On 4/24/2023 6:54 PM, Michal Hocko wrote:
On Mon 24-04-23 18:46:40, Baolin Wang wrote:
On 4/24/2023 5:50 PM, Michal Hocko wrote:
On Sun 23-04-23 18:59:10, Baolin Wang wrote:
We've already used pfn_to_online_page() for start pfn to make sure
Who is we? I do not see any note explicitly requiring that start_pfn has
to be valid for __pageblock_pfn_to_page.
Sorry for confusing, what I mean is the __pageblock_pfn_to_page() function,
which has used pfn_to_online_page() for start pfn. So the pfn_valid() in
__pageblock_pfn_to_page() for start pfn is unnecessary.
I will update the commit log to make it clear.
Your comment suggested that the check _has_ already been done. Which is
not the case. pfn_to_online_page is called later in the function so I
guess you should rephrase as following:
"
__pageblock_pfn_to_page currently performs both pfn_valid check and
pfn_to_online_page. The former one is redundant because the latter is a
stronger check. Drop pfn_valid.
"
Yes, will change the commit log.
With that or something going along with that. Feel free to add
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Thanks.
it is online and valid, so the pfn_valid() for the start pfn is
unnecessary, drop it.
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
---
Changes from v1:
- Collect reviewed tags. Thanks David and Ying.
---
mm/page_alloc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 9de2a18519a1..6457b64fe562 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1512,7 +1512,7 @@ struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
/* end_pfn is one past the range we are checking */
end_pfn--;
- if (!pfn_valid(start_pfn) || !pfn_valid(end_pfn))
+ if (!pfn_valid(end_pfn))
return NULL;
start_page = pfn_to_online_page(start_pfn);
--
2.27.0
