IB: Refactor umem to use linear SG table

This patch refactors the IB core umem code and vendor drivers to use a
linear (chained) SG table instead of chunk list.  With this change the
relevant code becomes clearer—no need for nested loops to build and
use umem.

Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

16 files changed, 448 insertions, 552 deletions

diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index a8411232207..a3a2e9c1639 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -42,29 +42,29 @@
 
 #include "uverbs.h"
 
-#define IB_UMEM_MAX_PAGE_CHUNK						\
-	((PAGE_SIZE - offsetof(struct ib_umem_chunk, page_list)) /	\
-	 ((void *) &((struct ib_umem_chunk *) 0)->page_list[1] -	\
-	  (void *) &((struct ib_umem_chunk *) 0)->page_list[0]))
 
 static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int dirty)
 {
-	struct ib_umem_chunk *chunk, *tmp;
+	struct scatterlist *sg;
+	struct page *page;
 	int i;
 
-	list_for_each_entry_safe(chunk, tmp, &umem->chunk_list, list) {
-		ib_dma_unmap_sg(dev, chunk->page_list,
-				chunk->nents, DMA_BIDIRECTIONAL);
-		for (i = 0; i < chunk->nents; ++i) {
-			struct page *page = sg_page(&chunk->page_list[i]);
+	if (umem->nmap > 0)
+		ib_dma_unmap_sg(dev, umem->sg_head.sgl,
+				umem->nmap,
+				DMA_BIDIRECTIONAL);
 
-			if (umem->writable && dirty)
-				set_page_dirty_lock(page);
-			put_page(page);
-		}
+	for_each_sg(umem->sg_head.sgl, sg, umem->npages, i) {
 
-		kfree(chunk);
+		page = sg_page(sg);
+		if (umem->writable && dirty)
+			set_page_dirty_lock(page);
+		put_page(page);
 	}
+
+	sg_free_table(&umem->sg_head);
+	return;
+
 }
 
 /**
@@ -81,15 +81,15 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
 	struct ib_umem *umem;
 	struct page **page_list;
 	struct vm_area_struct **vma_list;
-	struct ib_umem_chunk *chunk;
 	unsigned long locked;
 	unsigned long lock_limit;
 	unsigned long cur_base;
 	unsigned long npages;
 	int ret;
-	int off;
 	int i;
 	DEFINE_DMA_ATTRS(attrs);
+	struct scatterlist *sg, *sg_list_start;
+	int need_release = 0;
 
 	if (dmasync)
 		dma_set_attr(DMA_ATTR_WRITE_BARRIER, &attrs);
@@ -97,7 +97,7 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
 	if (!can_do_mlock())
 		return ERR_PTR(-EPERM);
 
-	umem = kmalloc(sizeof *umem, GFP_KERNEL);
+	umem = kzalloc(sizeof *umem, GFP_KERNEL);
 	if (!umem)
 		return ERR_PTR(-ENOMEM);
 
@@ -117,8 +117,6 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
 	/* We assume the memory is from hugetlb until proved otherwise */
 	umem->hugetlb   = 1;
 
-	INIT_LIST_HEAD(&umem->chunk_list);
-
 	page_list = (struct page **) __get_free_page(GFP_KERNEL);
 	if (!page_list) {
 		kfree(umem);
@@ -147,7 +145,18 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
 
 	cur_base = addr & PAGE_MASK;
 
-	ret = 0;
+	if (npages == 0) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = sg_alloc_table(&umem->sg_head, npages, GFP_KERNEL);
+	if (ret)
+		goto out;
+
+	need_release = 1;
+	sg_list_start = umem->sg_head.sgl;
+
 	while (npages) {
 		ret = get_user_pages(current, current->mm, cur_base,
 				     min_t(unsigned long, npages,
@@ -157,54 +166,38 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
 		if (ret < 0)
 			goto out;
 
+		umem->npages += ret;
 		cur_base += ret * PAGE_SIZE;
 		npages   -= ret;
 
-		off = 0;
-
-		while (ret) {
-			chunk = kmalloc(sizeof *chunk + sizeof (struct scatterlist) *
-					min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK),
-					GFP_KERNEL);
-			if (!chunk) {
-				ret = -ENOMEM;
-				goto out;
-			}
-
-			chunk->nents = min_t(int, ret, IB_UMEM_MAX_PAGE_CHUNK);
-			sg_init_table(chunk->page_list, chunk->nents);
-			for (i = 0; i < chunk->nents; ++i) {
-				if (vma_list &&
-				    !is_vm_hugetlb_page(vma_list[i + off]))
-					umem->hugetlb = 0;
-				sg_set_page(&chunk->page_list[i], page_list[i + off], PAGE_SIZE, 0);
-			}
-
-			chunk->nmap = ib_dma_map_sg_attrs(context->device,
-							  &chunk->page_list[0],
-							  chunk->nents,
-							  DMA_BIDIRECTIONAL,
-							  &attrs);
-			if (chunk->nmap <= 0) {
-				for (i = 0; i < chunk->nents; ++i)
-					put_page(sg_page(&chunk->page_list[i]));
-				kfree(chunk);
-
-				ret = -ENOMEM;
-				goto out;
-			}
-
-			ret -= chunk->nents;
-			off += chunk->nents;
-			list_add_tail(&chunk->list, &umem->chunk_list);
+		for_each_sg(sg_list_start, sg, ret, i) {
+			if (vma_list && !is_vm_hugetlb_page(vma_list[i]))
+				umem->hugetlb = 0;
+
+			sg_set_page(sg, page_list[i], PAGE_SIZE, 0);
 		}
 
-		ret = 0;
+		/* preparing for next loop */
+		sg_list_start = sg;
 	}
 
+	umem->nmap = ib_dma_map_sg_attrs(context->device,
+				  umem->sg_head.sgl,
+				  umem->npages,
+				  DMA_BIDIRECTIONAL,
+				  &attrs);
+
+	if (umem->nmap <= 0) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ret = 0;
+
 out:
 	if (ret < 0) {
-		__ib_umem_release(context->device, umem, 0);
+		if (need_release)
+			__ib_umem_release(context->device, umem, 0);
 		kfree(umem);
 	} else
 		current->mm->pinned_vm = locked;
@@ -278,17 +271,16 @@ EXPORT_SYMBOL(ib_umem_release);
 
 int ib_umem_page_count(struct ib_umem *umem)
 {
-	struct ib_umem_chunk *chunk;
 	int shift;
 	int i;
 	int n;
+	struct scatterlist *sg;
 
 	shift = ilog2(umem->page_size);
 
 	n = 0;
-	list_for_each_entry(chunk, &umem->chunk_list, list)
-		for (i = 0; i < chunk->nmap; ++i)
-			n += sg_dma_len(&chunk->page_list[i]) >> shift;
+	for_each_sg(umem->sg_head.sgl, sg, umem->nmap, i)
+		n += sg_dma_len(sg) >> shift;
 
 	return n;
 }
diff --git a/drivers/infiniband/hw/amso1100/c2_provider.c b/drivers/infiniband/hw/amso1100/c2_provider.c
index 07eb3a8067d..8af33cf1fc4 100644
--- a/drivers/infiniband/hw/amso1100/c2_provider.c
+++ b/drivers/infiniband/hw/amso1100/c2_provider.c
@@ -431,9 +431,9 @@ static struct ib_mr *c2_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 	u64 *pages;
 	u64 kva = 0;
 	int shift, n, len;
-	int i, j, k;
+	int i, k, entry;
 	int err = 0;
-	struct ib_umem_chunk *chunk;
+	struct scatterlist *sg;
 	struct c2_pd *c2pd = to_c2pd(pd);
 	struct c2_mr *c2mr;
 
