Re: [PATCH] percpu-refcount: support synchronous switch to atomic mode.

[Shaohua Li]

On Wed, Mar 22, 2017 at 11:00:29AM -0400, Tejun Heo wrote:
> On Wed, Mar 22, 2017 at 12:50:12PM +1100, NeilBrown wrote:
> > 
> > percpu_ref_switch_to_atomic_sync() schedules the switch
> > to atomic mode, then waits for it to complete.
> > 
> > Also export percpu_ref_switch_to_* so they can be used from modules.
> > 
> > This will be used in md/raid to count the number of pending write
> > requests to an array.
> > We occasionally need to check if the count is zero, but most often
> > we don't care.
> > We always want updates to the counter to be fast, as in some cases
> > we count every 4K page.
> > 
> > Signed-off-by: NeilBrown <neilb@xxxxxxxx>
> 
> Acked-by: Tejun Heo <tj@xxxxxxxxxx>
> 
> Please feel free to route through other patches through md tree.  If
> preferable, I can route it through percpu/for-4.12.

Thanks, Tejun. I applied it to md tree, that will avoid a lot of troubles.

Thanks,
Shaohua