[merged mm-hotfixes-stable] mm-more-ptep_get-conversion.patch removed from -mm tree

[merged mm-hotfixes-stable] mm-more-ptep_get-conversion.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm: more ptep_get() conversion
has been removed from the -mm tree.  Its filename was
     mm-more-ptep_get-conversion.patch

This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Ryan Roberts <ryan.roberts@arm.com>
Subject: mm: more ptep_get() conversion
Date: Tue, 14 Nov 2023 15:49:45 +0000

Commit c33c794828f2 ("mm: ptep_get() conversion") converted all (non-arch)
call sites to use ptep_get() instead of doing a direct dereference of the
pte.  Full rationale can be found in that commit's log.

Since then, three new call sites have snuck in, which directly dereference
the pte, so let's fix those up.

Unfortunately there is no reliable automated mechanism to catch these; I'm
relying on a combination of Coccinelle (which throws up a lot of false
positives) and some compiler magic to force a compiler error on
dereference (While this approach finds dereferences, it also yields a
non-booting kernel so can't be committed).

Link: https://lkml.kernel.org/r/20231114154945.490401-1-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/filemap.c     |    2 +-
 mm/ksm.c         |    2 +-
 mm/userfaultfd.c |    2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

--- a/mm/filemap.c~mm-more-ptep_get-conversion
+++ a/mm/filemap.c
@@ -3443,7 +3443,7 @@ static vm_fault_t filemap_map_folio_rang
 		 * handled in the specific fault path, and it'll prohibit the
 		 * fault-around logic.
 		 */
-		if (!pte_none(vmf->pte[count]))
+		if (!pte_none(ptep_get(&vmf->pte[count])))
 			goto skip;
 
 		count++;
--- a/mm/ksm.c~mm-more-ptep_get-conversion
+++ a/mm/ksm.c
@@ -468,7 +468,7 @@ static int break_ksm_pmd_entry(pmd_t *pm
 			page = pfn_swap_entry_to_page(entry);
 	}
 	/* return 1 if the page is an normal ksm page or KSM-placed zero page */
-	ret = (page && PageKsm(page)) || is_ksm_zero_pte(*pte);
+	ret = (page && PageKsm(page)) || is_ksm_zero_pte(ptent);
 	pte_unmap_unlock(pte, ptl);
 	return ret;
 }
--- a/mm/userfaultfd.c~mm-more-ptep_get-conversion
+++ a/mm/userfaultfd.c
@@ -312,7 +312,7 @@ static int mfill_atomic_pte_poison(pmd_t
 
 	ret = -EEXIST;
 	/* Refuse to overwrite any PTE, even a PTE marker (e.g. UFFD WP). */
-	if (!pte_none(*dst_pte))
+	if (!pte_none(ptep_get(dst_pte)))
 		goto out_unlock;
 
 	set_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
_

Patches currently in -mm which might be from ryan.roberts@arm.com are