On Wed, Oct 23, 2019 at 11:42:29AM +0300, Nikolay Borisov wrote:
> On 17.10.19 г. 22:38 ч., David Sterba wrote:
> > @@ -294,7 +299,8 @@ void btrfs_tree_lock(struct extent_buffer *eb)
> > */
> > void btrfs_tree_unlock(struct extent_buffer *eb)
> > {
> > - int blockers = eb->blocking_writers;
> > + /* This is read both locked and unlocked */
> > + int blockers = READ_ONCE(eb->blocking_writers);
>
> Actually aren't we guaranteed that btrfs_tree_unlock's caller is the
> owner of blocking_writers meaning we can use plain loads as per:
>
> "The owning CPU or thread may use plain loads..."
That's right, I'll remove READ_ONCE and leave a comment as it's not
obvious from the context.
