Initial import

1 files changed, 1465 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/qib/qib_user_sdma.c b/drivers/infiniband/hw/qib/qib_user_sdma.c
new file mode 100644
index 000000000..3e0677c51
--- /dev/null
+++ b/drivers/infiniband/hw/qib/qib_user_sdma.c
@@ -0,0 +1,1465 @@
+/*
+ * Copyright (c) 2007, 2008, 2009 QLogic Corporation. 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
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#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 "qib.h"
+#include "qib_user_sdma.h"
+
+/* minimum size of header */
+#define QIB_USER_SDMA_MIN_HEADER_LENGTH 64
+/* expected size of headers (for dma_pool) */
+#define QIB_USER_SDMA_EXP_HEADER_LENGTH 64
+/* attempt to drain the queue for 5secs */
+#define QIB_USER_SDMA_DRAIN_TIMEOUT 250
+
+/*
+ * track how many times a process open this driver.
+ */
+static struct rb_root qib_user_sdma_rb_root = RB_ROOT;
+
+struct qib_user_sdma_rb_node {
+	struct rb_node node;
+	int refcount;
+	pid_t pid;
+};
+
+struct qib_user_sdma_pkt {
+	struct list_head list;  /* list element */
+
+	u8  tiddma;		/* if this is NEW tid-sdma */
+	u8  largepkt;		/* this is large pkt from kmalloc */
+	u16 frag_size;		/* frag size used by PSM */
+	u16 index;              /* last header index or push index */
+	u16 naddr;              /* dimension of addr (1..3) ... */
+	u16 addrlimit;		/* addr array size */
+	u16 tidsmidx;		/* current tidsm index */
+	u16 tidsmcount;		/* tidsm array item count */
+	u16 payload_size;	/* payload size so far for header */
+	u32 bytes_togo;		/* bytes for processing */
+	u32 counter;            /* sdma pkts queued counter for this entry */
+	struct qib_tid_session_member *tidsm;	/* tid session member array */
+	struct qib_user_sdma_queue *pq;	/* which pq this pkt belongs to */
+	u64 added;              /* global descq number of entries */
+
+	struct {
+		u16 offset;                     /* offset for kvaddr, addr */
+		u16 length;                     /* length in page */
+		u16 first_desc;			/* first desc */
+		u16 last_desc;			/* last desc */
+		u16 put_page;                   /* should we put_page? */
+		u16 dma_mapped;                 /* is page dma_mapped? */
+		u16 dma_length;			/* for dma_unmap_page() */
+		u16 padding;
+		struct page *page;              /* may be NULL (coherent mem) */
+		void *kvaddr;                   /* FIXME: only for pio hack */
+		dma_addr_t addr;
+	} addr[4];   /* max pages, any more and we coalesce */
+};
+
+struct qib_user_sdma_queue {
+	/*
+	 * pkts sent to dma engine are queued on this
+	 * list head.  the type of the elements of this
+	 * list are struct qib_user_sdma_pkt...
+	 */
+	struct list_head sent;
+
+	/*
+	 * Because above list will be accessed by both process and
+	 * signal handler, we need a spinlock for it.
+	 */
+	spinlock_t sent_lock ____cacheline_aligned_in_smp;
+
+	/* headers with expected length are allocated from here... */
+	char header_cache_name[64];
+	struct dma_pool *header_cache;
+
+	/* packets are allocated from the slab cache... */
+	char pkt_slab_name[64];
+	struct kmem_cache *pkt_slab;
+
+	/* as packets go on the queued queue, they are counted... */
+	u32 counter;
+	u32 sent_counter;
+	/* pending packets, not sending yet */
+	u32 num_pending;
+	/* sending packets, not complete yet */
+	u32 num_sending;
+	/* global descq number of entry of last sending packet */
+	u64 added;
+
+	/* dma page table */
+	struct rb_root dma_pages_root;
+
+	struct qib_user_sdma_rb_node *sdma_rb_node;
+
+	/* protect everything above... */
+	struct mutex lock;
+};
+
+static struct qib_user_sdma_rb_node *
+qib_user_sdma_rb_search(struct rb_root *root, pid_t pid)
+{
+	struct qib_user_sdma_rb_node *sdma_rb_node;
+	struct rb_node *node = root->rb_node;
+
+	while (node) {
+		sdma_rb_node = container_of(node,
+			struct qib_user_sdma_rb_node, node);
+		if (pid < sdma_rb_node->pid)
+			node = node->rb_left;
+		else if (pid > sdma_rb_node->pid)
+			node = node->rb_right;
+		else
+			return sdma_rb_node;
+	}
+	return NULL;
+}
+
+static int
+qib_user_sdma_rb_insert(struct rb_root *root, struct qib_user_sdma_rb_node *new)
+{
+	struct rb_node **node = &(root->rb_node);
+	struct rb_node *parent = NULL;
+	struct qib_user_sdma_rb_node *got;
+
+	while (*node) {
+		got = container_of(*node, struct qib_user_sdma_rb_node, node);
+		parent = *node;
+		if (new->pid < got->pid)
+			node = &((*node)->rb_left);
+		else if (new->pid > got->pid)
+			node = &((*node)->rb_right);
+		else
+			return 0;
+	}
+
+	rb_link_node(&new->node, parent, node);
+	rb_insert_color(&new->node, root);
+	return 1;
+}
+
+struct qib_user_sdma_queue *
+qib_user_sdma_queue_create(struct device *dev, int unit, int ctxt, int sctxt)
+{
+	struct qib_user_sdma_queue *pq =
+		kmalloc(sizeof(struct qib_user_sdma_queue), GFP_KERNEL);
+	struct qib_user_sdma_rb_node *sdma_rb_node;
+
+	if (!pq)
+		goto done;
+
