[PATCH v2] drm: Fix a infinite loop condition when order becomes 0

[Christian König]

Am 16.03.22 um 07:34 schrieb Arunpravin Paneer Selvam:
> handle a situation in the condition order-- == min_order,
> when order = 0 and min_order = 0, leading to order = -1,
> it now won't exit the loop. To avoid this problem,
> added a order check in the same condition, (i.e)
> when order is 0, we return -ENOSPC
>
> v2: use full name in email program and in Signed-off tag
>
> Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam at amd.com>

Acked-by: Christian König <christian.koenig at amd.com>

BTW while going over the code I've seen this here in the function:

...
                 if (!pages)
                         break;
         } while (1);


Can that be changed to "} while (pages);" instead? Would probably be a 
little bit cleaner.

Regards,
Christian.

> ---
>   drivers/gpu/drm/drm_buddy.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
> index 72f52f293249..5ab66aaf2bbd 100644
> --- a/drivers/gpu/drm/drm_buddy.c
> +++ b/drivers/gpu/drm/drm_buddy.c
> @@ -685,7 +685,7 @@ int drm_buddy_alloc_blocks(struct drm_buddy *mm,
>   			if (!IS_ERR(block))
>   				break;
>   
> -			if (order-- == min_order) {
> +			if (!order || order-- == min_order) {
>   				err = -ENOSPC;
>   				goto err_free;
>   			}
>
> base-commit: 3bd60c0259406c5ca3ce5cdc958fb910ad4b8175