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| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2024-04-26 16:45:02 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-05-06 02:53:54 +0200 |
| commit | 73b4a0cd8243709870701349611722ba3c351815 (patch) | |
| tree | f6721da2b4d95e28d6fbd14923b4f9afbb182a47 /mm/userfaultfd.c | |
| parent | mm: delay the check for a NULL anon_vma (diff) | |
| download | linux-73b4a0cd8243709870701349611722ba3c351815.tar.xz linux-73b4a0cd8243709870701349611722ba3c351815.zip | |
mm: fix some minor per-VMA lock issues in userfaultfd
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@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/userfaultfd.c')
| -rw-r--r-- | mm/userfaultfd.c | 20 |
1 files changed, 9 insertions, 11 deletions
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 8b1005ef9dfa..d9e82ae68244 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -56,17 +56,16 @@ struct vm_area_struct *find_vma_and_prepare_anon(struct mm_struct *mm, #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(struct mm_struct *mm, 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_lock(struct mm_struct *dst_mm, { 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_struct *mm, 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_struct *mm, } /* - * 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_struct *mm, 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); |