+	pq->counter = 0;
+	pq->sent_counter = 0;
+	pq->num_pending = 0;
+	pq->num_sending = 0;
+	pq->added = 0;
+	pq->sdma_rb_node = NULL;
+
+	INIT_LIST_HEAD(&pq->sent);
+	spin_lock_init(&pq->sent_lock);
+	mutex_init(&pq->lock);
+
+	snprintf(pq->pkt_slab_name, sizeof(pq->pkt_slab_name),
+		 "qib-user-sdma-pkts-%u-%02u.%02u", unit, ctxt, sctxt);
+	pq->pkt_slab = kmem_cache_create(pq->pkt_slab_name,
+					 sizeof(struct qib_user_sdma_pkt),
+					 0, 0, NULL);
+
+	if (!pq->pkt_slab)
+		goto err_kfree;
+
+	snprintf(pq->header_cache_name, sizeof(pq->header_cache_name),
+		 "qib-user-sdma-headers-%u-%02u.%02u", unit, ctxt, sctxt);
+	pq->header_cache = dma_pool_create(pq->header_cache_name,
+					   dev,
+					   QIB_USER_SDMA_EXP_HEADER_LENGTH,
+					   4, 0);
+	if (!pq->header_cache)
+		goto err_slab;
+
+	pq->dma_pages_root = RB_ROOT;
+
+	sdma_rb_node = qib_user_sdma_rb_search(&qib_user_sdma_rb_root,
+					current->pid);
+	if (sdma_rb_node) {
+		sdma_rb_node->refcount++;
+	} else {
+		int ret;
+
+		sdma_rb_node = kmalloc(sizeof(
+			struct qib_user_sdma_rb_node), GFP_KERNEL);
+		if (!sdma_rb_node)
+			goto err_rb;
+
+		sdma_rb_node->refcount = 1;
+		sdma_rb_node->pid = current->pid;
+
+		ret = qib_user_sdma_rb_insert(&qib_user_sdma_rb_root,
+					sdma_rb_node);
+		BUG_ON(ret == 0);
+	}
+	pq->sdma_rb_node = sdma_rb_node;
+
+	goto done;
+
+err_rb:
+	dma_pool_destroy(pq->header_cache);
+err_slab:
+	kmem_cache_destroy(pq->pkt_slab);
+err_kfree:
+	kfree(pq);
+	pq = NULL;
+
+done:
+	return pq;
+}
+
+static void qib_user_sdma_init_frag(struct qib_user_sdma_pkt *pkt,
+				    int i, u16 offset, u16 len,
+				    u16 first_desc, u16 last_desc,
+				    u16 put_page, u16 dma_mapped,
+				    struct page *page, void *kvaddr,
+				    dma_addr_t dma_addr, u16 dma_length)
+{
+	pkt->addr[i].offset = offset;
+	pkt->addr[i].length = len;
+	pkt->addr[i].first_desc = first_desc;
+	pkt->addr[i].last_desc = last_desc;
+	pkt->addr[i].put_page = put_page;
+	pkt->addr[i].dma_mapped = dma_mapped;
+	pkt->addr[i].page = page;
+	pkt->addr[i].kvaddr = kvaddr;
+	pkt->addr[i].addr = dma_addr;
+	pkt->addr[i].dma_length = dma_length;
+}
+
+static void *qib_user_sdma_alloc_header(struct qib_user_sdma_queue *pq,
+				size_t len, dma_addr_t *dma_addr)
+{
+	void *hdr;
+
+	if (len == QIB_USER_SDMA_EXP_HEADER_LENGTH)
+		hdr = dma_pool_alloc(pq->header_cache, GFP_KERNEL,
+					     dma_addr);
+	else
+		hdr = NULL;
+
+	if (!hdr) {
+		hdr = kmalloc(len, GFP_KERNEL);
+		if (!hdr)
+			return NULL;
+
+		*dma_addr = 0;
+	}
+
+	return hdr;
+}
+
+static int qib_user_sdma_page_to_frags(const struct qib_devdata *dd,
+				       struct qib_user_sdma_queue *pq,
+				       struct qib_user_sdma_pkt *pkt,
+				       struct page *page, u16 put,
+				       u16 offset, u16 len, void *kvaddr)
+{
+	__le16 *pbc16;
+	void *pbcvaddr;
+	struct qib_message_header *hdr;
+	u16 newlen, pbclen, lastdesc, dma_mapped;
+	u32 vcto;
+	union qib_seqnum seqnum;
+	dma_addr_t pbcdaddr;
+	dma_addr_t dma_addr =
+		dma_map_page(&dd->pcidev->dev,
+			page, offset, len, DMA_TO_DEVICE);
+	int ret = 0;
+
+	if (dma_mapping_error(&dd->pcidev->dev, dma_addr)) {
+		/*
+		 * dma mapping error, pkt has not managed
+		 * this page yet, return the page here so
+		 * the caller can ignore this page.
+		 */
+		if (put) {
+			put_page(page);
+		} else {
+			/* coalesce case */
+			kunmap(page);
+			__free_page(page);
+		}
+		ret = -ENOMEM;
+		goto done;
+	}
+	offset = 0;
+	dma_mapped = 1;
+
+
+next_fragment:
+
+	/*
+	 * In tid-sdma, the transfer length is restricted by
+	 * receiver side current tid page length.
+	 */
+	if (pkt->tiddma && len > pkt->tidsm[pkt->tidsmidx].length)
+		newlen = pkt->tidsm[pkt->tidsmidx].length;
+	else
+		newlen = len;
+
+	/*
+	 * Then the transfer length is restricted by MTU.
+	 * the last descriptor flag is determined by:
+	 * 1. the current packet is at frag size length.
+	 * 2. the current tid page is done if tid-sdma.
+	 * 3. there is no more byte togo if sdma.
+	 */
+	lastdesc = 0;
+	if ((pkt->payload_size + newlen) >= pkt->frag_size) {
+		newlen = pkt->frag_size - pkt->payload_size;
+		lastdesc = 1;
+	} else if (pkt->tiddma) {
+		if (newlen == pkt->tidsm[pkt->tidsmidx].length)
+			lastdesc = 1;
+	} else {
+		if (newlen == pkt->bytes_togo)
+			lastdesc = 1;
+	}
+
+	/* fill the next fragment in this page */
+	qib_user_sdma_init_frag(pkt, pkt->naddr, /* index */
+		offset, newlen,		/* offset, len */
+		0, lastdesc,		/* first last desc */
+		put, dma_mapped,	/* put page, dma mapped */
+		page, kvaddr,		/* struct page, virt addr */
+		dma_addr, len);		/* dma addr, dma length */
+	pkt->bytes_togo -= newlen;
+	pkt->payload_size += newlen;
+	pkt->naddr++;
+	if (pkt->naddr == pkt->addrlimit) {
+		ret = -EFAULT;
+		goto done;
+	}
+
+	/* If there is no more byte togo. (lastdesc==1) */
+	if (pkt->bytes_togo == 0) {
+		/* The packet is done, header is not dma mapped yet.