@@ -452,10 +452,7 @@ static struct ib_mr *c2_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 	}
 
 	shift = ffs(c2mr->umem->page_size) - 1;
-
-	n = 0;
-	list_for_each_entry(chunk, &c2mr->umem->chunk_list, list)
-		n += chunk->nents;
+	n = c2mr->umem->nmap;
 
 	pages = kmalloc(n * sizeof(u64), GFP_KERNEL);
 	if (!pages) {
@@ -464,14 +461,12 @@ static struct ib_mr *c2_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 	}
 
 	i = 0;
-	list_for_each_entry(chunk, &c2mr->umem->chunk_list, list) {
-		for (j = 0; j < chunk->nmap; ++j) {
-			len = sg_dma_len(&chunk->page_list[j]) >> shift;
-			for (k = 0; k < len; ++k) {
-				pages[i++] =
-					sg_dma_address(&chunk->page_list[j]) +
-					(c2mr->umem->page_size * k);
-			}
+	for_each_sg(c2mr->umem->sg_head.sgl, sg, c2mr->umem->nmap, entry) {
+		len = sg_dma_len(sg) >> shift;
+		for (k = 0; k < len; ++k) {
+			pages[i++] =
+				sg_dma_address(sg) +
+				(c2mr->umem->page_size * k);
 		}
 	}
 
diff --git a/drivers/infiniband/hw/cxgb3/iwch_provider.c b/drivers/infiniband/hw/cxgb3/iwch_provider.c
index d2283837d45..811b24a539c 100644
--- a/drivers/infiniband/hw/cxgb3/iwch_provider.c
+++ b/drivers/infiniband/hw/cxgb3/iwch_provider.c
@@ -618,14 +618,13 @@ static struct ib_mr *iwch_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 {
 	__be64 *pages;
 	int shift, n, len;
-	int i, j, k;
+	int i, k, entry;
 	int err = 0;
-	struct ib_umem_chunk *chunk;
 	struct iwch_dev *rhp;
 	struct iwch_pd *php;
 	struct iwch_mr *mhp;
 	struct iwch_reg_user_mr_resp uresp;
-
+	struct scatterlist *sg;
 	PDBG("%s ib_pd %p\n", __func__, pd);
 
 	php = to_iwch_pd(pd);
@@ -645,9 +644,7 @@ static struct ib_mr *iwch_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 
 	shift = ffs(mhp->umem->page_size) - 1;
 
-	n = 0;
-	list_for_each_entry(chunk, &mhp->umem->chunk_list, list)
-		n += chunk->nents;
+	n = mhp->umem->nmap;
 
 	err = iwch_alloc_pbl(mhp, n);
 	if (err)
@@ -661,12 +658,10 @@ static struct ib_mr *iwch_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 
 	i = n = 0;
 
-	list_for_each_entry(chunk, &mhp->umem->chunk_list, list)
-		for (j = 0; j < chunk->nmap; ++j) {
-			len = sg_dma_len(&chunk->page_list[j]) >> shift;
+	for_each_sg(mhp->umem->sg_head.sgl, sg, mhp->umem->nmap, entry) {
+			len = sg_dma_len(sg) >> shift;
 			for (k = 0; k < len; ++k) {
-				pages[i++] = cpu_to_be64(sg_dma_address(
-					&chunk->page_list[j]) +
+				pages[i++] = cpu_to_be64(sg_dma_address(sg) +
 					mhp->umem->page_size * k);
 				if (i == PAGE_SIZE / sizeof *pages) {
 					err = iwch_write_pbl(mhp, pages, i, n);
@@ -676,7 +671,7 @@ static struct ib_mr *iwch_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 					i = 0;
 				}
 			}
-		}
+	}
 
 	if (i)
 		err = iwch_write_pbl(mhp, pages, i, n);
diff --git a/drivers/infiniband/hw/cxgb4/mem.c b/drivers/infiniband/hw/cxgb4/mem.c
index 41b11951a30..392d422b00c 100644
--- a/drivers/infiniband/hw/cxgb4/mem.c
+++ b/drivers/infiniband/hw/cxgb4/mem.c
@@ -678,9 +678,9 @@ struct ib_mr *c4iw_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 {
 	__be64 *pages;
 	int shift, n, len;
-	int i, j, k;
+	int i, k, entry;
 	int err = 0;
-	struct ib_umem_chunk *chunk;
+	struct scatterlist *sg;
 	struct c4iw_dev *rhp;
 	struct c4iw_pd *php;
 	struct c4iw_mr *mhp;
@@ -710,10 +710,7 @@ struct ib_mr *c4iw_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 
 	shift = ffs(mhp->umem->page_size) - 1;
 
-	n = 0;
-	list_for_each_entry(chunk, &mhp->umem->chunk_list, list)
-		n += chunk->nents;
-
+	n = mhp->umem->nmap;
 	err = alloc_pbl(mhp, n);
 	if (err)
 		goto err;
@@ -726,24 +723,22 @@ struct ib_mr *c4iw_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 
 	i = n = 0;
 
-	list_for_each_entry(chunk, &mhp->umem->chunk_list, list)
-		for (j = 0; j < chunk->nmap; ++j) {
-			len = sg_dma_len(&chunk->page_list[j]) >> shift;
-			for (k = 0; k < len; ++k) {
-				pages[i++] = cpu_to_be64(sg_dma_address(
-					&chunk->page_list[j]) +
-					mhp->umem->page_size * k);
-				if (i == PAGE_SIZE / sizeof *pages) {
-					err = write_pbl(&mhp->rhp->rdev,
-					      pages,
-					      mhp->attr.pbl_addr + (n << 3), i);
-					if (err)
-						goto pbl_done;
-					n += i;
-					i = 0;
-				}
+	for_each_sg(mhp->umem->sg_head.sgl, sg, mhp->umem->nmap, entry) {
+		len = sg_dma_len(sg) >> shift;
+		for (k = 0; k < len; ++k) {
+			pages[i++] = cpu_to_be64(sg_dma_address(sg) +
+				mhp->umem->page_size * k);
+			if (i == PAGE_SIZE / sizeof *pages) {
+				err = write_pbl(&mhp->rhp->rdev,
+				      pages,
+				      mhp->attr.pbl_addr + (n << 3), i);
+				if (err)
+					goto pbl_done;
+				n += i;
+				i = 0;
 			}
 		}
+	}
 
