MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
can deliver is MAX_ORDER-1.

Fix MAX_ORDER usage in page_reporting_register().

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
---
 mm/page_reporting.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/page_reporting.c b/mm/page_reporting.c
index c65813a9dc78..275b466de37b 100644
--- a/mm/page_reporting.c
+++ b/mm/page_reporting.c
@@ -370,7 +370,7 @@ int page_reporting_register(struct page_reporting_dev_info *prdev)
 	 */
 
 	if (page_reporting_order == -1) {
-		if (prdev->order > 0 && prdev->order <= MAX_ORDER)
+		if (prdev->order > 0 && prdev->order < MAX_ORDER)
 			page_reporting_order = prdev->order;
 		else
 			page_reporting_order = pageblock_order;
-- 
2.39.2

On 3/15/23 12:31, Kirill A. Shutemov wrote:
> MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
> can deliver is MAX_ORDER-1.
> 
> Fix MAX_ORDER usage in page_reporting_register().
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

Reviewed-by: Vlastimil Babka <vbabka@suse.cz>

> Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
> ---
>  mm/page_reporting.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/page_reporting.c b/mm/page_reporting.c
> index c65813a9dc78..275b466de37b 100644
> --- a/mm/page_reporting.c
> +++ b/mm/page_reporting.c
> @@ -370,7 +370,7 @@ int page_reporting_register(struct page_reporting_dev_info *prdev)
>  	 */
>  
>  	if (page_reporting_order == -1) {
> -		if (prdev->order > 0 && prdev->order <= MAX_ORDER)
> +		if (prdev->order > 0 && prdev->order < MAX_ORDER)
>  			page_reporting_order = prdev->order;
>  		else
>  			page_reporting_order = pageblock_order;