Accept a folio as an argument and return a folio result. Removes
a call to compound_head() in do_swap_page(), and prevents folio &
page from getting out of sync in unuse_pte().
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
include/linux/ksm.h | 6 +++---
mm/ksm.c | 21 +++++++++++----------
mm/memory.c | 8 ++++----
mm/swapfile.c | 8 +++++---
4 files changed, 23 insertions(+), 20 deletions(-)
diff --git a/include/linux/ksm.h b/include/linux/ksm.h
index 4643d5244e77..401348e9f92b 100644
--- a/include/linux/ksm.h
+++ b/include/linux/ksm.h
@@ -76,7 +76,7 @@ static inline void ksm_exit(struct mm_struct *mm)
* We'd like to make this conditional on vma->vm_flags & VM_MERGEABLE,
* but what if the vma was unmerged while the page was swapped out?
*/
-struct page *ksm_might_need_to_copy(struct page *page,
+struct folio *ksm_might_need_to_copy(struct folio *folio,
struct vm_area_struct *vma, unsigned long addr);
void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc);
@@ -129,10 +129,10 @@ static inline int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
return 0;
}
-static inline struct page *ksm_might_need_to_copy(struct page *page,
+static inline struct folio *ksm_might_need_to_copy(struct folio *folio,
struct vm_area_struct *vma, unsigned long addr)
{
- return page;
+ return folio;
}
static inline void rmap_walk_ksm(struct folio *folio,
diff --git a/mm/ksm.c b/mm/ksm.c
index b93389a3780e..16532fa85a46 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -2875,30 +2875,30 @@ void __ksm_exit(struct mm_struct *mm)
trace_ksm_exit(mm);
}
-struct page *ksm_might_need_to_copy(struct page *page,
+struct folio *ksm_might_need_to_copy(struct folio *folio,
struct vm_area_struct *vma, unsigned long addr)
{
- struct folio *folio = page_folio(page);
+ struct page *page = folio_page(folio, 0);
struct anon_vma *anon_vma = folio_anon_vma(folio);
struct folio *new_folio;
if (folio_test_large(folio))
- return page;
+ return folio;
if (folio_test_ksm(folio)) {
if (folio_stable_node(folio) &&
!(ksm_run & KSM_RUN_UNMERGE))
- return page; /* no need to copy it */
+ return folio; /* no need to copy it */
} else if (!anon_vma) {
- return page; /* no need to copy it */
+ return folio; /* no need to copy it */
} else if (folio->index == linear_page_index(vma, addr) &&
anon_vma->root == vma->anon_vma->root) {
- return page; /* still no need to copy it */
+ return folio; /* still no need to copy it */
}
if (PageHWPoison(page))
return ERR_PTR(-EHWPOISON);
if (!folio_test_uptodate(folio))
- return page; /* let do_swap_page report the error */
+ return folio; /* let do_swap_page report the error */
new_folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma, addr, false);
if (new_folio &&
@@ -2907,9 +2907,10 @@ struct page *ksm_might_need_to_copy(struct page *page,
new_folio = NULL;
}
if (new_folio) {
- if (copy_mc_user_highpage(&new_folio->page, page, addr, vma)) {
+ if (copy_mc_user_highpage(folio_page(new_folio, 0), page,
+ addr, vma)) {
folio_put(new_folio);
- memory_failure_queue(page_to_pfn(page), 0);
+ memory_failure_queue(folio_pfn(folio), 0);
return ERR_PTR(-EHWPOISON);
}
folio_set_dirty(new_folio);
@@ -2920,7 +2921,7 @@ struct page *ksm_might_need_to_copy(struct page *page,
#endif
}
- return new_folio ? &new_folio->page : NULL;
+ return new_folio;
}
void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc)
diff --git a/mm/memory.c b/mm/memory.c
index 055647120f01..318f923134e4 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3942,15 +3942,15 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
* page->index of !PageKSM() pages would be nonlinear inside the
* anon VMA -- PageKSM() is lost on actual swapout.
*/
- page = ksm_might_need_to_copy(page, vma, vmf->address);
- if (unlikely(!page)) {
+ folio = ksm_might_need_to_copy(folio, vma, vmf->address);
+ if (unlikely(!folio)) {
ret = VM_FAULT_OOM;
goto out_page;
- } else if (unlikely(PTR_ERR(page) == -EHWPOISON)) {
+ } else if (unlikely(folio == ERR_PTR(-EHWPOISON))) {
ret = VM_FAULT_HWPOISON;
goto out_page;
}
- folio = page_folio(page);
+ page = folio_page(folio, 0);
/*
* If we want to map a page that's in the swapcache writable, we
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 8be70912e298..0371b7b3cd27 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1749,11 +1749,13 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
int ret = 1;
swapcache = page;
- page = ksm_might_need_to_copy(page, vma, addr);
- if (unlikely(!page))
+ folio = ksm_might_need_to_copy(folio, vma, addr);
+ if (unlikely(!folio))
return -ENOMEM;
- else if (unlikely(PTR_ERR(page) == -EHWPOISON))
+ else if (unlikely(folio == ERR_PTR(-EHWPOISON)))
hwpoisoned = true;
+ else
+ page = folio_file_page(folio, swp_offset(entry));
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
if (unlikely(!pte || !pte_same_as_swp(ptep_get(pte),
--
2.42.0
