From: Daniel Vetter <daniel@ffwll.ch>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: "Daniel Vetter" <daniel.vetter@ffwll.ch>,
"DRI Development" <dri-devel@lists.freedesktop.org>,
LKML <linux-kernel@vger.kernel.org>,
kvm@vger.kernel.org, linux-mm@kvack.org,
linux-arm-kernel@lists.infradead.org,
linux-samsung-soc@vger.kernel.org, linux-media@vger.kernel.org,
"Daniel Vetter" <daniel.vetter@intel.com>,
"Christoph Hellwig" <hch@infradead.org>,
"Kees Cook" <keescook@chromium.org>,
"Dan Williams" <dan.j.williams@intel.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"John Hubbard" <jhubbard@nvidia.com>,
"Jérôme Glisse" <jglisse@redhat.com>, "Jan Kara" <jack@suse.cz>
Subject: Re: [PATCH v6 17/17] RFC: mm: add mmu_notifier argument to follow_pfn
Date: Tue, 24 Nov 2020 15:28:14 +0100 [thread overview]
Message-ID: <20201124142814.GM401619@phenom.ffwll.local> (raw)
In-Reply-To: <20201120183029.GQ244516@ziepe.ca>
On Fri, Nov 20, 2020 at 02:30:29PM -0400, Jason Gunthorpe wrote:
> On Thu, Nov 19, 2020 at 03:41:46PM +0100, Daniel Vetter wrote:
> > @@ -4805,21 +4824,15 @@ EXPORT_SYMBOL(follow_pte_pmd);
> > * Return: zero and the pfn at @pfn on success, -ve otherwise.
> > */
> > int follow_pfn(struct vm_area_struct *vma, unsigned long address,
> > - unsigned long *pfn)
> > + unsigned long *pfn, struct mmu_notifier *subscription)
> > {
> > - int ret = -EINVAL;
> > - spinlock_t *ptl;
> > - pte_t *ptep;
> > + if (WARN_ON(!subscription->mm))
> > + return -EINVAL;
> >
> > + if (WARN_ON(subscription->mm != vma->vm_mm))
> > + return -EINVAL;
>
> These two things are redundant right? vma->vm_mm != NULL?
Yup, will remove.
> BTW, why do we even have this for nommu? If the only caller is kvm,
> can you even compile kvm on nommu??
Kinda makes sense, but I have no idea how to make sure with compile
testing this is really the case. And I didn't see any hard evidence in
Kconfig or Makefile that mmu notifiers requires CONFIG_MMU. So not sure
what to do here.
Should I just remove the nommu version of follow_pfn and see what happens?
We can't remove it earlier since it's still used by other subsystems.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
next prev parent reply other threads:[~2020-11-24 14:28 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-19 14:41 [PATCH v6 00/17] follow_pfn and other iomap races Daniel Vetter
2020-11-19 14:41 ` [PATCH v6 01/17] drm/exynos: Stop using frame_vector helpers Daniel Vetter
2020-11-19 14:41 ` [PATCH v6 02/17] drm/exynos: Use FOLL_LONGTERM for g2d cmdlists Daniel Vetter
2020-11-19 14:41 ` [PATCH v6 03/17] misc/habana: Stop using frame_vector helpers Daniel Vetter
2020-11-21 12:47 ` Oded Gabbay
2020-11-19 14:41 ` [PATCH v6 04/17] misc/habana: Use FOLL_LONGTERM for userptr Daniel Vetter
2020-11-21 10:15 ` Oded Gabbay
2020-11-19 14:41 ` [PATCH v6 05/17] mm/frame-vector: Use FOLL_LONGTERM Daniel Vetter
2020-11-19 14:41 ` [PATCH v6 06/17] media: videobuf2: Move frame_vector into media subsystem Daniel Vetter
2020-11-20 8:07 ` Hans Verkuil
2020-11-19 14:41 ` [PATCH v6 07/17] mm: Close race in generic_access_phys Daniel Vetter
2020-11-19 14:41 ` [PATCH v6 08/17] mm: Add unsafe_follow_pfn Daniel Vetter
2020-11-19 14:41 ` [PATCH v6 09/17] media/videbuf1|2: Mark follow_pfn usage as unsafe Daniel Vetter
2020-11-20 8:06 ` Hans Verkuil
2020-11-20 8:28 ` Hans Verkuil
2020-11-20 8:32 ` Tomasz Figa
2020-11-20 9:18 ` Daniel Vetter
2020-11-20 10:38 ` Hans Verkuil
2020-11-20 10:51 ` Daniel Vetter
2020-11-20 12:08 ` Hans Verkuil
2020-11-20 12:23 ` Tomasz Figa
2020-11-24 14:16 ` Daniel Vetter
2020-11-19 14:41 ` [PATCH v6 10/17] vfio/type1: Mark follow_pfn " Daniel Vetter
2020-11-19 14:41 ` [PATCH v6 11/17] PCI: Obey iomem restrictions for procfs mmap Daniel Vetter
2020-11-19 14:41 ` [PATCH v6 12/17] /dev/mem: Only set filp->f_mapping Daniel Vetter
2020-11-19 14:41 ` [PATCH v6 13/17] resource: Move devmem revoke code to resource framework Daniel Vetter
2020-11-19 14:41 ` [PATCH v6 14/17] sysfs: Support zapping of binary attr mmaps Daniel Vetter
2020-11-19 14:41 ` [PATCH v6 15/17] PCI: Revoke mappings like devmem Daniel Vetter
2020-11-19 14:41 ` [PATCH v6 16/17] RFC: kvm: pass kvm argument to follow_pfn callsites Daniel Vetter
2020-11-20 15:33 ` Paolo Bonzini
2020-11-20 15:44 ` Daniel Vetter
2020-11-20 15:55 ` Paolo Bonzini
2020-11-19 14:41 ` [PATCH v6 17/17] RFC: mm: add mmu_notifier argument to follow_pfn Daniel Vetter
2020-11-20 18:30 ` Jason Gunthorpe
2020-11-24 14:28 ` Daniel Vetter [this message]
2020-11-24 15:55 ` Jason Gunthorpe
2020-11-25 9:00 ` Daniel Vetter
2020-11-27 13:12 ` [PATCH v6 00/17] follow_pfn and other iomap races Jason Gunthorpe
2020-11-27 15:36 ` Daniel Vetter
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