--- zzzz-none-000/linux-3.10.107/drivers/infiniband/hw/qib/qib_user_sdma.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/drivers/infiniband/hw/qib/qib_user_sdma.c	2021-02-04 17:41:59.000000000 +0000
@@ -50,23 +50,50 @@
 /* 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 500
+#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 {
-	u8 naddr;               /* dimension of addr (1..3) ... */
+	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 {
-		u32 offset;                     /* offset for kvaddr, addr */
-		u32 length;                     /* length in page */
-		u8  put_page;                   /* should we put_page? */
-		u8  dma_mapped;                 /* is page dma_mapped? */
+		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 list_head list;  /* list element */
 };
 
 struct qib_user_sdma_queue {
@@ -77,6 +104,12 @@
 	 */
 	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;
@@ -88,27 +121,83 @@
 	/* 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;
-	INIT_LIST_HEAD(&pq->sent);
+	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),
@@ -131,8 +220,31 @@
 
 	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:
@@ -144,34 +256,310 @@
 }
 
 static void qib_user_sdma_init_frag(struct qib_user_sdma_pkt *pkt,
-				    int i, size_t offset, size_t len,
-				    int put_page, int dma_mapped,
-				    struct page *page,
-				    void *kvaddr, dma_addr_t dma_addr)
+				    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 void qib_user_sdma_init_header(struct qib_user_sdma_pkt *pkt,
-				      u32 counter, size_t offset,
-				      size_t len, int dma_mapped,
-				      struct page *page,
-				      void *kvaddr, dma_addr_t dma_addr)
-{
-	pkt->naddr = 1;
-	pkt->counter = counter;
-	qib_user_sdma_init_frag(pkt, 0, offset, len, 0, dma_mapped, page,
-				kvaddr, dma_addr);
+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)
@@ -182,7 +570,6 @@
 	char *mpage;
 	int i;
 	int len = 0;
-	dma_addr_t dma_addr;
 
 	if (!page) {
 		ret = -ENOMEM;
@@ -205,17 +592,8 @@
 		len += iov[i].iov_len;
 	}
 
-	dma_addr = dma_map_page(&dd->pcidev->dev, page, 0, len,
-				DMA_TO_DEVICE);
-	if (dma_mapping_error(&dd->pcidev->dev, dma_addr)) {
-		ret = -ENOMEM;
-		goto free_unmap;
-	}
-
-	qib_user_sdma_init_frag(pkt, 1, 0, len, 0, 1, page, mpage_save,
-				dma_addr);
-	pkt->naddr = 2;
-
+	ret = qib_user_sdma_page_to_frags(dd, pq, pkt,
+			page, 0, 0, len, mpage_save);
 	goto done;
 
 free_unmap:
@@ -238,16 +616,6 @@
 	return 1 + ((epage - spage) >> PAGE_SHIFT);
 }
 
-/*
- * Truncate length to page boundary.
- */
-static int qib_user_sdma_page_length(unsigned long addr, unsigned long len)
-{
-	const unsigned long offset = addr & ~PAGE_MASK;
-
-	return ((offset + len) > PAGE_SIZE) ? (PAGE_SIZE - offset) : len;
-}
-
 static void qib_user_sdma_free_pkt_frag(struct device *dev,
 					struct qib_user_sdma_queue *pq,
 					struct qib_user_sdma_pkt *pkt,
@@ -256,10 +624,11 @@
 	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].length,
+				       pkt->addr[i].dma_length,
 				       DMA_TO_DEVICE);
 
 		if (pkt->addr[i].kvaddr)
@@ -269,54 +638,80 @@
 			put_page(pkt->addr[i].page);
 		else
 			__free_page(pkt->addr[i].page);
-	} else if (pkt->addr[i].kvaddr)
-		/* free coherent mem from cache... */
-		dma_pool_free(pq->header_cache,
+	} 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[2];
-	int j;
-	int ret;
-
-	ret = get_user_pages_fast(addr, npages, 0, pages);
-
-	if (ret != npages) {
-		int i;
-
-		for (i = 0; i < ret; i++)
-			put_page(pages[i]);
-
-		ret = -ENOMEM;
-		goto done;
-	}
+	struct page *pages[8];
+	int i, j;
+	int ret = 0;
 
-	for (j = 0; j < npages; j++) {
-		/* map the pages... */
-		const int flen = qib_user_sdma_page_length(addr, tlen);
-		dma_addr_t dma_addr =
-			dma_map_page(&dd->pcidev->dev,
-				     pages[j], 0, flen, DMA_TO_DEVICE);
-		unsigned long fofs = addr & ~PAGE_MASK;
+	while (npages) {
+		if (npages > 8)
+			j = 8;
+		else
+			j = npages;
 
