From: Daniel Vetter <daniel@ffwll.ch> To: "Christian König" <christian.koenig@amd.com> Cc: Andrew Morton <akpm@linux-foundation.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, dri-devel <dri-devel@lists.freedesktop.org>, "moderated list:DMA BUFFER SHARING FRAMEWORK" <linaro-mm-sig@lists.linaro.org>, Linux MM <linux-mm@kvack.org>, "open list:DMA BUFFER SHARING FRAMEWORK" <linux-media@vger.kernel.org> Subject: Re: [PATCH 1/2] drm/shmem-helpers: revert "Redirect mmap for imported dma-buf" Date: Tue, 15 Sep 2020 13:07:18 +0200 [thread overview] Message-ID: <CAKMK7uHDuzzh_w=7w7m3EoHyx+3HOVawoj2QbJL+9F1+1LULbw@mail.gmail.com> (raw) In-Reply-To: <92b77d29-ae9b-b9cd-4e03-f193aa386cae@gmail.com> On Tue, Sep 15, 2020 at 1:03 PM Christian König <ckoenig.leichtzumerken@gmail.com> wrote: > > Am 15.09.20 um 12:39 schrieb Daniel Vetter: > > On Mon, Sep 14, 2020 at 3:29 PM Christian König > > <ckoenig.leichtzumerken@gmail.com> wrote: > >> This reverts commit 26d3ac3cb04d171a861952e89324e347598a347f. > >> > >> We need to figure out if dma_buf_mmap() is valid or not first. > >> > >> Signed-off-by: Christian König <christian.koenig@amd.com> > > The trouble is that doing dma-buf mmap by looking at the struct pages > > behind the sg list and just inserting those into userspace doesn't > > really work any better. You still won't get the unmap_mapping_range > > and hence pte shoot-down. So maybe dma_buf_mmap forwarding doesn't > > work, but this doesn't make it any better. > > Good point. Question is what should we do? Return -EPERM? IIrc there's userspace which expects this to work, but I think it's also only trying to do this with simpler drivers that don't need unmap_mapping_range to work correctly. Or it's simply that no one ever reported the bugs. It's a bit a mess :-/ -Daniel > > > > > Also commit message should probably explain a bit the context here, > > not a lot of people have been in our private discussion on this. > > Well, that's certain true. > > Christian. > > > -Daniel > > > >> --- > >> drivers/gpu/drm/drm_gem_shmem_helper.c | 3 --- > >> 1 file changed, 3 deletions(-) > >> > >> diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c > >> index 0a952f27c184..cd727343f72b 100644 > >> --- a/drivers/gpu/drm/drm_gem_shmem_helper.c > >> +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c > >> @@ -594,9 +594,6 @@ 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); > >> - > >> shmem = to_drm_gem_shmem_obj(obj); > >> > >> ret = drm_gem_shmem_get_pages(shmem); > >> -- > >> 2.17.1 > >> > >> _______________________________________________ > >> dri-devel mailing list > >> dri-devel@lists.freedesktop.org > >> https://lists.freedesktop.org/mailman/listinfo/dri-devel > > > > > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
WARNING: multiple messages have this Message-ID (diff)
From: Daniel Vetter <daniel@ffwll.ch> To: "Christian König" <christian.koenig@amd.com> Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, dri-devel <dri-devel@lists.freedesktop.org>, "moderated list:DMA BUFFER SHARING FRAMEWORK" <linaro-mm-sig@lists.linaro.org>, Linux MM <linux-mm@kvack.org>, Andrew Morton <akpm@linux-foundation.org>, "open list:DMA BUFFER SHARING FRAMEWORK" <linux-media@vger.kernel.org> Subject: Re: [PATCH 1/2] drm/shmem-helpers: revert "Redirect mmap for imported dma-buf" Date: Tue, 15 Sep 2020 13:07:18 +0200 [thread overview] Message-ID: <CAKMK7uHDuzzh_w=7w7m3EoHyx+3HOVawoj2QbJL+9F1+1LULbw@mail.gmail.com> (raw) In-Reply-To: <92b77d29-ae9b-b9cd-4e03-f193aa386cae@gmail.com> On Tue, Sep 15, 2020 at 1:03 PM Christian König <ckoenig.leichtzumerken@gmail.com> wrote: > > Am 15.09.20 um 12:39 schrieb Daniel Vetter: > > On Mon, Sep 14, 2020 at 3:29 PM Christian König > > <ckoenig.leichtzumerken@gmail.com> wrote: > >> This reverts commit 26d3ac3cb04d171a861952e89324e347598a347f. > >> > >> We need to figure out if dma_buf_mmap() is valid or not first. > >> > >> Signed-off-by: Christian König <christian.koenig@amd.com> > > The trouble is that doing dma-buf mmap by looking at the struct pages > > behind the sg list and just inserting those into userspace doesn't > > really work any better. You still won't get the unmap_mapping_range > > and hence pte shoot-down. So maybe dma_buf_mmap forwarding doesn't > > work, but this doesn't make it any better. > > Good point. Question is what should we do? Return -EPERM? IIrc there's userspace which expects this to work, but I think it's also only trying to do this with