linux-next: build failure after merge of the drm-misc tree

[Qiang Yu]

On Tue, Apr 2, 2019 at 7:26 PM Matthew Wilcox <willy at infradead.org> wrote:
>
> On Tue, Apr 02, 2019 at 01:55:03PM +0800, Qiang Yu wrote:
> > Thanks, patch is:
> > Reviewed-by: Qiang Yu <yuq825 at gmail.com>
>
> This looks like a fairly naive conversion from the old IDR API to the
> XArray API.  You should be able to remove mgr->lock entirely, relying on
> the xa_lock for synchronising free and get.

I'm afraid the a little complex free path may involve some might sleep
functions so use a mutex lock instead of spinlock.

> If you think it's worth it,
> you could even use kfree_rcu() to free the ctx and kref_get_unless_zero()
> and then your get path would be lock-free.

I can take a look this way, thanks.