lkml.org 
[lkml]   [2023]   [Jan]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v4 06/19] irqdomain: Drop revmap mutex
On Tue, Jan 17, 2023 at 10:23:20PM +0100, Thomas Gleixner wrote:
> On Mon, Jan 16 2023 at 14:50, Johan Hovold wrote:
> > The global irq_domain_mutex is now held in all paths that update the
> > revmap structures so there is no longer any need for the revmap mutex.
>
> This can also go after the 3rd race fix, but ...
>
> > static void irq_domain_clear_mapping(struct irq_domain *domain,
> > irq_hw_number_t hwirq)
> > {
> > + lockdep_assert_held(&irq_domain_mutex);
>
> these lockdep asserts want to be part of the [dis]association race
> fixes. They are completely unrelated to the removal of the revmap_mutex.

No, they are very much related to the removal of the revmap_mutex. These
functions deal with the revmap structures which before this patch were
clearly only modified with the revmap_mutex held.

The lockdep assert is here to guarantee that my claim that all current
(and future) paths that end up modifying these structures do so under
the irq_domain_mutex instead.

> Your race fixes change the locking and you want to ensure that all
> callers comply right there, no?

I want to make sure that all callers of these function comply, yes.
That's why the asserts belong in this patch.

Johan

\
 
 \ /
  Last update: 2023-03-26 23:45    [W:0.062 / U:0.116 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site