Am 26.11.21 um 08:49 schrieb guangming.cao@mediatek.com:

From: Guangming Guangming.Cao@mediatek.com

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

Reviewed-by: Christian König christian.koenig@amd.com

Cc: stable@vger.kernel.org # 5.11.*

v4: Correct commit message 1. Cc stable@vger.kernel.org in commit message and add required kernel version. 2. Add reviewed-by since patch V2 and V4 are same and V2 is reviewed by Robin. 3. There is no new code change in V4. V3: Cc stable@vger.kernel.org 1. This patch needs to be merged stable branch, add stable@vger.kernel.org in mail list. 2. Correct some spelling mistake. 3. There is No new code change in V3. V2: use 'for_each_sgtable_sg' to 'replece for_each_sg' as suggested by Robin.

---

drivers/dma-buf/heaps/system_heap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c index 23a7e74ef966..8660508f3684 100644 --- 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(struct dma_buf *dmabuf) 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));