The first entry of error_states[], { reserved, reserved, MF_MSG_KERNEL, me_kernel }, is unreachable. identify_page_state() has two callers, and neither one can dispatch a PG_reserved page to me_kernel(): * memory_failure() reaches identify_page_state() only after get_hwpoison_page() returned 1. get_any_page() reaches that return only via __get_hwpoison_page(), which only takes a refcount when the page is HWPoisonHandlable(). HWPoisonHandlable() is an allowlist for LRU, free-buddy, and (for soft-offline) movable_ops pages -- PG_reserved pages do not satisfy any of these, so they fail with -EBUSY/-EIO long before identify_page_state() runs. * try_memory_failure_hugetlb() reaches identify_page_state() only via the MF_HUGETLB_IN_USED branch, where the page is necessarily a hugetlb folio. hugetlb folios don't carry PG_reserved at that point: hugetlb_folio_init_vmemmap() calls __folio_clear_reserved() during init, so the reserved entry would not match even if it were still present. me_kernel() never executes and the entry exists only to be matched against by code that cannot see it. Drop the entry, the me_kernel() helper, and the now-unused "reserved" macro. Leave the MF_MSG_KERNEL enum value in place: it remains part of the tracepoint and pr_err() string tables, and follow-on work to classify unrecoverable kernel pages can reuse it without churning the user-visible enum. No functional change. Suggested-by: David Hildenbrand Acked-by: David Hildenbrand (Arm) Reviewed-by: Lance Yang Acked-by: Miaohe Lin Signed-off-by: Breno Leitao --- mm/memory-failure.c | 14 -------------- 1 file changed, 14 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 51508a55c4055..f4d3e6e20e13f 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -980,17 +980,6 @@ static bool has_extra_refcount(struct page_state *ps, struct page *p, return false; } -/* - * Error hit kernel page. - * Do nothing, try to be lucky and not touch this instead. For a few cases we - * could be more sophisticated. - */ -static int me_kernel(struct page_state *ps, struct page *p) -{ - unlock_page(p); - return MF_IGNORED; -} - /* * Page in unknown state. Do nothing. * This is a catch-all in case we fail to make sense of the page state. @@ -1199,10 +1188,8 @@ static int me_huge_page(struct page_state *ps, struct page *p) #define mlock (1UL << PG_mlocked) #define lru (1UL << PG_lru) #define head (1UL << PG_head) -#define reserved (1UL << PG_reserved) static struct page_state error_states[] = { - { reserved, reserved, MF_MSG_KERNEL, me_kernel }, /* * free pages are specially detected outside this table: * PG_buddy pages only make a small fraction of all free pages. @@ -1234,7 +1221,6 @@ static struct page_state error_states[] = { #undef mlock #undef lru #undef head -#undef reserved static void update_per_node_mf_stats(unsigned long pfn, enum mf_result result) -- 2.53.0-Meta