
+				     7, 16, 14, (__force u16)val);
+		if (idx < 0)
+			return idx;
+	}
+
+	trace_hfi1_sdma_user_header_ahg(pq->dd, pq->ctxt, pq->subctxt,
+					req->info.comp_idx, req->sde->this_idx,
+					req->ahg_idx, ahg, idx, tidval);
+	sdma_txinit_ahg(&tx->txreq,
+			SDMA_TXREQ_F_USE_AHG,
+			datalen, req->ahg_idx, idx,
+			ahg, sizeof(req->hdr),
+			user_sdma_txreq_cb);
+
+	return idx;
+}
+
+/**
+ * user_sdma_txreq_cb() - SDMA tx request completion callback.
+ * @txreq: valid sdma tx request
+ * @status: success/failure of request
+ *
+ * Called when the SDMA progress state machine gets notification that
+ * the SDMA descriptors for this tx request have been processed by the
+ * DMA engine. Called in interrupt context.
+ * Only do work on completed sequences.
+ */
+static void user_sdma_txreq_cb(struct sdma_txreq *txreq, int status)
+{
+	struct user_sdma_txreq *tx =
+		container_of(txreq, struct user_sdma_txreq, txreq);
+	struct user_sdma_request *req;
+	struct hfi1_user_sdma_pkt_q *pq;
+	struct hfi1_user_sdma_comp_q *cq;
+	enum hfi1_sdma_comp_state state = COMPLETE;
+
+	if (!tx->req)
+		return;
+
+	req = tx->req;
+	pq = req->pq;
+	cq = req->cq;
+
+	if (status != SDMA_TXREQ_S_OK) {
+		SDMA_DBG(req, "SDMA completion with error %d",
+			 status);
+		WRITE_ONCE(req->has_error, 1);
+		state = ERROR;
+	}
+
+	req->seqcomp = tx->seqnum;
+	kmem_cache_free(pq->txreq_cache, tx);
+
+	/* sequence isn't complete?  We are done */
+	if (req->seqcomp != req->info.npkts - 1)
+		return;
+
+	user_sdma_free_request(req);
+	set_comp_state(pq, cq, req->info.comp_idx, state, status);
+	pq_update(pq);
+}
+
+static inline void pq_update(struct hfi1_user_sdma_pkt_q *pq)
+{
+	if (atomic_dec_and_test(&pq->n_reqs))
+		wake_up(&pq->wait);
+}
+
+static void user_sdma_free_request(struct user_sdma_request *req)
+{
+	if (!list_empty(&req->txps)) {
+		struct sdma_txreq *t, *p;
+
+		list_for_each_entry_safe(t, p, &req->txps, list) {
+			struct user_sdma_txreq *tx =
+				container_of(t, struct user_sdma_txreq, txreq);
+			list_del_init(&t->list);
+			sdma_txclean(req->pq->dd, t);
+			kmem_cache_free(req->pq->txreq_cache, tx);
+		}
+	}
+
+	kfree(req->tids);
+	clear_bit(req->info.comp_idx, req->pq->req_in_use);
+}
+
+static inline void set_comp_state(struct hfi1_user_sdma_pkt_q *pq,
+				  struct hfi1_user_sdma_comp_q *cq,
+				  u16 idx, enum hfi1_sdma_comp_state state,
+				  int ret)
+{
+	if (state == ERROR)
+		cq->comps[idx].errcode = -ret;
+	smp_wmb(); /* make sure errcode is visible first */
+	cq->comps[idx].status = state;
+	trace_hfi1_sdma_user_completion(pq->dd, pq->ctxt, pq->subctxt,
+					idx, state, ret);
+}
+
+static void unpin_vector_pages(struct mm_struct *mm, struct page **pages,
+			       unsigned int start, unsigned int npages)
+{
+	hfi1_release_user_pages(mm, pages + start, npages, false);
+	kfree(pages);
+}
+
+static void free_system_node(struct sdma_mmu_node *node)
+{
+	if (node->npages) {
+		unpin_vector_pages(mm_from_sdma_node(node), node->pages, 0,
+				   node->npages);
+		atomic_sub(node->npages, &node->pq->n_locked);
+	}
+	kfree(node);
+}
+
+/*
+ * kref_get()'s an additional kref on the returned rb_node to prevent rb_node
+ * from being released until after rb_node is assigned to an SDMA descriptor
+ * (struct sdma_desc) under add_system_iovec_to_sdma_packet(), even if the
+ * virtual address range for rb_node is invalidated between now and then.