 	if (i)
 		err = write_pbl(&mhp->rhp->rdev, pages,
diff --git a/drivers/infiniband/hw/ehca/ehca_classes.h b/drivers/infiniband/hw/ehca/ehca_classes.h
index f08f6eaf3fa..bd45e0f3923 100644
--- a/drivers/infiniband/hw/ehca/ehca_classes.h
+++ b/drivers/infiniband/hw/ehca/ehca_classes.h
@@ -322,7 +322,7 @@ struct ehca_mr_pginfo {
 		} phy;
 		struct { /* type EHCA_MR_PGI_USER section */
 			struct ib_umem *region;
-			struct ib_umem_chunk *next_chunk;
+			struct scatterlist *next_sg;
 			u64 next_nmap;
 		} usr;
 		struct { /* type EHCA_MR_PGI_FMR section */
diff --git a/drivers/infiniband/hw/ehca/ehca_mrmw.c b/drivers/infiniband/hw/ehca/ehca_mrmw.c
index bcfb0c18362..7168f594d45 100644
--- a/drivers/infiniband/hw/ehca/ehca_mrmw.c
+++ b/drivers/infiniband/hw/ehca/ehca_mrmw.c
@@ -400,10 +400,7 @@ reg_user_mr_fallback:
 	pginfo.num_hwpages = num_hwpages;
 	pginfo.u.usr.region = e_mr->umem;
 	pginfo.next_hwpage = e_mr->umem->offset / hwpage_size;
-	pginfo.u.usr.next_chunk = list_prepare_entry(pginfo.u.usr.next_chunk,
-						     (&e_mr->umem->chunk_list),
-						     list);
-
+	pginfo.u.usr.next_sg = pginfo.u.usr.region->sg_head.sgl;
 	ret = ehca_reg_mr(shca, e_mr, (u64 *)virt, length, mr_access_flags,
 			  e_pd, &pginfo, &e_mr->ib.ib_mr.lkey,
 			  &e_mr->ib.ib_mr.rkey, EHCA_REG_MR);
@@ -1858,61 +1855,39 @@ static int ehca_set_pagebuf_user1(struct ehca_mr_pginfo *pginfo,
 				  u64 *kpage)
 {
 	int ret = 0;
-	struct ib_umem_chunk *prev_chunk;
-	struct ib_umem_chunk *chunk;
 	u64 pgaddr;
-	u32 i = 0;
 	u32 j = 0;
 	int hwpages_per_kpage = PAGE_SIZE / pginfo->hwpage_size;
-
-	/* loop over desired chunk entries */
-	chunk      = pginfo->u.usr.next_chunk;
-	prev_chunk = pginfo->u.usr.next_chunk;
-	list_for_each_entry_continue(
-		chunk, (&(pginfo->u.usr.region->chunk_list)), list) {
-		for (i = pginfo->u.usr.next_nmap; i < chunk->nmap; ) {
-			pgaddr = page_to_pfn(sg_page(&chunk->page_list[i]))
-				<< PAGE_SHIFT ;
-			*kpage = pgaddr + (pginfo->next_hwpage *
-					   pginfo->hwpage_size);
-			if ( !(*kpage) ) {
-				ehca_gen_err("pgaddr=%llx "
-					     "chunk->page_list[i]=%llx "
-					     "i=%x next_hwpage=%llx",
-					     pgaddr, (u64)sg_dma_address(
-						     &chunk->page_list[i]),
-					     i, pginfo->next_hwpage);
-				return -EFAULT;
-			}
-			(pginfo->hwpage_cnt)++;
-			(pginfo->next_hwpage)++;
-			kpage++;
-			if (pginfo->next_hwpage % hwpages_per_kpage == 0) {
-				(pginfo->kpage_cnt)++;
-				(pginfo->u.usr.next_nmap)++;
-				pginfo->next_hwpage = 0;
-				i++;
-			}
-			j++;
-			if (j >= number) break;
+	struct scatterlist **sg = &pginfo->u.usr.next_sg;
+
+	while (*sg != NULL) {
+		pgaddr = page_to_pfn(sg_page(*sg))
+			<< PAGE_SHIFT;
+		*kpage = pgaddr + (pginfo->next_hwpage *
+				   pginfo->hwpage_size);
+		if (!(*kpage)) {
+			ehca_gen_err("pgaddr=%llx "
+				     "sg_dma_address=%llx "
+				     "entry=%llx next_hwpage=%llx",
+				     pgaddr, (u64)sg_dma_address(*sg),
+				     pginfo->u.usr.next_nmap,
+				     pginfo->next_hwpage);
+			return -EFAULT;
 		}
-		if ((pginfo->u.usr.next_nmap >= chunk->nmap) &&
-		    (j >= number)) {
-			pginfo->u.usr.next_nmap = 0;
-			prev_chunk = chunk;
-			break;
-		} else if (pginfo->u.usr.next_nmap >= chunk->nmap) {
-			pginfo->u.usr.next_nmap = 0;
-			prev_chunk = chunk;
-		} else if (j >= number)
+		(pginfo->hwpage_cnt)++;
+		(pginfo->next_hwpage)++;
+		kpage++;
+		if (pginfo->next_hwpage % hwpages_per_kpage == 0) {
+			(pginfo->kpage_cnt)++;
+			(pginfo->u.usr.next_nmap)++;
+			pginfo->next_hwpage = 0;
+			*sg = sg_next(*sg);
+		}
+		j++;
+		if (j >= number)
 			break;
-		else
-			prev_chunk = chunk;
 	}
-	pginfo->u.usr.next_chunk =
-		list_prepare_entry(prev_chunk,
-				   (&(pginfo->u.usr.region->chunk_list)),
-				   list);
+
 	return ret;
 }
 
@@ -1920,20 +1895,19 @@ static int ehca_set_pagebuf_user1(struct ehca_mr_pginfo *pginfo,
  * check given pages for contiguous layout
  * last page addr is returned in prev_pgaddr for further check
  */
-static int ehca_check_kpages_per_ate(struct scatterlist *page_list,
-				     int start_idx, int end_idx,
+static int ehca_check_kpages_per_ate(struct scatterlist **sg,
+				     int num_pages,
 				     u64 *prev_pgaddr)
 {
-	int t;
-	for (t = start_idx; t <= end_idx; t++) {
-		u64 pgaddr = page_to_pfn(sg_page(&page_list[t])) << PAGE_SHIFT;
+	for (; *sg && num_pages > 0; *sg = sg_next(*sg), num_pages--) {
+		u64 pgaddr = page_to_pfn(sg_page(*sg)) << PAGE_SHIFT;
 		if (ehca_debug_level >= 3)
 			ehca_gen_dbg("chunk_page=%llx value=%016llx", pgaddr,
 				     *(u64 *)__va(pgaddr));
 		if (pgaddr - PAGE_SIZE != *prev_pgaddr) {
 			ehca_gen_err("uncontiguous page found pgaddr=%llx "
-				     "prev_pgaddr=%llx page_list_i=%x",
-				     pgaddr, *prev_pgaddr, t);
+				     "prev_pgaddr=%llx entries_left_in_hwpage=%x",
+				     pgaddr, *prev_pgaddr, num_pages);
 			return -EINVAL;
 		}
 		*prev_pgaddr = pgaddr;
@@ -1947,111 +1921,80 @@ static int ehca_set_pagebuf_user2(struct ehca_mr_pginfo *pginfo,
 				  u64 *kpage)
 {
 	int ret = 0;
-	struct ib_umem_chunk *prev_chunk;
-	struct ib_umem_chunk *chunk;
 	u64 pgaddr, prev_pgaddr;
-	u32 i = 0;
 	u32 j = 0;
 	int kpages_per_hwpage = pginfo->hwpage_size / PAGE_SIZE;
 	int nr_kpages = kpages_per_hwpage;
+	struct scatterlist **sg = &pginfo->u.usr.next_sg;
+
+	while (*sg != NULL) {
 
-	/* loop over desired chunk entries */
-	chunk      = pginfo->u.usr.next_chunk;
-	prev_chunk = pginfo->u.usr.next_chunk;
-	list_for_each_entry_continue(
-		chunk, (&(pginfo->u.usr.region->chunk_list)), list) {
-		for (i = pginfo->u.usr.next_nmap; i < chunk->nmap; ) {
-			if (nr_kpages == kpages_per_hwpage) {
-				pgaddr = ( page_to_pfn(sg_page(&chunk->page_list[i]))
-					   << PAGE_SHIFT );
-				*kpage = pgaddr;
-				if ( !(*kpage) ) {
-					ehca_gen_err("pgaddr=%llx i=%x",
-						     pgaddr, i);
+		if (nr_kpages == kpages_per_hwpage) {
+			pgaddr = (page_to_pfn(sg_page(*sg))
+				   << PAGE_SHIFT);
+			*kpage = pgaddr;
+			if (!(*kpage)) {
+				ehca_gen_err("pgaddr=%llx entry=%llx",
+					     pgaddr, pginfo->u.usr.next_nmap);
+				ret = -EFAULT;
+				return ret;
+			}
+			/*
+			 * The first page in a hwpage must be aligned;
+			 * the first MR page is exempt from this rule.
+			 */
+			if (pgaddr & (pginfo->hwpage_size - 1)) {
+				if (pginfo->hwpage_cnt) {
+					ehca_gen_err(
+						"invalid alignment "
+						"pgaddr=%llx entry=%llx "
+						"mr_pgsize=%llx",
+						pgaddr, pginfo->u.usr.next_nmap,
+						pginfo->hwpage_size);
 					ret = -EFAULT;
 					return ret;
 				}
-				/*
-				 * The first page in a hwpage must be aligned;
-				 * the first MR page is exempt from this rule.
-				 */
-				if (pgaddr & (pginfo->hwpage_size - 1)) {
-					if (pginfo->hwpage_cnt) {
-						ehca_gen_err(
-							"invalid alignment "
-							"pgaddr=%llx i=%x "
-							"mr_pgsize=%llx",
-							pgaddr, i,
-							pginfo->hwpage_size);
-						ret = -EFAULT;
-						return ret;
-					}
-					/* first MR page */
-					pginfo->kpage_cnt =
-						(pgaddr &
-						 (pginfo->hwpage_size - 1)) >>
-						PAGE_SHIFT;
-					nr_kpages -= pginfo->kpage_cnt;
-					*kpage = pgaddr &
-						 ~(pginfo->hwpage_size - 1);
-				}
-				if (ehca_debug_level >= 3) {
-					u64 val = *(u64 *)__va(pgaddr);
-					ehca_gen_dbg("kpage=%llx chunk_page=%llx "
-						     "value=%016llx",
-						     *kpage, pgaddr, val);
-				}
-				prev_pgaddr = pgaddr;
-				i++;
-				pginfo->kpage_cnt++;
-				pginfo->u.usr.next_nmap++;
-				nr_kpages--;
-				if (!nr_kpages)
-					goto next_kpage;
-				continue;
+				/* first MR page */
+				pginfo->kpage_cnt =
+					(pgaddr &
+					 (pginfo->hwpage_size - 1)) >>
+					PAGE_SHIFT;
+				nr_kpages -= pginfo->kpage_cnt;
+				*kpage = pgaddr &
+					 ~(pginfo->hwpage_size - 1);
 			}
-			if (i + nr_kpages > chunk->nmap) {
-				ret = ehca_check_kpages_per_ate(
-					chunk->page_list, i,
-					chunk->nmap - 1, &prev_pgaddr);
-				if (ret) return ret;
-				pginfo->kpage_cnt += chunk->nmap - i;
-				pginfo->u.usr.next_nmap += chunk->nmap - i;
-				nr_kpages -= chunk->nmap - i;
-				break;
+			if (ehca_debug_level >= 3) {
+				u64 val = *(u64 *)__va(pgaddr);
+				ehca_gen_dbg("kpage=%llx page=%llx "
+					     "value=%016llx",
+					     *kpage, pgaddr, val);
 			}
+			prev_pgaddr = pgaddr;
+			*sg = sg_next(*sg);
+			pginfo->kpage_cnt++;
+			pginfo->u.usr.next_nmap++;
+			nr_kpages--;
+			if (!nr_kpages)
+				goto next_kpage;
+			continue;
+		}
+
+		ret = ehca_check_kpages_per_ate(sg, nr_kpages,
+						&prev_pgaddr);
+		if (ret)
+			return ret;
+		pginfo->kpage_cnt += nr_kpages;
+		pginfo->u.usr.next_nmap += nr_kpages;
 
