Re: [PATCH v4 4/4] dma-buf: heaps: add chunk heap to dmabuf heaps

[John Stultz <john.stultz@linaro.org>]

On Thu, Jan 21, 2021 at 9:55 AM Minchan Kim <minchan@kernel.org> wrote:

Hey Minchan,
  Thanks for sending this out! I'm still working through testing with
this patch set, so I may have some more feedback tomorrow, but a few
quick items I did hit below.

> +
> +#define CHUNK_PREFIX "chunk-"
> +
> +static int register_chunk_heap(struct chunk_heap *chunk_heap_info)
> +{
> +       struct dma_heap_export_info exp_info;
> +       const char *name = cma_get_name(chunk_heap_info->cma);
> +       size_t len = strlen(CHUNK_PREFIX) + strlen(name) + 1;
> +       char *buf = kmalloc(len, GFP_KERNEL);
> +
> +       if (!buf)
> +               return -ENOMEM;
> +
> +       sprintf(buf, CHUNK_PREFIX"%s", cma_get_name(chunk_heap_info->cma));
> +       buf[len] = '\0';
> +
> +       exp_info.name = buf;
> +       exp_info.name = cma_get_name(chunk_heap_info->cma);

I think you intended to delete this line, as it's overwriting your
prefixed name.

> +       exp_info.ops = &chunk_heap_ops;
> +       exp_info.priv = chunk_heap_info;
> +
> +       chunk_heap_info->heap = dma_heap_add(&exp_info);
> +       if (IS_ERR(chunk_heap_info->heap)) {
> +               kfree(buf);
> +               return PTR_ERR(chunk_heap_info->heap);
> +       }
> +
> +       return 0;
> +}
> +
> +static int __init chunk_heap_init(void)
> +{
> +       unsigned int i;
> +
> +       for (i = 0; i < chunk_heap_count; i++)
> +               register_chunk_heap(&chunk_heaps[i]);
> +
> +       return 0;
> +}
> +module_init(chunk_heap_init);
> +
> +#ifdef CONFIG_OF_EARLY_FLATTREE
> +
> +static int __init dmabuf_chunk_heap_area_init(struct reserved_mem *rmem)
> +{
> +       int ret;
> +       struct cma *cma;
> +       struct chunk_heap *chunk_heap_info;
> +       const __be32 *chunk_order;
> +
> +       phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
> +       phys_addr_t mask = align - 1;
> +
> +       if ((rmem->base & mask) || (rmem->size & mask)) {
> +               pr_err("Incorrect alignment for CMA region\n");
> +               return -EINVAL;

Passing this check can be tough if you're using dynamically assigned
rmem, so it might be helpful for debugging to print the base/size/mask
values?

thanks
-john