Re: [PATCH] dma_heap: use sg_table.orig_nents in sg_table release flow

[Robin Murphy]

On 2021-11-25 12:46, guangming.cao@xxxxxxxxxxxx wrote:
> From: Guangming <Guangming.Cao@xxxxxxxxxxxx>
>
> Use (sg_table.orig_nents) rather than (sg_table.nents) to traverse
> sg_table to free sg_table.
> Use (sg_table.nents) maybe will casuse some pages can't be freed.

...and this sort of bug is precisely why we have the 
for_each_sgtable_sg() helper ;)

Robin.

> Signed-off-by: Guangming <Guangming.Cao@xxxxxxxxxxxx>
> ---
>   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..ce10d4eb674c 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_sg(table->sgl, sg, table->orig_nents, i) {
>   		struct page *page = sg_page(sg);
>   
>   		__free_pages(page, compound_order(page));