From: Jason Gunthorpe <jgg@ziepe.ca>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Jérôme Glisse" <jglisse@redhat.com>,
linux-s390@vger.kernel.org,
linux-samsung-soc <linux-samsung-soc@vger.kernel.org>,
"Jan Kara" <jack@suse.cz>, "Pawel Osciak" <pawel@osciak.com>,
kvm@vger.kernel.org, "John Hubbard" <jhubbard@nvidia.com>,
"Mauro Carvalho Chehab" <mchehab@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
"DRI Development" <dri-devel@lists.freedesktop.org>,
"Tomasz Figa" <tfiga@chromium.org>,
"Linux MM" <linux-mm@kvack.org>,
"Kyungmin Park" <kyungmin.park@samsung.com>,
"Daniel Vetter" <daniel.vetter@intel.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Marek Szyprowski" <m.szyprowski@samsung.com>,
"Dan Williams" <dan.j.williams@intel.com>,
"Linux ARM" <linux-arm-kernel@lists.infradead.org>,
"open list:DMA BUFFER SHARING FRAMEWORK"
<linux-media@vger.kernel.org>
Subject: Re: [PATCH 05/13] mm/frame-vector: Use FOLL_LONGTERM
Date: Wed, 7 Oct 2020 14:33:23 -0300 [thread overview]
Message-ID: <20201007173323.GV5177@ziepe.ca> (raw)
In-Reply-To: <CAKMK7uGTpZcHwrBNQOXwzDAzyfSgoLSt_Dae_3hMRE2xwGx+GA@mail.gmail.com>
On Wed, Oct 07, 2020 at 07:12:24PM +0200, Daniel Vetter wrote:
> On Wed, Oct 7, 2020 at 6:53 PM Jason Gunthorpe <jgg@ziepe.ca> wrote:
> >
> > On Wed, Oct 07, 2020 at 06:44:18PM +0200, Daniel Vetter wrote:
> > >
> > > - /*
> > > - * While get_vaddr_frames() could be used for transient (kernel
> > > - * controlled lifetime) pinning of memory pages all current
> > > - * users establish long term (userspace controlled lifetime)
> > > - * page pinning. Treat get_vaddr_frames() like
> > > - * get_user_pages_longterm() and disallow it for filesystem-dax
> > > - * mappings.
> > > - */
> > > - if (vma_is_fsdax(vma)) {
> > > - ret = -EOPNOTSUPP;
> > > - goto out;
> > > - }
> > > -
> > > - if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
> > > - vec->got_ref = true;
> > > - vec->is_pfns = false;
> > > - ret = pin_user_pages_locked(start, nr_frames,
> > > - gup_flags, (struct page **)(vec->ptrs), &locked);
> > > - goto out;
> > > - }
> >
> > The vm_flags still need to be checked before going into the while
> > loop. If the break is taken then nothing would check vm_flags
>
> Hm right that's a bin inconsistent. follow_pfn also checks for this,
> so I think we can just ditch this entirely both here and in the do {}
> while () check, simplifying the latter to just while (vma). Well, just
> make it a real loop with less confusing control flow probably.
It does read very poorly with the redundant check, espeically since I
keep forgetting follow_pfn does it too :\
Jason
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next prev parent reply other threads:[~2020-10-08 7:21 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-07 16:44 [PATCH 00/13] follow_pfn and other iomap races Daniel Vetter
2020-10-07 16:44 ` [PATCH 01/13] drm/exynos: Stop using frame_vector helpers Daniel Vetter
2020-10-07 20:32 ` John Hubbard
2020-10-07 21:32 ` Daniel Vetter
2020-10-07 21:36 ` John Hubbard
2020-10-07 21:50 ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 02/13] drm/exynos: Use FOLL_LONGTERM for g2d cmdlists Daniel Vetter
2020-10-07 20:43 ` John Hubbard
2020-10-07 16:44 ` [PATCH 03/13] misc/habana: Stop using frame_vector helpers Daniel Vetter
2020-10-07 20:38 ` John Hubbard
2020-10-07 16:44 ` [PATCH 04/13] misc/habana: Use FOLL_LONGTERM for userptr Daniel Vetter
2020-10-07 20:46 ` John Hubbard
2020-10-07 16:44 ` [PATCH 05/13] mm/frame-vector: Use FOLL_LONGTERM Daniel Vetter
2020-10-07 16:53 ` Jason Gunthorpe
2020-10-07 17:12 ` Daniel Vetter
2020-10-07 17:33 ` Jason Gunthorpe [this message]
2020-10-07 21:13 ` John Hubbard
2020-10-07 21:30 ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 06/13] media: videobuf2: Move frame_vector into media subsystem Daniel Vetter
2020-10-07 22:18 ` John Hubbard
2020-10-07 16:44 ` [PATCH 07/13] mm: close race in generic_access_phys Daniel Vetter
2020-10-07 17:27 ` Jason Gunthorpe
2020-10-07 18:01 ` Daniel Vetter
2020-10-07 23:21 ` Jason Gunthorpe
2020-10-08 0:44 ` John Hubbard
2020-10-08 7:23 ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 08/13] s390/pci: Remove races against pte updates Daniel Vetter
2020-10-08 16:44 ` Gerald Schaefer
2020-10-08 17:16 ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 09/13] PCI: obey iomem restrictions for procfs mmap Daniel Vetter
2020-10-07 18:46 ` Bjorn Helgaas
2020-10-07 16:44 ` [PATCH 10/13] PCI: revoke mappings like devmem Daniel Vetter
2020-10-07 18:41 ` Bjorn Helgaas
2020-10-07 19:24 ` Daniel Vetter
2020-10-07 19:33 ` Dan Williams
2020-10-07 19:47 ` Daniel Vetter
2020-10-07 22:23 ` Dan Williams
2020-10-07 22:29 ` Dan Williams
2020-10-08 8:09 ` Daniel Vetter
2020-10-07 23:24 ` Jason Gunthorpe
2020-10-08 7:31 ` Daniel Vetter
2020-10-08 7:49 ` Dan Williams
2020-10-08 8:13 ` Daniel Vetter
2020-10-08 8:35 ` Dan Williams
2020-10-08 12:41 ` Jason Gunthorpe
2020-10-07 16:44 ` [PATCH 11/13] mm: add unsafe_follow_pfn Daniel Vetter
2020-10-07 17:36 ` Jason Gunthorpe
2020-10-07 18:10 ` Daniel Vetter
2020-10-07 19:00 ` Jason Gunthorpe
2020-10-07 19:38 ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 12/13] media/videbuf1|2: Mark follow_pfn usage as unsafe Daniel Vetter
2020-10-07 16:44 ` [PATCH 13/13] vfio/type1: Mark follow_pfn " Daniel Vetter
2020-10-07 17:39 ` Jason Gunthorpe
2020-10-07 18:14 ` Daniel Vetter
2020-10-07 18:47 ` Jason Gunthorpe
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