-			ret = ehca_check_kpages_per_ate(chunk->page_list, i,
-							i + nr_kpages - 1,
-							&prev_pgaddr);
-			if (ret) return ret;
-			i += nr_kpages;
-			pginfo->kpage_cnt += nr_kpages;
-			pginfo->u.usr.next_nmap += nr_kpages;
 next_kpage:
-			nr_kpages = kpages_per_hwpage;
-			(pginfo->hwpage_cnt)++;
-			kpage++;
-			j++;
-			if (j >= number) break;
-		}
-		if ((pginfo->u.usr.next_nmap >= chunk->nmap) &&
-		    (j >= number)) {
-			pginfo->u.usr.next_nmap = 0;
-			prev_chunk = chunk;
-			break;
-		} else if (pginfo->u.usr.next_nmap >= chunk->nmap) {
-			pginfo->u.usr.next_nmap = 0;
-			prev_chunk = chunk;
-		} else if (j >= number)
+		nr_kpages = kpages_per_hwpage;
+		(pginfo->hwpage_cnt)++;
+		kpage++;
+		j++;
+		if (j >= number)
 			break;
-		else
-			prev_chunk = chunk;
 	}
-	pginfo->u.usr.next_chunk =
-		list_prepare_entry(prev_chunk,
-				   (&(pginfo->u.usr.region->chunk_list)),
-				   list);
+
 	return ret;
 }
 
diff --git a/drivers/infiniband/hw/ipath/ipath_mr.c b/drivers/infiniband/hw/ipath/ipath_mr.c
index e346d3890a0..5e61e9bff69 100644
--- a/drivers/infiniband/hw/ipath/ipath_mr.c
+++ b/drivers/infiniband/hw/ipath/ipath_mr.c
@@ -188,8 +188,8 @@ struct ib_mr *ipath_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 {
 	struct ipath_mr *mr;
 	struct ib_umem *umem;
-	struct ib_umem_chunk *chunk;
-	int n, m, i;
+	int n, m, entry;
+	struct scatterlist *sg;
 	struct ib_mr *ret;
 
 	if (length == 0) {
@@ -202,10 +202,7 @@ struct ib_mr *ipath_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 	if (IS_ERR(umem))
 		return (void *) umem;
 
-	n = 0;
-	list_for_each_entry(chunk, &umem->chunk_list, list)
-		n += chunk->nents;
-
+	n = umem->nmap;
 	mr = alloc_mr(n, &to_idev(pd->device)->lk_table);
 	if (!mr) {
 		ret = ERR_PTR(-ENOMEM);
@@ -224,22 +221,20 @@ struct ib_mr *ipath_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 
 	m = 0;
 	n = 0;
-	list_for_each_entry(chunk, &umem->chunk_list, list) {
-		for (i = 0; i < chunk->nents; i++) {
-			void *vaddr;
-
-			vaddr = page_address(sg_page(&chunk->page_list[i]));
-			if (!vaddr) {
-				ret = ERR_PTR(-EINVAL);
-				goto bail;
-			}
-			mr->mr.map[m]->segs[n].vaddr = vaddr;
-			mr->mr.map[m]->segs[n].length = umem->page_size;
-			n++;
-			if (n == IPATH_SEGSZ) {
-				m++;
-				n = 0;
-			}
+	for_each_sg(umem->sg_head.sgl, sg, umem->nmap, entry) {
+		void *vaddr;
+
+		vaddr = page_address(sg_page(sg));
+		if (!vaddr) {
+			ret = ERR_PTR(-EINVAL);
+			goto bail;
+		}
+		mr->mr.map[m]->segs[n].vaddr = vaddr;
+		mr->mr.map[m]->segs[n].length = umem->page_size;
+		n++;
+		if (n == IPATH_SEGSZ) {
+			m++;
+			n = 0;
 		}
 	}
 	ret = &mr->ibmr;
diff --git a/drivers/infiniband/hw/mlx4/doorbell.c b/drivers/infiniband/hw/mlx4/doorbell.c
index 8aee4233b38..c5174098636 100644
--- a/drivers/infiniband/hw/mlx4/doorbell.c
+++ b/drivers/infiniband/hw/mlx4/doorbell.c
@@ -45,7 +45,6 @@ int mlx4_ib_db_map_user(struct mlx4_ib_ucontext *context, unsigned long virt,
 			struct mlx4_db *db)
 {
 	struct mlx4_ib_user_db_page *page;
-	struct ib_umem_chunk *chunk;
 	int err = 0;
 
 	mutex_lock(&context->db_page_mutex);
@@ -73,8 +72,7 @@ int mlx4_ib_db_map_user(struct mlx4_ib_ucontext *context, unsigned long virt,
 	list_add(&page->list, &context->db_page_list);
 
 found:
-	chunk = list_entry(page->umem->chunk_list.next, struct ib_umem_chunk, list);
-	db->dma		= sg_dma_address(chunk->page_list) + (virt & ~PAGE_MASK);
+	db->dma = sg_dma_address(page->umem->sg_head.sgl) + (virt & ~PAGE_MASK);
 	db->u.user_page = page;
 	++page->refcnt;
 
diff --git a/drivers/infiniband/hw/mlx4/mr.c b/drivers/infiniband/hw/mlx4/mr.c
index e471f089ff0..cb2a8727f3f 100644
--- a/drivers/infiniband/hw/mlx4/mr.c
+++ b/drivers/infiniband/hw/mlx4/mr.c
@@ -90,11 +90,11 @@ int mlx4_ib_umem_write_mtt(struct mlx4_ib_dev *dev, struct mlx4_mtt *mtt,
 			   struct ib_umem *umem)
 {
 	u64 *pages;
-	struct ib_umem_chunk *chunk;
-	int i, j, k;
+	int i, k, entry;
 	int n;
 	int len;
 	int err = 0;
+	struct scatterlist *sg;
 
 	pages = (u64 *) __get_free_page(GFP_KERNEL);
 	if (!pages)
@@ -102,26 +102,25 @@ int mlx4_ib_umem_write_mtt(struct mlx4_ib_dev *dev, struct mlx4_mtt *mtt,
 
 	i = n = 0;
 
