All of lore.kernel.org
 help / color / mirror / Atom feed
From: Jason Gunthorpe <jgg@ziepe.ca>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "DRI Development" <dri-devel@lists.freedesktop.org>,
	LKML <linux-kernel@vger.kernel.org>,
	kvm@vger.kernel.org, "Linux MM" <linux-mm@kvack.org>,
	"Linux ARM" <linux-arm-kernel@lists.infradead.org>,
	linux-samsung-soc <linux-samsung-soc@vger.kernel.org>,
	"open list:DMA BUFFER SHARING FRAMEWORK"
	<linux-media@vger.kernel.org>,
	linux-s390@vger.kernel.org,
	"Daniel Vetter" <daniel.vetter@intel.com>,
	"Pawel Osciak" <pawel@osciak.com>,
	"Marek Szyprowski" <m.szyprowski@samsung.com>,
	"Kyungmin Park" <kyungmin.park@samsung.com>,
	"Tomasz Figa" <tfiga@chromium.org>,
	"Mauro Carvalho Chehab" <mchehab@kernel.org>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"John Hubbard" <jhubbard@nvidia.com>,
	"Jérôme Glisse" <jglisse@redhat.com>, "Jan Kara" <jack@suse.cz>,
	"Dan Williams" <dan.j.williams@intel.com>
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

WARNING: multiple messages have this Message-ID
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

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID
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
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

  reply	other threads:[~2020-10-07 17:33 UTC|newest]