-		if (dma_mapping_error(&dd->pcidev->dev, dma_addr)) {
+		ret = get_user_pages_fast(addr, j, 0, pages);
+		if (ret != j) {
+			i = 0;
+			j = ret;
 			ret = -ENOMEM;
-			goto done;
+			goto free_pages;
 		}
 
-		qib_user_sdma_init_frag(pkt, pkt->naddr, fofs, flen, 1, 1,
-					pages[j], kmap(pages[j]), dma_addr);
+		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;
+		}
 
-		pkt->naddr++;
-		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;
 }
@@ -334,7 +729,7 @@
 		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, pkt, addr,
+		ret = qib_user_sdma_pin_pages(dd, pq, pkt, addr,
 					      iov[idx].iov_len, npages);
 		if (ret < 0)
 			goto free_pkt;
@@ -343,9 +738,22 @@
 	goto done;
 
 free_pkt:
-	for (idx = 0; idx < pkt->naddr; idx++)
+	/* 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;
 }
@@ -358,8 +766,9 @@
 {
 	int ret = 0;
 
-	if (npages >= ARRAY_SIZE(pkt->addr))
-		ret = qib_user_sdma_coalesce(dd, pkt, iov, niov);
+	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);
 
@@ -379,7 +788,10 @@
 		for (i = 0; i < pkt->naddr; i++)
 			qib_user_sdma_free_pkt_frag(dev, pq, pkt, i);
 
-		kmem_cache_free(pq->pkt_slab, pkt);
+		if (pkt->largepkt)
+			kfree(pkt);
+		else
+			kmem_cache_free(pq->pkt_slab, pkt);
 	}
 	INIT_LIST_HEAD(list);
 }
@@ -392,63 +804,48 @@
  * 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,
-				    struct list_head *list,
 				    const struct iovec *iov,
 				    unsigned long niov,
-				    int maxpkts)
+				    struct list_head *list,
+				    int *maxpkts, int *ndesc)
 {
 	unsigned long idx = 0;
 	int ret = 0;
 	int npkts = 0;
-	struct page *page = NULL;
 	__le32 *pbc;
 	dma_addr_t dma_addr;
 	struct qib_user_sdma_pkt *pkt = NULL;
 	size_t len;
 	size_t nw;
 	u32 counter = pq->counter;
-	int dma_mapped = 0;
+	u16 frag_size;
 
-	while (idx < niov && npkts < maxpkts) {
+	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;
 
-		dma_mapped = 0;
 		len = iov[idx].iov_len;
 		nw = len >> 2;
-		page = NULL;
-
-		pkt = kmem_cache_alloc(pq->pkt_slab, GFP_KERNEL);
-		if (!pkt) {
-			ret = -ENOMEM;
-			goto free_list;
-		}
 
 		if (len < QIB_USER_SDMA_MIN_HEADER_LENGTH ||
 		    len > PAGE_SIZE || len & 3 || addr & 3) {
 			ret = -EINVAL;
-			goto free_pkt;
+			goto free_list;
 		}
 
-		if (len == QIB_USER_SDMA_EXP_HEADER_LENGTH)
-			pbc = dma_pool_alloc(pq->header_cache, GFP_KERNEL,
-					     &dma_addr);
-		else
-			pbc = NULL;
-
+		pbc = qib_user_sdma_alloc_header(pq, len, &dma_addr);
 		if (!pbc) {
-			page = alloc_page(GFP_KERNEL);
-			if (!page) {
-				ret = -ENOMEM;
-				goto free_pkt;
-			}
-			pbc = kmap(page);
+			ret = -ENOMEM;
+			goto free_list;
 		}
 
 		cfur = copy_from_user(pbc, iov[idx].iov_base, len);
@@ -473,8 +870,8 @@
 		 * we can verify that the packet is consistent with the
 		 * iovec lengths.
 		 */
-		pktnw = le32_to_cpu(*pbc) & QIB_PBC_LENGTH_MASK;
-		if (pktnw < pktnwc || pktnw > pktnwc + (PAGE_SIZE >> 2)) {
+		pktnw = le32_to_cpu(*pbc) & 0xFFFF;
+		if (pktnw < pktnwc) {
 			ret = -EINVAL;
 			goto free_pbc;
 		}
@@ -485,17 +882,14 @@
 			const unsigned long faddr =
 				(unsigned long) iov[idx].iov_base;
 
-			if (slen & 3 || faddr & 3 || !slen ||
-			    slen > PAGE_SIZE) {
+			if (slen & 3 || faddr & 3 || !slen) {
 				ret = -EINVAL;
 				goto free_pbc;
 			}
 
