From: Jason Gunthorpe <jgg@ziepe.ca>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: "Christian König" <christian.koenig@amd.com>,
"Linux MM" <linux-mm@kvack.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>,
"Andrew Morton" <akpm@linux-foundation.org>,
"open list:DMA BUFFER SHARING FRAMEWORK"
<linux-media@vger.kernel.org>
Subject: Re: [Linaro-mm-sig] Changing vma->vm_file in dma_buf_mmap()
Date: Thu, 17 Sep 2020 08:31:10 -0300 [thread overview]
Message-ID: <20200917113110.GE8409@ziepe.ca> (raw)
In-Reply-To: <CAKMK7uE=UqZD3PVC8XZAXrgGH-VsUF_-YQD3MLV8KK1kpxO4yQ@mail.gmail.com>
On Thu, Sep 17, 2020 at 10:09:12AM +0200, Daniel Vetter wrote:
> Yeah, but it doesn't work when forwarding from the drm chardev to the
> dma-buf on the importer side, since you'd need a ton of different
> address spaces. And you still rely on the core code picking up your
> pgoff mangling, which feels about as risky to me as the vma file
> pointer wrangling - if it's not consistently applied the reverse map
> is toast and unmap_mapping_range doesn't work correctly for our needs.
I would think the pgoff has to be translated at the same time the
vm->vm_file is changed?
The owner of the dma_buf should have one virtual address space and FD,
all its dma bufs should be linked to it, and all pgoffs translated to
that space.
Jason
WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@ziepe.ca>
To: Daniel Vetter <daniel@ffwll.ch>
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>,
"Christian König" <christian.koenig@amd.com>,
"open list:DMA BUFFER SHARING FRAMEWORK"
<linux-media@vger.kernel.org>
Subject: Re: [Linaro-mm-sig] Changing vma->vm_file in dma_buf_mmap()
Date: Thu, 17 Sep 2020 08:31:10 -0300 [thread overview]
Message-ID: <20200917113110.GE8409@ziepe.ca> (raw)
In-Reply-To: <CAKMK7uE=UqZD3PVC8XZAXrgGH-VsUF_-YQD3MLV8KK1kpxO4yQ@mail.gmail.com>
On Thu, Sep 17, 2020 at 10:09:12AM +0200, Daniel Vetter wrote:
> Yeah, but it doesn't work when forwarding from the drm chardev to the
> dma-buf on the importer side, since you'd need a ton of different
> address spaces. And you still rely on the core code picking up your
> pgoff mangling, which feels about as risky to me as the vma file
> pointer wrangling - if it's not consistently applied the reverse map
> is toast and unmap_mapping_range doesn't work correctly for our needs.
I would think the pgoff has to be translated at the same time the
vm->vm_file is changed?
The owner of the dma_buf should have one virtual address space and FD,
all its dma bufs should be linked to it, and all pgoffs translated to
that space.
Jason
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dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2020-09-17 11:39 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
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 [this message]
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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