-	list_for_each_entry(chunk, &umem->chunk_list, list)
-		for (j = 0; j < chunk->nmap; ++j) {
-			len = sg_dma_len(&chunk->page_list[j]) >> mtt->page_shift;
-			for (k = 0; k < len; ++k) {
-				pages[i++] = sg_dma_address(&chunk->page_list[j]) +
-					umem->page_size * k;
-				/*
-				 * Be friendly to mlx4_write_mtt() and
-				 * pass it chunks of appropriate size.
-				 */
-				if (i == PAGE_SIZE / sizeof (u64)) {
-					err = mlx4_write_mtt(dev->dev, mtt, n,
-							     i, pages);
-					if (err)
-						goto out;
-					n += i;
-					i = 0;
-				}
+	for_each_sg(umem->sg_head.sgl, sg, umem->nmap, entry) {
+		len = sg_dma_len(sg) >> mtt->page_shift;
+		for (k = 0; k < len; ++k) {
+			pages[i++] = sg_dma_address(sg) +
+				umem->page_size * k;
+			/*
+			 * Be friendly to mlx4_write_mtt() and
+			 * pass it chunks of appropriate size.
+			 */
+			if (i == PAGE_SIZE / sizeof (u64)) {
+				err = mlx4_write_mtt(dev->dev, mtt, n,
+						     i, pages);
+				if (err)
+					goto out;
+				n += i;
+				i = 0;
 			}
 		}
+	}
 
 	if (i)
 		err = mlx4_write_mtt(dev->dev, mtt, n, i, pages);
diff --git a/drivers/infiniband/hw/mlx5/doorbell.c b/drivers/infiniband/hw/mlx5/doorbell.c
index 256a23344f2..ece028fc47d 100644
--- a/drivers/infiniband/hw/mlx5/doorbell.c
+++ b/drivers/infiniband/hw/mlx5/doorbell.c
@@ -47,7 +47,6 @@ int mlx5_ib_db_map_user(struct mlx5_ib_ucontext *context, unsigned long virt,
 			struct mlx5_db *db)
 {
 	struct mlx5_ib_user_db_page *page;
-	struct ib_umem_chunk *chunk;
 	int err = 0;
 
 	mutex_lock(&context->db_page_mutex);
@@ -75,8 +74,7 @@ int mlx5_ib_db_map_user(struct mlx5_ib_ucontext *context, unsigned long virt,
 	list_add(&page->list, &context->db_page_list);
 
 found:
-	chunk = list_entry(page->umem->chunk_list.next, struct ib_umem_chunk, list);
-	db->dma		= sg_dma_address(chunk->page_list) + (virt & ~PAGE_MASK);
+	db->dma = sg_dma_address(page->umem->sg_head.sgl) + (virt & ~PAGE_MASK);
 	db->u.user_page = page;
 	++page->refcnt;
 
diff --git a/drivers/infiniband/hw/mlx5/mem.c b/drivers/infiniband/hw/mlx5/mem.c
index 3a5322870b9..8499aec94db 100644
--- a/drivers/infiniband/hw/mlx5/mem.c
+++ b/drivers/infiniband/hw/mlx5/mem.c
@@ -44,16 +44,17 @@
 void mlx5_ib_cont_pages(struct ib_umem *umem, u64 addr, int *count, int *shift,
 			int *ncont, int *order)
 {
-	struct ib_umem_chunk *chunk;
 	unsigned long tmp;
 	unsigned long m;
-	int i, j, k;
+	int i, k;
 	u64 base = 0;
 	int p = 0;
 	int skip;
 	int mask;
 	u64 len;
 	u64 pfn;
+	struct scatterlist *sg;
+	int entry;
 
 	addr = addr >> PAGE_SHIFT;
 	tmp = (unsigned long)addr;
@@ -61,32 +62,31 @@ void mlx5_ib_cont_pages(struct ib_umem *umem, u64 addr, int *count, int *shift,
 	skip = 1 << m;
 	mask = skip - 1;
 	i = 0;
-	list_for_each_entry(chunk, &umem->chunk_list, list)
-		for (j = 0; j < chunk->nmap; j++) {
-			len = sg_dma_len(&chunk->page_list[j]) >> PAGE_SHIFT;
-			pfn = sg_dma_address(&chunk->page_list[j]) >> PAGE_SHIFT;
-			for (k = 0; k < len; k++) {
-				if (!(i & mask)) {
-					tmp = (unsigned long)pfn;
-					m = min(m, find_first_bit(&tmp, sizeof(tmp)));
+	for_each_sg(umem->sg_head.sgl, sg, umem->nmap, entry) {
+		len = sg_dma_len(sg) >> PAGE_SHIFT;
+		pfn = sg_dma_address(sg) >> PAGE_SHIFT;
+		for (k = 0; k < len; k++) {
+			if (!(i & mask)) {
+				tmp = (unsigned long)pfn;
+				m = min(m, find_first_bit(&tmp, sizeof(tmp)));
+				skip = 1 << m;
+				mask = skip - 1;
+				base = pfn;
+				p = 0;
+			} else {
+				if (base + p != pfn) {
+					tmp = (unsigned long)p;
+					m = find_first_bit(&tmp, sizeof(tmp));
 					skip = 1 << m;
 					mask = skip - 1;
 					base = pfn;
 					p = 0;
-				} else {
-					if (base + p != pfn) {
-						tmp = (unsigned long)p;
-						m = find_first_bit(&tmp, sizeof(tmp));
-						skip = 1 << m;
-						mask = skip - 1;
-						base = pfn;
-						p = 0;
-					}
 				}
-				p++;
-				i++;
 			}
+			p++;
+			i++;
 		}
+	}
 
 	if (i) {
 		m = min_t(unsigned long, ilog2(roundup_pow_of_two(i)), m);
@@ -112,32 +112,32 @@ void mlx5_ib_populate_pas(struct mlx5_ib_dev *dev, struct ib_umem *umem,
 {
 	int shift = page_shift - PAGE_SHIFT;
 	int mask = (1 << shift) - 1;
-	struct ib_umem_chunk *chunk;
-	int i, j, k;
+	int i, k;
 	u64 cur = 0;
 	u64 base;
 	int len;
+	struct scatterlist *sg;
+	int entry;
 
 	i = 0;
-	list_for_each_entry(chunk, &umem->chunk_list, list)
-		for (j = 0; j < chunk->nmap; j++) {
-			len = sg_dma_len(&chunk->page_list[j]) >> PAGE_SHIFT;
-			base = sg_dma_address(&chunk->page_list[j]);
-			for (k = 0; k < len; k++) {
-				if (!(i & mask)) {
-					cur = base + (k << PAGE_SHIFT);
-					if (umr)
-						cur |= 3;
+	for_each_sg(umem->sg_head.sgl, sg, umem->nmap, entry) {
+		len = sg_dma_len(sg) >> PAGE_SHIFT;
+		base = sg_dma_address(sg);
+		for (k = 0; k < len; k++) {
+			if (!(i & mask)) {
+				cur = base + (k << PAGE_SHIFT);
+				if (umr)
+					cur |= 3;
 
-					pas[i >> shift] = cpu_to_be64(cur);
-					mlx5_ib_dbg(dev, "pas[%d] 0x%llx\n",
-						    i >> shift, be64_to_cpu(pas[i >> shift]));
-				}  else
-					mlx5_ib_dbg(dev, "=====> 0x%llx\n",
-						    base + (k << PAGE_SHIFT));
-				i++;
-			}
+				pas[i >> shift] = cpu_to_be64(cur);
+				mlx5_ib_dbg(dev, "pas[%d] 0x%llx\n",
+					    i >> shift, be64_to_cpu(pas[i >> shift]));
+			}  else
+				mlx5_ib_dbg(dev, "=====> 0x%llx\n",
+					    base + (k << PAGE_SHIFT));
+			i++;
 		}
+	}
 }
 
 int mlx5_ib_get_buf_offset(u64 addr, int page_shift, u32 *offset)
diff --git a/drivers/infiniband/hw/mthca/mthca_provider.c b/drivers/infiniband/hw/mthca/mthca_provider.c
index 5b71d43bd89..64408000f1c 100644
--- a/drivers/infiniband/hw/mthca/mthca_provider.c
+++ b/drivers/infiniband/hw/mthca/mthca_provider.c
@@ -976,12 +976,12 @@ static struct ib_mr *mthca_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 				       u64 virt, int acc, struct ib_udata *udata)
 {
 	struct mthca_dev *dev = to_mdev(pd->device);
-	struct ib_umem_chunk *chunk;
+	struct scatterlist *sg;
 	struct mthca_mr *mr;
 	struct mthca_reg_mr ucmd;
 	u64 *pages;
 	int shift, n, len;
-	int i, j, k;
+	int i, k, entry;
 	int err = 0;
 	int write_mtt_size;
 