-			npages++;
-			if ((faddr & PAGE_MASK) !=
-			    ((faddr + slen - 1) & PAGE_MASK))
-				npages++;
+			npages += qib_user_sdma_num_pages(&iov[idx]);
 
+			bytes_togo += slen;
 			pktnwc += slen >> 2;
 			idx++;
 			nfrags++;
@@ -506,48 +900,140 @@
 			goto free_pbc;
 		}
 
-		if (page) {
-			dma_addr = dma_map_page(&dd->pcidev->dev,
-						page, 0, len, DMA_TO_DEVICE);
-			if (dma_mapping_error(&dd->pcidev->dev, dma_addr)) {
+		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++;
+			}
 
-			dma_mapped = 1;
+			/*
+			 * 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);
 		}
-
-		qib_user_sdma_init_header(pkt, counter, 0, len, dma_mapped,
-					  page, pbc, dma_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_pbc_dma;
+				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_pbc_dma:
-	if (dma_mapped)
-		dma_unmap_page(&dd->pcidev->dev, dma_addr, len, DMA_TO_DEVICE);
+free_pkt:
+	if (pkt->largepkt)
+		kfree(pkt);
+	else
+		kmem_cache_free(pq->pkt_slab, pkt);
 free_pbc:
-	if (page) {
-		kunmap(page);
-		__free_page(page);
-	} else
+	if (dma_addr)
 		dma_pool_free(pq->header_cache, pbc, dma_addr);
-free_pkt:
-	kmem_cache_free(pq->pkt_slab, pkt);
+	else
+		kfree(pbc);
 free_list:
 	qib_user_sdma_free_pkt_list(&dd->pcidev->dev, pq, list);
 done:
@@ -568,10 +1054,20 @@
 	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;
 
@@ -582,7 +1078,9 @@
 
 		/* one more packet cleaned */
 		ret++;
+		pq->num_sending--;
 	}
+	spin_unlock_irqrestore(&pq->sent_lock, flags);
 
 	if (!list_empty(&free_list)) {
 		u32 counter;
@@ -603,8 +1101,13 @@
 	if (!pq)
 		return;
 
-	kmem_cache_destroy(pq->pkt_slab);
+	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);
 }
 
@@ -626,6 +1129,7 @@
 			       struct qib_user_sdma_queue *pq)
 {
 	struct qib_devdata *dd = ppd->dd;
+	unsigned long flags;
 	int i;
 
 	if (!pq)
@@ -633,39 +1137,54 @@
 
 	for (i = 0; i < QIB_USER_SDMA_DRAIN_TIMEOUT; i++) {
 		mutex_lock(&pq->lock);
-		if (list_empty(&pq->sent)) {
+		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(10);
+		msleep(20);
 	}
 
-	if (!list_empty(&pq->sent)) {
+	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);
-		mutex_lock(&pq->lock);
 		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(struct qib_pportdata *ppd,
+static inline __le64 qib_sdma_make_desc0(u8 gen,
 					 u64 addr, u64 dwlen, u64 dwoffset)
 {
-	u8 tmpgen;
-
-	tmpgen = ppd->sdma_generation;
-
 	return cpu_to_le64(/* SDmaPhyAddr[31:0] */
 			   ((addr & 0xfffffffcULL) << 32) |
 			   /* SDmaGeneration[1:0] */
-			   ((tmpgen & 3ULL) << 30) |
+			   ((gen & 3ULL) << 30) |
 			   /* SDmaDwordCount[10:0] */
 			   ((dwlen & 0x7ffULL) << 16) |
 			   /* SDmaBufOffset[12:2] */
@@ -691,7 +1210,7 @@
 
 static void qib_user_sdma_send_frag(struct qib_pportdata *ppd,
 				    struct qib_user_sdma_pkt *pkt, int idx,
-				    unsigned ofs, u16 tail)
+				    unsigned ofs, u16 tail, u8 gen)
 {
 	const u64 addr = (u64) pkt->addr[idx].addr +
 		(u64) pkt->addr[idx].offset;
@@ -701,105 +1220,157 @@
 
 	descqp = &ppd->sdma_descq[tail].qw[0];
 
-	descq0 = qib_sdma_make_desc0(ppd, addr, dwlen, ofs);
-	if (idx == 0)
+	descq0 = qib_sdma_make_desc0(gen, addr, dwlen, ofs);
+	if (pkt->addr[idx].first_desc)
 		descq0 = qib_sdma_make_first_desc0(descq0);
-	if (idx == pkt->naddr - 1)
+	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);
 }
 
