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-rw-r--r--drivers/infiniband/core/umem.c34
-rw-r--r--include/linux/scatterlist.h19
-rw-r--r--include/rdma/ib_umem.h1
-rw-r--r--lib/scatterlist.c127
-rw-r--r--lib/sg_pool.c3
-rw-r--r--tools/testing/scatterlist/main.c45
6 files changed, 136 insertions, 93 deletions
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index b741758e528f..42481e7a72e8 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -59,7 +59,7 @@ static void __ib_umem_release(struct ib_device *dev, struct ib_umem *umem, int d
 		unpin_user_page_range_dirty_lock(sg_page(sg),
 			DIV_ROUND_UP(sg->length, PAGE_SIZE), make_dirty);
 
-	sg_free_table(&umem->sg_head);
+	sg_free_append_table(&umem->sgt_append);
 }
 
 /**
@@ -155,8 +155,7 @@ struct ib_umem *ib_umem_get(struct ib_device *device, unsigned long addr,
 	unsigned long dma_attr = 0;
 	struct mm_struct *mm;
 	unsigned long npages;
-	int ret;
-	struct scatterlist *sg = NULL;
+	int pinned, ret;
 	unsigned int gup_flags = FOLL_WRITE;
 
 	/*
@@ -216,28 +215,33 @@ struct ib_umem *ib_umem_get(struct ib_device *device, unsigned long addr,
 
 	while (npages) {
 		cond_resched();
-		ret = pin_user_pages_fast(cur_base,
+		pinned = pin_user_pages_fast(cur_base,
 					  min_t(unsigned long, npages,
 						PAGE_SIZE /
 						sizeof(struct page *)),
 					  gup_flags | FOLL_LONGTERM, page_list);
-		if (ret < 0)
+		if (pinned < 0) {
+			ret = pinned;
 			goto umem_release;
+		}
 
-		cur_base += ret * PAGE_SIZE;
-		npages -= ret;
-		sg = sg_alloc_append_table_from_pages(&umem->sg_head, page_list,
-				ret, 0, ret << PAGE_SHIFT,
-				ib_dma_max_seg_size(device), sg, npages,
-				GFP_KERNEL);
-		umem->sg_nents = umem->sg_head.nents;
-		if (IS_ERR(sg)) {
-			unpin_user_pages_dirty_lock(page_list, ret, 0);
-			ret = PTR_ERR(sg);
+		cur_base += pinned * PAGE_SIZE;
+		npages -= pinned;
+		ret = sg_alloc_append_table_from_pages(
+			&umem->sgt_append, page_list, pinned, 0,
+			pinned << PAGE_SHIFT, ib_dma_max_seg_size(device),
+			npages, GFP_KERNEL);
+		umem->sg_nents = umem->sgt_append.sgt.nents;
+		if (ret) {
+			memcpy(&umem->sg_head.sgl, &umem->sgt_append.sgt,
+			       sizeof(umem->sgt_append.sgt));
+			unpin_user_pages_dirty_lock(page_list, pinned, 0);
 			goto umem_release;
 		}
 	}
 
+	memcpy(&umem->sg_head.sgl, &umem->sgt_append.sgt,
+	       sizeof(umem->sgt_append.sgt));
 	if (access & IB_ACCESS_RELAXED_ORDERING)
 		dma_attr |= DMA_ATTR_WEAK_ORDERING;
 
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 5c700f2a0d18..266754a55327 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -39,6 +39,12 @@ struct sg_table {
 	unsigned int orig_nents;	/* original size of list */
 };
 
