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

[Daniel Vetter]

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.
-Daniel

> 
> Acked-by: Thomas Zimmermann <tzimmermann at 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 at intel.com>
> > Cc: Dave Airlie <airlied at redhat.com>
> > Cc: Sean Paul <sean at poorly.run>
> > Cc: Gerd Hoffmann <kraxel at redhat.com>
> > Cc: Thomas Zimmermann <tzimmermann at suse.de>
> > Cc: Alex Deucher <alexander.deucher at amd.com>
> > Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> > Cc: Thomas Gleixner <tglx at linutronix.de>
> > Cc: Sam Ravnborg <sam at 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