[PATCH v1 06/39] mm/rmap: add hugetlb sanity checks

David Hildenbrand
2023-12-11T15:57:22Z

Let's make sure we end up with the right folios in the right functions.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
include/linux/rmap.h | 7 +++++++
mm/rmap.c | 6 ++++++
2 files changed, 13 insertions(+)

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 4c0650e9f6db..e3857d26b944 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -217,6 +217,7 @@ void hugetlb_add_new_anon_rmap(struct folio *, struct vm_area_struct *,
static inline int hugetlb_try_dup_anon_rmap(struct folio *folio,
struct vm_area_struct *vma)
{
+ VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio);
VM_WARN_ON_FOLIO(!folio_test_anon(folio), folio);

if (PageAnonExclusive(&folio->page)) {
@@ -231,6 +232,7 @@ static inline int hugetlb_try_dup_anon_rmap(struct folio *folio,
/* See page_try_share_anon_rmap() */
static inline int hugetlb_try_share_anon_rmap(struct folio *folio)
{
+ VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio);
VM_WARN_ON_FOLIO(!folio_test_anon(folio), folio);
VM_WARN_ON_FOLIO(!PageAnonExclusive(&folio->page), folio);

@@ -253,6 +255,7 @@ static inline int hugetlb_try_share_anon_rmap(struct folio *folio)

static inline void hugetlb_add_file_rmap(struct folio *folio)
{
+ VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio);
VM_WARN_ON_FOLIO(folio_test_anon(folio), folio);

atomic_inc(&folio->_entire_mapcount);
@@ -260,11 +263,15 @@ static inline void hugetlb_add_file_rmap(struct folio *folio)

static inline void hugetlb_remove_rmap(struct folio *folio)
{
+ VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio);
+
atomic_dec(&folio->_entire_mapcount);
}

static inline void __page_dup_rmap(struct page *page, bool compound)
{
+ VM_WARN_ON(folio_test_hugetlb(page_folio(page)));
+
if (compound) {
struct folio *folio = (struct folio *)page;

diff --git a/mm/rmap.c b/mm/rmap.c
index e210ac1b73de..41597da14f26 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1343,6 +1343,7 @@ void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
{
int nr = folio_nr_pages(folio);

+ VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio);
VM_BUG_ON_VMA(address < vma->vm_start ||
address + (nr << PAGE_SHIFT) > vma->vm_end, vma);
__folio_set_swapbacked(folio);
@@ -1395,6 +1396,7 @@ void folio_add_file_rmap_range(struct folio *folio, struct page *page,
unsigned int nr_pmdmapped = 0, first;
int nr = 0;

+ VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio);
VM_WARN_ON_FOLIO(compound && !folio_test_pmd_mappable(folio), folio);

/* Is page being mapped by PTE? Is this its first map to be added? */
@@ -1480,6 +1482,7 @@ void page_remove_rmap(struct page *page, struct vm_area_struct *vma,
bool last;
enum node_stat_item idx;

+ VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio);
VM_BUG_ON_PAGE(compound && !PageHead(page), page);

/* Is page being unmapped by PTE? Is this its last map to be removed? */
@@ -2632,6 +2635,7 @@ void rmap_walk_locked(struct folio *folio, struct rmap_walk_control *rwc)
void hugetlb_add_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
unsigned long address, rmap_t flags)
{
+ VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio);
VM_WARN_ON_FOLIO(!folio_test_anon(folio), folio);

atomic_inc(&folio->_entire_mapcount);
@@ -2644,6 +2648,8 @@ void hugetlb_add_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
void hugetlb_add_new_anon_rmap(struct folio *folio,
struct vm_area_struct *vma, unsigned long address)
{
+ VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio);
+
BUG_ON(address < vma->vm_start || address >= vma->vm_end);
/* increment count (starts at -1) */
atomic_set(&folio->_entire_mapcount, 0);
--
2.43.0