Messages in this thread | | | Date | Fri, 22 Apr 2022 06:03:17 -1000 | From | Tejun Heo <> | Subject | Re: [PATCH v8 01/10] kernfs: Remove reference counting for kernfs_open_node. |
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On Sun, Apr 10, 2022 at 12:37:10PM +1000, Imran Khan wrote: > @@ -768,15 +765,15 @@ void kernfs_drain_open_files(struct kernfs_node *kn) > if (!(kn->flags & (KERNFS_HAS_MMAP | KERNFS_HAS_RELEASE))) > return; > > - spin_lock_irq(&kernfs_open_node_lock); > on = kn->attr.open; > - if (on) > - atomic_inc(&on->refcnt); > - spin_unlock_irq(&kernfs_open_node_lock); > if (!on) > return; > > mutex_lock(&kernfs_open_file_mutex); > + if (!kn->attr.open) { > + mutex_unlock(&kernfs_open_file_mutex); > + return; > + }
What if @on got freed and new one got allocated between the lockless check and the locked check? Is there a reason to keep the lockless check at all?
> list_for_each_entry(of, &on->files, list) { > struct inode *inode = file_inode(of->file);
Thanks.
-- tejun
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