From: Daniel Vetter <daniel@ffwll.ch>
To: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
Gerd Hoffmann <kraxel@redhat.com>,
DRI Development <dri-devel@lists.freedesktop.org>,
Daniel Vetter <daniel.vetter@intel.com>
Subject: Re: [PATCH 7/9] drm/shmem-helpers: Redirect mmap for imported dma-buf
Date: Thu, 14 May 2020 14:47:10 +0200 [thread overview]
Message-ID: <20200514124710.GX206103@phenom.ffwll.local> (raw)
In-Reply-To: <0032ff1a-c2a3-23ec-79e1-342bacaf9b33@suse.de>
On Thu, May 14, 2020 at 09:23:37AM +0200, Thomas Zimmermann wrote:
> Hi
>
> Am 11.05.20 um 11:35 schrieb Daniel Vetter:
> > Currently this seems to work by converting the sgt into a pages array,
> > and then treating it like a native object. Do the right thing and
> > redirect mmap to the exporter.
> >
> > With this nothing is calling get_pages anymore on imported dma-buf,
> > and we can start to remove the use of the ->pages array for that case.
> >
> > v2: Rebase
> >
> > Cc: Gerd Hoffmann <kraxel@redhat.com>
> > Cc: Rob Herring <robh@kernel.org>
> > Cc: Noralf Trønnes <noralf@tronnes.org>
> > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> > ---
> > drivers/gpu/drm/drm_gem_shmem_helper.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
> > index b9cba5cc61c3..117a7841e284 100644
> > --- a/drivers/gpu/drm/drm_gem_shmem_helper.c
> > +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
> > @@ -551,6 +551,9 @@ int drm_gem_shmem_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
> > /* Remove the fake offset */
> > vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node);
> >
> > + if (obj->import_attach)
> > + return dma_buf_mmap(obj->dma_buf, vma, 0);
> > +
>
> Just a question: how does it work with the fake value in vm_pgoffset?
> The offset is a DRM-specific thing and the dma-buf exporter expects the
> real offset?
For drm chardev file descriptor we have one file, but want to let
userspace map arbitrary objects. So an object gets a allocated an area
within the over drm mmap space, this fake offset.
For dma-buf mmap otoh there's a 1:1 mapping between fd and object, so no
additional offset needed.
-Daniel
>
> With this question clarified:
>
> Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
>
>
> > shmem = to_drm_gem_shmem_obj(obj);
> >
> > ret = drm_gem_shmem_get_pages(shmem);
> >
>
> --
> 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
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next prev parent reply other threads:[~2020-05-14 12:47 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-11 9:35 [PATCH 0/9] shmem helper untangling Daniel Vetter
2020-05-11 9:35 ` [PATCH 1/9] drm/msm: Don't call dma_buf_vunmap without _vmap Daniel Vetter
2020-05-11 15:24 ` Rob Clark
2020-05-11 15:28 ` Daniel Vetter
2020-05-11 20:36 ` Rob Clark
2020-05-14 20:11 ` [PATCH] " Daniel Vetter
2020-05-28 8:29 ` Daniel Vetter
2020-05-31 16:02 ` Rob Clark
2020-06-03 12:46 ` Daniel Vetter
2020-05-11 9:35 ` [PATCH 2/9] drm/gem: WARN if drm_gem_get_pages is called on a private obj Daniel Vetter
2020-05-14 7:45 ` Thomas Zimmermann
2020-05-11 9:35 ` [PATCH 3/9] drm/doc: Some polish for shmem helpers Daniel Vetter
2020-05-11 11:12 ` Thomas Zimmermann
2020-05-14 20:05 ` Daniel Vetter
2020-05-15 6:26 ` Thomas Zimmermann
2020-05-11 9:35 ` [PATCH 4/9] drm/virtio: Call the right " Daniel Vetter
2020-05-14 7:46 ` Thomas Zimmermann
2020-05-11 9:35 ` [PATCH 5/9] drm/udl: Don't call get/put_pages on imported dma-buf Daniel Vetter
2020-05-11 11:23 ` Thomas Zimmermann
2020-05-11 11:37 ` Daniel Vetter
2020-05-11 12:04 ` Thomas Zimmermann
2020-05-14 7:25 ` Thomas Zimmermann
2020-05-14 12:47 ` Daniel Vetter
2020-06-03 12:57 ` Daniel Vetter
2020-05-11 9:35 ` [PATCH 6/9] drm/shmem-helpers: Don't call get/put_pages on imported dma-buf in vmap Daniel Vetter
2020-05-14 7:16 ` Thomas Zimmermann
2020-05-14 12:49 ` Daniel Vetter
2020-05-14 20:22 ` [PATCH] " Daniel Vetter
2020-05-11 9:35 ` [PATCH 7/9] drm/shmem-helpers: Redirect mmap for imported dma-buf Daniel Vetter
2020-05-14 7:23 ` Thomas Zimmermann
2020-05-14 12:47 ` Daniel Vetter [this message]
2020-05-27 18:32 ` Thomas Zimmermann
2020-05-27 19:34 ` Daniel Vetter
2020-05-28 12:53 ` Thomas Zimmermann
2020-05-11 9:35 ` [PATCH 8/9] drm/shmem-helpers: Ensure get_pages is not called on " Daniel Vetter
2020-05-14 7:30 ` Thomas Zimmermann
2020-06-03 13:12 ` Daniel Vetter
2020-06-08 14:40 ` Thomas Zimmermann
2020-06-08 15:04 ` Daniel Vetter
2020-05-11 9:35 ` [PATCH 9/9] drm/shmem-helpers: Simplify dma-buf importing Daniel Vetter
2020-05-14 7:44 ` Thomas Zimmermann
2020-05-14 12:55 ` Daniel Vetter
2020-05-14 15:26 ` Thomas Zimmermann
2020-05-20 18:02 ` [PATCH] " Daniel Vetter
2020-05-29 13:34 ` Boris Brezillon
2020-05-29 13:35 ` Boris Brezillon
2020-05-29 13:49 ` Boris Brezillon
2020-05-29 14:05 ` Daniel Vetter
2020-05-29 14:36 ` Boris Brezillon
2020-06-15 8:23 ` [PATCH 9/9] " Thomas Zimmermann
2020-05-29 13:52 ` [PATCH 0/9] shmem helper untangling Boris Brezillon
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