+		 * it should be from kmalloc */
+		if (!pkt->addr[pkt->index].addr) {
+			pkt->addr[pkt->index].addr =
+				dma_map_single(&dd->pcidev->dev,
+					pkt->addr[pkt->index].kvaddr,
+					pkt->addr[pkt->index].dma_length,
+					DMA_TO_DEVICE);
+			if (dma_mapping_error(&dd->pcidev->dev,
+					pkt->addr[pkt->index].addr)) {
+				ret = -ENOMEM;
+				goto done;
+			}
+			pkt->addr[pkt->index].dma_mapped = 1;
+		}
+
+		goto done;
+	}
+
+	/* If tid-sdma, advance tid info. */
+	if (pkt->tiddma) {
+		pkt->tidsm[pkt->tidsmidx].length -= newlen;
+		if (pkt->tidsm[pkt->tidsmidx].length) {
+			pkt->tidsm[pkt->tidsmidx].offset += newlen;
+		} else {
+			pkt->tidsmidx++;
+			if (pkt->tidsmidx == pkt->tidsmcount) {
+				ret = -EFAULT;
+				goto done;
+			}
+		}
+	}
+
+	/*
+	 * If this is NOT the last descriptor. (newlen==len)
+	 * the current packet is not done yet, but the current
+	 * send side page is done.
+	 */
+	if (lastdesc == 0)
+		goto done;
+
+	/*
+	 * If running this driver under PSM with message size
+	 * fitting into one transfer unit, it is not possible
+	 * to pass this line. otherwise, it is a buggggg.
+	 */
+
+	/*
+	 * Since the current packet is done, and there are more
+	 * bytes togo, we need to create a new sdma header, copying
+	 * from previous sdma header and modify both.
+	 */
+	pbclen = pkt->addr[pkt->index].length;
+	pbcvaddr = qib_user_sdma_alloc_header(pq, pbclen, &pbcdaddr);
+	if (!pbcvaddr) {
+		ret = -ENOMEM;
+		goto done;
+	}
+	/* Copy the previous sdma header to new sdma header */
+	pbc16 = (__le16 *)pkt->addr[pkt->index].kvaddr;
+	memcpy(pbcvaddr, pbc16, pbclen);
+
+	/* Modify the previous sdma header */
+	hdr = (struct qib_message_header *)&pbc16[4];
+
+	/* New pbc length */
+	pbc16[0] = cpu_to_le16(le16_to_cpu(pbc16[0])-(pkt->bytes_togo>>2));
+
+	/* New packet length */
+	hdr->lrh[2] = cpu_to_be16(le16_to_cpu(pbc16[0]));
+
+	if (pkt->tiddma) {
+		/* turn on the header suppression */
+		hdr->iph.pkt_flags =
+			cpu_to_le16(le16_to_cpu(hdr->iph.pkt_flags)|0x2);
+		/* turn off ACK_REQ: 0x04 and EXPECTED_DONE: 0x20 */
+		hdr->flags &= ~(0x04|0x20);
+	} else {
+		/* turn off extra bytes: 20-21 bits */
+		hdr->bth[0] = cpu_to_be32(be32_to_cpu(hdr->bth[0])&0xFFCFFFFF);
+		/* turn off ACK_REQ: 0x04 */
+		hdr->flags &= ~(0x04);
+	}
+
+	/* New kdeth checksum */
+	vcto = le32_to_cpu(hdr->iph.ver_ctxt_tid_offset);
+	hdr->iph.chksum = cpu_to_le16(QIB_LRH_BTH +
+		be16_to_cpu(hdr->lrh[2]) -
+		((vcto>>16)&0xFFFF) - (vcto&0xFFFF) -
+		le16_to_cpu(hdr->iph.pkt_flags));
+
+	/* The packet is done, header is not dma mapped yet.
+	 * it should be from kmalloc */
+	if (!pkt->addr[pkt->index].addr) {
+		pkt->addr[pkt->index].addr =
+			dma_map_single(&dd->pcidev->dev,
+				pkt->addr[pkt->index].kvaddr,
+				pkt->addr[pkt->index].dma_length,
+				DMA_TO_DEVICE);
+		if (dma_mapping_error(&dd->pcidev->dev,
+				pkt->addr[pkt->index].addr)) {
+			ret = -ENOMEM;
+			goto done;
+		}
+		pkt->addr[pkt->index].dma_mapped = 1;
+	}
+
+	/* Modify the new sdma header */
+	pbc16 = (__le16 *)pbcvaddr;
+	hdr = (struct qib_message_header *)&pbc16[4];
+
+	/* New pbc length */
+	pbc16[0] = cpu_to_le16(le16_to_cpu(pbc16[0])-(pkt->payload_size>>2));
+
+	/* New packet length */
+	hdr->lrh[2] = cpu_to_be16(le16_to_cpu(pbc16[0]));
+
+	if (pkt->tiddma) {
+		/* Set new tid and offset for new sdma header */
+		hdr->iph.ver_ctxt_tid_offset = cpu_to_le32(
+			(le32_to_cpu(hdr->iph.ver_ctxt_tid_offset)&0xFF000000) +
+			(pkt->tidsm[pkt->tidsmidx].tid<<QLOGIC_IB_I_TID_SHIFT) +
+			(pkt->tidsm[pkt->tidsmidx].offset>>2));
+	} else {
+		/* Middle protocol new packet offset */
+		hdr->uwords[2] += pkt->payload_size;
+	}
+
+	/* New kdeth checksum */
+	vcto = le32_to_cpu(hdr->iph.ver_ctxt_tid_offset);
+	hdr->iph.chksum = cpu_to_le16(QIB_LRH_BTH +
+		be16_to_cpu(hdr->lrh[2]) -
+		((vcto>>16)&0xFFFF) - (vcto&0xFFFF) -
+		le16_to_cpu(hdr->iph.pkt_flags));
+
+	/* Next sequence number in new sdma header */
+	seqnum.val = be32_to_cpu(hdr->bth[2]);
+	if (pkt->tiddma)
+		seqnum.seq++;
