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>

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);
 
+	for_each_sg(umem->sg_head.sgl, sg, umem->npages, i) {
+
+		page = sg_page(sg);
 		if (umem->writable && dirty)
 			set_page_dirty_lock(page);
 		put_page(page);
 	}
 
-		kfree(chunk);
-	}
+	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,
@@ -157,53 +166,37 @@ 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;
+		for_each_sg(sg_list_start, sg, ret, i) {
+			if (vma_list && !is_vm_hugetlb_page(vma_list[i]))
+				umem->hugetlb = 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;
+			sg_set_page(sg, page_list[i], PAGE_SIZE, 0);
 		}
 
-			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);
+		/* preparing for next loop */
+		sg_list_start = sg;
 	}
 
-			chunk->nmap = ib_dma_map_sg_attrs(context->device,
-							  &chunk->page_list[0],
-							  chunk->nents,
+	umem->nmap = ib_dma_map_sg_attrs(context->device,
+				  umem->sg_head.sgl,
+				  umem->npages,
 				  DMA_BIDIRECTIONAL,
 				  &attrs);
-			if (chunk->nmap <= 0) {
-				for (i = 0; i < chunk->nents; ++i)
-					put_page(sg_page(&chunk->page_list[i]));
-				kfree(chunk);
 
+	if (umem->nmap <= 0) {
 		ret = -ENOMEM;
 		goto out;
 	}
 
-			ret -= chunk->nents;
-			off += chunk->nents;
-			list_add_tail(&chunk->list, &umem->chunk_list);
-		}
-
 	ret = 0;
-	}
 
 out:
 	if (ret < 0) {
+		if (need_release)
 			__ib_umem_release(context->device, umem, 0);
 		kfree(umem);
 	} else
@@ -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;
 }

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) {
@@ -464,16 +461,14 @@ 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_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(&chunk->page_list[j]) +
+				sg_dma_address(sg) +
 				(c2mr->umem->page_size * k);
 		}
 	}
-	}
 
 	kva = virt;
   	err = c2_nsmr_register_phys_kern(to_c2dev(pd->device),

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);

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;
@@ -726,12 +723,10 @@ 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_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 = write_pbl(&mhp->rhp->rdev,

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 */

drivers/infiniband/hw/ehca/ehca_mrmw.c

@@ -400,10 +400,7 @@ struct ib_mr *ehca_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 	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);
@@ -1858,30 +1855,23 @@ 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;
+	struct scatterlist **sg = &pginfo->u.usr.next_sg;
 
-	/* 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 ;
+	while (*sg != NULL) {
+		pgaddr = page_to_pfn(sg_page(*sg))
+			<< PAGE_SHIFT;
 		*kpage = pgaddr + (pginfo->next_hwpage *
 				   pginfo->hwpage_size);
-			if ( !(*kpage) ) {
+		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);
+				     "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;
 		}
 		(pginfo->hwpage_cnt)++;
@@ -1891,28 +1881,13 @@ static int ehca_set_pagebuf_user1(struct ehca_mr_pginfo *pginfo,
 			(pginfo->kpage_cnt)++;
 			(pginfo->u.usr.next_nmap)++;
 			pginfo->next_hwpage = 0;
-				i++;
+			*sg = sg_next(*sg);
 		}
 		j++;
-			if (j >= number) break;
-		}
-		if ((pginfo->u.usr.next_nmap >= chunk->nmap) &&
-		    (j >= number)) {
-			pginfo->u.usr.next_nmap = 0;
-			prev_chunk = chunk;
+		if (j >= number)
 			break;
-		} else if (pginfo->u.usr.next_nmap >= chunk->nmap) {
-			pginfo->u.usr.next_nmap = 0;
-			prev_chunk = chunk;
-		} else 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;
@@ -1947,27 +1921,21 @@ 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 );
+			pgaddr = (page_to_pfn(sg_page(*sg))
+				   << PAGE_SHIFT);
 			*kpage = pgaddr;
-				if ( !(*kpage) ) {
-					ehca_gen_err("pgaddr=%llx i=%x",
-						     pgaddr, i);
+			if (!(*kpage)) {
+				ehca_gen_err("pgaddr=%llx entry=%llx",
+					     pgaddr, pginfo->u.usr.next_nmap);
 				ret = -EFAULT;
 				return ret;
 			}
@@ -1979,9 +1947,9 @@ static int ehca_set_pagebuf_user2(struct ehca_mr_pginfo *pginfo,
 				if (pginfo->hwpage_cnt) {
 					ehca_gen_err(
 						"invalid alignment "
-							"pgaddr=%llx i=%x "
+						"pgaddr=%llx entry=%llx "
 						"mr_pgsize=%llx",
-							pgaddr, i,
+						pgaddr, pginfo->u.usr.next_nmap,
 						pginfo->hwpage_size);
 					ret = -EFAULT;
 					return ret;
@@ -1997,12 +1965,12 @@ static int ehca_set_pagebuf_user2(struct ehca_mr_pginfo *pginfo,
 			}
 			if (ehca_debug_level >= 3) {
 				u64 val = *(u64 *)__va(pgaddr);
-					ehca_gen_dbg("kpage=%llx chunk_page=%llx "
+				ehca_gen_dbg("kpage=%llx page=%llx "
 					     "value=%016llx",
 					     *kpage, pgaddr, val);
 			}
 			prev_pgaddr = pgaddr;
-				i++;
+			*sg = sg_next(*sg);
 			pginfo->kpage_cnt++;
 			pginfo->u.usr.next_nmap++;
 			nr_kpages--;
@@ -2010,48 +1978,23 @@ static int ehca_set_pagebuf_user2(struct ehca_mr_pginfo *pginfo,
 				goto next_kpage;
 			continue;
 		}
-			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;
-			}
 
