* [PATCH] xen/p2m: Export set_phys_to_machine.
@ 2013-09-06 14:00 Konrad Rzeszutek Wilk
2013-09-06 14:06 ` [Xen-devel] " Jan Beulich
` (3 more replies)
0 siblings, 4 replies; 10+ messages in thread
From: Konrad Rzeszutek Wilk @ 2013-09-06 14:00 UTC (permalink / raw)
To: linux-kernel, xen-devel, boris.ostrovsky, david.vrabel
Cc: Konrad Rzeszutek Wilk
We have already exported 'get_phys_to_machine' and there are
third-party drivers that depend on this other symbol. As such
lets make this balanced and also export this symbol.
Reported-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
arch/x86/xen/p2m.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 0d4ec35..cdb96bc 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -847,6 +847,7 @@ bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
return true;
}
+EXPORT_SYMBOL_GPL(set_phys_to_machine);
#define M2P_OVERRIDE_HASH_SHIFT 10
#define M2P_OVERRIDE_HASH (1 << M2P_OVERRIDE_HASH_SHIFT)
--
1.8.3.1
^ permalink raw reply related [flat|nested] 10+ messages in thread* Re: [Xen-devel] [PATCH] xen/p2m: Export set_phys_to_machine.
2013-09-06 14:00 [PATCH] xen/p2m: Export set_phys_to_machine Konrad Rzeszutek Wilk
@ 2013-09-06 14:06 ` Jan Beulich
2013-09-06 14:39 ` Konrad Rzeszutek Wilk
2013-09-06 14:39 ` [Xen-devel] " Konrad Rzeszutek Wilk
2013-09-06 14:06 ` Jan Beulich
` (2 subsequent siblings)
3 siblings, 2 replies; 10+ messages in thread
From: Jan Beulich @ 2013-09-06 14:06 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: david.vrabel, xen-devel, boris.ostrovsky, linux-kernel
>>> On 06.09.13 at 16:00, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote:
> We have already exported 'get_phys_to_machine' and there are
> third-party drivers that depend on this other symbol. As such
> lets make this balanced and also export this symbol.
I tend to disagree: Allowing external modules read access to some
internal state is quite different from also allowing them to alter it.
Jan
> Reported-by: Yuval Shaia <yuval.shaia@oracle.com>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> ---
> arch/x86/xen/p2m.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
> index 0d4ec35..cdb96bc 100644
> --- a/arch/x86/xen/p2m.c
> +++ b/arch/x86/xen/p2m.c
> @@ -847,6 +847,7 @@ bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
>
> return true;
> }
> +EXPORT_SYMBOL_GPL(set_phys_to_machine);
>
> #define M2P_OVERRIDE_HASH_SHIFT 10
> #define M2P_OVERRIDE_HASH (1 << M2P_OVERRIDE_HASH_SHIFT)
> --
> 1.8.3.1
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [PATCH] xen/p2m: Export set_phys_to_machine.
2013-09-06 14:06 ` [Xen-devel] " Jan Beulich
@ 2013-09-06 14:39 ` Konrad Rzeszutek Wilk
2013-09-06 14:39 ` [Xen-devel] " Konrad Rzeszutek Wilk
1 sibling, 0 replies; 10+ messages in thread
From: Konrad Rzeszutek Wilk @ 2013-09-06 14:39 UTC (permalink / raw)
To: Jan Beulich; +Cc: xen-devel, boris.ostrovsky, david.vrabel, linux-kernel
On Fri, Sep 06, 2013 at 03:06:02PM +0100, Jan Beulich wrote:
> >>> On 06.09.13 at 16:00, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote:
> > We have already exported 'get_phys_to_machine' and there are
> > third-party drivers that depend on this other symbol. As such
> > lets make this balanced and also export this symbol.
>
> I tend to disagree: Allowing external modules read access to some
> internal state is quite different from also allowing them to alter it.
I am not following you. We have drivers in the kernel that do
this now. For example xen-netfront uses set_phys_to_machine.
Oddly it can be built as a module. I am wondering how it actually
works without this EXPORT symbol.
>
> Jan
>
> > Reported-by: Yuval Shaia <yuval.shaia@oracle.com>
> > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> > ---
> > arch/x86/xen/p2m.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
> > index 0d4ec35..cdb96bc 100644
> > --- a/arch/x86/xen/p2m.c
> > +++ b/arch/x86/xen/p2m.c
> > @@ -847,6 +847,7 @@ bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
> >
> > return true;
> > }
> > +EXPORT_SYMBOL_GPL(set_phys_to_machine);
> >
> > #define M2P_OVERRIDE_HASH_SHIFT 10
> > #define M2P_OVERRIDE_HASH (1 << M2P_OVERRIDE_HASH_SHIFT)
> > --
> > 1.8.3.1
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xen.org
> > http://lists.xen.org/xen-devel
>
>
>
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Xen-devel] [PATCH] xen/p2m: Export set_phys_to_machine.