+	else
+		seqnum.pkt++;
+	hdr->bth[2] = cpu_to_be32(seqnum.val);
+
+	/* Init new sdma header. */
+	qib_user_sdma_init_frag(pkt, pkt->naddr, /* index */
+		0, pbclen,		/* offset, len */
+		1, 0,			/* first last desc */
+		0, 0,			/* put page, dma mapped */
+		NULL, pbcvaddr,		/* struct page, virt addr */
+		pbcdaddr, pbclen);	/* dma addr, dma length */
+	pkt->index = pkt->naddr;
+	pkt->payload_size = 0;
+	pkt->naddr++;
+	if (pkt->naddr == pkt->addrlimit) {
+		ret = -EFAULT;
+		goto done;
+	}
+
+	/* Prepare for next fragment in this page */
+	if (newlen != len) {
+		if (dma_mapped) {
+			put = 0;
+			dma_mapped = 0;
+			page = NULL;
+			kvaddr = NULL;
+		}
+		len -= newlen;
+		offset += newlen;
+
+		goto next_fragment;
+	}
+
+done:
+	return ret;
+}
+
+/* we've too many pages in the iovec, coalesce to a single page */
+static int qib_user_sdma_coalesce(const struct qib_devdata *dd,
+				  struct qib_user_sdma_queue *pq,
+				  struct qib_user_sdma_pkt *pkt,
+				  const struct iovec *iov,
+				  unsigned long niov)
+{
+	int ret = 0;
+	struct page *page = alloc_page(GFP_KERNEL);
+	void *mpage_save;
+	char *mpage;
+	int i;
+	int len = 0;
+
+	if (!page) {
+		ret = -ENOMEM;
+		goto done;
+	}
+
+	mpage = kmap(page);
+	mpage_save = mpage;
+	for (i = 0; i < niov; i++) {
+		int cfur;
+
+		cfur = copy_from_user(mpage,
+				      iov[i].iov_base, iov[i].iov_len);
+		if (cfur) {
+			ret = -EFAULT;
+			goto free_unmap;
+		}
+
+		mpage += iov[i].iov_len;
+		len += iov[i].iov_len;
+	}
+
+	ret = qib_user_sdma_page_to_frags(dd, pq, pkt,
+			page, 0, 0, len, mpage_save);
+	goto done;
+
+free_unmap:
+	kunmap(page);
+	__free_page(page);
+done:
+	return ret;
+}
+
+/*
+ * How many pages in this iovec element?
+ */
+static int qib_user_sdma_num_pages(const struct iovec *iov)
+{
+	const unsigned long addr  = (unsigned long) iov->iov_base;
+	const unsigned long  len  = iov->iov_len;
+	const unsigned long spage = addr & PAGE_MASK;
+	const unsigned long epage = (addr + len - 1) & PAGE_MASK;
+
+	return 1 + ((epage - spage) >> PAGE_SHIFT);
+}
+
+static void qib_user_sdma_free_pkt_frag(struct device *dev,
+					struct qib_user_sdma_queue *pq,
+					struct qib_user_sdma_pkt *pkt,
+					int frag)
+{
+	const int i = frag;
+
+	if (pkt->addr[i].page) {
+		/* only user data has page */
+		if (pkt->addr[i].dma_mapped)
+			dma_unmap_page(dev,
+				       pkt->addr[i].addr,
+				       pkt->addr[i].dma_length,
+				       DMA_TO_DEVICE);
+
+		if (pkt->addr[i].kvaddr)
+			kunmap(pkt->addr[i].page);
+
+		if (pkt->addr[i].put_page)
+			put_page(pkt->addr[i].page);
+		else
+			__free_page(pkt->addr[i].page);
+	} else if (pkt->addr[i].kvaddr) {
+		/* for headers */
+		if (pkt->addr[i].dma_mapped) {
+			/* from kmalloc & dma mapped */
+			dma_unmap_single(dev,
+				       pkt->addr[i].addr,
+				       pkt->addr[i].dma_length,
+				       DMA_TO_DEVICE);
+			kfree(pkt->addr[i].kvaddr);
+		} else if (pkt->addr[i].addr) {
+			/* free coherent mem from cache... */
+			dma_pool_free(pq->header_cache,
+			      pkt->addr[i].kvaddr, pkt->addr[i].addr);
+		} else {
+			/* from kmalloc but not dma mapped */
+			kfree(pkt->addr[i].kvaddr);
+		}
+	}
+}
+
+/* return number of pages pinned... */
+static int qib_user_sdma_pin_pages(const struct qib_devdata *dd,
+				   struct qib_user_sdma_queue *pq,
+				   struct qib_user_sdma_pkt *pkt,
+				   unsigned long addr, int tlen, int npages)
+{
+	struct page *pages[8];
+	int i, j;
+	int ret = 0;
+
+	while (npages) {
+		if (npages > 8)
+			j = 8;
+		else
+			j = npages;
+
+		ret = get_user_pages_fast(addr, j, 0, pages);
+		if (ret != j) {
+			i = 0;
+			j = ret;
+			ret = -ENOMEM;
+			goto free_pages;
+		}
+
+		for (i = 0; i < j; i++) {
+			/* map the pages... */
+			unsigned long fofs = addr & ~PAGE_MASK;
+			int flen = ((fofs + tlen) > PAGE_SIZE) ?
+				(PAGE_SIZE - fofs) : tlen;
+
+			ret = qib_user_sdma_page_to_frags(dd, pq, pkt,
+				pages[i], 1, fofs, flen, NULL);
+			if (ret < 0) {
+				/* current page has beed taken
+				 * care of inside above call.