Thread overview: 166+ 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 ` Daniel Vetter
2020-10-07 16:44 ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 01/13] drm/exynos: Stop using frame_vector helpers Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 20:32   ` John Hubbard
2020-10-07 20:32     ` John Hubbard
2020-10-07 20:32     ` John Hubbard
2020-10-07 21:32     ` Daniel Vetter
2020-10-07 21:32       ` Daniel Vetter
2020-10-07 21:32       ` Daniel Vetter
2020-10-07 21:36       ` John Hubbard
2020-10-07 21:36         ` John Hubbard
2020-10-07 21:36         ` John Hubbard
2020-10-07 21:50         ` Daniel Vetter
2020-10-07 21:50           ` Daniel Vetter
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 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 20:43   ` John Hubbard
2020-10-07 20:43     ` John Hubbard
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 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 20:38   ` John Hubbard
2020-10-07 20:38     ` John Hubbard
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 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 20:46   ` John Hubbard
2020-10-07 20:46     ` John Hubbard
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 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:53   ` Jason Gunthorpe
2020-10-07 16:53     ` Jason Gunthorpe
2020-10-07 16:53     ` Jason Gunthorpe
2020-10-07 17:12     ` Daniel Vetter
2020-10-07 17:12       ` Daniel Vetter
2020-10-07 17:12       ` Daniel Vetter
2020-10-07 17:33       ` Jason Gunthorpe [this message]
2020-10-07 17:33         ` Jason Gunthorpe
2020-10-07 17:33         ` Jason Gunthorpe
2020-10-07 21:13   ` John Hubbard
2020-10-07 21:13     ` John Hubbard
2020-10-07 21:13     ` John Hubbard
2020-10-07 21:30     ` Daniel Vetter
2020-10-07 21:30       ` Daniel Vetter
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 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 22:18   ` John Hubbard
2020-10-07 22:18     ` John Hubbard
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 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 17:27   ` Jason Gunthorpe
2020-10-07 17:27     ` Jason Gunthorpe
2020-10-07 17:27     ` Jason Gunthorpe
2020-10-07 18:01     ` Daniel Vetter
2020-10-07 18:01       ` Daniel Vetter
2020-10-07 18:01       ` Daniel Vetter
2020-10-07 23:21       ` Jason Gunthorpe
2020-10-07 23:21         ` Jason Gunthorpe
2020-10-07 23:21         ` Jason Gunthorpe
2020-10-08  0:44   ` John Hubbard
2020-10-08  0:44     ` John Hubbard
2020-10-08  0:44     ` John Hubbard
2020-10-08  7:23     ` Daniel Vetter
2020-10-08  7:23       ` Daniel Vetter
2020-10-08  7:23       ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 08/13] s390/pci: Remove races against pte updates Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-08 16:44   ` Gerald Schaefer
2020-10-08 16:44     ` Gerald Schaefer
2020-10-08 16:44     ` Gerald Schaefer
2020-10-08 17:16     ` Daniel Vetter
2020-10-08 17:16       ` Daniel Vetter
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 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 18:46   ` Bjorn Helgaas
2020-10-07 18:46     ` Bjorn Helgaas
2020-10-07 18:46     ` Bjorn Helgaas
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 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 18:41   ` Bjorn Helgaas
2020-10-07 18:41     ` Bjorn Helgaas
2020-10-07 18:41     ` Bjorn Helgaas
2020-10-07 19:24     ` Daniel Vetter
2020-10-07 19:24       ` Daniel Vetter
2020-10-07 19:24       ` Daniel Vetter
2020-10-07 19:33   ` Dan Williams
2020-10-07 19:33     ` Dan Williams
2020-10-07 19:33     ` Dan Williams
2020-10-07 19:47     ` Daniel Vetter
2020-10-07 19:47       ` Daniel Vetter
2020-10-07 19:47       ` Daniel Vetter
2020-10-07 22:23       ` Dan Williams
2020-10-07 22:23         ` Dan Williams
2020-10-07 22:23         ` Dan Williams
2020-10-07 22:29         ` Dan Williams
2020-10-07 22:29           ` Dan Williams
2020-10-07 22:29           ` Dan Williams
2020-10-08  8:09           ` Daniel Vetter
2020-10-08  8:09             ` Daniel Vetter
2020-10-08  8:09             ` Daniel Vetter
2020-10-07 23:24     ` Jason Gunthorpe
2020-10-07 23:24       ` Jason Gunthorpe
2020-10-07 23:24       ` Jason Gunthorpe
2020-10-08  7:31       ` Daniel Vetter
2020-10-08  7:31         ` Daniel Vetter
2020-10-08  7:31         ` Daniel Vetter
2020-10-08  7:49       ` Dan Williams
2020-10-08  7:49         ` Dan Williams
2020-10-08  7:49         ` Dan Williams
2020-10-08  8:13         ` Daniel Vetter
2020-10-08  8:13           ` Daniel Vetter
2020-10-08  8:13           ` Daniel Vetter
2020-10-08  8:35           ` Dan Williams
2020-10-08  8:35             ` Dan Williams
2020-10-08  8:35             ` Dan Williams
2020-10-08 12:41         ` Jason Gunthorpe
2020-10-08 12:41           ` Jason Gunthorpe
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 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 17:36   ` Jason Gunthorpe
2020-10-07 17:36     ` Jason Gunthorpe
2020-10-07 17:36     ` Jason Gunthorpe
2020-10-07 18:10     ` Daniel Vetter
2020-10-07 18:10       ` Daniel Vetter
2020-10-07 18:10       ` Daniel Vetter
2020-10-07 19:00       ` Jason Gunthorpe
2020-10-07 19:00         ` Jason Gunthorpe
2020-10-07 19:00         ` Jason Gunthorpe
2020-10-07 19:38         ` Daniel Vetter
2020-10-07 19:38           ` Daniel Vetter
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   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:44 ` [PATCH 13/13] vfio/type1: Mark follow_pfn " Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 16:44   ` Daniel Vetter
2020-10-07 17:39   ` Jason Gunthorpe
2020-10-07 17:39     ` Jason Gunthorpe
2020-10-07 17:39     ` Jason Gunthorpe
2020-10-07 18:14     ` Daniel Vetter
2020-10-07 18:14       ` Daniel Vetter
2020-10-07 18:14       ` Daniel Vetter
2020-10-07 18:47       ` Jason Gunthorpe
2020-10-07 18:47         ` Jason Gunthorpe
2020-10-07 18:47         ` Jason Gunthorpe

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201007173323.GV5177@ziepe.ca \
    --to=jgg@ziepe.ca \
    --cc=akpm@linux-foundation.org \
    --cc=dan.j.williams@intel.com \
    --cc=daniel.vetter@ffwll.ch \
    --cc=daniel.vetter@intel.com \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=jack@suse.cz \
    --cc=jglisse@redhat.com \
    --cc=jhubbard@nvidia.com \
    --cc=kvm@vger.kernel.org \
    --cc=kyungmin.park@samsung.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-media@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-s390@vger.kernel.org \
    --cc=linux-samsung-soc@vger.kernel.org \
    --cc=m.szyprowski@samsung.com \
    --cc=mchehab@kernel.org \
    --cc=pawel@osciak.com \
    --cc=tfiga@chromium.org \
    --subject='Re: [PATCH 05/13] mm/frame-vector: Use FOLL_LONGTERM' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.