+struct sg_append_table {
+	struct sg_table sgt;		/* The scatter list table */
+	struct scatterlist *prv;	/* last populated sge in the table */
+	unsigned int total_nents;	/* Total entries in the table */
+};
+
 /*
  * Notes on SG table design.
  *
@@ -280,16 +286,17 @@ typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t);
 typedef void (sg_free_fn)(struct scatterlist *, unsigned int);
 
 void __sg_free_table(struct sg_table *, unsigned int, unsigned int,
-		     sg_free_fn *);
+		     sg_free_fn *, unsigned int);
 void sg_free_table(struct sg_table *);
+void sg_free_append_table(struct sg_append_table *sgt);
 int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int,
 		     struct scatterlist *, unsigned int, gfp_t, sg_alloc_fn *);
 int sg_alloc_table(struct sg_table *, unsigned int, gfp_t);
-struct scatterlist *sg_alloc_append_table_from_pages(struct sg_table *sgt,
-		struct page **pages, unsigned int n_pages, unsigned int offset,
-		unsigned long size, unsigned int max_segment,
-		struct scatterlist *prv, unsigned int left_pages,
-		gfp_t gfp_mask);
+int sg_alloc_append_table_from_pages(struct sg_append_table *sgt,
+				     struct page **pages, unsigned int n_pages,
+				     unsigned int offset, unsigned long size,
+				     unsigned int max_segment,
+				     unsigned int left_pages, gfp_t gfp_mask);
 int sg_alloc_table_from_pages_segment(struct sg_table *sgt, struct page **pages,
 				      unsigned int n_pages, unsigned int offset,
 				      unsigned long size,
diff --git a/include/rdma/ib_umem.h b/include/rdma/ib_umem.h
index 676c57f5ca80..33cb23b2ee3c 100644
--- a/include/rdma/ib_umem.h
+++ b/include/rdma/ib_umem.h
@@ -26,6 +26,7 @@ struct ib_umem {
 	u32 is_odp : 1;
 	u32 is_dmabuf : 1;
 	struct work_struct	work;
+	struct sg_append_table  sgt_append;
 	struct sg_table sg_head;
 	int             nmap;
 	unsigned int    sg_nents;
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index 611c63d4a958..f4b1ff78ab2d 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -182,6 +182,7 @@ static void sg_kfree(struct scatterlist *sg, unsigned int nents)
  * @nents_first_chunk: Number of entries int the (preallocated) first
  * 	scatterlist chunk, 0 means no such preallocated first chunk
  * @free_fn:	Free function
+ * @num_ents:	Number of entries in the table
  *
  *  Description:
  *    Free an sg table previously allocated and setup with
@@ -190,7 +191,8 @@ static void sg_kfree(struct scatterlist *sg, unsigned int nents)
  *
  **/
 void __sg_free_table(struct sg_table *table, unsigned int max_ents,
-		     unsigned int nents_first_chunk, sg_free_fn *free_fn)
+		     unsigned int nents_first_chunk, sg_free_fn *free_fn,
+		     unsigned int num_ents)
 {
 	struct scatterlist *sgl, *next;
 	unsigned curr_max_ents = nents_first_chunk ?: max_ents;
@@ -199,8 +201,8 @@ void __sg_free_table(struct sg_table *table, unsigned int max_ents,
 		return;
 
 	sgl = table->sgl;
-	while (table->orig_nents) {
-		unsigned int alloc_size = table->orig_nents;
+	while (num_ents) {
+		unsigned int alloc_size = num_ents;
 		unsigned int sg_size;
 
 		/*
@@ -218,7 +220,7 @@ void __sg_free_table(struct sg_table *table, unsigned int max_ents,
 			next = NULL;
 		}
 
-		table->orig_nents -= sg_size;
+		num_ents -= sg_size;
 		if (nents_first_chunk)
 			nents_first_chunk = 0;
 		else
@@ -232,13 +234,27 @@ void __sg_free_table(struct sg_table *table, unsigned int max_ents,
 EXPORT_SYMBOL(__sg_free_table);
 
 /**
+ * sg_free_append_table - Free a previously allocated append sg table.
+ * @table:	 The mapped sg append table header
+ *
+ **/
+void sg_free_append_table(struct sg_append_table *table)
+{
+	__sg_free_table(&table->sgt, SG_MAX_SINGLE_ALLOC, false, sg_kfree,
+			table->total_nents);
+}
+EXPORT_SYMBOL(sg_free_append_table);
+
+
+/**
  * sg_free_table - Free a previously allocated sg table
  * @table:	The mapped sg table header
  *
  **/
 void sg_free_table(struct sg_table *table)
 {
-	__sg_free_table(table, SG_MAX_SINGLE_ALLOC, false, sg_kfree);
+	__sg_free_table(table, SG_MAX_SINGLE_ALLOC, false, sg_kfree,
+			table->orig_nents);
 }
 EXPORT_SYMBOL(sg_free_table);
 