+				 */
+				i++;
+				goto free_pages;
+			}
+
+			addr += flen;
+			tlen -= flen;
+		}
+
+		npages -= j;
+	}
+
+	goto done;
+
+	/* if error, return all pages not managed by pkt */
+free_pages:
+	while (i < j)
+		put_page(pages[i++]);
+
+done:
+	return ret;
+}
+
+static int qib_user_sdma_pin_pkt(const struct qib_devdata *dd,
+				 struct qib_user_sdma_queue *pq,
+				 struct qib_user_sdma_pkt *pkt,
+				 const struct iovec *iov,
+				 unsigned long niov)
+{
+	int ret = 0;
+	unsigned long idx;
+
+	for (idx = 0; idx < niov; idx++) {
+		const int npages = qib_user_sdma_num_pages(iov + idx);
+		const unsigned long addr = (unsigned long) iov[idx].iov_base;
+
+		ret = qib_user_sdma_pin_pages(dd, pq, pkt, addr,
+					      iov[idx].iov_len, npages);
+		if (ret < 0)
+			goto free_pkt;
+	}
+
+	goto done;
+
+free_pkt:
+	/* we need to ignore the first entry here */
+	for (idx = 1; idx < pkt->naddr; idx++)
+		qib_user_sdma_free_pkt_frag(&dd->pcidev->dev, pq, pkt, idx);
+
+	/* need to dma unmap the first entry, this is to restore to
+	 * the original state so that caller can free the memory in
+	 * error condition. Caller does not know if dma mapped or not*/
+	if (pkt->addr[0].dma_mapped) {
+		dma_unmap_single(&dd->pcidev->dev,
+		       pkt->addr[0].addr,
+		       pkt->addr[0].dma_length,
+		       DMA_TO_DEVICE);
+		pkt->addr[0].addr = 0;
+		pkt->addr[0].dma_mapped = 0;
+	}
+
+done:
+	return ret;
+}
+
+static int qib_user_sdma_init_payload(const struct qib_devdata *dd,
+				      struct qib_user_sdma_queue *pq,
+				      struct qib_user_sdma_pkt *pkt,
+				      const struct iovec *iov,
+				      unsigned long niov, int npages)
+{
+	int ret = 0;
+
+	if (pkt->frag_size == pkt->bytes_togo &&
+			npages >= ARRAY_SIZE(pkt->addr))
+		ret = qib_user_sdma_coalesce(dd, pq, pkt, iov, niov);
+	else
+		ret = qib_user_sdma_pin_pkt(dd, pq, pkt, iov, niov);
+
+	return ret;
+}
+
+/* free a packet list -- return counter value of last packet */
+static void qib_user_sdma_free_pkt_list(struct device *dev,
+					struct qib_user_sdma_queue *pq,
+					struct list_head *list)
+{
+	struct qib_user_sdma_pkt *pkt, *pkt_next;
+
+	list_for_each_entry_safe(pkt, pkt_next, list, list) {
+		int i;
+
+		for (i = 0; i < pkt->naddr; i++)
+			qib_user_sdma_free_pkt_frag(dev, pq, pkt, i);
+
+		if (pkt->largepkt)
+			kfree(pkt);
+		else
+			kmem_cache_free(pq->pkt_slab, pkt);
+	}
+	INIT_LIST_HEAD(list);
+}
+
+/*
+ * copy headers, coalesce etc -- pq->lock must be held
+ *
+ * we queue all the packets to list, returning the
+ * number of bytes total.  list must be empty initially,
+ * as, if there is an error we clean it...
+ */
+static int qib_user_sdma_queue_pkts(const struct qib_devdata *dd,
+				    struct qib_pportdata *ppd,
+				    struct qib_user_sdma_queue *pq,
+				    const struct iovec *iov,
+				    unsigned long niov,
+				    struct list_head *list,
+				    int *maxpkts, int *ndesc)
+{
+	unsigned long idx = 0;
+	int ret = 0;
+	int npkts = 0;
+	__le32 *pbc;
+	dma_addr_t dma_addr;
+	struct qib_user_sdma_pkt *pkt = NULL;
+	size_t len;
+	size_t nw;
+	u32 counter = pq->counter;
+	u16 frag_size;
+
+	while (idx < niov && npkts < *maxpkts) {
+		const unsigned long addr = (unsigned long) iov[idx].iov_base;
+		const unsigned long idx_save = idx;
+		unsigned pktnw;
+		unsigned pktnwc;
+		int nfrags = 0;
+		int npages = 0;
+		int bytes_togo = 0;
+		int tiddma = 0;
+		int cfur;
+
+		len = iov[idx].iov_len;
+		nw = len >> 2;
+
+		if (len < QIB_USER_SDMA_MIN_HEADER_LENGTH ||
+		    len > PAGE_SIZE || len & 3 || addr & 3) {
+			ret = -EINVAL;
+			goto free_list;
+		}
+
+		pbc = qib_user_sdma_alloc_header(pq, len, &dma_addr);
+		if (!pbc) {
+			ret = -ENOMEM;
+			goto free_list;
+		}
+
+		cfur = copy_from_user(pbc, iov[idx].iov_base, len);
+		if (cfur) {
+			ret = -EFAULT;
+			goto free_pbc;
+		}
+
+		/*
+		 * This assignment is a bit strange.  it's because the
+		 * the pbc counts the number of 32 bit words in the full
+		 * packet _except_ the first word of the pbc itself...
+		 */
+		pktnwc = nw - 1;
+
+		/*
+		 * pktnw computation yields the number of 32 bit words
+		 * that the caller has indicated in the PBC.  note that
+		 * this is one less than the total number of words that
+		 * goes to the send DMA engine as the first 32 bit word
+		 * of the PBC itself is not counted.  Armed with this count,
+		 * we can verify that the packet is consistent with the
+		 * iovec lengths.
+		 */
+		pktnw = le32_to_cpu(*pbc) & 0xFFFF;
+		if (pktnw < pktnwc) {
+			ret = -EINVAL;
+			goto free_pbc;
+		}
+
+		idx++;
+		while (pktnwc < pktnw && idx < niov) {
+			const size_t slen = iov[idx].iov_len;
+			const unsigned long faddr =
+				(unsigned long) iov[idx].iov_base;
+
+			if (slen & 3 || faddr & 3 || !slen) {
+				ret = -EINVAL;
+				goto free_pbc;
+			}
+
+			npages += qib_user_sdma_num_pages(&iov[idx]);
+
+			bytes_togo += slen;
+			pktnwc += slen >> 2;
+			idx++;
+			nfrags++;
+		}
+
+		if (pktnwc != pktnw) {
+			ret = -EINVAL;
+			goto free_pbc;
+		}
+
+		frag_size = ((le32_to_cpu(*pbc))>>16) & 0xFFFF;
+		if (((frag_size ? frag_size : bytes_togo) + len) >
+						ppd->ibmaxlen) {
+			ret = -EINVAL;
+			goto free_pbc;
+		}
+
+		if (frag_size) {
+			int pktsize, tidsmsize, n;
+
+			n = npages*((2*PAGE_SIZE/frag_size)+1);
+			pktsize = sizeof(*pkt) + sizeof(pkt->addr[0])*n;
+
+			/*
+			 * Determine if this is tid-sdma or just sdma.
