From: Jason Gunthorpe <jgg@ziepe.ca>
To: "Christian König" <christian.koenig@amd.com>
Cc: Daniel Vetter <daniel@ffwll.ch>,
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: [Linaro-mm-sig] Changing vma->vm_file in dma_buf_mmap()
Date: Thu, 17 Sep 2020 13:39:07 -0300 [thread overview]
Message-ID: <20200917163907.GI8409@ziepe.ca> (raw)
In-Reply-To: <b9e65f47-b5c8-db09-117a-a8e22a5b6c71@amd.com>
On Thu, Sep 17, 2020 at 06:06:14PM +0200, Christian König wrote:
> > > If it is already taking a page fault I'm not sure the extra function
> > > call indirection is going to be a big deal. Having a uniform VMA
> > > sounds saner than every driver custom rolling something.
> > >
> > > When I unwound a similar mess in RDMA all the custom VMA stuff in the
> > > drivers turned out to be generally buggy, at least.
> > >
> > > Is vma->vm_file->private_data universally a dma_buf pointer at least?
> > Nope. I think if you want this without some large scale rewrite of a
> > lot of code we'd need a vmops->get_dmabuf or similar. Not pretty, but
> > would get the job done.
>
> Yeah, agree that sounds like the simplest approach.
I don't think that will fly, it is clearly only papering over a mess
inside DRM/dma buf :\
Jason
WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@ziepe.ca>
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: [Linaro-mm-sig] Changing vma->vm_file in dma_buf_mmap()
Date: Thu, 17 Sep 2020 13:39:07 -0300 [thread overview]
Message-ID: <20200917163907.GI8409@ziepe.ca> (raw)
In-Reply-To: <b9e65f47-b5c8-db09-117a-a8e22a5b6c71@amd.com>
On Thu, Sep 17, 2020 at 06:06:14PM +0200, Christian König wrote:
> > > If it is already taking a page fault I'm not sure the extra function
> > > call indirection is going to be a big deal. Having a uniform VMA
> > > sounds saner than every driver custom rolling something.
> > >
> > > When I unwound a similar mess in RDMA all the custom VMA stuff in the
> > > drivers turned out to be generally buggy, at least.
> > >
> > > Is vma->vm_file->private_data universally a dma_buf pointer at least?
> > Nope. I think if you want this without some large scale rewrite of a
> > lot of code we'd need a vmops->get_dmabuf or similar. Not pretty, but
> > would get the job done.
>
> Yeah, agree that sounds like the simplest approach.
I don't think that will fly, it is clearly only papering over a mess
inside DRM/dma buf :\
Jason
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next prev parent reply other threads:[~2020-09-17 16:40 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
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 [this message]
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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