From: Jason Gunthorpe <jgg@ziepe.ca>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Christian König" <ckoenig.leichtzumerken@gmail.com>,
"Christian König" <christian.koenig@amd.com>,
"DRI Development" <dri-devel@lists.freedesktop.org>,
"Intel Graphics Development" <intel-gfx@lists.freedesktop.org>,
"Thomas Zimmermann" <tzimmermann@suse.de>,
"Suren Baghdasaryan" <surenb@google.com>,
"Matthew Wilcox" <willy@infradead.org>,
"John Stultz" <john.stultz@linaro.org>,
"Daniel Vetter" <daniel.vetter@intel.com>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org
Subject: Re: [Linaro-mm-sig] Re: [PATCH] dma-buf: Require VM_PFNMAP vma for mmap
Date: Wed, 23 Nov 2022 08:46:27 -0400 [thread overview]
Message-ID: <Y34WI9SZdiH/p1tA@ziepe.ca> (raw)
In-Reply-To: <CAKMK7uFjmzewqv3r4hL9hvLADwV536n2n6xbAWaUvmAcStr5KQ@mail.gmail.com>
On Wed, Nov 23, 2022 at 11:06:55AM +0100, Daniel Vetter wrote:
> > Maybe a GFP flag to set the page reference count to zero or something
> > like this?
>
> Hm yeah that might work. I'm not sure what it will all break though?
> And we'd need to make sure that underflowing the page refcount dies in
> a backtrace.
Mucking with the refcount like this to protect against crazy out of
tree drives seems horrible..
The WARN_ON(pag_count(p) != 1) seems like a reasonable thing to do
though, though you must combine this with the special PTE flag..
Jason
next prev parent reply other threads:[~2022-11-23 13:00 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-22 17:08 [PATCH] dma-buf: Require VM_PFNMAP vma for mmap Daniel Vetter
2022-11-22 18:03 ` Jason Gunthorpe
2022-11-22 18:08 ` Daniel Vetter
2022-11-22 18:50 ` Jason Gunthorpe
2022-11-22 19:29 ` Daniel Vetter
2022-11-22 19:34 ` Jason Gunthorpe
2022-11-22 19:50 ` Daniel Vetter
2022-11-23 9:06 ` Christian König
2022-11-23 9:30 ` Daniel Vetter
2022-11-23 9:39 ` [Linaro-mm-sig] " Christian König
2022-11-23 10:06 ` Daniel Vetter
2022-11-23 12:46 ` Jason Gunthorpe [this message]
2022-11-23 12:49 ` Christian König
2022-11-23 12:53 ` Jason Gunthorpe
2022-11-23 13:12 ` Christian König
2022-11-23 13:28 ` Jason Gunthorpe
2022-11-23 14:28 ` Daniel Vetter
2022-11-23 15:04 ` Jason Gunthorpe
2022-11-23 16:22 ` Daniel Vetter
2022-11-23 14:34 ` Daniel Vetter
2022-11-23 15:08 ` Jason Gunthorpe
2022-11-23 15:15 ` Christian König
2022-11-23 16:26 ` Daniel Vetter
2022-11-23 16:26 ` Jason Gunthorpe
2022-11-23 8:07 ` Thomas Zimmermann
2022-11-23 9:33 ` Daniel Vetter
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