@@ -359,13 +375,12 @@ int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask)
 	ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC,
 			       NULL, 0, gfp_mask, sg_kmalloc);
 	if (unlikely(ret))
-		__sg_free_table(table, SG_MAX_SINGLE_ALLOC, 0, sg_kfree);
-
+		sg_free_table(table);
 	return ret;
 }
 EXPORT_SYMBOL(sg_alloc_table);
 
-static struct scatterlist *get_next_sg(struct sg_table *table,
+static struct scatterlist *get_next_sg(struct sg_append_table *table,
 				       struct scatterlist *cur,
 				       unsigned long needed_sges,
 				       gfp_t gfp_mask)
@@ -386,54 +401,52 @@ static struct scatterlist *get_next_sg(struct sg_table *table,
 		return ERR_PTR(-ENOMEM);
 	sg_init_table(new_sg, alloc_size);
 	if (cur) {
+		table->total_nents += alloc_size - 1;
 		__sg_chain(next_sg, new_sg);
-		table->orig_nents += alloc_size - 1;
 	} else {
-		table->sgl = new_sg;
-		table->orig_nents = alloc_size;
-		table->nents = 0;
+		table->sgt.sgl = new_sg;
+		table->total_nents = alloc_size;
 	}
 	return new_sg;
 }
 
 /**
- * sg_alloc_append_table_from_pages - Allocate and initialize an sg table from
- *			         an array of pages
- * @sgt:	 The sg table header to use
- * @pages:	 Pointer to an array of page pointers
- * @n_pages:	 Number of pages in the pages array
+ * sg_alloc_append_table_from_pages - Allocate and initialize an append sg
+ *                                    table from an array of pages
+ * @sgt_append:  The sg append table to use
+ * @pages:       Pointer to an array of page pointers
+ * @n_pages:     Number of pages in the pages array
  * @offset:      Offset from start of the first page to the start of a buffer
  * @size:        Number of valid bytes in the buffer (after offset)
  * @max_segment: Maximum size of a scatterlist element in bytes
- * @prv:	 Last populated sge in sgt
  * @left_pages:  Left pages caller have to set after this call
  * @gfp_mask:	 GFP allocation mask
  *
  * Description:
- *    If @prv is NULL, allocate and initialize an sg table from a list of pages,
- *    else reuse the scatterlist passed in at @prv.
- *    Contiguous ranges of the pages are squashed into a single scatterlist
- *    entry up to the maximum size specified in @max_segment.  A user may
- *    provide an offset at a start and a size of valid data in a buffer
- *    specified by the page array.
+ *    In the first call it allocate and initialize an sg table from a list of
+ *    pages, else reuse the scatterlist from sgt_append. Contiguous ranges of
+ *    the pages are squashed into a single scatterlist entry up to the maximum
+ *    size specified in @max_segment.  A user may provide an offset at a start
+ *    and a size of valid data in a buffer specified by the page array. The
+ *    returned sg table is released by sg_free_append_table
  *
  * Returns:
- *   Last SGE in sgt on success, PTR_ERR on otherwise.
- *   The allocation in @sgt must be released by sg_free_table.
+ *   0 on success, negative error on failure
  *
  * Notes:
  *   If this function returns non-0 (eg failure), the caller must call
- *   sg_free_table() to cleanup any leftover allocations.
+ *   sg_free_append_table() to cleanup any leftover allocations.
+ *
+ *   In the fist call, sgt_append must by initialized.
  */
-struct scatterlist *sg_alloc_append_table_from_pages(struct sg_table *sgt,
+int sg_alloc_append_table_from_pages(struct sg_append_table *sgt_append,
 		struct page **pages, unsigned int n_pages, unsigned int offset,
 		unsigned long size, unsigned int max_segment,
-		struct scatterlist *prv, unsigned int left_pages,
-		gfp_t gfp_mask)
+		unsigned int left_pages, gfp_t gfp_mask)
 {
 	unsigned int chunks, cur_page, seg_len, i, prv_len = 0;
 	unsigned int added_nents = 0;
-	struct scatterlist *s = prv;
+	struct scatterlist *s = sgt_append->prv;
 