simpler drivers that don't need unmap_mapping_range to work correctly. Or it's simply that no one ever reported the bugs. It's a bit a mess :-/ -Daniel > > > > > Also commit message should probably explain a bit the context here, > > not a lot of people have been in our private discussion on this. > > Well, that's certain true. > > Christian. > > > -Daniel > > > >> --- > >> drivers/gpu/drm/drm_gem_shmem_helper.c | 3 --- > >> 1 file changed, 3 deletions(-) > >> > >> diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c > >> index 0a952f27c184..cd727343f72b 100644 > >> --- a/drivers/gpu/drm/drm_gem_shmem_helper.c > >> +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c > >> @@ -594,9 +594,6 @@ 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); > >> - > >> shmem = to_drm_gem_shmem_obj(obj); > >> > >> ret = drm_gem_shmem_get_pages(shmem); > >> -- > >> 2.17.1 > >> > >> _______________________________________________ > >> dri-devel mailing list > >> dri-devel@lists.freedesktop.org > >> https://lists.freedesktop.org/mailman/listinfo/dri-devel > > > > > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2020-09-15 11:24 UTC|newest] Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-09-14 13:29 Changing vma->vm_file in dma_buf_mmap() Christian König 2020-09-14 13:29 ` Christian König 2020-09-14 13:29 ` [PATCH 1/2] drm/shmem-helpers: revert "Redirect mmap for imported dma-buf" Christian König 2020-09-14 13:29 ` Christian König 2020-09-15 10:39 ` Daniel Vetter 2020-09-15 10:39 ` Daniel Vetter 2020-09-15 10:39 ` Daniel Vetter 2020-09-15 11:03 ` Christian König 2020-09-15 11:03 ` Christian König 2020-09-15 11:03 ` Christian König 2020-09-15 11:07 ` Daniel Vetter [this message] 2020-09-15 11:07 ` Daniel Vetter 2020-09-15 11:07 ` Daniel Vetter 2020-09-14 13:29 ` [PATCH 2/2] mm: introduce vma_set_file function Christian König 2020-09-14 13:29 ` Christian König 2020-09-15 9:19 ` kernel test robot 2020-09-15 9:19 ` kernel test robot 2020-09-15 9:19 ` kernel test robot 2020-09-15 11:57 ` kernel test robot 2020-09-15 11:57 ` kernel test robot 2020-09-15 11:57 ` kernel test robot 2020-09-14 13:30 ` Changing vma->vm_file in dma_buf_mmap() Christian König 2020-09-14 13:30 ` Christian König 2020-09-14 14:06 ` Jason Gunthorpe 2020-09-14 14:06 ` Jason Gunthorpe 2020-09-14 18:26 ` Christian König 2020-09-14 18:26 ` Christian König 2020-09-16 9:53 ` Daniel Vetter 2020-09-16 9:53 ` Daniel Vetter 2020-09-16 10:14 ` Christian König 2020-09-16 10:14 ` Christian König 2020-09-16 11:45 ` Christian König 2020-09-16 11:45 ` Christian König 2020-09-16 12:41 ` Daniel Vetter 2020-09-16 12:41 ` Daniel Vetter 2020-09-16 12:41 ` Daniel Vetter 2020-09-16 14:07 ` Jason Gunthorpe 2020-09-16 14:07 ` Jason Gunthorpe 2020-09-16 14:14 ` Christian König 2020-09-16 14:14 ` Christian König 2020-09-16 15:24 ` Daniel Vetter 2020-09-16 15:24 ` Daniel Vetter 2020-09-16 15:24 ` Daniel Vetter 2020-09-16 15:31 ` [Linaro-mm-sig] " Christian König 2020-09-16 15:31 ` Christian König 2020-09-16 15:31 ` Christian König 2020-09-17 6:23 ` Daniel Vetter 2020-09-17 6:23 ` Daniel Vetter 2020-09-17 6:23 ` Daniel Vetter 2020-09-17 7:11 ` Christian König 2020-09-17 7:11 ` Christian König 2020-09-17 7:11 ` Christian König 2020-09-17 8:09 ` Daniel Vetter 2020-09-17 8:09 ` Daniel Vetter 2020-09-17 8:09 ` Daniel Vetter 2020-09-17 11:31 ` Jason Gunthorpe 2020-09-17 11:31 ` Jason Gunthorpe 2020-09-17 12:03 ` Christian König 2020-09-17 12:03 ` Christian König 2020-09-17 12:18 ` Jason Gunthorpe 2020-09-17 12:18 ` Jason Gunthorpe 2020-09-17 12:18 ` Jason Gunthorpe 2020-09-17 12:24 ` Christian König 2020-09-17 12:24 ` Christian König 2020-09-17 12:24 ` Christian König 2020-09-17 12:26 ` Daniel Vetter 2020-09-17 12:26 ` Daniel Vetter 2020-09-17 12:26 ` Daniel Vetter 2020-09-17 14:35 ` Jason Gunthorpe 2020-09-17 14:35 ` Jason Gunthorpe 2020-09-17 14:35 ` Jason Gunthorpe 2020-09-17 14:54 ` Christian König 2020-09-17 14:54 ` Christian König 2020-09-17 14:54 ` Christian König 2020-09-17 15:24 ` Jason Gunthorpe 2020-09-17 15:24 ` Jason Gunthorpe 2020-09-17 15:24 ` Jason Gunthorpe 2020-09-17 15:37 ` Daniel Vetter 2020-09-17 15:37 ` Daniel Vetter 2020-09-17 16:06 ` Christian König 2020-09-17 16:06 ` Christian König 2020-09-17 16:06 ` Christian König 2020-09-17 16:39 ` Jason Gunthorpe 2020-09-17 16:39 ` Jason Gunthorpe 2020-09-17 16:39 ` Jason Gunthorpe 2020-09-17 17:23 ` Daniel Vetter 2020-09-17 17:23 ` Daniel Vetter
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