Re: [PATCH v4 5/6] drm/gem-shmem: Track folio accessed/dirty status in mmap

[Boris Brezillon <boris.brezillon@collabora.com>]

On Fri, 13 Mar 2026 12:04:25 +0000
Biju Das <biju.das.jz@bp.renesas.com> wrote:

> > -----Original Message-----
> > From: dri-devel <dri-devel-bounces@lists.freedesktop.org> On Behalf Of Boris Brezillon
> > Sent: 13 March 2026 11:57
> > Subject: Re: [PATCH v4 5/6] drm/gem-shmem: Track folio accessed/dirty status in mmap
> > 
> > On Fri, 13 Mar 2026 11:29:47 +0100
> > Thomas Zimmermann <tzimmermann@suse.de> wrote:
> >   
> > > Hi
> > >
> > > Am 13.03.26 um 11:18 schrieb Boris Brezillon:
> > > [...]  
> > > >>>>> +	if (drm_WARN_ON(obj->dev, !shmem->pages || page_offset >= num_pages))
> > > >>>>> +		return VM_FAULT_SIGBUS;
> > > >>>>> +
> > > >>>>> +	file_update_time(vma->vm_file);
> > > >>>>> +
> > > >>>>> +	folio_mark_dirty(page_folio(shmem->pages[page_offset]));  
> > > > Do we need a folio_mark_dirty_lock() here?  
> > >
> > > There is a helper for that with some documentation. [1]  
> > 
> > This [1] seems to solve the problem for me. Still unsure about the folio_mark_dirty_lock vs
> > folio_mark_dirty though.
> > 
> > [1]https://yhbt.net/lore/dri-devel/20260312155027.1682606-1-pedrodemargomes@gmail.com/  
> 
> FYI, I used folio_mark_dirty_lock() still it does not solve the issue with weston hang.

The patch I pointed to has nothing to do with folio_mark_dirty_lock(),
It's a bug caused by huge page mapping changes.