It isn't true for only SPARSEMEM configs to assume that a compound page
has virtually contiguous page structs, so use nth_page to iterate each
page.
Signed-off-by: Chen Wandun <[email protected]>
---
include/linux/mm.h | 2 ++
mm/page_alloc.c | 12 +++++++-----
2 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 355075fb2654..ef48cfef7c67 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -212,9 +212,11 @@ int overcommit_policy_handler(struct ctl_table *, int, void *, size_t *,
#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
#define nth_page(page,n) pfn_to_page(page_to_pfn((page)) + (n))
+#define page_nth(head, tail) (page_to_pfn(tail) - page_to_pfn(head))
#define folio_page_idx(folio, p) (page_to_pfn(p) - folio_pfn(folio))
#else
#define nth_page(page,n) ((page) + (n))
+#define page_nth(head, tail) ((tail) - (head))
#define folio_page_idx(folio, p) ((p) - &(folio)->page)
#endif
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 855211dea13e..09bc63992d20 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -721,7 +721,7 @@ static void prep_compound_head(struct page *page, unsigned int order)
static void prep_compound_tail(struct page *head, int tail_idx)
{
- struct page *p = head + tail_idx;
+ struct page *p = nth_page(head, tail_idx);
p->mapping = TAIL_MAPPING;
set_compound_head(p, head);
@@ -1213,7 +1213,7 @@ static int free_tail_pages_check(struct page *head_page, struct page *page)
ret = 0;
goto out;
}
- switch (page - head_page) {
+ switch (page_nth(head_page, page)) {
case 1:
/* the first tail page: ->mapping may be compound_mapcount() */
if (unlikely(compound_mapcount(page))) {
@@ -1322,6 +1322,7 @@ static __always_inline bool free_pages_prepare(struct page *page,
if (unlikely(order)) {
bool compound = PageCompound(page);
int i;
+ struct page *tail_page;
VM_BUG_ON_PAGE(compound && compound_order(page) != order, page);
@@ -1330,13 +1331,14 @@ static __always_inline bool free_pages_prepare(struct page *page,
ClearPageHasHWPoisoned(page);
}
for (i = 1; i < (1 << order); i++) {
+ tail_page = nth_page(page, i);
if (compound)
- bad += free_tail_pages_check(page, page + i);
- if (unlikely(check_free_page(page + i))) {
+ bad += free_tail_pages_check(page, tail_page);
+ if (unlikely(check_free_page(tail_page))) {
bad++;
continue;
}
- (page + i)->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
+ tail_page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
}
}
if (PageMappingFlags(page))
--
2.18.0.huawei.25