-			ret = ehca_check_kpages_per_ate(chunk->page_list, i,
-							i + nr_kpages - 1,
+		ret = ehca_check_kpages_per_ate(sg, nr_kpages,
 						&prev_pgaddr);
-			if (ret) return ret;
-			i += nr_kpages;
+		if (ret)
+			return ret;
 		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)
+		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;
 }
 

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);
@@ -224,11 +221,10 @@ 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++) {
+	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;
@@ -241,7 +237,6 @@ struct ib_mr *ipath_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 			n = 0;
 		}
 	}
-	}
 	ret = &mr->ibmr;
 
 bail:

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;
 

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)
@@ -102,11 +102,10 @@ 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_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(&chunk->page_list[j]) +
+			pages[i++] = sg_dma_address(sg) +
 				umem->page_size * k;
 			/*
 			 * Be friendly to mlx4_write_mtt() and

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;
 

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;
@@ -61,10 +62,9 @@ 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_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;
@@ -112,17 +112,17 @@ 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_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);

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)) {
@@ -1030,11 +1027,10 @@ 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_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(&chunk->page_list[j]) +
+			pages[i++] = sg_dma_address(sg) +
 				mr->umem->page_size * k;
 			/*
 			 * Be friendly to write_mtt and pass it chunks

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)) {
@@ -2380,21 +2381,18 @@ 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) {
+			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(&chunk->page_list[nmap_index]));
+						  (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])) {
+				if (!sg_dma_len(sg)) {
 					ib_umem_release(region);
 					nes_free_resource(nesadapter, nesadapter->allocated_mrs,
 							  stag_index);
@@ -2404,12 +2402,12 @@ static struct ib_mr *nes_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 					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 += 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++) {
+				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)
+					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) {
@@ -2479,29 +2477,29 @@ static struct ib_mr *nes_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 					if (single_page) {
 						if (page_count != 0) {
 							if ((last_dma_addr+4096) !=
-										(sg_dma_address(&chunk->page_list[nmap_index])+
+									(sg_dma_address(sg)+
 									(page_index*4096)))
 								single_page = 0;
-								last_dma_addr = sg_dma_address(&chunk->page_list[nmap_index])+
+							last_dma_addr = sg_dma_address(sg)+
 									(page_index*4096);
 						} else {
-								first_dma_addr = sg_dma_address(&chunk->page_list[nmap_index])+
+							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])+
+							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(&chunk->page_list[nmap_index])+
+							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",
@@ -2613,17 +2611,20 @@ 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++) {
+			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(&chunk->page_list[nmap_index])+
+							(sg_dma_address(sg)+
 							(page_index*4096)));
 					((__le32 *)pbl)[1] = cpu_to_le32(((u64)
-								(sg_dma_address(&chunk->page_list[nmap_index])+
+							(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,
@@ -2631,7 +2632,7 @@ static struct ib_mr *nes_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 					pbl++;
 				}
 			}
-			}
+
 			if (req.reg_type == IWNES_MEMREG_TYPE_QP) {
 				list_add_tail(&nespbl->list, &nes_ucontext->qp_reg_mem_list);
 			} else {

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;
@@ -739,20 +739,18 @@ 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_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
-						(&chunk->page_list[i]) +
+					(sg) +
 					(umem->page_size * pg_cnt));
 			pbe->pa_hi =
 			    cpu_to_le32(upper_32_bits
 					((sg_dma_address
-						  (&chunk->page_list[i]) +
+					  (sg) +
 					  umem->page_size * pg_cnt)));
 			pbe_cnt += 1;
 			total_num_pbes += 1;
@@ -771,7 +769,7 @@ static void build_user_pbes(struct ocrdma_dev *dev, struct ocrdma_mr *mr,
 				pbe = (struct ocrdma_pbe *)pbl_tbl->va;
 				pbe_cnt = 0;
 			}
-			}
+
 		}
 	}
 }

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;
@@ -285,7 +282,6 @@ struct ib_mr *qib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 				n = 0;
 			}
 	}
-	}
 	ret = &mr->ibmr;
 
 bail:

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;
+	struct sg_table sg_head;
 	int             nmap;
-	struct scatterlist      page_list[0];
+	int             npages;
 };
 
 #ifdef CONFIG_INFINIBAND_USER_MEM