+ */
+static struct sdma_mmu_node *find_system_node(struct mmu_rb_handler *handler,
+					      unsigned long start,
+					      unsigned long end)
+{
+	struct mmu_rb_node *rb_node;
+	unsigned long flags;
+
+	spin_lock_irqsave(&handler->lock, flags);
+	rb_node = hfi1_mmu_rb_get_first(handler, start, (end - start));
+	if (!rb_node) {
+		spin_unlock_irqrestore(&handler->lock, flags);
+		return NULL;
+	}
+
+	/* "safety" kref to prevent release before add_system_iovec_to_sdma_packet() */
+	kref_get(&rb_node->refcount);
+	spin_unlock_irqrestore(&handler->lock, flags);
+
+	return container_of(rb_node, struct sdma_mmu_node, rb);
+}
+
+static int pin_system_pages(struct user_sdma_request *req,
+			    uintptr_t start_address, size_t length,
+			    struct sdma_mmu_node *node, int npages)
+{
+	struct hfi1_user_sdma_pkt_q *pq = req->pq;
+	int pinned, cleared;
+	struct page **pages;
+
+	pages = kcalloc(npages, sizeof(*pages), GFP_KERNEL);
+	if (!pages)
+		return -ENOMEM;
+
+retry:
+	if (!hfi1_can_pin_pages(pq->dd, current->mm, atomic_read(&pq->n_locked),
+				npages)) {
+		SDMA_DBG(req, "Evicting: nlocked %u npages %u",
+			 atomic_read(&pq->n_locked), npages);
+		cleared = sdma_cache_evict(pq, npages);
+		if (cleared >= npages)
+			goto retry;
+	}
+
+	SDMA_DBG(req, "Acquire user pages start_address %lx node->npages %u npages %u",
+		 start_address, node->npages, npages);
+	pinned = hfi1_acquire_user_pages(current->mm, start_address, npages, 0,
+					 pages);
+
+	if (pinned < 0) {
+		kfree(pages);
+		SDMA_DBG(req, "pinned %d", pinned);
+		return pinned;
+	}
+	if (pinned != npages) {
+		unpin_vector_pages(current->mm, pages, node->npages, pinned);
+		SDMA_DBG(req, "npages %u pinned %d", npages, pinned);
+		return -EFAULT;
+	}
+	node->rb.addr = start_address;
+	node->rb.len = length;
+	node->pages = pages;
+	node->npages = npages;
+	atomic_add(pinned, &pq->n_locked);
+	SDMA_DBG(req, "done. pinned %d", pinned);
+	return 0;
+}
+
+/*
+ * kref refcount on *node_p will be 2 on successful addition: one kref from
+ * kref_init() for mmu_rb_handler and one kref to prevent *node_p from being
+ * released until after *node_p is assigned to an SDMA descriptor (struct
+ * sdma_desc) under add_system_iovec_to_sdma_packet(), even if the virtual
+ * address range for *node_p is invalidated between now and then.
+ */
+static int add_system_pinning(struct user_sdma_request *req,
+			      struct sdma_mmu_node **node_p,
+			      unsigned long start, unsigned long len)
+
+{
+	struct hfi1_user_sdma_pkt_q *pq = req->pq;
+	struct sdma_mmu_node *node;
+	int ret;
+
+	node = kzalloc(sizeof(*node), GFP_KERNEL);
+	if (!node)
+		return -ENOMEM;
+
+	/* First kref "moves" to mmu_rb_handler */
+	kref_init(&node->rb.refcount);
+
+	/* "safety" kref to prevent release before add_system_iovec_to_sdma_packet() */
+	kref_get(&node->rb.refcount);
+
+	node->pq = pq;
+	ret = pin_system_pages(req, start, len, node, PFN_DOWN(len));
+	if (ret == 0) {
+		ret = hfi1_mmu_rb_insert(pq->handler, &node->rb);
+		if (ret)
+			free_system_node(node);
+		else
+			*node_p = node;
+
+		return ret;
+	}
+
+	kfree(node);
+	return ret;
+}
+
+static int get_system_cache_entry(struct user_sdma_request *req,
+				  struct sdma_mmu_node **node_p,
+				  size_t req_start, size_t req_len)
+{
+	struct hfi1_user_sdma_pkt_q *pq = req->pq;
+	u64 start = ALIGN_DOWN(req_start, PAGE_SIZE);
+	u64 end = PFN_ALIGN(req_start + req_len);
+	struct mmu_rb_handler *handler = pq->handler;
+	int ret;
+
+	if ((end - start) == 0) {
+		SDMA_DBG(req,
+			 "Request for empty cache entry req_start %lx req_len %lx start %llx end %llx",
+			 req_start, req_len, start, end);
+		return -EINVAL;
+	}
+
+	SDMA_DBG(req, "req_start %lx req_len %lu", req_start, req_len);
+
+	while (1) {
+		struct sdma_mmu_node *node =
+			find_system_node(handler, start, end);
+		u64 prepend_len = 0;
+
+		SDMA_DBG(req, "node %p start %llx end %llu", node, start, end);
+		if (!node) {
+			ret = add_system_pinning(req, node_p, start,
+						 end - start);
+			if (ret == -EEXIST) {
+				/*
+				 * Another execution context has inserted a
+				 * conficting entry first.