 	/*
 	 * The algorithm below requires max_segment to be aligned to PAGE_SIZE
@@ -441,25 +454,26 @@ struct scatterlist *sg_alloc_append_table_from_pages(struct sg_table *sgt,
 	 */
 	max_segment = ALIGN_DOWN(max_segment, PAGE_SIZE);
 	if (WARN_ON(max_segment < PAGE_SIZE))
-		return ERR_PTR(-EINVAL);
+		return -EINVAL;
 
-	if (IS_ENABLED(CONFIG_ARCH_NO_SG_CHAIN) && prv)
-		return ERR_PTR(-EOPNOTSUPP);
+	if (IS_ENABLED(CONFIG_ARCH_NO_SG_CHAIN) && sgt_append->prv)
+		return -EOPNOTSUPP;
 
-	if (prv) {
-		unsigned long paddr = (page_to_pfn(sg_page(prv)) * PAGE_SIZE +
-				       prv->offset + prv->length) /
-				      PAGE_SIZE;
+	if (sgt_append->prv) {
+		unsigned long paddr =
+			(page_to_pfn(sg_page(sgt_append->prv)) * PAGE_SIZE +
+			 sgt_append->prv->offset + sgt_append->prv->length) /
+			PAGE_SIZE;
 
 		if (WARN_ON(offset))
-			return ERR_PTR(-EINVAL);
+			return -EINVAL;
 
 		/* Merge contiguous pages into the last SG */
-		prv_len = prv->length;
+		prv_len = sgt_append->prv->length;
 		while (n_pages && page_to_pfn(pages[0]) == paddr) {
-			if (prv->length + PAGE_SIZE > max_segment)
+			if (sgt_append->prv->length + PAGE_SIZE > max_segment)
 				break;
-			prv->length += PAGE_SIZE;
+			sgt_append->prv->length += PAGE_SIZE;
 			paddr++;
 			pages++;
 			n_pages--;
@@ -496,15 +510,16 @@ struct scatterlist *sg_alloc_append_table_from_pages(struct sg_table *sgt,
 		}
 
 		/* Pass how many chunks might be left */
-		s = get_next_sg(sgt, s, chunks - i + left_pages, gfp_mask);
+		s = get_next_sg(sgt_append, s, chunks - i + left_pages,
+				gfp_mask);
 		if (IS_ERR(s)) {
 			/*
 			 * Adjust entry length to be as before function was
 			 * called.
 			 */
-			if (prv)
-				prv->length = prv_len;
-			return s;
+			if (sgt_append->prv)
+				sgt_append->prv->length = prv_len;
+			return PTR_ERR(s);
 		}
 		chunk_size = ((j - cur_page) << PAGE_SHIFT) - offset;
 		sg_set_page(s, pages[cur_page],
@@ -514,11 +529,13 @@ struct scatterlist *sg_alloc_append_table_from_pages(struct sg_table *sgt,
 		offset = 0;
 		cur_page = j;
 	}
-	sgt->nents += added_nents;
+	sgt_append->sgt.nents += added_nents;
+	sgt_append->sgt.orig_nents = sgt_append->sgt.nents;
+	sgt_append->prv = s;
 out:
 	if (!left_pages)
 		sg_mark_end(s);
-	return s;
+	return 0;
 }
 EXPORT_SYMBOL(sg_alloc_append_table_from_pages);
 
