fs/proc/task_mmu: convert pagemap_hugetlb_range() to work on folios

Patch series "fs/proc/task_mmu: convert hugetlb functions to work on folis".

Let's convert two more functions, getting rid of two more page_mapcount()
calls.

This patch (of 2):

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, also check for PMD table sharing, like we do in
smaps_hugetlb_range().

No functional change intended, except that we would now detect hugetlb
folios shared via PMD table sharing correctly.

Link: https://lkml.kernel.org/r/20240417092313.753919-1-david@redhat.com
Link: https://lkml.kernel.org/r/20240417092313.753919-2-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>

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 8ff79bd427ec680a3fe73d03d31b3274e4d28afb..cd6e45e0cde8ec6619b72661b1b478039d22e319 100644 (file)
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1578,12 +1578,13 @@ static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
 
        pte = huge_ptep_get(ptep);
        if (pte_present(pte)) {
-               struct page *page = pte_page(pte);
+               struct folio *folio = page_folio(pte_page(pte));
 
-               if (!PageAnon(page))
+               if (!folio_test_anon(folio))
                        flags |= PM_FILE;
 
-               if (page_mapcount(page) == 1)
+               if (!folio_likely_mapped_shared(folio) &&
+                   !hugetlb_pmd_shared(ptep))
                        flags |= PM_MMAP_EXCLUSIVE;
 
                if (huge_pte_uffd_wp(pte))