[PATCH] drm/buddy: Fix the range bias clear memory allocation issue

[Daniel Vetter]

On Wed, May 08, 2024 at 12:27:20PM +0530, Arunpravin Paneer Selvam wrote:
> Problem statement: During the system boot time, an application request
> for the bulk volume of cleared range bias memory when the clear_avail
> is zero, we dont fallback into normal allocation method as we had an
> unnecessary clear_avail check which prevents the fallback method leads
> to fb allocation failure following system goes into unresponsive state.
> 
> Solution: Remove the unnecessary clear_avail check in the range bias
> allocation function.
> 
> Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam at amd.com>
> Fixes: 96950929eb23 ("drm/buddy: Implement tracking clear page feature")
> Reviewed-by: Matthew Auld <matthew.auld at intel.com>
> ---
>  drivers/gpu/drm/drm_buddy.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Can you please also add a kunit test case to exercise this corner case and
make sure it stays fixed?

Thanks, Sima
> 
> diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
> index 284ebae71cc4..831929ac95eb 100644
> --- a/drivers/gpu/drm/drm_buddy.c
> +++ b/drivers/gpu/drm/drm_buddy.c
> @@ -574,7 +574,7 @@ __drm_buddy_alloc_range_bias(struct drm_buddy *mm,
>  
>  	block = __alloc_range_bias(mm, start, end, order,
>  				   flags, fallback);
> -	if (IS_ERR(block) && mm->clear_avail)
> +	if (IS_ERR(block))
>  		return __alloc_range_bias(mm, start, end, order,
>  					  flags, !fallback);
>  
> -- 
> 2.25.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch