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* [PATCH] PCI: Also set up legacy files only after sysfs init
       [not found] <d958eb8e32d5dd6ffd981b92cd54fe7b3fcebab9>
@ 2021-02-05 13:36 ` Daniel Vetter
  2021-02-10 17:43   ` Daniel Vetter
  2021-02-10 21:40   ` Bjorn Helgaas
  0 siblings, 2 replies; 4+ messages in thread
From: Daniel Vetter @ 2021-02-05 13:36 UTC (permalink / raw)
  To: LKML
  Cc: DRI Development, Daniel Vetter, Daniel Vetter, Stephen Rothwell,
	Jason Gunthorpe, Kees Cook, Dan Williams, Andrew Morton,
	John Hubbard, Jérôme Glisse, Jan Kara,
	Greg Kroah-Hartman, linux-mm, linux-arm-kernel,
	linux-samsung-soc, linux-media, Bjorn Helgaas, linux-pci

We are already doing this for all the regular sysfs files on PCI
devices, but not yet on the legacy io files on the PCI buses. Thus far
no problem, but in the next patch I want to wire up iomem revoke
support. That needs the vfs up and running already to make sure that
iomem_get_mapping() works.

Wire it up exactly like the existing code in
pci_create_sysfs_dev_files(). Note that pci_remove_legacy_files()
doesn't need a check since the one for pci_bus->legacy_io is
sufficient.

An alternative solution would be to implement a callback in sysfs to
set up the address space from iomem_get_mapping() when userspace calls
mmap(). This also works, but Greg didn't really like that just to work
around an ordering issue when the kernel loads initially.

v2: Improve commit message (Bjorn)

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-mm@kvack.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: linux-media@vger.kernel.org
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
---
 drivers/pci/pci-sysfs.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index fb072f4b3176..0c45b4f7b214 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -927,6 +927,9 @@ void pci_create_legacy_files(struct pci_bus *b)
 {
 	int error;
 
+	if (!sysfs_initialized)
+		return;
+
 	b->legacy_io = kcalloc(2, sizeof(struct bin_attribute),
 			       GFP_ATOMIC);
 	if (!b->legacy_io)
@@ -1448,6 +1451,7 @@ void pci_remove_sysfs_dev_files(struct pci_dev *pdev)
 static int __init pci_sysfs_init(void)
 {
 	struct pci_dev *pdev = NULL;
+	struct pci_bus *pbus = NULL;
 	int retval;
 
 	sysfs_initialized = 1;
@@ -1459,6 +1463,9 @@ static int __init pci_sysfs_init(void)
 		}
 	}
 
+	while ((pbus = pci_find_next_bus(pbus)))
+		pci_create_legacy_files(pbus);
+
 	return 0;
 }
 late_initcall(pci_sysfs_init);
-- 
2.30.0


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] PCI: Also set up legacy files only after sysfs init
  2021-02-05 13:36 ` [PATCH] PCI: Also set up legacy files only after sysfs init Daniel Vetter
@ 2021-02-10 17:43   ` Daniel Vetter
  2021-02-10 21:40   ` Bjorn Helgaas
  1 sibling, 0 replies; 4+ messages in thread
From: Daniel Vetter @ 2021-02-10 17:43 UTC (permalink / raw)
  To: LKML
  Cc: DRI Development, Daniel Vetter, Stephen Rothwell,
	Jason Gunthorpe, Kees Cook, Dan Williams, Andrew Morton,
	John Hubbard, Jérôme Glisse, Jan Kara,
	Greg Kroah-Hartman, Linux MM, Linux ARM, linux-samsung-soc,
	open list:DMA BUFFER SHARING FRAMEWORK, Bjorn Helgaas, Linux PCI

Hi Bjorn,

Can you ack this for merging through my topic branch with the other
follow_pfn/iomem revoke fixes for 5.12?

If not, what's the plan for getting this (or equivalent functionality)
in for 5.13? I have more of these follow_pfn/iomem revoke patches on
top, so I'd like to get the first cut merged sooner than later if
possible. And the other prep work has been in -next since -rc1.

Thanks, Daniel

On Fri, Feb 5, 2021 at 2:36 PM Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
>
> We are already doing this for all the regular sysfs files on PCI
> devices, but not yet on the legacy io files on the PCI buses. Thus far
> no problem, but in the next patch I want to wire up iomem revoke
> support. That needs the vfs up and running already to make sure that
> iomem_get_mapping() works.
>
> Wire it up exactly like the existing code in
> pci_create_sysfs_dev_files(). Note that pci_remove_legacy_files()
> doesn't need a check since the one for pci_bus->legacy_io is
> sufficient.
>
> An alternative solution would be to implement a callback in sysfs to
> set up the address space from iomem_get_mapping() when userspace calls
> mmap(). This also works, but Greg didn't really like that just to work
> around an ordering issue when the kernel loads initially.
>
> v2: Improve commit message (Bjorn)
>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Stephen Rothwell <sfr@canb.auug.org.au>
> Cc: Jason Gunthorpe <jgg@ziepe.ca>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: John Hubbard <jhubbard@nvidia.com>
> Cc: Jérôme Glisse <jglisse@redhat.com>
> Cc: Jan Kara <jack@suse.cz>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: linux-mm@kvack.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-samsung-soc@vger.kernel.org
> Cc: linux-media@vger.kernel.org
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: linux-pci@vger.kernel.org
> ---
>  drivers/pci/pci-sysfs.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index fb072f4b3176..0c45b4f7b214 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -927,6 +927,9 @@ void pci_create_legacy_files(struct pci_bus *b)
>  {
>         int error;
>
> +       if (!sysfs_initialized)
> +               return;
> +
>         b->legacy_io = kcalloc(2, sizeof(struct bin_attribute),
>                                GFP_ATOMIC);
>         if (!b->legacy_io)
> @@ -1448,6 +1451,7 @@ void pci_remove_sysfs_dev_files(struct pci_dev *pdev)
>  static int __init pci_sysfs_init(void)
>  {
>         struct pci_dev *pdev = NULL;
> +       struct pci_bus *pbus = NULL;
>         int retval;
>
>         sysfs_initialized = 1;
> @@ -1459,6 +1463,9 @@ static int __init pci_sysfs_init(void)
>                 }
>         }
>
> +       while ((pbus = pci_find_next_bus(pbus)))
> +               pci_create_legacy_files(pbus);
> +
>         return 0;
>  }
>  late_initcall(pci_sysfs_init);
> --
> 2.30.0
>


-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] PCI: Also set up legacy files only after sysfs init
  2021-02-05 13:36 ` [PATCH] PCI: Also set up legacy files only after sysfs init Daniel Vetter
  2021-02-10 17:43   ` Daniel Vetter
@ 2021-02-10 21:40   ` Bjorn Helgaas
  2021-02-11 14:56     ` Daniel Vetter
  1 sibling, 1 reply; 4+ messages in thread
From: Bjorn Helgaas @ 2021-02-10 21:40 UTC (permalink / raw)
  To: Daniel Vetter
  Cc: LKML, Stephen Rothwell, linux-samsung-soc, Jan Kara, Kees Cook,
	Greg Kroah-Hartman, linux-pci, DRI Development, linux-mm,
	Jason Gunthorpe, Jérôme Glisse, John Hubbard,
	Bjorn Helgaas, Daniel Vetter, Dan Williams, Andrew Morton,
	linux-arm-kernel, linux-media

On Fri, Feb 05, 2021 at 02:36:32PM +0100, Daniel Vetter wrote:
> We are already doing this for all the regular sysfs files on PCI
> devices, but not yet on the legacy io files on the PCI buses. Thus far
> no problem, but in the next patch I want to wire up iomem revoke
> support. That needs the vfs up and running already to make sure that
> iomem_get_mapping() works.
> 
> Wire it up exactly like the existing code in
> pci_create_sysfs_dev_files(). Note that pci_remove_legacy_files()
> doesn't need a check since the one for pci_bus->legacy_io is
> sufficient.
> 
> An alternative solution would be to implement a callback in sysfs to
> set up the address space from iomem_get_mapping() when userspace calls
> mmap(). This also works, but Greg didn't really like that just to work
> around an ordering issue when the kernel loads initially.
> 
> v2: Improve commit message (Bjorn)
> 
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

I wish we weren't extending a known-racy mechanism to do this, but at
least we're not *adding* a brand new race.

> Cc: Stephen Rothwell <sfr@canb.auug.org.au>
> Cc: Jason Gunthorpe <jgg@ziepe.ca>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: John Hubbard <jhubbard@nvidia.com>
> Cc: Jérôme Glisse <jglisse@redhat.com>
> Cc: Jan Kara <jack@suse.cz>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: linux-mm@kvack.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-samsung-soc@vger.kernel.org
> Cc: linux-media@vger.kernel.org
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: linux-pci@vger.kernel.org
> ---
>  drivers/pci/pci-sysfs.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index fb072f4b3176..0c45b4f7b214 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -927,6 +927,9 @@ void pci_create_legacy_files(struct pci_bus *b)
>  {
>  	int error;
>  
> +	if (!sysfs_initialized)
> +		return;
> +
>  	b->legacy_io = kcalloc(2, sizeof(struct bin_attribute),
>  			       GFP_ATOMIC);
>  	if (!b->legacy_io)
> @@ -1448,6 +1451,7 @@ void pci_remove_sysfs_dev_files(struct pci_dev *pdev)
>  static int __init pci_sysfs_init(void)
>  {
>  	struct pci_dev *pdev = NULL;
> +	struct pci_bus *pbus = NULL;
>  	int retval;
>  
>  	sysfs_initialized = 1;
> @@ -1459,6 +1463,9 @@ static int __init pci_sysfs_init(void)
>  		}
>  	}
>  
> +	while ((pbus = pci_find_next_bus(pbus)))
> +		pci_create_legacy_files(pbus);
> +
>  	return 0;
>  }
>  late_initcall(pci_sysfs_init);
> -- 
> 2.30.0
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] PCI: Also set up legacy files only after sysfs init
  2021-02-10 21:40   ` Bjorn Helgaas
@ 2021-02-11 14:56     ` Daniel Vetter
  0 siblings, 0 replies; 4+ messages in thread
From: Daniel Vetter @ 2021-02-11 14:56 UTC (permalink / raw)
  To: Bjorn Helgaas
  Cc: LKML, Stephen Rothwell, linux-samsung-soc, Jan Kara, Kees Cook,
	Greg Kroah-Hartman, Linux PCI, DRI Development, Linux MM,
	Jason Gunthorpe, Jérôme Glisse, John Hubbard,
	Bjorn Helgaas, Daniel Vetter, Dan Williams, Andrew Morton,
	Linux ARM, open list:DMA BUFFER SHARING FRAMEWORK

On Wed, Feb 10, 2021 at 10:40 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
>
> On Fri, Feb 05, 2021 at 02:36:32PM +0100, Daniel Vetter wrote:
> > We are already doing this for all the regular sysfs files on PCI
> > devices, but not yet on the legacy io files on the PCI buses. Thus far
> > no problem, but in the next patch I want to wire up iomem revoke
> > support. That needs the vfs up and running already to make sure that
> > iomem_get_mapping() works.
> >
> > Wire it up exactly like the existing code in
> > pci_create_sysfs_dev_files(). Note that pci_remove_legacy_files()
> > doesn't need a check since the one for pci_bus->legacy_io is
> > sufficient.
> >
> > An alternative solution would be to implement a callback in sysfs to
> > set up the address space from iomem_get_mapping() when userspace calls
> > mmap(). This also works, but Greg didn't really like that just to work
> > around an ordering issue when the kernel loads initially.
> >
> > v2: Improve commit message (Bjorn)
> >
> > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
>
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
>
> I wish we weren't extending a known-racy mechanism to do this, but at
> least we're not *adding* a brand new race.

Yeah it's not great. Thanks for looking at both again, I'll fix up the
typos on the 2nd one and merge them both.

Cheers, Daniel

>
> > Cc: Stephen Rothwell <sfr@canb.auug.org.au>
> > Cc: Jason Gunthorpe <jgg@ziepe.ca>
> > Cc: Kees Cook <keescook@chromium.org>
> > Cc: Dan Williams <dan.j.williams@intel.com>
> > Cc: Andrew Morton <akpm@linux-foundation.org>
> > Cc: John Hubbard <jhubbard@nvidia.com>
> > Cc: Jérôme Glisse <jglisse@redhat.com>
> > Cc: Jan Kara <jack@suse.cz>
> > Cc: Dan Williams <dan.j.williams@intel.com>
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Cc: linux-mm@kvack.org
> > Cc: linux-arm-kernel@lists.infradead.org
> > Cc: linux-samsung-soc@vger.kernel.org
> > Cc: linux-media@vger.kernel.org
> > Cc: Bjorn Helgaas <bhelgaas@google.com>
> > Cc: linux-pci@vger.kernel.org
> > ---
> >  drivers/pci/pci-sysfs.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> >
> > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> > index fb072f4b3176..0c45b4f7b214 100644
> > --- a/drivers/pci/pci-sysfs.c
> > +++ b/drivers/pci/pci-sysfs.c
> > @@ -927,6 +927,9 @@ void pci_create_legacy_files(struct pci_bus *b)
> >  {
> >       int error;
> >
> > +     if (!sysfs_initialized)
> > +             return;
> > +
> >       b->legacy_io = kcalloc(2, sizeof(struct bin_attribute),
> >                              GFP_ATOMIC);
> >       if (!b->legacy_io)
> > @@ -1448,6 +1451,7 @@ void pci_remove_sysfs_dev_files(struct pci_dev *pdev)
> >  static int __init pci_sysfs_init(void)
> >  {
> >       struct pci_dev *pdev = NULL;
> > +     struct pci_bus *pbus = NULL;
> >       int retval;
> >
> >       sysfs_initialized = 1;
> > @@ -1459,6 +1463,9 @@ static int __init pci_sysfs_init(void)
> >               }
> >       }
> >
> > +     while ((pbus = pci_find_next_bus(pbus)))
> > +             pci_create_legacy_files(pbus);
> > +
> >       return 0;
> >  }
> >  late_initcall(pci_sysfs_init);
> > --
> > 2.30.0
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel



-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-02-11 15:05 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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     [not found] <d958eb8e32d5dd6ffd981b92cd54fe7b3fcebab9>
2021-02-05 13:36 ` [PATCH] PCI: Also set up legacy files only after sysfs init Daniel Vetter
2021-02-10 17:43   ` Daniel Vetter
2021-02-10 21:40   ` Bjorn Helgaas
2021-02-11 14:56     ` Daniel Vetter

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