@@ -550,8 +567,18 @@ int sg_alloc_table_from_pages_segment(struct sg_table *sgt, struct page **pages,
 				unsigned long size, unsigned int max_segment,
 				gfp_t gfp_mask)
 {
-	return PTR_ERR_OR_ZERO(sg_alloc_append_table_from_pages(sgt, pages,
-			n_pages, offset, size, max_segment, NULL, 0, gfp_mask));
+	struct sg_append_table append = {};
+	int err;
+
+	err = sg_alloc_append_table_from_pages(&append, pages, n_pages, offset,
+					       size, max_segment, 0, gfp_mask);
+	if (err) {
+		sg_free_append_table(&append);
+		return err;
+	}
+	memcpy(sgt, &append.sgt, sizeof(*sgt));
+	WARN_ON(append.total_nents != sgt->orig_nents);
+	return 0;
 }
 EXPORT_SYMBOL(sg_alloc_table_from_pages_segment);
 
diff --git a/lib/sg_pool.c b/lib/sg_pool.c
index db29e5c1f790..a0b1a52cd6f7 100644
--- a/lib/sg_pool.c
+++ b/lib/sg_pool.c
@@ -90,7 +90,8 @@ void sg_free_table_chained(struct sg_table *table,
 	if (nents_first_chunk == 1)
 		nents_first_chunk = 0;
 
-	__sg_free_table(table, SG_CHUNK_SIZE, nents_first_chunk, sg_pool_free);
+	__sg_free_table(table, SG_CHUNK_SIZE, nents_first_chunk, sg_pool_free,
+			table->orig_nents);
 }
 EXPORT_SYMBOL_GPL(sg_free_table_chained);
 
diff --git a/tools/testing/scatterlist/main.c b/tools/testing/scatterlist/main.c
index c2ff9179c2cc..08465a701cd5 100644
--- a/tools/testing/scatterlist/main.c
+++ b/tools/testing/scatterlist/main.c
@@ -85,43 +85,46 @@ int main(void)
 
 	for (i = 0, test = tests; test->expected_segments; test++, i++) {
 		int left_pages = test->pfn_app ? test->num_pages : 0;
+		struct sg_append_table append = {};
 		struct page *pages[MAX_PAGES];
-		struct sg_table st;
-		struct scatterlist *sg = NULL;
 		int ret;
 
 		set_pages(pages, test->pfn, test->num_pages);
 
-		if (test->pfn_app) {
-			sg = sg_alloc_append_table_from_pages(
-				&st, pages, test->num_pages, 0, test->size,
-				test->max_seg, NULL, left_pages, GFP_KERNEL);
-			assert(PTR_ERR_OR_ZERO(sg) == test->alloc_ret);
-		} else {
+		if (test->pfn_app)
+			ret = sg_alloc_append_table_from_pages(
+				&append, pages, test->num_pages, 0, test->size,
+				test->max_seg, left_pages, GFP_KERNEL);
+		else
 			ret = sg_alloc_table_from_pages_segment(
-				&st, pages, test->num_pages, 0, test->size,
-				test->max_seg, GFP_KERNEL);
-			assert(ret == test->alloc_ret);
-		}
+				&append.sgt, pages, test->num_pages, 0,
+				test->size, test->max_seg, GFP_KERNEL);
+
+		assert(ret == test->alloc_ret);
 
 		if (test->alloc_ret)
 			continue;
 
 		if (test->pfn_app) {
 			set_pages(pages, test->pfn_app, test->num_pages);
-			sg = sg_alloc_append_table_from_pages(
-				&st, pages, test->num_pages, 0, test->size,
-				test->max_seg, sg, 0, GFP_KERNEL);
+			ret = sg_alloc_append_table_from_pages(
+				&append, pages, test->num_pages, 0, test->size,
+				test->max_seg, 0, GFP_KERNEL);
 
-			assert(PTR_ERR_OR_ZERO(sg) == test->alloc_ret);
+			assert(ret == test->alloc_ret);
 		}
 
-		VALIDATE(st.nents == test->expected_segments, &st, test);
+		VALIDATE(append.sgt.nents == test->expected_segments,
+			 &append.sgt, test);
 		if (!test->pfn_app)
-			VALIDATE(st.orig_nents == test->expected_segments, &st,
-				 test);
-
-		sg_free_table(&st);
+			VALIDATE(append.sgt.orig_nents ==
+					 test->expected_segments,
+				 &append.sgt, test);
+
+		if (test->pfn_app)
+			sg_free_append_table(&append);
+		else
+			sg_free_table(&append.sgt);
 	}
 
 	assert(i == (sizeof(tests) / sizeof(tests[0])) - 1);