@@ -1009,10 +1009,7 @@ static struct ib_mr *mthca_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 	}
 
 	shift = ffs(mr->umem->page_size) - 1;
-
-	n = 0;
-	list_for_each_entry(chunk, &mr->umem->chunk_list, list)
-		n += chunk->nents;
+	n = mr->umem->nmap;
 
 	mr->mtt = mthca_alloc_mtt(dev, n);
 	if (IS_ERR(mr->mtt)) {
@@ -1030,25 +1027,24 @@ static struct ib_mr *mthca_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 
 	write_mtt_size = min(mthca_write_mtt_size(dev), (int) (PAGE_SIZE / sizeof *pages));
 
-	list_for_each_entry(chunk, &mr->umem->chunk_list, list)
-		for (j = 0; j < chunk->nmap; ++j) {
-			len = sg_dma_len(&chunk->page_list[j]) >> shift;
-			for (k = 0; k < len; ++k) {
-				pages[i++] = sg_dma_address(&chunk->page_list[j]) +
-					mr->umem->page_size * k;
-				/*
-				 * Be friendly to write_mtt and pass it chunks
-				 * of appropriate size.
-				 */
-				if (i == write_mtt_size) {
-					err = mthca_write_mtt(dev, mr->mtt, n, pages, i);
-					if (err)
-						goto mtt_done;
-					n += i;
-					i = 0;
-				}
+	for_each_sg(mr->umem->sg_head.sgl, sg, mr->umem->nmap, entry) {
+		len = sg_dma_len(sg) >> shift;
+		for (k = 0; k < len; ++k) {
+			pages[i++] = sg_dma_address(sg) +
+				mr->umem->page_size * k;
+			/*
+			 * Be friendly to write_mtt and pass it chunks
+			 * of appropriate size.
+			 */
+			if (i == write_mtt_size) {
+				err = mthca_write_mtt(dev, mr->mtt, n, pages, i);
+				if (err)
+					goto mtt_done;
+				n += i;
+				i = 0;
 			}
 		}
+	}
 
 	if (i)
 		err = mthca_write_mtt(dev, mr->mtt, n, pages, i);
diff --git a/drivers/infiniband/hw/nes/nes_verbs.c b/drivers/infiniband/hw/nes/nes_verbs.c
index 8308e363476..32d3682daaf 100644
--- a/drivers/infiniband/hw/nes/nes_verbs.c
+++ b/drivers/infiniband/hw/nes/nes_verbs.c
@@ -2307,7 +2307,7 @@ static struct ib_mr *nes_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 	struct nes_device *nesdev = nesvnic->nesdev;
 	struct nes_adapter *nesadapter = nesdev->nesadapter;
 	struct ib_mr *ibmr = ERR_PTR(-EINVAL);
-	struct ib_umem_chunk *chunk;
+	struct scatterlist *sg;
 	struct nes_ucontext *nes_ucontext;
 	struct nes_pbl *nespbl;
 	struct nes_mr *nesmr;
@@ -2315,7 +2315,7 @@ static struct ib_mr *nes_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 	struct nes_mem_reg_req req;
 	struct nes_vpbl vpbl;
 	struct nes_root_vpbl root_vpbl;
-	int nmap_index, page_index;
+	int entry, page_index;
 	int page_count = 0;
 	int err, pbl_depth = 0;
 	int chunk_pages;
@@ -2330,6 +2330,7 @@ static struct ib_mr *nes_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 	u16 pbl_count;
 	u8 single_page = 1;
 	u8 stag_key;
+	int first_page = 1;
 
 	region = ib_umem_get(pd->uobject->context, start, length, acc, 0);
 	if (IS_ERR(region)) {
@@ -2380,128 +2381,125 @@ static struct ib_mr *nes_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 			}
 			nesmr->region = region;
 
-			list_for_each_entry(chunk, &region->chunk_list, list) {
-				nes_debug(NES_DBG_MR, "Chunk: nents = %u, nmap = %u .\n",
-						chunk->nents, chunk->nmap);
-				for (nmap_index = 0; nmap_index < chunk->nmap; ++nmap_index) {
-					if (sg_dma_address(&chunk->page_list[nmap_index]) & ~PAGE_MASK) {
-						ib_umem_release(region);
-						nes_free_resource(nesadapter, nesadapter->allocated_mrs, stag_index);
-						nes_debug(NES_DBG_MR, "Unaligned Memory Buffer: 0x%x\n",
-								(unsigned int) sg_dma_address(&chunk->page_list[nmap_index]));
-						ibmr = ERR_PTR(-EINVAL);
-						kfree(nesmr);
-						goto reg_user_mr_err;
-					}
+			for_each_sg(region->sg_head.sgl, sg, region->nmap, entry) {
+				if (sg_dma_address(sg) & ~PAGE_MASK) {
+					ib_umem_release(region);
+					nes_free_resource(nesadapter, nesadapter->allocated_mrs, stag_index);
+					nes_debug(NES_DBG_MR, "Unaligned Memory Buffer: 0x%x\n",
+						  (unsigned int) sg_dma_address(sg));
+					ibmr = ERR_PTR(-EINVAL);
+					kfree(nesmr);
+					goto reg_user_mr_err;
+				}
 
-					if (!sg_dma_len(&chunk->page_list[nmap_index])) {
-						ib_umem_release(region);
-						nes_free_resource(nesadapter, nesadapter->allocated_mrs,
-								stag_index);
-						nes_debug(NES_DBG_MR, "Invalid Buffer Size\n");
-						ibmr = ERR_PTR(-EINVAL);
-						kfree(nesmr);
-						goto reg_user_mr_err;
-					}
+				if (!sg_dma_len(sg)) {
+					ib_umem_release(region);
+					nes_free_resource(nesadapter, nesadapter->allocated_mrs,
+							  stag_index);
+					nes_debug(NES_DBG_MR, "Invalid Buffer Size\n");
+					ibmr = ERR_PTR(-EINVAL);
+					kfree(nesmr);
+					goto reg_user_mr_err;
+				}
 
