linux-kernel - [PATCH v3 1/2] mm/page_alloc: drop the unnecessary pfn

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Message-Id: <c3868b58c6714c09a43440d7d02c7b4eed6e03f6.1682342634.git.baolin.wang@linux.alibaba.com>
Date:   Mon, 24 Apr 2023 21:45:39 +0800
From:   Baolin Wang <baolin.wang@...ux.alibaba.com>
To:     akpm@...ux-foundation.org
Cc:     rppt@...nel.org, ying.huang@...el.com, mgorman@...hsingularity.net,
        vbabka@...e.cz, mhocko@...e.com, david@...hat.com,
        baolin.wang@...ux.alibaba.com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v3 1/2] mm/page_alloc: drop the unnecessary pfn_valid() for start pfn

__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().

Signed-off-by: Baolin Wang <baolin.wang@...ux.alibaba.com>
Reviewed-by: David Hildenbrand <david@...hat.com>
Reviewed-by: "Huang, Ying" <ying.huang@...el.com>
Acked-by: Michal Hocko <mhocko@...e.com>
---
Changes from v2:
 - Update the commit message per Michal. Thanks.
 - Add acked tag from Michal.
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