+			 */
+			tiddma = (((le32_to_cpu(pbc[7])>>
+				QLOGIC_IB_I_TID_SHIFT)&
+				QLOGIC_IB_I_TID_MASK) !=
+				QLOGIC_IB_I_TID_MASK);
+
+			if (tiddma)
+				tidsmsize = iov[idx].iov_len;
+			else
+				tidsmsize = 0;
+
+			pkt = kmalloc(pktsize+tidsmsize, GFP_KERNEL);
+			if (!pkt) {
+				ret = -ENOMEM;
+				goto free_pbc;
+			}
+			pkt->largepkt = 1;
+			pkt->frag_size = frag_size;
+			pkt->addrlimit = n + ARRAY_SIZE(pkt->addr);
+
+			if (tiddma) {
+				char *tidsm = (char *)pkt + pktsize;
+
+				cfur = copy_from_user(tidsm,
+					iov[idx].iov_base, tidsmsize);
+				if (cfur) {
+					ret = -EFAULT;
+					goto free_pkt;
+				}
+				pkt->tidsm =
+					(struct qib_tid_session_member *)tidsm;
+				pkt->tidsmcount = tidsmsize/
+					sizeof(struct qib_tid_session_member);
+				pkt->tidsmidx = 0;
+				idx++;
+			}
+
+			/*
+			 * pbc 'fill1' field is borrowed to pass frag size,
+			 * we need to clear it after picking frag size, the
+			 * hardware requires this field to be zero.
+			 */
+			*pbc = cpu_to_le32(le32_to_cpu(*pbc) & 0x0000FFFF);
+		} else {
+			pkt = kmem_cache_alloc(pq->pkt_slab, GFP_KERNEL);
+			if (!pkt) {
+				ret = -ENOMEM;
+				goto free_pbc;
+			}
+			pkt->largepkt = 0;
+			pkt->frag_size = bytes_togo;
+			pkt->addrlimit = ARRAY_SIZE(pkt->addr);
+		}
+		pkt->bytes_togo = bytes_togo;
+		pkt->payload_size = 0;
+		pkt->counter = counter;
+		pkt->tiddma = tiddma;
+
+		/* setup the first header */
+		qib_user_sdma_init_frag(pkt, 0, /* index */
+			0, len,		/* offset, len */
+			1, 0,		/* first last desc */
+			0, 0,		/* put page, dma mapped */
+			NULL, pbc,	/* struct page, virt addr */
+			dma_addr, len);	/* dma addr, dma length */
+		pkt->index = 0;
+		pkt->naddr = 1;
+
+		if (nfrags) {
+			ret = qib_user_sdma_init_payload(dd, pq, pkt,
+							 iov + idx_save + 1,
+							 nfrags, npages);
+			if (ret < 0)
+				goto free_pkt;
+		} else {
+			/* since there is no payload, mark the
+			 * header as the last desc. */
+			pkt->addr[0].last_desc = 1;
+
+			if (dma_addr == 0) {
+				/*
+				 * the header is not dma mapped yet.
+				 * it should be from kmalloc.
+				 */
+				dma_addr = dma_map_single(&dd->pcidev->dev,
+					pbc, len, DMA_TO_DEVICE);
+				if (dma_mapping_error(&dd->pcidev->dev,
+								dma_addr)) {
+					ret = -ENOMEM;
+					goto free_pkt;
+				}
+				pkt->addr[0].addr = dma_addr;
+				pkt->addr[0].dma_mapped = 1;
+			}
+		}
+
+		counter++;
+		npkts++;
+		pkt->pq = pq;
+		pkt->index = 0; /* reset index for push on hw */
+		*ndesc += pkt->naddr;
+
+		list_add_tail(&pkt->list, list);
+	}
+
+	*maxpkts = npkts;
+	ret = idx;
+	goto done;
+
+free_pkt:
+	if (pkt->largepkt)
+		kfree(pkt);
+	else
+		kmem_cache_free(pq->pkt_slab, pkt);
+free_pbc:
+	if (dma_addr)
+		dma_pool_free(pq->header_cache, pbc, dma_addr);
+	else
+		kfree(pbc);
+free_list:
+	qib_user_sdma_free_pkt_list(&dd->pcidev->dev, pq, list);
+done:
+	return ret;
+}
+
+static void qib_user_sdma_set_complete_counter(struct qib_user_sdma_queue *pq,
+					       u32 c)
+{
+	pq->sent_counter = c;
+}
+
+/* try to clean out queue -- needs pq->lock */
+static int qib_user_sdma_queue_clean(struct qib_pportdata *ppd,
+				     struct qib_user_sdma_queue *pq)
+{
+	struct qib_devdata *dd = ppd->dd;
+	struct list_head free_list;
+	struct qib_user_sdma_pkt *pkt;
+	struct qib_user_sdma_pkt *pkt_prev;
+	unsigned long flags;
+	int ret = 0;
+
+	if (!pq->num_sending)
+		return 0;
+
+	INIT_LIST_HEAD(&free_list);
+
+	/*
+	 * We need this spin lock here because interrupt handler
+	 * might modify this list in qib_user_sdma_send_desc(), also
+	 * we can not get interrupted, otherwise it is a deadlock.
+	 */
+	spin_lock_irqsave(&pq->sent_lock, flags);
+	list_for_each_entry_safe(pkt, pkt_prev, &pq->sent, list) {
+		s64 descd = ppd->sdma_descq_removed - pkt->added;
+
+		if (descd < 0)
+			break;
+
+		list_move_tail(&pkt->list, &free_list);
+
+		/* one more packet cleaned */
+		ret++;
+		pq->num_sending--;
+	}
+	spin_unlock_irqrestore(&pq->sent_lock, flags);
+
+	if (!list_empty(&free_list)) {
+		u32 counter;
+
+		pkt = list_entry(free_list.prev,
+				 struct qib_user_sdma_pkt, list);
+		counter = pkt->counter;
+
+		qib_user_sdma_free_pkt_list(&dd->pcidev->dev, pq, &free_list);
+		qib_user_sdma_set_complete_counter(pq, counter);
+	}
+
+	return ret;
+}
+
+void qib_user_sdma_queue_destroy(struct qib_user_sdma_queue *pq)
+{
+	if (!pq)
+		return;
+
+	pq->sdma_rb_node->refcount--;
+	if (pq->sdma_rb_node->refcount == 0) {
+		rb_erase(&pq->sdma_rb_node->node, &qib_user_sdma_rb_root);
+		kfree(pq->sdma_rb_node);
+	}
+	dma_pool_destroy(pq->header_cache);
+	kmem_cache_destroy(pq->pkt_slab);
+	kfree(pq);
+}
+
+/* clean descriptor queue, returns > 0 if some elements cleaned */
+static int qib_user_sdma_hwqueue_clean(struct qib_pportdata *ppd)
+{
+	int ret;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ppd->sdma_lock, flags);
+	ret = qib_sdma_make_progress(ppd);
+	spin_unlock_irqrestore(&ppd->sdma_lock, flags);
+
+	return ret;
+}
+
+/* we're in close, drain packets so that we can cleanup successfully... */
+void qib_user_sdma_queue_drain(struct qib_pportdata *ppd,
+			       struct qib_user_sdma_queue *pq)
+{
+	struct qib_devdata *dd = ppd->dd;
+	unsigned long flags;
+	int i;
+
+	if (!pq)
+		return;
+
+	for (i = 0; i < QIB_USER_SDMA_DRAIN_TIMEOUT; i++) {
+		mutex_lock(&pq->lock);
+		if (!pq->num_pending && !pq->num_sending) {
+			mutex_unlock(&pq->lock);
+			break;
+		}
+		qib_user_sdma_hwqueue_clean(ppd);
+		qib_user_sdma_queue_clean(ppd, pq);
+		mutex_unlock(&pq->lock);
+		msleep(20);
+	}
+
+	if (pq->num_pending || pq->num_sending) {
+		struct qib_user_sdma_pkt *pkt;
+		struct qib_user_sdma_pkt *pkt_prev;
+		struct list_head free_list;
+
+		mutex_lock(&pq->lock);
+		spin_lock_irqsave(&ppd->sdma_lock, flags);
+		/*
+		 * Since we hold sdma_lock, it is safe without sent_lock.
