mm: renovate page_address_in_vma()

This function doesn't modify any of its arguments, so if we make a few
other functions take const pointers, we can make page_address_in_vma()
take const pointers too.  All of its callers have the containing folio
already, so pass that in as an argument instead of recalculating it.  Also
add kernel-doc

Link: https://lkml.kernel.org/r/20241005200121.3231142-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 3 insertions, 4 deletions

diff --git a/mm/ksm.c b/mm/ksm.c
index e596bc1b5fa7..b813225a806d 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1256,7 +1256,7 @@ static int write_protect_page(struct vm_area_struct *vma, struct folio *folio,
 	if (WARN_ON_ONCE(folio_test_large(folio)))
 		return err;
 
-	pvmw.address = page_address_in_vma(&folio->page, vma);
+	pvmw.address = page_address_in_vma(folio, folio_page(folio, 0), vma);
 	if (pvmw.address == -EFAULT)
 		goto out;
 
@@ -1340,7 +1340,7 @@ static int replace_page(struct vm_area_struct *vma, struct page *page,
 {
 	struct folio *kfolio = page_folio(kpage);
 	struct mm_struct *mm = vma->vm_mm;
-	struct folio *folio;
+	struct folio *folio = page_folio(page);
 	pmd_t *pmd;
 	pmd_t pmde;
 	pte_t *ptep;
@@ -1350,7 +1350,7 @@ static int replace_page(struct vm_area_struct *vma, struct page *page,
 	int err = -EFAULT;
 	struct mmu_notifier_range range;
 
-	addr = page_address_in_vma(page, vma);
+	addr = page_address_in_vma(folio, page, vma);
 	if (addr == -EFAULT)
 		goto out;
 
@@ -1416,7 +1416,6 @@ static int replace_page(struct vm_area_struct *vma, struct page *page,
 	ptep_clear_flush(vma, addr, ptep);
 	set_pte_at(mm, addr, ptep, newpte);
 
-	folio = page_folio(page);
 	folio_remove_rmap_pte(folio, page, vma);
 	if (!folio_mapped(folio))
 		folio_free_swap(folio);