+				 */
+				continue;
+			}
+			return ret;
+		}
+
+		if (node->rb.addr <= start) {
+			/*
+			 * This entry covers at least part of the region. If it doesn't extend
+			 * to the end, then this will be called again for the next segment.
+			 */
+			*node_p = node;
+			return 0;
+		}
+
+		SDMA_DBG(req, "prepend: node->rb.addr %lx, node->rb.refcount %d",
+			 node->rb.addr, kref_read(&node->rb.refcount));
+		prepend_len = node->rb.addr - start;
+
+		/*
+		 * This node will not be returned, instead a new node
+		 * will be. So release the reference.
+		 */
+		kref_put(&node->rb.refcount, hfi1_mmu_rb_release);
+
+		/* Prepend a node to cover the beginning of the allocation */
+		ret = add_system_pinning(req, node_p, start, prepend_len);
+		if (ret == -EEXIST) {
+			/* Another execution context has inserted a conficting entry first. */
+			continue;
+		}
+		return ret;
+	}
+}
+
+static void sdma_mmu_rb_node_get(void *ctx)
+{
+	struct mmu_rb_node *node = ctx;
+
+	kref_get(&node->refcount);
+}
+
+static void sdma_mmu_rb_node_put(void *ctx)
+{
+	struct sdma_mmu_node *node = ctx;
+
+	kref_put(&node->rb.refcount, hfi1_mmu_rb_release);
+}
+
+static int add_mapping_to_sdma_packet(struct user_sdma_request *req,
+				      struct user_sdma_txreq *tx,
+				      struct sdma_mmu_node *cache_entry,
+				      size_t start,
+				      size_t from_this_cache_entry)
+{
+	struct hfi1_user_sdma_pkt_q *pq = req->pq;
+	unsigned int page_offset;
+	unsigned int from_this_page;
+	size_t page_index;
+	void *ctx;
+	int ret;
+
+	/*
+	 * Because the cache may be more fragmented than the memory that is being accessed,
+	 * it's not strictly necessary to have a descriptor per cache entry.
+	 */
+
+	while (from_this_cache_entry) {
+		page_index = PFN_DOWN(start - cache_entry->rb.addr);
+
+		if (page_index >= cache_entry->npages) {
+			SDMA_DBG(req,
+				 "Request for page_index %zu >= cache_entry->npages %u",
+				 page_index, cache_entry->npages);
+			return -EINVAL;
+		}
+
+		page_offset = start - ALIGN_DOWN(start, PAGE_SIZE);
+		from_this_page = PAGE_SIZE - page_offset;
+
+		if (from_this_page < from_this_cache_entry) {
+			ctx = NULL;
+		} else {
+			/*
+			 * In the case they are equal the next line has no practical effect,
+			 * but it's better to do a register to register copy than a conditional
+			 * branch.
+			 */
+			from_this_page = from_this_cache_entry;
+			ctx = cache_entry;
+		}
+
+		ret = sdma_txadd_page(pq->dd, &tx->txreq,
+				      cache_entry->pages[page_index],
+				      page_offset, from_this_page,
+				      ctx,
+				      sdma_mmu_rb_node_get,
+				      sdma_mmu_rb_node_put);
+		if (ret) {
+			/*
+			 * When there's a failure, the entire request is freed by
+			 * user_sdma_send_pkts().