-					region_length += sg_dma_len(&chunk->page_list[nmap_index]);
-					chunk_pages = sg_dma_len(&chunk->page_list[nmap_index]) >> 12;
-					region_length -= skip_pages << 12;
-					for (page_index=skip_pages; page_index < chunk_pages; page_index++) {
-						skip_pages = 0;
-						if ((page_count!=0)&&(page_count<<12)-(region->offset&(4096-1))>=region->length)
-							goto enough_pages;
-						if ((page_count&0x01FF) == 0) {
-							if (page_count >= 1024 * 512) {
+				region_length += sg_dma_len(sg);
+				chunk_pages = sg_dma_len(sg) >> 12;
+				region_length -= skip_pages << 12;
+				for (page_index = skip_pages; page_index < chunk_pages; page_index++) {
+					skip_pages = 0;
+					if ((page_count != 0) && (page_count<<12)-(region->offset&(4096-1)) >= region->length)
+						goto enough_pages;
+					if ((page_count&0x01FF) == 0) {
+						if (page_count >= 1024 * 512) {
+							ib_umem_release(region);
+							nes_free_resource(nesadapter,
+									  nesadapter->allocated_mrs, stag_index);
+							kfree(nesmr);
+							ibmr = ERR_PTR(-E2BIG);
+							goto reg_user_mr_err;
+						}
+						if (root_pbl_index == 1) {
+							root_vpbl.pbl_vbase = pci_alloc_consistent(nesdev->pcidev,
+									8192, &root_vpbl.pbl_pbase);
+							nes_debug(NES_DBG_MR, "Allocating root PBL, va = %p, pa = 0x%08X\n",
+								  root_vpbl.pbl_vbase, (unsigned int)root_vpbl.pbl_pbase);
+							if (!root_vpbl.pbl_vbase) {
 								ib_umem_release(region);
-								nes_free_resource(nesadapter,
-										nesadapter->allocated_mrs, stag_index);
+								pci_free_consistent(nesdev->pcidev, 4096, vpbl.pbl_vbase,
+										    vpbl.pbl_pbase);
+								nes_free_resource(nesadapter, nesadapter->allocated_mrs,
+										  stag_index);
 								kfree(nesmr);
-								ibmr = ERR_PTR(-E2BIG);
+								ibmr = ERR_PTR(-ENOMEM);
 								goto reg_user_mr_err;
 							}
-							if (root_pbl_index == 1) {
-								root_vpbl.pbl_vbase = pci_alloc_consistent(nesdev->pcidev,
-										8192, &root_vpbl.pbl_pbase);
-								nes_debug(NES_DBG_MR, "Allocating root PBL, va = %p, pa = 0x%08X\n",
-										root_vpbl.pbl_vbase, (unsigned int)root_vpbl.pbl_pbase);
-								if (!root_vpbl.pbl_vbase) {
-									ib_umem_release(region);
-									pci_free_consistent(nesdev->pcidev, 4096, vpbl.pbl_vbase,
-											vpbl.pbl_pbase);
-									nes_free_resource(nesadapter, nesadapter->allocated_mrs,
-											stag_index);
-									kfree(nesmr);
-									ibmr = ERR_PTR(-ENOMEM);
-									goto reg_user_mr_err;
-								}
-								root_vpbl.leaf_vpbl = kzalloc(sizeof(*root_vpbl.leaf_vpbl)*1024,
-										GFP_KERNEL);
-								if (!root_vpbl.leaf_vpbl) {
-									ib_umem_release(region);
-									pci_free_consistent(nesdev->pcidev, 8192, root_vpbl.pbl_vbase,
-											root_vpbl.pbl_pbase);
-									pci_free_consistent(nesdev->pcidev, 4096, vpbl.pbl_vbase,
-											vpbl.pbl_pbase);
-									nes_free_resource(nesadapter, nesadapter->allocated_mrs,
-											stag_index);
-									kfree(nesmr);
-									ibmr = ERR_PTR(-ENOMEM);
-									goto reg_user_mr_err;
-								}
-								root_vpbl.pbl_vbase[0].pa_low =
-										cpu_to_le32((u32)vpbl.pbl_pbase);
-								root_vpbl.pbl_vbase[0].pa_high =
-										cpu_to_le32((u32)((((u64)vpbl.pbl_pbase) >> 32)));
-								root_vpbl.leaf_vpbl[0] = vpbl;
-							}
-							vpbl.pbl_vbase = pci_alloc_consistent(nesdev->pcidev, 4096,
-									&vpbl.pbl_pbase);
-							nes_debug(NES_DBG_MR, "Allocating leaf PBL, va = %p, pa = 0x%08X\n",
-									vpbl.pbl_vbase, (unsigned int)vpbl.pbl_pbase);
-							if (!vpbl.pbl_vbase) {
+							root_vpbl.leaf_vpbl = kzalloc(sizeof(*root_vpbl.leaf_vpbl)*1024,
+									GFP_KERNEL);
+							if (!root_vpbl.leaf_vpbl) {
 								ib_umem_release(region);
-								nes_free_resource(nesadapter, nesadapter->allocated_mrs, stag_index);
-								ibmr = ERR_PTR(-ENOMEM);
+								pci_free_consistent(nesdev->pcidev, 8192, root_vpbl.pbl_vbase,
+										    root_vpbl.pbl_pbase);
+								pci_free_consistent(nesdev->pcidev, 4096, vpbl.pbl_vbase,
+										    vpbl.pbl_pbase);
+								nes_free_resource(nesadapter, nesadapter->allocated_mrs,
+										  stag_index);
 								kfree(nesmr);
+								ibmr = ERR_PTR(-ENOMEM);
 								goto reg_user_mr_err;
 							}
-							if (1 <= root_pbl_index) {
-								root_vpbl.pbl_vbase[root_pbl_index].pa_low =
-										cpu_to_le32((u32)vpbl.pbl_pbase);
-								root_vpbl.pbl_vbase[root_pbl_index].pa_high =
-										cpu_to_le32((u32)((((u64)vpbl.pbl_pbase)>>32)));
-								root_vpbl.leaf_vpbl[root_pbl_index] = vpbl;
-							}
-							root_pbl_index++;
-							cur_pbl_index = 0;
+							root_vpbl.pbl_vbase[0].pa_low =
+									cpu_to_le32((u32)vpbl.pbl_pbase);
+							root_vpbl.pbl_vbase[0].pa_high =
+									cpu_to_le32((u32)((((u64)vpbl.pbl_pbase) >> 32)));
+							root_vpbl.leaf_vpbl[0] = vpbl;
 						}
-						if (single_page) {
-							if (page_count != 0) {
-								if ((last_dma_addr+4096) !=
-										(sg_dma_address(&chunk->page_list[nmap_index])+
-										(page_index*4096)))
-									single_page = 0;
-								last_dma_addr = sg_dma_address(&chunk->page_list[nmap_index])+
-										(page_index*4096);
-							} else {
-								first_dma_addr = sg_dma_address(&chunk->page_list[nmap_index])+
-										(page_index*4096);
-								last_dma_addr = first_dma_addr;
-							}
+						vpbl.pbl_vbase = pci_alloc_consistent(nesdev->pcidev, 4096,
+								&vpbl.pbl_pbase);
+						nes_debug(NES_DBG_MR, "Allocating leaf PBL, va = %p, pa = 0x%08X\n",
+							  vpbl.pbl_vbase, (unsigned int)vpbl.pbl_pbase);
+						if (!vpbl.pbl_vbase) {
+							ib_umem_release(region);
+							nes_free_resource(nesadapter, nesadapter->allocated_mrs, stag_index);
+							ibmr = ERR_PTR(-ENOMEM);
+							kfree(nesmr);
+							goto reg_user_mr_err;
+						}
+						if (1 <= root_pbl_index) {
+							root_vpbl.pbl_vbase[root_pbl_index].pa_low =
+									cpu_to_le32((u32)vpbl.pbl_pbase);
+							root_vpbl.pbl_vbase[root_pbl_index].pa_high =
+									cpu_to_le32((u32)((((u64)vpbl.pbl_pbase)>>32)));
+							root_vpbl.leaf_vpbl[root_pbl_index] = vpbl;
+						}
+						root_pbl_index++;
+						cur_pbl_index = 0;
+					}
+					if (single_page) {
+						if (page_count != 0) {
+							if ((last_dma_addr+4096) !=
+									(sg_dma_address(sg)+
+									(page_index*4096)))
+								single_page = 0;
+							last_dma_addr = sg_dma_address(sg)+
+									(page_index*4096);
+						} else {
+							first_dma_addr = sg_dma_address(sg)+
+									(page_index*4096);
+							last_dma_addr = first_dma_addr;
 						}
-
-						vpbl.pbl_vbase[cur_pbl_index].pa_low =
-								cpu_to_le32((u32)(sg_dma_address(&chunk->page_list[nmap_index])+
-								(page_index*4096)));
-						vpbl.pbl_vbase[cur_pbl_index].pa_high =
-								cpu_to_le32((u32)((((u64)(sg_dma_address(&chunk->page_list[nmap_index])+
-								(page_index*4096))) >> 32)));
-						cur_pbl_index++;
-						page_count++;
 					}
+
+					vpbl.pbl_vbase[cur_pbl_index].pa_low =
+							cpu_to_le32((u32)(sg_dma_address(sg)+
+							(page_index*4096)));
+					vpbl.pbl_vbase[cur_pbl_index].pa_high =
+							cpu_to_le32((u32)((((u64)(sg_dma_address(sg)+
+							(page_index*4096))) >> 32)));
+					cur_pbl_index++;
+					page_count++;
 				}
 			}
+
 			enough_pages:
 			nes_debug(NES_DBG_MR, "calculating stag, stag_index=0x%08x, driver_key=0x%08x,"
 					" stag_key=0x%08x\n",
@@ -2613,25 +2611,28 @@ static struct ib_mr *nes_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 				  nespbl->pbl_size, (unsigned long) nespbl->pbl_pbase,
 				  (void *) nespbl->pbl_vbase, nespbl->user_base);
 
