Re: [PATCH 2/7] drm/selftests: add drm buddy alloc limit testcase

[Matthew Auld <matthew.auld@intel.com>]

On 03/02/2022 13:32, Arunpravin wrote:
> add a test to check the maximum allocation limit
> 
> Signed-off-by: Arunpravin <Arunpravin.PaneerSelvam@amd.com>
> ---
>   .../gpu/drm/selftests/drm_buddy_selftests.h   |  1 +
>   drivers/gpu/drm/selftests/test-drm_buddy.c    | 60 +++++++++++++++++++
>   2 files changed, 61 insertions(+)
> 
> diff --git a/drivers/gpu/drm/selftests/drm_buddy_selftests.h b/drivers/gpu/drm/selftests/drm_buddy_selftests.h
> index a4bcf3a6dfe3..ebe16162762f 100644
> --- a/drivers/gpu/drm/selftests/drm_buddy_selftests.h
> +++ b/drivers/gpu/drm/selftests/drm_buddy_selftests.h
> @@ -7,3 +7,4 @@
>    * Tests are executed in order by igt/drm_buddy
>    */
>   selftest(sanitycheck, igt_sanitycheck) /* keep first (selfcheck for igt) */
> +selftest(buddy_alloc_limit, igt_buddy_alloc_limit)
> diff --git a/drivers/gpu/drm/selftests/test-drm_buddy.c b/drivers/gpu/drm/selftests/test-drm_buddy.c
> index 51e4d393d22c..fd7d1a112458 100644
> --- a/drivers/gpu/drm/selftests/test-drm_buddy.c
> +++ b/drivers/gpu/drm/selftests/test-drm_buddy.c
> @@ -16,6 +16,66 @@
>   
>   static unsigned int random_seed;
>   
> +static int igt_buddy_alloc_limit(void *arg)
> +{
> +	u64 end, size = U64_MAX, start = 0;
> +	struct drm_buddy_block *block;
> +	unsigned long flags = 0;
> +	LIST_HEAD(allocated);
> +	struct drm_buddy mm;
> +	int err;
> +
> +	size = end = round_down(size, 4096);
> +	err = drm_buddy_init(&mm, size, PAGE_SIZE);
> +	if (err)
> +		return err;
> +
> +	if (mm.max_order != DRM_BUDDY_MAX_ORDER) {
> +		pr_err("mm.max_order(%d) != %d\n",
> +		       mm.max_order, DRM_BUDDY_MAX_ORDER);
> +		err = -EINVAL;
> +		goto out_fini;
> +	}
> +
> +	err = drm_buddy_alloc_blocks(&mm, start, end, size,
> +				     PAGE_SIZE, &allocated, flags);
> +
> +	if (unlikely(err))
> +		goto out_free;
> +
> +	block = list_first_entry_or_null(&allocated,
> +					 struct drm_buddy_block,
> +					 link);
> +
> +	if (!block)

err = -EINVAL;

> +		goto out_fini;
> +
> +	if (drm_buddy_block_order(block) != mm.max_order) {
> +		pr_err("block order(%d) != %d\n",
> +		       drm_buddy_block_order(block), mm.max_order);
> +		err = -EINVAL;
> +		goto out_free;
> +	}
> +
> +	if (drm_buddy_block_size(&mm, block) !=
> +	    BIT_ULL(mm.max_order) * PAGE_SIZE) {
> +		pr_err("block size(%llu) != %llu\n",
> +		       drm_buddy_block_size(&mm, block),
> +		       BIT_ULL(mm.max_order) * PAGE_SIZE);
> +		err = -EINVAL;
> +		goto out_free;
> +	}
> +
> +	if (!err)

Always true AFAICT?

> +		pr_info("%s - succeeded\n", __func__);

I guess this could be made part of the run_selftests()? It looks like it 
already prints the current test, perhaps that is already enough?

With the err = -EINVAL change, feel free to add,
Reviewed-by: Matthew Auld <matthew.auld@intel.com>

> +
> +out_free:
> +	drm_buddy_free_list(&mm, &allocated);
> +out_fini:
> +	drm_buddy_fini(&mm);
> +	return err;
> +}
> +
>   static int igt_sanitycheck(void *ignored)
>   {
>   	pr_info("%s - ok!\n", __func__);