+		 */
+		if (pq->num_pending) {
+			list_for_each_entry_safe(pkt, pkt_prev,
+					&ppd->sdma_userpending, list) {
+				if (pkt->pq == pq) {
+					list_move_tail(&pkt->list, &pq->sent);
+					pq->num_pending--;
+					pq->num_sending++;
+				}
+			}
+		}
+		spin_unlock_irqrestore(&ppd->sdma_lock, flags);
+
+		qib_dev_err(dd, "user sdma lists not empty: forcing!\n");
+		INIT_LIST_HEAD(&free_list);
+		list_splice_init(&pq->sent, &free_list);
+		pq->num_sending = 0;
+		qib_user_sdma_free_pkt_list(&dd->pcidev->dev, pq, &free_list);
+		mutex_unlock(&pq->lock);
+	}
+}
+
+static inline __le64 qib_sdma_make_desc0(u8 gen,
+					 u64 addr, u64 dwlen, u64 dwoffset)
+{
+	return cpu_to_le64(/* SDmaPhyAddr[31:0] */
+			   ((addr & 0xfffffffcULL) << 32) |
+			   /* SDmaGeneration[1:0] */
+			   ((gen & 3ULL) << 30) |
+			   /* SDmaDwordCount[10:0] */
+			   ((dwlen & 0x7ffULL) << 16) |
+			   /* SDmaBufOffset[12:2] */
+			   (dwoffset & 0x7ffULL));
+}
+
+static inline __le64 qib_sdma_make_first_desc0(__le64 descq)
+{
+	return descq | cpu_to_le64(1ULL << 12);
+}
+
+static inline __le64 qib_sdma_make_last_desc0(__le64 descq)
+{
+					      /* last */  /* dma head */
+	return descq | cpu_to_le64(1ULL << 11 | 1ULL << 13);
+}
+
+static inline __le64 qib_sdma_make_desc1(u64 addr)
+{
+	/* SDmaPhyAddr[47:32] */
+	return cpu_to_le64(addr >> 32);
+}
+
+static void qib_user_sdma_send_frag(struct qib_pportdata *ppd,
+				    struct qib_user_sdma_pkt *pkt, int idx,
+				    unsigned ofs, u16 tail, u8 gen)
+{
+	const u64 addr = (u64) pkt->addr[idx].addr +
+		(u64) pkt->addr[idx].offset;
+	const u64 dwlen = (u64) pkt->addr[idx].length / 4;
+	__le64 *descqp;
+	__le64 descq0;
+
+	descqp = &ppd->sdma_descq[tail].qw[0];
+
+	descq0 = qib_sdma_make_desc0(gen, addr, dwlen, ofs);
+	if (pkt->addr[idx].first_desc)
+		descq0 = qib_sdma_make_first_desc0(descq0);
+	if (pkt->addr[idx].last_desc) {
+		descq0 = qib_sdma_make_last_desc0(descq0);
+		if (ppd->sdma_intrequest) {
+			descq0 |= cpu_to_le64(1ULL << 15);
+			ppd->sdma_intrequest = 0;
+		}
+	}
+
+	descqp[0] = descq0;
+	descqp[1] = qib_sdma_make_desc1(addr);
+}
+
+void qib_user_sdma_send_desc(struct qib_pportdata *ppd,
+				struct list_head *pktlist)
+{
+	struct qib_devdata *dd = ppd->dd;
+	u16 nfree, nsent;
+	u16 tail, tail_c;
+	u8 gen, gen_c;
+
+	nfree = qib_sdma_descq_freecnt(ppd);
+	if (!nfree)
+		return;
+
+retry:
+	nsent = 0;
+	tail_c = tail = ppd->sdma_descq_tail;
+	gen_c = gen = ppd->sdma_generation;
+	while (!list_empty(pktlist)) {
+		struct qib_user_sdma_pkt *pkt =
+			list_entry(pktlist->next, struct qib_user_sdma_pkt,
+				   list);
+		int i, j, c = 0;
+		unsigned ofs = 0;
+		u16 dtail = tail;
+
+		for (i = pkt->index; i < pkt->naddr && nfree; i++) {
+			qib_user_sdma_send_frag(ppd, pkt, i, ofs, tail, gen);
+			ofs += pkt->addr[i].length >> 2;
+
+			if (++tail == ppd->sdma_descq_cnt) {
+				tail = 0;
+				++gen;
+				ppd->sdma_intrequest = 1;
+			} else if (tail == (ppd->sdma_descq_cnt>>1)) {
+				ppd->sdma_intrequest = 1;
+			}
+			nfree--;
+			if (pkt->addr[i].last_desc == 0)
+				continue;
+
+			/*
+			 * If the packet is >= 2KB mtu equivalent, we
+			 * have to use the large buffers, and have to
+			 * mark each descriptor as part of a large
+			 * buffer packet.
