[PATCH 6.1.y 1/2] mm/migrate_device: page_remove_rmap() -> folio_remove_rmap_pte()

[Sasha Levin <sashal@kernel.org>]

From: David Hildenbrand <david@redhat.com>

[ Upstream commit 5b205c7f2684764c8a9cc3442986623d4d6e87f1 ]

Let's convert migrate_vma_collect_pmd().  While at it, perform more folio
conversion.

Link: https://lkml.kernel.org/r/20231220224504.646757-30-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: 63867c82d0c0 ("mm: migrate_device: fix pte_pfn/pte_dirty called on non-present PTE")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 mm/migrate_device.c | 39 +++++++++++++++++++++------------------
 1 file changed, 21 insertions(+), 18 deletions(-)

diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index afe3b2d2e7b9d..e198569bb3324 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c
@@ -114,6 +114,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 
 	for (; addr < end; addr += PAGE_SIZE, ptep++) {
 		unsigned long mpfn = 0, pfn;
+		struct folio *folio;
 		struct page *page;
 		swp_entry_t entry;
 		pte_t pte;
@@ -175,41 +176,43 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 		}
 
 		/*
-		 * By getting a reference on the page we pin it and that blocks
+		 * By getting a reference on the folio we pin it and that blocks
 		 * any kind of migration. Side effect is that it "freezes" the
 		 * pte.
 		 *
-		 * We drop this reference after isolating the page from the lru
-		 * for non device page (device page are not on the lru and thus
+		 * We drop this reference after isolating the folio from the lru
+		 * for non device folio (device folio are not on the lru and thus
 		 * can't be dropped from it).
 		 */
-		get_page(page);
+		folio = page_folio(page);
+		folio_get(folio);
 
 		/*
-		 * We rely on trylock_page() to avoid deadlock between
+		 * We rely on folio_trylock() to avoid deadlock between
 		 * concurrent migrations where each is waiting on the others
-		 * page lock. If we can't immediately lock the page we fail this
+		 * folio lock. If we can't immediately lock the folio we fail this
 		 * migration as it is only best effort anyway.
 		 *
-		 * If we can lock the page it's safe to set up a migration entry
-		 * now. In the common case where the page is mapped once in a
+		 * If we can lock the folio it's safe to set up a migration entry
+		 * now. In the common case where the folio is mapped once in a
 		 * single process setting up the migration entry now is an
 		 * optimisation to avoid walking the rmap later with
 		 * try_to_migrate().
 		 */
-		if (trylock_page(page)) {
+		if (folio_trylock(folio)) {
 			bool anon_exclusive;
 			pte_t swp_pte;
 
-			flush_cache_page(vma, addr, pte_pfn(*ptep));
-			anon_exclusive = PageAnon(page) && PageAnonExclusive(page);
+			flush_cache_page(vma, addr, pte_pfn(pte));
+			anon_exclusive = folio_test_anon(folio) &&
+					  PageAnonExclusive(page);
 			if (anon_exclusive) {
 				pte = ptep_clear_flush(vma, addr, ptep);
 
 				if (page_try_share_anon_rmap(page)) {
 					set_pte_at(mm, addr, ptep, pte);
-					unlock_page(page);
-					put_page(page);
+					folio_unlock(folio);
+					folio_put(folio);
 					mpfn = 0;
 					goto next;
 				}
@@ -221,7 +224,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 
 			/* Set the dirty flag on the folio now the pte is gone. */
 			if (pte_dirty(pte))
-				folio_mark_dirty(page_folio(page));
+				folio_mark_dirty(folio);
 
 			/* Setup special migration page table entry */
 			if (mpfn & MIGRATE_PFN_WRITE)
@@ -255,16 +258,16 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 
 			/*
 			 * This is like regular unmap: we remove the rmap and
-			 * drop page refcount. Page won't be freed, as we took
-			 * a reference just above.
+			 * drop the folio refcount. The folio won't be freed, as
+			 * we took a reference just above.
 			 */
 			page_remove_rmap(page, vma, false);
-			put_page(page);
+			folio_put(folio);
 
 			if (pte_present(pte))
 				unmapped++;
 		} else {
-			put_page(page);
+			folio_put(folio);
 			mpfn = 0;
 		}
 
-- 
2.53.0