linux-kernel - [Patch v3 1/5] mm/page_alloc.c: bad_[reason|flags] is not necessary when PageHWPoison

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Date:   Sat, 11 Apr 2020 22:03:53 +0000
From:   Wei Yang <richard.weiyang@...il.com>
To:     akpm@...ux-foundation.org
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        rientjes@...gle.com, anshuman.khandual@....com, david@...hat.com,
        Wei Yang <richard.weiyang@...il.com>
Subject: [Patch v3 1/5] mm/page_alloc.c: bad_[reason|flags] is not necessary when PageHWPoison

Since function returns directly, bad_[reason|flags] is not used any
where. And move this to the first.

This is a following cleanup for commit e570f56cccd21 ("mm:
check_new_page_bad() directly returns in __PG_HWPOISON case")

Signed-off-by: Wei Yang <richard.weiyang@...il.com>
Acked-by: Michal Hocko <mhocko@...e.com>
Reviewed-by: David Hildenbrand <david@...hat.com>

---
v3:
  * move this handling to the first case
---
 mm/page_alloc.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index f49f28f1220b..7327dc039069 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2037,19 +2037,17 @@ static void check_new_page_bad(struct page *page)
 	const char *bad_reason = NULL;
 	unsigned long bad_flags = 0;
 
+	if (unlikely(page->flags & __PG_HWPOISON)) {
+		/* Don't complain about hwpoisoned pages */
+		page_mapcount_reset(page); /* remove PageBuddy */
+		return;
+	}
 	if (unlikely(atomic_read(&page->_mapcount) != -1))
 		bad_reason = "nonzero mapcount";
 	if (unlikely(page->mapping != NULL))
 		bad_reason = "non-NULL mapping";
 	if (unlikely(page_ref_count(page) != 0))
 		bad_reason = "nonzero _refcount";
-	if (unlikely(page->flags & __PG_HWPOISON)) {
-		bad_reason = "HWPoisoned (hardware-corrupted)";
-		bad_flags = __PG_HWPOISON;
-		/* Don't complain about hwpoisoned pages */
-		page_mapcount_reset(page); /* remove PageBuddy */
-		return;
-	}
 	if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_PREP)) {
 		bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag set";
 		bad_flags = PAGE_FLAGS_CHECK_AT_PREP;
-- 
2.23.0