diff options
| -rw-r--r-- | fs/afs/file.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/afs/file.c b/fs/afs/file.c index 3d33b221d9ca..ef2cc8f565d2 100644 --- a/fs/afs/file.c +++ b/fs/afs/file.c @@ -417,13 +417,17 @@ static void afs_add_open_mmap(struct afs_vnode *vnode) static void afs_drop_open_mmap(struct afs_vnode *vnode) { - if (!atomic_dec_and_test(&vnode->cb_nr_mmap)) + if (atomic_add_unless(&vnode->cb_nr_mmap, -1, 1)) return; down_write(&vnode->volume->open_mmaps_lock); - if (atomic_read(&vnode->cb_nr_mmap) == 0) + read_seqlock_excl(&vnode->cb_lock); + // the only place where ->cb_nr_mmap may hit 0 + // see __afs_break_callback() for the other side... + if (atomic_dec_and_test(&vnode->cb_nr_mmap)) list_del_init(&vnode->cb_mmap_link); + read_sequnlock_excl(&vnode->cb_lock); up_write(&vnode->volume->open_mmaps_lock); flush_work(&vnode->cb_work); |