diff options
| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2025-11-19 04:26:35 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-11-24 15:08:55 -0800 |
| commit | ecf371b2cabee6a2bfb61f87d71c9f02a9ff34d7 (patch) | |
| tree | 2fb824b2c9c0ea1b01ed91d49ada55aac122ba0d | |
| parent | 31807483d3952059d395c2a73b1fa9625db9b366 (diff) | |
mm: tweak __vma_enter_locked()
Move the commentary on how __vma_enter_locked() behaves from the body of
__vma_start_write() to the head of __vma_enter_locked() and merge it with
the existing documentation. Also add a call to
mmap_assert_write_locked().
Link: https://lkml.kernel.org/r/20251119042639.3937024-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/mmap_lock.c | 13 |
1 files changed, 5 insertions, 8 deletions
diff --git a/mm/mmap_lock.c b/mm/mmap_lock.c index f2532af6208c..e6e5570d1ec7 100644 --- a/mm/mmap_lock.c +++ b/mm/mmap_lock.c @@ -46,9 +46,9 @@ EXPORT_SYMBOL(__mmap_lock_do_trace_released); #ifdef CONFIG_MMU #ifdef CONFIG_PER_VMA_LOCK /* - * Return value: 0 if vma detached, - * 1 if vma attached with no readers, - * -EINTR if signal received, + * __vma_enter_locked() returns 0 immediately if the vma is not + * attached, otherwise it waits for any current readers to finish and + * returns 1. Returns -EINTR if a signal is received while waiting. */ static inline int __vma_enter_locked(struct vm_area_struct *vma, bool detaching, int state) @@ -56,6 +56,8 @@ static inline int __vma_enter_locked(struct vm_area_struct *vma, int err; unsigned int tgt_refcnt = VMA_LOCK_OFFSET; + mmap_assert_write_locked(vma->vm_mm); + /* Additional refcnt if the vma is attached. */ if (!detaching) tgt_refcnt++; @@ -91,11 +93,6 @@ int __vma_start_write(struct vm_area_struct *vma, unsigned int mm_lock_seq, { int locked; - /* - * __vma_enter_locked() returns false immediately if the vma is not - * attached, otherwise it waits until refcnt is indicating that vma - * is attached with no readers. - */ locked = __vma_enter_locked(vma, false, state); if (locked < 0) return locked; |