2013-09-06 14:06 ` [Xen-devel] " Jan Beulich
2013-09-06 14:39 ` Konrad Rzeszutek Wilk
@ 2013-09-06 14:39 ` Konrad Rzeszutek Wilk
2013-09-06 14:49 ` Jan Beulich
2013-09-06 14:49 ` Jan Beulich
1 sibling, 2 replies; 10+ messages in thread
From: Konrad Rzeszutek Wilk @ 2013-09-06 14:39 UTC (permalink / raw)
To: Jan Beulich; +Cc: david.vrabel, xen-devel, boris.ostrovsky, linux-kernel
On Fri, Sep 06, 2013 at 03:06:02PM +0100, Jan Beulich wrote:
> >>> On 06.09.13 at 16:00, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote:
> > We have already exported 'get_phys_to_machine' and there are
> > third-party drivers that depend on this other symbol. As such
> > lets make this balanced and also export this symbol.
>
> I tend to disagree: Allowing external modules read access to some
> internal state is quite different from also allowing them to alter it.
I am not following you. We have drivers in the kernel that do
this now. For example xen-netfront uses set_phys_to_machine.
Oddly it can be built as a module. I am wondering how it actually
works without this EXPORT symbol.
>
> Jan
>
> > Reported-by: Yuval Shaia <yuval.shaia@oracle.com>
> > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> > ---
> > arch/x86/xen/p2m.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
> > index 0d4ec35..cdb96bc 100644
> > --- a/arch/x86/xen/p2m.c
> > +++ b/arch/x86/xen/p2m.c
> > @@ -847,6 +847,7 @@ bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
> >
> > return true;
> > }
> > +EXPORT_SYMBOL_GPL(set_phys_to_machine);
> >
> > #define M2P_OVERRIDE_HASH_SHIFT 10
> > #define M2P_OVERRIDE_HASH (1 << M2P_OVERRIDE_HASH_SHIFT)
> > --
> > 1.8.3.1
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xen.org
> > http://lists.xen.org/xen-devel
>
>
>
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [Xen-devel] [PATCH] xen/p2m: Export set_phys_to_machine.
2013-09-06 14:39 ` [Xen-devel] " Konrad Rzeszutek Wilk
@ 2013-09-06 14:49 ` Jan Beulich
2013-09-06 14:49 ` Jan Beulich
1 sibling, 0 replies; 10+ messages in thread
From: Jan Beulich @ 2013-09-06 14:49 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: david.vrabel, xen-devel, boris.ostrovsky, linux-kernel
>>> On 06.09.13 at 16:39, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote:
> On Fri, Sep 06, 2013 at 03:06:02PM +0100, Jan Beulich wrote:
>> >>> On 06.09.13 at 16:00, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote:
>> > We have already exported 'get_phys_to_machine' and there are
>> > third-party drivers that depend on this other symbol. As such
>> > lets make this balanced and also export this symbol.
>>
>> I tend to disagree: Allowing external modules read access to some
>> internal state is quite different from also allowing them to alter it.
>
> I am not following you. We have drivers in the kernel that do
> this now. For example xen-netfront uses set_phys_to_machine.
In which case exporting it would be fine (and necessary). But you
explicitly said "third-party drivers".
> Oddly it can be built as a module. I am wondering how it actually
> works without this EXPORT symbol.
See the early return in xennet_release_rx_bufs() - the use of
the symbol is in dead code.
Jan
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] xen/p2m: Export set_phys_to_machine.
2013-09-06 14:39 ` [Xen-devel] " Konrad Rzeszutek Wilk
2013-09-06 14:49 ` Jan Beulich
@ 2013-09-06 14:49 ` Jan Beulich
1 sibling, 0 replies; 10+ messages in thread
From: Jan Beulich @ 2013-09-06 14:49 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: xen-devel, boris.ostrovsky, david.vrabel, linux-kernel
>>> On 06.09.13 at 16:39, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote:
> On Fri, Sep 06, 2013 at 03:06:02PM +0100, Jan Beulich wrote:
>> >>> On 06.09.13 at 16:00, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote:
>> > We have already exported 'get_phys_to_machine' and there are
>> > third-party drivers that depend on this other symbol. As such
>> > lets make this balanced and also export this symbol.
>>
>> I tend to disagree: Allowing external modules read access to some
>> internal state is quite different from also allowing them to alter it.
>
> I am not following you. We have drivers in the kernel that do
> this now. For example xen-netfront uses set_phys_to_machine.
In which case exporting it would be fine (and necessary). But you
explicitly said "third-party drivers".
> Oddly it can be built as a module. I am wondering how it actually
> works without this EXPORT symbol.
See the early return in xennet_release_rx_bufs() - the use of
the symbol is in dead code.
Jan
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] xen/p2m: Export set_phys_to_machine.