-			list_for_each_entry(chunk, &region->chunk_list, list) {
-				for (nmap_index = 0; nmap_index < chunk->nmap; ++nmap_index) {
-					chunk_pages = sg_dma_len(&chunk->page_list[nmap_index]) >> 12;
-					chunk_pages += (sg_dma_len(&chunk->page_list[nmap_index]) & (4096-1)) ? 1 : 0;
-					nespbl->page = sg_page(&chunk->page_list[0]);
-					for (page_index=0; page_index<chunk_pages; page_index++) {
-						((__le32 *)pbl)[0] = cpu_to_le32((u32)
-								(sg_dma_address(&chunk->page_list[nmap_index])+
-								(page_index*4096)));
-						((__le32 *)pbl)[1] = cpu_to_le32(((u64)
-								(sg_dma_address(&chunk->page_list[nmap_index])+
-								(page_index*4096)))>>32);
-						nes_debug(NES_DBG_MR, "pbl=%p, *pbl=0x%016llx, 0x%08x%08x\n", pbl,
-								(unsigned long long)*pbl,
-								le32_to_cpu(((__le32 *)pbl)[1]), le32_to_cpu(((__le32 *)pbl)[0]));
-						pbl++;
-					}
+			for_each_sg(region->sg_head.sgl, sg, region->nmap, entry) {
+				chunk_pages = sg_dma_len(sg) >> 12;
+				chunk_pages += (sg_dma_len(sg) & (4096-1)) ? 1 : 0;
+				if (first_page) {
+					nespbl->page = sg_page(sg);
+					first_page = 0;
+				}
+
+				for (page_index = 0; page_index < chunk_pages; page_index++) {
+					((__le32 *)pbl)[0] = cpu_to_le32((u32)
+							(sg_dma_address(sg)+
+							(page_index*4096)));
+					((__le32 *)pbl)[1] = cpu_to_le32(((u64)
+							(sg_dma_address(sg)+
+							(page_index*4096)))>>32);
+					nes_debug(NES_DBG_MR, "pbl=%p, *pbl=0x%016llx, 0x%08x%08x\n", pbl,
+						  (unsigned long long)*pbl,
+						  le32_to_cpu(((__le32 *)pbl)[1]), le32_to_cpu(((__le32 *)pbl)[0]));
+					pbl++;
 				}
 			}
+
 			if (req.reg_type == IWNES_MEMREG_TYPE_QP) {
 				list_add_tail(&nespbl->list, &nes_ucontext->qp_reg_mem_list);
 			} else {
diff --git a/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c b/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c
index e0cc201be41..0de3473fa7d 100644
--- a/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c
+++ b/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c
@@ -726,10 +726,10 @@ static void build_user_pbes(struct ocrdma_dev *dev, struct ocrdma_mr *mr,
 			    u32 num_pbes)
 {
 	struct ocrdma_pbe *pbe;
-	struct ib_umem_chunk *chunk;
+	struct scatterlist *sg;
 	struct ocrdma_pbl *pbl_tbl = mr->hwmr.pbl_table;
 	struct ib_umem *umem = mr->umem;
-	int i, shift, pg_cnt, pages, pbe_cnt, total_num_pbes = 0;
+	int shift, pg_cnt, pages, pbe_cnt, entry, total_num_pbes = 0;
 
 	if (!mr->hwmr.num_pbes)
 		return;
@@ -739,39 +739,37 @@ static void build_user_pbes(struct ocrdma_dev *dev, struct ocrdma_mr *mr,
 
 	shift = ilog2(umem->page_size);
 
-	list_for_each_entry(chunk, &umem->chunk_list, list) {
-		/* get all the dma regions from the chunk. */
-		for (i = 0; i < chunk->nmap; i++) {
-			pages = sg_dma_len(&chunk->page_list[i]) >> shift;
-			for (pg_cnt = 0; pg_cnt < pages; pg_cnt++) {
-				/* store the page address in pbe */
-				pbe->pa_lo =
-				    cpu_to_le32(sg_dma_address
-						(&chunk->page_list[i]) +
-						(umem->page_size * pg_cnt));
-				pbe->pa_hi =
-				    cpu_to_le32(upper_32_bits
-						((sg_dma_address
-						  (&chunk->page_list[i]) +
-						  umem->page_size * pg_cnt)));
-				pbe_cnt += 1;
-				total_num_pbes += 1;
-				pbe++;
-
-				/* if done building pbes, issue the mbx cmd. */
-				if (total_num_pbes == num_pbes)
-					return;
-
-				/* if the given pbl is full storing the pbes,
-				 * move to next pbl.
-				 */
-				if (pbe_cnt ==
-					(mr->hwmr.pbl_size / sizeof(u64))) {
-					pbl_tbl++;
-					pbe = (struct ocrdma_pbe *)pbl_tbl->va;
-					pbe_cnt = 0;
-				}
+	for_each_sg(umem->sg_head.sgl, sg, umem->nmap, entry) {
+		pages = sg_dma_len(sg) >> shift;
+		for (pg_cnt = 0; pg_cnt < pages; pg_cnt++) {
+			/* store the page address in pbe */
+			pbe->pa_lo =
+			    cpu_to_le32(sg_dma_address
+					(sg) +
+					(umem->page_size * pg_cnt));
+			pbe->pa_hi =
+			    cpu_to_le32(upper_32_bits
+					((sg_dma_address
+					  (sg) +
+					  umem->page_size * pg_cnt)));
+			pbe_cnt += 1;
+			total_num_pbes += 1;
+			pbe++;
+
+			/* if done building pbes, issue the mbx cmd. */
+			if (total_num_pbes == num_pbes)
+				return;
+
+			/* if the given pbl is full storing the pbes,
+			 * move to next pbl.
+			 */
+			if (pbe_cnt ==
+				(mr->hwmr.pbl_size / sizeof(u64))) {
+				pbl_tbl++;
+				pbe = (struct ocrdma_pbe *)pbl_tbl->va;
+				pbe_cnt = 0;
 			}
+
 		}
 	}
 }
diff --git a/drivers/infiniband/hw/qib/qib_mr.c b/drivers/infiniband/hw/qib/qib_mr.c
index e6687ded821..9bbb55347cc 100644
--- a/drivers/infiniband/hw/qib/qib_mr.c
+++ b/drivers/infiniband/hw/qib/qib_mr.c
@@ -232,8 +232,8 @@ struct ib_mr *qib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 {
 	struct qib_mr *mr;
 	struct ib_umem *umem;
-	struct ib_umem_chunk *chunk;
-	int n, m, i;
+	struct scatterlist *sg;
+	int n, m, entry;
 	struct ib_mr *ret;
 
 	if (length == 0) {
@@ -246,9 +246,7 @@ struct ib_mr *qib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 	if (IS_ERR(umem))
 		return (void *) umem;
 
-	n = 0;
-	list_for_each_entry(chunk, &umem->chunk_list, list)
-		n += chunk->nents;
+	n = umem->nmap;
 
 	mr = alloc_mr(n, pd);
 	if (IS_ERR(mr)) {
@@ -268,11 +266,10 @@ struct ib_mr *qib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 		mr->mr.page_shift = ilog2(umem->page_size);
 	m = 0;
 	n = 0;
-	list_for_each_entry(chunk, &umem->chunk_list, list) {
-		for (i = 0; i < chunk->nents; i++) {
+	for_each_sg(umem->sg_head.sgl, sg, umem->nmap, entry) {
 			void *vaddr;
 
-			vaddr = page_address(sg_page(&chunk->page_list[i]));
+			vaddr = page_address(sg_page(sg));
 			if (!vaddr) {
 				ret = ERR_PTR(-EINVAL);
 				goto bail;
@@ -284,7 +281,6 @@ struct ib_mr *qib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 				m++;
 				n = 0;
 			}
-		}
 	}
 	ret = &mr->ibmr;
 
diff --git a/include/rdma/ib_umem.h b/include/rdma/ib_umem.h
index 9ee0d2e51b1..1ea0b65c4cf 100644
--- a/include/rdma/ib_umem.h
+++ b/include/rdma/ib_umem.h
@@ -46,17 +46,12 @@ struct ib_umem {
 	int			page_size;
 	int                     writable;
 	int                     hugetlb;
-	struct list_head	chunk_list;
 	struct work_struct	work;
 	struct mm_struct       *mm;
 	unsigned long		diff;
-};
-
-struct ib_umem_chunk {
-	struct list_head	list;
-	int                     nents;
-	int                     nmap;
-	struct scatterlist      page_list[0];
+	struct sg_table sg_head;
+	int             nmap;
+	int             npages;
 };
 
 #ifdef CONFIG_INFINIBAND_USER_MEM