The quilt patch titled
Subject: mm: fix some minor per-VMA lock issues in userfaultfd
has been removed from the -mm tree. Its filename was
mm-fix-some-minor-per-vma-lock-issues-in-userfaultfd.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: fix some minor per-VMA lock issues in userfaultfd
Date: Fri, 26 Apr 2024 15:45:02 +0100
Rename lock_vma() to uffd_lock_vma() because it really is uffd specific.
Remove comment referencing unlock_vma() which doesn't exist. Fix the
comment about lock_vma_under_rcu() which I just made incorrect.
Link: https://lkml.kernel.org/r/20240426144506.1290619-4-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/userfaultfd.c | 20 +++++++++-----------
1 file changed, 9 insertions(+), 11 deletions(-)
--- a/mm/userfaultfd.c~mm-fix-some-minor-per-vma-lock-issues-in-userfaultfd
+++ a/mm/userfaultfd.c
@@ -56,17 +56,16 @@ struct vm_area_struct *find_vma_and_prep
#ifdef CONFIG_PER_VMA_LOCK
/*
- * lock_vma() - Lookup and lock vma corresponding to @address.
+ * uffd_lock_vma() - Lookup and lock vma corresponding to @address.
* @mm: mm to search vma in.
* @address: address that the vma should contain.
*
- * Should be called without holding mmap_lock. vma should be unlocked after use
- * with unlock_vma().
+ * Should be called without holding mmap_lock.
*
* Return: A locked vma containing @address, -ENOENT if no vma is found, or
* -ENOMEM if anon_vma couldn't be allocated.
*/
-static struct vm_area_struct *lock_vma(struct mm_struct *mm,
+static struct vm_area_struct *uffd_lock_vma(struct mm_struct *mm,
unsigned long address)
{
struct vm_area_struct *vma;
@@ -74,9 +73,8 @@ static struct vm_area_struct *lock_vma(s
vma = lock_vma_under_rcu(mm, address);
if (vma) {
/*
- * lock_vma_under_rcu() only checks anon_vma for private
- * anonymous mappings. But we need to ensure it is assigned in
- * private file-backed vmas as well.
+ * We know we're going to need to use anon_vma, so check
+ * that early.
*/
if (!(vma->vm_flags & VM_SHARED) && unlikely(!vma->anon_vma))
vma_end_read(vma);
@@ -107,7 +105,7 @@ static struct vm_area_struct *uffd_mfill
{
struct vm_area_struct *dst_vma;
- dst_vma = lock_vma(dst_mm, dst_start);
+ dst_vma = uffd_lock_vma(dst_mm, dst_start);
if (IS_ERR(dst_vma) || validate_dst_vma(dst_vma, dst_start + len))
return dst_vma;
@@ -1401,7 +1399,7 @@ static int uffd_move_lock(struct mm_stru
struct vm_area_struct *vma;
int err;
- vma = lock_vma(mm, dst_start);
+ vma = uffd_lock_vma(mm, dst_start);
if (IS_ERR(vma))
return PTR_ERR(vma);
@@ -1416,7 +1414,7 @@ static int uffd_move_lock(struct mm_stru
}
/*
- * Using lock_vma() to get src_vma can lead to following deadlock:
+ * Using uffd_lock_vma() to get src_vma can lead to following deadlock:
*
* Thread1 Thread2
* ------- -------
@@ -1438,7 +1436,7 @@ static int uffd_move_lock(struct mm_stru
err = find_vmas_mm_locked(mm, dst_start, src_start, dst_vmap, src_vmap);
if (!err) {
/*
- * See comment in lock_vma() as to why not using
+ * See comment in uffd_lock_vma() as to why not using
* vma_start_read() here.
*/
down_read(&(*dst_vmap)->vm_lock->lock);
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
squashfs-convert-squashfs_symlink_read_folio-to-use-folio-apis.patch
squashfs-remove-calls-to-set-the-folio-error-flag.patch
nilfs2-remove-calls-to-folio_set_error-and-folio_clear_error.patch
