Re: [PATCH 5/9] drm/udl: Don't call get/put_pages on imported dma-buf

[Daniel Vetter <daniel@ffwll.ch>]

On Thu, May 14, 2020 at 02:47:57PM +0200, Daniel Vetter wrote:
> On Thu, May 14, 2020 at 09:25:18AM +0200, Thomas Zimmermann wrote:
> > Hi,
> > 
> > given the upcoming removal of this file, I don't know if you really want
> > to merge this patch. If so, please see my comment on patch 6 and
> 
> Yeah I can wait for your patch to land, I just looked at that series. I'm
> kinda just keeping this around as a reminder locally.

Still applied cleanly to drm-misc-next, so I applied it.
-Daniel

> -Daniel
> 
> > 
> > Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
> > 
> > Am 11.05.20 um 11:35 schrieb Daniel Vetter:
> > > There's no direct harm, because for the shmem helpers these are noops
> > > on imported buffers. The trouble is in the locks these take - I want
> > > to change dma_buf_vmap locking, and so need to make sure that we only
> > > ever take certain locks on one side of the dma-buf interface: Either
> > > for exporters, or for importers.
> > > 
> > > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> > > Cc: Dave Airlie <airlied@redhat.com>
> > > Cc: Sean Paul <sean@poorly.run>
> > > Cc: Gerd Hoffmann <kraxel@redhat.com>
> > > Cc: Thomas Zimmermann <tzimmermann@suse.de>
> > > Cc: Alex Deucher <alexander.deucher@amd.com>
> > > Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> > > Cc: Thomas Gleixner <tglx@linutronix.de>
> > > Cc: Sam Ravnborg <sam@ravnborg.org>
> > > ---
> > >  drivers/gpu/drm/udl/udl_gem.c | 22 ++++++++++++----------
> > >  1 file changed, 12 insertions(+), 10 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/udl/udl_gem.c b/drivers/gpu/drm/udl/udl_gem.c
> > > index b6e26f98aa0a..c68d3e265329 100644
> > > --- a/drivers/gpu/drm/udl/udl_gem.c
> > > +++ b/drivers/gpu/drm/udl/udl_gem.c
> > > @@ -46,29 +46,31 @@ static void *udl_gem_object_vmap(struct drm_gem_object *obj)
> > >  	if (shmem->vmap_use_count++ > 0)
> > >  		goto out;
> > >  
> > > -	ret = drm_gem_shmem_get_pages(shmem);
> > > -	if (ret)
> > > -		goto err_zero_use;
> > > -
> > > -	if (obj->import_attach)
> > > +	if (obj->import_attach) {
> > >  		shmem->vaddr = dma_buf_vmap(obj->import_attach->dmabuf);
> > > -	else
> > > +	} else {
> > > +		ret = drm_gem_shmem_get_pages(shmem);
> > > +		if (ret)
> > > +			goto err;
> > > +
> > >  		shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT,
> > >  				    VM_MAP, PAGE_KERNEL);
> > >  
> > > +		if (!shmem->vaddr)
> > > +			drm_gem_shmem_put_pages(shmem);
> > > +	}
> > > +
> > >  	if (!shmem->vaddr) {
> > >  		DRM_DEBUG_KMS("Failed to vmap pages\n");
> > >  		ret = -ENOMEM;
> > > -		goto err_put_pages;
> > > +		goto err;
> > >  	}
> > >  
> > >  out:
> > >  	mutex_unlock(&shmem->vmap_lock);
> > >  	return shmem->vaddr;
> > >  
> > > -err_put_pages:
> > > -	drm_gem_shmem_put_pages(shmem);
> > > -err_zero_use:
> > > +err:
> > >  	shmem->vmap_use_count = 0;
> > >  	mutex_unlock(&shmem->vmap_lock);
> > >  	return ERR_PTR(ret);
> > > 
> > 
> > -- 
> > Thomas Zimmermann
> > Graphics Driver Developer
> > SUSE Software Solutions Germany GmbH
> > Maxfeldstr. 5, 90409 Nürnberg, Germany
> > (HRB 36809, AG Nürnberg)
> > Geschäftsführer: Felix Imendörffer
> > 
> 
> 
> 
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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