mm/hwpoison: introduce folio_contain_hwpoisoned_page() helper

Patch series "mm/vmscan: don't try to reclaim hwpoison folio".

Fix a bug during memory reclaim if folio is hwpoisoned.


This patch (of 2):

Introduce helper folio_contain_hwpoisoned_page() to check if the entire
folio is hwpoisoned or it contains hwpoisoned pages.

Link: https://lkml.kernel.org/r/20250318083939.987651-1-tujinjiang@huawei.com
Link: https://lkml.kernel.org/r/20250318083939.987651-2-tujinjiang@huawei.com
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: <stable@vger,kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/page-flags.h

@@ -1098,6 +1098,12 @@ static inline bool is_page_hwpoison(const struct page *page)
 	return folio_test_hugetlb(folio) && PageHWPoison(&folio->page);
 }
 
+static inline bool folio_contain_hwpoisoned_page(struct folio *folio)
+{
+	return folio_test_hwpoison(folio) ||
+	    (folio_test_large(folio) && folio_test_has_hwpoisoned(folio));
+}
+
 bool is_free_buddy_page(const struct page *page);
 
 PAGEFLAG(Isolated, isolated, PF_ANY);

mm/memory_hotplug.c

@@ -1828,8 +1828,7 @@ static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
 		if (unlikely(page_folio(page) != folio))
 			goto put_folio;
 
-		if (folio_test_hwpoison(folio) ||
-		    (folio_test_large(folio) && folio_test_has_hwpoisoned(folio))) {
+		if (folio_contain_hwpoisoned_page(folio)) {
 			if (WARN_ON(folio_test_lru(folio)))
 				folio_isolate_lru(folio);
 			if (folio_mapped(folio)) {

mm/shmem.c

@@ -3290,8 +3290,7 @@ shmem_write_begin(struct file *file, struct address_space *mapping,
 	if (ret)
 		return ret;
 
-	if (folio_test_hwpoison(folio) ||
-	    (folio_test_large(folio) && folio_test_has_hwpoisoned(folio))) {
+	if (folio_contain_hwpoisoned_page(folio)) {
 		folio_unlock(folio);
 		folio_put(folio);
 		return -EIO;