[PATCH 6.1.y 3/5] fs/proc/task_mmu: convert smaps_hugetlb_range() to work on folios

[Sasha Levin <sashal@kernel.org>]

From: David Hildenbrand <david@redhat.com>

[ Upstream commit 6401a2e6900843a77a27873c0529dea68f61193d ]

Let's get rid of another page_mapcount() check and simply use
folio_likely_mapped_shared(), which is precise for hugetlb folios.

While at it, use huge_ptep_get() + pte_page() instead of ptep_get() +
vm_normal_page(), just like we do in pagemap_hugetlb_range().

No functional change intended.

Link: https://lkml.kernel.org/r/20240417092313.753919-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

On this stable tree, use folio_estimated_sharers() and wrap
pfn_swap_entry_to_page() with page_folio().  These are the equivalent APIs
available before folio_likely_mapped_shared() and pfn_swap_entry_folio() were
introduced.

Stable-dep-of: e87df0d5d696 ("mm/page_vma_mapped: use huge_ptep_get() for hugetlb")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/proc/task_mmu.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 484886cdd272c..39ce3cf7d5add 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -726,18 +726,20 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask,
 {
 	struct mem_size_stats *mss = walk->private;
 	struct vm_area_struct *vma = walk->vma;
-	struct page *page = NULL;
+	pte_t ptent = huge_ptep_get(pte);
+	struct folio *folio = NULL;
 
-	if (pte_present(*pte)) {
-		page = vm_normal_page(vma, addr, *pte);
-	} else if (is_swap_pte(*pte)) {
-		swp_entry_t swpent = pte_to_swp_entry(*pte);
+	if (pte_present(ptent)) {
+		folio = page_folio(pte_page(ptent));
+	} else if (is_swap_pte(ptent)) {
+		swp_entry_t swpent = pte_to_swp_entry(ptent);
 
 		if (is_pfn_swap_entry(swpent))
-			page = pfn_swap_entry_to_page(swpent);
+			folio = page_folio(pfn_swap_entry_to_page(swpent));
 	}
-	if (page) {
-		if (page_mapcount(page) >= 2 || hugetlb_pmd_shared(pte))
+	if (folio) {
+		if (folio_estimated_sharers(folio) >= 2 ||
+		    hugetlb_pmd_shared(pte))
 			mss->shared_hugetlb += huge_page_size(hstate_vma(vma));
 		else
 			mss->private_hugetlb += huge_page_size(hstate_vma(vma));
-- 
2.53.0