2013-09-06 14:00 [PATCH] xen/p2m: Export set_phys_to_machine Konrad Rzeszutek Wilk
2013-09-06 14:06 ` [Xen-devel] " Jan Beulich
@ 2013-09-06 14:06 ` Jan Beulich
2013-09-06 16:07 ` David Vrabel
2013-09-06 16:07 ` David Vrabel
3 siblings, 0 replies; 10+ messages in thread
From: Jan Beulich @ 2013-09-06 14:06 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: xen-devel, boris.ostrovsky, david.vrabel, linux-kernel
>>> On 06.09.13 at 16:00, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote:
> We have already exported 'get_phys_to_machine' and there are
> third-party drivers that depend on this other symbol. As such
> lets make this balanced and also export this symbol.
I tend to disagree: Allowing external modules read access to some
internal state is quite different from also allowing them to alter it.
Jan
> Reported-by: Yuval Shaia <yuval.shaia@oracle.com>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> ---
> arch/x86/xen/p2m.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
> index 0d4ec35..cdb96bc 100644
> --- a/arch/x86/xen/p2m.c
> +++ b/arch/x86/xen/p2m.c
> @@ -847,6 +847,7 @@ bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
>
> return true;
> }
> +EXPORT_SYMBOL_GPL(set_phys_to_machine);
>
> #define M2P_OVERRIDE_HASH_SHIFT 10
> #define M2P_OVERRIDE_HASH (1 << M2P_OVERRIDE_HASH_SHIFT)
> --
> 1.8.3.1
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] xen/p2m: Export set_phys_to_machine.
2013-09-06 14:00 [PATCH] xen/p2m: Export set_phys_to_machine Konrad Rzeszutek Wilk
2013-09-06 14:06 ` [Xen-devel] " Jan Beulich
2013-09-06 14:06 ` Jan Beulich
@ 2013-09-06 16:07 ` David Vrabel
2013-09-06 16:07 ` David Vrabel
3 siblings, 0 replies; 10+ messages in thread
From: David Vrabel @ 2013-09-06 16:07 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk; +Cc: xen-devel, boris.ostrovsky, linux-kernel
On 06/09/13 15:00, Konrad Rzeszutek Wilk wrote:
> We have already exported 'get_phys_to_machine' and there are
> third-party drivers that depend on this other symbol. As such
> lets make this balanced and also export this symbol.
I'm not sure this is a good idea. It isn't clear why any out of tree
driver would need to mess with the p2m (or that we would actually trust
a third party driver to do this correctly...).
Also, the general kernel policy is not to export symbols that aren't
used by something in the kernel tree itself.
David
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH] xen/p2m: Export set_phys_to_machine.
2013-09-06 14:00 [PATCH] xen/p2m: Export set_phys_to_machine Konrad Rzeszutek Wilk
` (2 preceding siblings ...)
2013-09-06 16:07 ` David Vrabel
@ 2013-09-06 16:07 ` David Vrabel
3 siblings, 0 replies; 10+ messages in thread
From: David Vrabel @ 2013-09-06 16:07 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk; +Cc: linux-kernel, xen-devel, boris.ostrovsky
On 06/09/13 15:00, Konrad Rzeszutek Wilk wrote:
> We have already exported 'get_phys_to_machine' and there are
> third-party drivers that depend on this other symbol. As such
> lets make this balanced and also export this symbol.
I'm not sure this is a good idea. It isn't clear why any out of tree
driver would need to mess with the p2m (or that we would actually trust
a third party driver to do this correctly...).
Also, the general kernel policy is not to export symbols that aren't
used by something in the kernel tree itself.
David
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH] xen/p2m: Export set_phys_to_machine.
@ 2013-09-06 14:00 Konrad Rzeszutek Wilk
0 siblings, 0 replies; 10+ messages in thread
From: Konrad Rzeszutek Wilk @ 2013-09-06 14:00 UTC (permalink / raw)
To: linux-kernel, xen-devel, boris.ostrovsky, david.vrabel
Cc: Konrad Rzeszutek Wilk
We have already exported 'get_phys_to_machine' and there are
third-party drivers that depend on this other symbol. As such
lets make this balanced and also export this symbol.
Reported-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
arch/x86/xen/p2m.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 0d4ec35..cdb96bc 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -847,6 +847,7 @@ bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
return true;
}
+EXPORT_SYMBOL_GPL(set_phys_to_machine);
#define M2P_OVERRIDE_HASH_SHIFT 10
#define M2P_OVERRIDE_HASH (1 << M2P_OVERRIDE_HASH_SHIFT)
--
1.8.3.1
^ permalink raw reply related [flat|nested] 10+ messages in thread
end of thread, other threads:[~2013-09-06 16:07 UTC | newest]
Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
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2013-09-06 14:00 [PATCH] xen/p2m: Export set_phys_to_machine Konrad Rzeszutek Wilk
2013-09-06 14:06 ` [Xen-devel] " Jan Beulich
2013-09-06 14:39 ` Konrad Rzeszutek Wilk
2013-09-06 14:39 ` [Xen-devel] " Konrad Rzeszutek Wilk
2013-09-06 14:49 ` Jan Beulich
2013-09-06 14:49 ` Jan Beulich
2013-09-06 14:06 ` Jan Beulich
2013-09-06 16:07 ` David Vrabel
2013-09-06 16:07 ` David Vrabel
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2013-09-06 14:00 Konrad Rzeszutek Wilk
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