-/* 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)
+void qib_user_sdma_send_desc(struct qib_pportdata *ppd,
+				struct list_head *pktlist)
 {
 	struct qib_devdata *dd = ppd->dd;
-	int ret = 0;
-	unsigned long flags;
-	u16 tail;
-	u8 generation;
-	u64 descq_added;
+	u16 nfree, nsent;
+	u16 tail, tail_c;
+	u8 gen, gen_c;
 
-	if (list_empty(pktlist))
-		return 0;
-
-	if (unlikely(!(ppd->lflags & QIBL_LINKACTIVE)))
-		return -ECOMM;
-
-	spin_lock_irqsave(&ppd->sdma_lock, flags);
-
-	/* keep a copy for restoring purposes in case of problems */
-	generation = ppd->sdma_generation;
-	descq_added = ppd->sdma_descq_added;
-
-	if (unlikely(!__qib_sdma_running(ppd))) {
-		ret = -ECOMM;
-		goto unlock;
-	}
+	nfree = qib_sdma_descq_freecnt(ppd);
+	if (!nfree)
+		return;
 
-	tail = ppd->sdma_descq_tail;
+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;
+		int i, j, c = 0;
 		unsigned ofs = 0;
 		u16 dtail = tail;
 
-		if (pkt->naddr > qib_sdma_descq_freecnt(ppd))
-			goto unlock_check_tail;
-
-		for (i = 0; i < pkt->naddr; i++) {
-			qib_user_sdma_send_frag(ppd, pkt, i, ofs, 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;
-				++ppd->sdma_generation;
+				++gen;
+				ppd->sdma_intrequest = 1;
+			} else if (tail == (ppd->sdma_descq_cnt>>1)) {
+				ppd->sdma_intrequest = 1;
 			}
-		}
-
-		if ((ofs << 2) > ppd->ibmaxlen) {
-			ret = -EMSGSIZE;
-			goto unlock;
-		}
+			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 (i = 0; i < pkt->naddr; i++) {
-				ppd->sdma_descq[dtail].qw[0] |=
-					cpu_to_le64(1ULL << 14);
-				if (++dtail == ppd->sdma_descq_cnt)
-					dtail = 0;
+			/*
+			 * 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 += pkt->naddr;
-		pkt->added = ppd->sdma_descq_added;
-		list_move_tail(&pkt->list, &pq->sent);
-		ret++;
+		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;
 	}
 
-unlock_check_tail:
 	/* advance the tail on the chip if necessary */
-	if (ppd->sdma_descq_tail != tail)
-		dd->f_sdma_update_tail(ppd, tail);
+	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;
 
-unlock:
-	if (unlikely(ret < 0)) {
-		ppd->sdma_generation = generation;
-		ppd->sdma_descq_added = descq_added;
+	/* 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;
 	}
-	spin_unlock_irqrestore(&ppd->sdma_lock, flags);
 
-	return ret;
+	/* 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,
@@ -821,16 +1392,20 @@
 	if (!qib_sdma_running(ppd))
 		goto done_unlock;
 
-	if (ppd->sdma_descq_added != ppd->sdma_descq_removed) {
+	/* 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) {
-		const int mxp = 8;
+		int mxp = 1;
+		int ndesc = 0;
 
-		ret = qib_user_sdma_queue_pkts(dd, pq, &list, iov, dim, mxp);
-		if (ret <= 0)
+		ret = qib_user_sdma_queue_pkts(dd, ppd, pq,
+				iov, dim, &list, &mxp, &ndesc);
+		if (ret < 0)
 			goto done_unlock;
 		else {
 			dim -= ret;
@@ -840,24 +1415,20 @@
 		/* force packets onto the sdma hw queue... */
 		if (!list_empty(&list)) {
 			/*
-			 * Lazily clean hw queue.  the 4 is a guess of about
-			 * how many sdma descriptors a packet will take (it
-			 * doesn't have to be perfect).
+			 * Lazily clean hw queue.
 			 */
-			if (qib_sdma_descq_freecnt(ppd) < ret * 4) {
+			if (qib_sdma_descq_freecnt(ppd) < ndesc) {
 				qib_user_sdma_hwqueue_clean(ppd);
-				qib_user_sdma_queue_clean(ppd, pq);
+				if (pq->num_sending)
+					qib_user_sdma_queue_clean(ppd, pq);
 			}
 
-			ret = qib_user_sdma_push_pkts(ppd, pq, &list);
+			ret = qib_user_sdma_push_pkts(ppd, pq, &list, mxp);
 			if (ret < 0)
 				goto done_unlock;
 			else {
-				npkts += ret;
-				pq->counter += ret;
-
-				if (!list_empty(&list))
-					goto done_unlock;
+				npkts += mxp;
+				pq->counter += mxp;
 			}
 		}
 	}