+			 */
+			SDMA_DBG(req,
+				 "sdma_txadd_page failed %d page_index %lu page_offset %u from_this_page %u",
+				 ret, page_index, page_offset, from_this_page);
+			return ret;
+		}
+		start += from_this_page;
+		from_this_cache_entry -= from_this_page;
+	}
+	return 0;
+}
+
+static int add_system_iovec_to_sdma_packet(struct user_sdma_request *req,
+					   struct user_sdma_txreq *tx,
+					   struct user_sdma_iovec *iovec,
+					   size_t from_this_iovec)
+{
+	while (from_this_iovec > 0) {
+		struct sdma_mmu_node *cache_entry;
+		size_t from_this_cache_entry;
+		size_t start;
+		int ret;
+
+		start = (uintptr_t)iovec->iov.iov_base + iovec->offset;
+		ret = get_system_cache_entry(req, &cache_entry, start,
+					     from_this_iovec);
+		if (ret) {
+			SDMA_DBG(req, "pin system segment failed %d", ret);
+			return ret;
+		}
+
+		from_this_cache_entry = cache_entry->rb.len - (start - cache_entry->rb.addr);
+		if (from_this_cache_entry > from_this_iovec)
+			from_this_cache_entry = from_this_iovec;
+
+		ret = add_mapping_to_sdma_packet(req, tx, cache_entry, start,
+						 from_this_cache_entry);
+
+		/*
+		 * Done adding cache_entry to zero or more sdma_desc. Can
+		 * kref_put() the "safety" kref taken under
+		 * get_system_cache_entry().
+		 */
+		kref_put(&cache_entry->rb.refcount, hfi1_mmu_rb_release);
+
+		if (ret) {
+			SDMA_DBG(req, "add system segment failed %d", ret);
+			return ret;
+		}
+
+		iovec->offset += from_this_cache_entry;
+		from_this_iovec -= from_this_cache_entry;
+	}
+
+	return 0;
+}
+
+static int add_system_pages_to_sdma_packet(struct user_sdma_request *req,
+					   struct user_sdma_txreq *tx,
+					   struct user_sdma_iovec *iovec,
+					   u32 *pkt_data_remaining)
+{
+	size_t remaining_to_add = *pkt_data_remaining;
+	/*
+	 * Walk through iovec entries, ensure the associated pages
+	 * are pinned and mapped, add data to the packet until no more
+	 * data remains to be added.
+	 */
+	while (remaining_to_add > 0) {
+		struct user_sdma_iovec *cur_iovec;
+		size_t from_this_iovec;
+		int ret;
+
+		cur_iovec = iovec;
+		from_this_iovec = iovec->iov.iov_len - iovec->offset;
+
+		if (from_this_iovec > remaining_to_add) {
+			from_this_iovec = remaining_to_add;
+		} else {
+			/* The current iovec entry will be consumed by this pass. */
+			req->iov_idx++;
+			iovec++;
+		}
+
+		ret = add_system_iovec_to_sdma_packet(req, tx, cur_iovec,
+						      from_this_iovec);
+		if (ret)
+			return ret;
+
+		remaining_to_add -= from_this_iovec;
+	}
+	*pkt_data_remaining = remaining_to_add;
+
+	return 0;
+}
+
+static bool sdma_rb_filter(struct mmu_rb_node *node, unsigned long addr,
+			   unsigned long len)
+{
+	return (bool)(node->addr == addr);
+}
+
+/*
+ * Return 1 to remove the node from the rb tree and call the remove op.
+ *
+ * Called with the rb tree lock held.
+ */
+static int sdma_rb_evict(void *arg, struct mmu_rb_node *mnode,
+			 void *evict_arg, bool *stop)
+{
+	struct sdma_mmu_node *node =
+		container_of(mnode, struct sdma_mmu_node, rb);
+	struct evict_data *evict_data = evict_arg;
+
+	/* this node will be evicted, add its pages to our count */
+	evict_data->cleared += node->npages;
+
+	/* have enough pages been cleared? */
+	if (evict_data->cleared >= evict_data->target)
+		*stop = true;
+
+	return 1; /* remove this node */
+}
+
+static void sdma_rb_remove(void *arg, struct mmu_rb_node *mnode)
+{
+	struct sdma_mmu_node *node =
+		container_of(mnode, struct sdma_mmu_node, rb);
+
+	free_system_node(node);
+}