[PATCH 5.15 060/207] dma-buf: system_heap: Use for_each_sgtable_sg in pages free flow

Greg Kroah-Hartman
2021-12-06T15:54:59Z

From: Guangming <Guangming.Cao@mediatek.com>

commit 679d94cd7d900871e5bc9cf780bd5b73af35ab42 upstream.

For previous version, it uses 'sg_table.nent's to traverse sg_table in pages
free flow.
However, 'sg_table.nents' is reassigned in 'dma_map_sg', it means the number of
created entries in the DMA adderess space.
So, use 'sg_table.nents' in pages free flow will case some pages can't be freed.

Here we should use sg_table.orig_nents to free pages memory, but use the
sgtable helper 'for each_sgtable_sg'(, instead of the previous rather common
helper 'for_each_sg' which maybe cause memory leak) is much better.

Fixes: d963ab0f15fb0 ("dma-buf: system_heap: Allocate higher order pages if available")
Signed-off-by: Guangming <Guangming.Cao@mediatek.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Cc: <stable@vger.kernel.org> # 5.11.*
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211126074904.88388-1-guangming.cao@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/dma-buf/heaps/system_heap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/dma-buf/heaps/system_heap.c
+++ b/drivers/dma-buf/heaps/system_heap.c
@@ -289,7 +289,7 @@ static void system_heap_dma_buf_release(
int i;

table = &buffer->sg_table;
- for_each_sg(table->sgl, sg, table->nents, i) {
+ for_each_sgtable_sg(table, sg, i) {
struct page *page = sg_page(sg);

__free_pages(page, compound_order(page));