[Linaro-mm-sig] Re: [PATCH] dma-buf: system_heap: Use LIST_HEAD() to initialize on stack list head

On Tue, May 19, 2026 at 08:51:00AM +0200, Christian König wrote:

On 5/19/26 08:05, Jisheng Zhang wrote:

...

Use LIST_HEAD to initialize on stack list head. No intentional functional impact.

Change generated with below coccinelle script:

@@ identifier name; @@

• struct list_head name;

• LIST_HEAD(name);

... when != name

• INIT_LIST_HEAD(&name);

The patch itself looks correct, but my question is why would we want to do that?

The benefit is: simpler code, combine the linked list defintion and initialization in one step, thus 1 LoC vs 2 LoCs; And potential bug prevention, e.g use the list before intialized. But I agree, no strong benefit here.

Initializing the list head (or any other result variable) directly before it is filled in is usually good practice.

Regards, Christian.

...

Signed-off-by: Jisheng Zhang jszhang@kernel.org

drivers/dma-buf/heaps/system_heap.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c index 03c2b87cb111..6f8b7138ff56 100644 --- a/drivers/dma-buf/heaps/system_heap.c +++ b/drivers/dma-buf/heaps/system_heap.c @@ -409,7 +409,7 @@ static struct dma_buf *system_heap_allocate(struct dma_heap *heap, struct dma_buf *dmabuf; struct sg_table *table; struct scatterlist *sg;

•   struct list_head pages;
  

•   LIST_HEAD(pages);
    struct page *page, *tmp_page;
    int i, ret = -ENOMEM;
  
  

@@ -423,7 +423,6 @@ static struct dma_buf *system_heap_allocate(struct dma_heap *heap, buffer->len = len; buffer->cc_shared = cc_shared;

•   INIT_LIST_HEAD(&pages);
    i = 0;
    while (size_remaining > 0) {
            /*
  

-- 2.53.0