+			 */
+			if (ofs > dd->piosize2kmax_dwords) {
+				for (j = pkt->index; j <= i; j++) {
+					ppd->sdma_descq[dtail].qw[0] |=
+						cpu_to_le64(1ULL << 14);
+					if (++dtail == ppd->sdma_descq_cnt)
+						dtail = 0;
+				}
+			}
+			c += i + 1 - pkt->index;
+			pkt->index = i + 1; /* index for next first */
+			tail_c = dtail = tail;
+			gen_c = gen;
+			ofs = 0;  /* reset for next packet */
+		}
+
+		ppd->sdma_descq_added += c;
+		nsent += c;
+		if (pkt->index == pkt->naddr) {
+			pkt->added = ppd->sdma_descq_added;
+			pkt->pq->added = pkt->added;
+			pkt->pq->num_pending--;
+			spin_lock(&pkt->pq->sent_lock);
+			pkt->pq->num_sending++;
+			list_move_tail(&pkt->list, &pkt->pq->sent);
+			spin_unlock(&pkt->pq->sent_lock);
+		}
+		if (!nfree || (nsent<<2) > ppd->sdma_descq_cnt)
+			break;
+	}
+
+	/* advance the tail on the chip if necessary */
+	if (ppd->sdma_descq_tail != tail_c) {
+		ppd->sdma_generation = gen_c;
+		dd->f_sdma_update_tail(ppd, tail_c);
+	}
+
+	if (nfree && !list_empty(pktlist))
+		goto retry;
+}
+
+/* pq->lock must be held, get packets on the wire... */
+static int qib_user_sdma_push_pkts(struct qib_pportdata *ppd,
+				 struct qib_user_sdma_queue *pq,
+				 struct list_head *pktlist, int count)
+{
+	unsigned long flags;
+
+	if (unlikely(!(ppd->lflags & QIBL_LINKACTIVE)))
+		return -ECOMM;
+
+	/* non-blocking mode */
+	if (pq->sdma_rb_node->refcount > 1) {
+		spin_lock_irqsave(&ppd->sdma_lock, flags);
+		if (unlikely(!__qib_sdma_running(ppd))) {
+			spin_unlock_irqrestore(&ppd->sdma_lock, flags);
+			return -ECOMM;
+		}
+		pq->num_pending += count;
+		list_splice_tail_init(pktlist, &ppd->sdma_userpending);
+		qib_user_sdma_send_desc(ppd, &ppd->sdma_userpending);
+		spin_unlock_irqrestore(&ppd->sdma_lock, flags);
+		return 0;
+	}
+
+	/* In this case, descriptors from this process are not
+	 * linked to ppd pending queue, interrupt handler
+	 * won't update this process, it is OK to directly
+	 * modify without sdma lock.
+	 */
+
+
+	pq->num_pending += count;
+	/*
+	 * Blocking mode for single rail process, we must
+	 * release/regain sdma_lock to give other process
+	 * chance to make progress. This is important for
+	 * performance.
+	 */
+	do {
+		spin_lock_irqsave(&ppd->sdma_lock, flags);
+		if (unlikely(!__qib_sdma_running(ppd))) {
+			spin_unlock_irqrestore(&ppd->sdma_lock, flags);
+			return -ECOMM;
+		}
+		qib_user_sdma_send_desc(ppd, pktlist);
+		if (!list_empty(pktlist))
+			qib_sdma_make_progress(ppd);
+		spin_unlock_irqrestore(&ppd->sdma_lock, flags);
+	} while (!list_empty(pktlist));
+
+	return 0;
+}
+
+int qib_user_sdma_writev(struct qib_ctxtdata *rcd,
+			 struct qib_user_sdma_queue *pq,
+			 const struct iovec *iov,
+			 unsigned long dim)
+{
+	struct qib_devdata *dd = rcd->dd;
+	struct qib_pportdata *ppd = rcd->ppd;
+	int ret = 0;
+	struct list_head list;
+	int npkts = 0;
+
+	INIT_LIST_HEAD(&list);
+
+	mutex_lock(&pq->lock);
+
+	/* why not -ECOMM like qib_user_sdma_push_pkts() below? */
+	if (!qib_sdma_running(ppd))
+		goto done_unlock;
+
+	/* if I have packets not complete yet */
+	if (pq->added > ppd->sdma_descq_removed)
+		qib_user_sdma_hwqueue_clean(ppd);
+	/* if I have complete packets to be freed */
+	if (pq->num_sending)
+		qib_user_sdma_queue_clean(ppd, pq);
+
+	while (dim) {
+		int mxp = 1;
+		int ndesc = 0;
+
+		ret = qib_user_sdma_queue_pkts(dd, ppd, pq,
+				iov, dim, &list, &mxp, &ndesc);
+		if (ret < 0)
+			goto done_unlock;
+		else {
+			dim -= ret;
+			iov += ret;
+		}
+
+		/* force packets onto the sdma hw queue... */
+		if (!list_empty(&list)) {
+			/*
+			 * Lazily clean hw queue.
+			 */
+			if (qib_sdma_descq_freecnt(ppd) < ndesc) {
+				qib_user_sdma_hwqueue_clean(ppd);
+				if (pq->num_sending)
+					qib_user_sdma_queue_clean(ppd, pq);
+			}
+
+			ret = qib_user_sdma_push_pkts(ppd, pq, &list, mxp);
+			if (ret < 0)
+				goto done_unlock;
+			else {
+				npkts += mxp;
+				pq->counter += mxp;
+			}
+		}
+	}
+
+done_unlock:
+	if (!list_empty(&list))
+		qib_user_sdma_free_pkt_list(&dd->pcidev->dev, pq, &list);
+	mutex_unlock(&pq->lock);
+
+	return (ret < 0) ? ret : npkts;
+}
+
+int qib_user_sdma_make_progress(struct qib_pportdata *ppd,
+				struct qib_user_sdma_queue *pq)
+{
+	int ret = 0;
+
+	mutex_lock(&pq->lock);
+	qib_user_sdma_hwqueue_clean(ppd);
+	ret = qib_user_sdma_queue_clean(ppd, pq);
+	mutex_unlock(&pq->lock);
+
+	return ret;
+}
+
+u32 qib_user_sdma_complete_counter(const struct qib_user_sdma_queue *pq)
+{
+	return pq ? pq->sent_counter : 0;
+}
+
+u32 qib_user_sdma_inflight_counter(struct qib_user_sdma_queue *pq)
+{
+	return pq ? pq->counter : 0;
+}