[PATCH v5 3/9] lib/scatterlist: Add sg_dup_table

[Yong Wu <yong.wu@xxxxxxxxxxxx>]

Prepare for the restricted heap to reuse, move it out from system_heap.c.
To keep the function name consistent, rename it to sg_dup_table.

Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
---
 drivers/dma-buf/heaps/system_heap.c | 27 +--------------------------
 include/linux/scatterlist.h         |  2 ++
 lib/scatterlist.c                   | 26 ++++++++++++++++++++++++++
 3 files changed, 29 insertions(+), 26 deletions(-)

diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c
index 9076d47ed2ef..204e55f92330 100644
--- a/drivers/dma-buf/heaps/system_heap.c
+++ b/drivers/dma-buf/heaps/system_heap.c
@@ -54,31 +54,6 @@ static gfp_t order_flags[] = {HIGH_ORDER_GFP, HIGH_ORDER_GFP, LOW_ORDER_GFP};
 static const unsigned int orders[] = {8, 4, 0};
 #define NUM_ORDERS ARRAY_SIZE(orders)
 
-static struct sg_table *dup_sg_table(struct sg_table *table)
-{
-	struct sg_table *new_table;
-	int ret, i;
-	struct scatterlist *sg, *new_sg;
-
-	new_table = kzalloc(sizeof(*new_table), GFP_KERNEL);
-	if (!new_table)
-		return ERR_PTR(-ENOMEM);
-
-	ret = sg_alloc_table(new_table, table->orig_nents, GFP_KERNEL);
-	if (ret) {
-		kfree(new_table);
-		return ERR_PTR(-ENOMEM);
-	}
-
-	new_sg = new_table->sgl;
-	for_each_sgtable_sg(table, sg, i) {
-		sg_set_page(new_sg, sg_page(sg), sg->length, sg->offset);
-		new_sg = sg_next(new_sg);
-	}
-
-	return new_table;
-}
-
 static int system_heap_attach(struct dma_buf *dmabuf,
 			      struct dma_buf_attachment *attachment)
 {
@@ -90,7 +65,7 @@ static int system_heap_attach(struct dma_buf *dmabuf,
 	if (!a)
 		return -ENOMEM;
 
-	table = dup_sg_table(&buffer->sg_table);
+	table = sg_dup_table(&buffer->sg_table);
 	if (IS_ERR(table)) {
 		kfree(a);
 		return -ENOMEM;
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index a6ad9018eca0..53a4cdc11f4f 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -538,6 +538,8 @@ size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents,
 size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents,
 		       size_t buflen, off_t skip);
 
+struct sg_table *sg_dup_table(struct sg_table *table);
+
 /*
  * Maximum number of entries that will be allocated in one piece, if
  * a list larger than this is required then chaining will be utilized.
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index 7bc2220fea80..3efcf728c13b 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -1100,6 +1100,32 @@ size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents,
 }
 EXPORT_SYMBOL(sg_zero_buffer);
 
+struct sg_table *sg_dup_table(struct sg_table *table)
+{
+	struct sg_table *new_table;
+	int ret, i;
+	struct scatterlist *sg, *new_sg;
+
+	new_table = kzalloc(sizeof(*new_table), GFP_KERNEL);
+	if (!new_table)
+		return ERR_PTR(-ENOMEM);
+
+	ret = sg_alloc_table(new_table, table->orig_nents, GFP_KERNEL);
+	if (ret) {
+		kfree(new_table);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	new_sg = new_table->sgl;
+	for_each_sgtable_sg(table, sg, i) {
+		sg_set_page(new_sg, sg_page(sg), sg->length, sg->offset);
+		new_sg = sg_next(new_sg);
+	}
+
+	return new_table;
+}
+EXPORT_SYMBOL(sg_dup_table);
+
 /*
  * Extract and pin a list of up to sg_max pages from UBUF- or IOVEC-class
  * iterators, and add them to the scatterlist.
-- 
2.25.1