On Di, 2019-03-19 at 13:14 +0100, Greg KH wrote:
> On Mon, Mar 18, 2019 at 02:17:11PM -0700, Matthew Wilcox wrote:
> > Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>
[..]
> > static int acm_alloc_minor(struct acm *acm)
> > {
> > - int minor;
> > -
> > - mutex_lock(&acm_minors_lock);
> > - minor = idr_alloc(&acm_minors, acm, 0, ACM_TTY_MINORS, GFP_KERNEL);
> > - mutex_unlock(&acm_minors_lock);
> > -
> > - return minor;
> > + return xa_alloc(&acm_minors, &acm->minor, acm,
> > + XA_LIMIT(0, ACM_TTY_MINORS - 1), GFP_KERNEL);
>
> So, the only thing "better" here is that you don't need a lock anymore?
Once this is accepted I can reduce the locking to a per instance
spinlock. But to start with a straight conversion is best.
Regards
Oliver
