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

[Jisheng Zhang]

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@xxxxxxxxxx>
> > ---
> >  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
> > 
>