2019-10-29 10:41:20

by Saurav Girepunje

[permalink] [raw]
Subject: [PATCH] arch: x86: kvm: mmu.c: use true/false for bool type

Use true/false for bool type "dbg" in mmu.c

Signed-off-by: Saurav Girepunje <[email protected]>
---
arch/x86/kvm/mmu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 24c23c66b226..c0b1df69ce0f 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -68,7 +68,7 @@ enum {
#undef MMU_DEBUG

#ifdef MMU_DEBUG
-static bool dbg = 0;
+static bool dbg = true;
module_param(dbg, bool, 0644);

#define pgprintk(x...) do { if (dbg) printk(x); } while (0)
--
2.20.1


2019-10-29 11:13:05

by Peter Zijlstra

[permalink] [raw]
Subject: Re: [PATCH] arch: x86: kvm: mmu.c: use true/false for bool type

On Tue, Oct 29, 2019 at 03:11:04PM +0530, Saurav Girepunje wrote:
> Use true/false for bool type "dbg" in mmu.c
>
> Signed-off-by: Saurav Girepunje <[email protected]>
> ---
> arch/x86/kvm/mmu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 24c23c66b226..c0b1df69ce0f 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -68,7 +68,7 @@ enum {
> #undef MMU_DEBUG
>
> #ifdef MMU_DEBUG
> -static bool dbg = 0;
> +static bool dbg = true;

You're actually changing the value from false to true. Please, if you
don't know C, don't touch things.

2019-10-29 13:46:34

by Saurav Girepunje

[permalink] [raw]
Subject: Re: [PATCH] arch: x86: kvm: mmu.c: use true/false for bool type

On Tue, Oct 29, 2019 at 11:13:00AM +0100, Peter Zijlstra wrote:
> On Tue, Oct 29, 2019 at 03:11:04PM +0530, Saurav Girepunje wrote:
> > Use true/false for bool type "dbg" in mmu.c
> >
> > Signed-off-by: Saurav Girepunje <[email protected]>
> > ---
> > arch/x86/kvm/mmu.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> > index 24c23c66b226..c0b1df69ce0f 100644
> > --- a/arch/x86/kvm/mmu.c
> > +++ b/arch/x86/kvm/mmu.c
> > @@ -68,7 +68,7 @@ enum {
> > #undef MMU_DEBUG
> >
> > #ifdef MMU_DEBUG
> > -static bool dbg = 0;
> > +static bool dbg = true;
>
> You're actually changing the value from false to true. Please, if you
> don't know C, don't touch things.
Hi,

Thanks for your review.
I accept that I have given wrong value "true" to debug variable. It's my bad my typo mistake.
I will make sure that I will not touch your exclusive C code where we can assign 0/1 to a bool variable,
As you have given me a free advice, I also request you to please don't review such small patches from newbie to discourage them.

Regards,
Saurav

2019-10-29 15:48:06

by Peter Zijlstra

[permalink] [raw]
Subject: Re: [PATCH] arch: x86: kvm: mmu.c: use true/false for bool type

On Tue, Oct 29, 2019 at 07:12:46PM +0530, SAURAV GIREPUNJE wrote:
> On Tue, Oct 29, 2019 at 11:13:00AM +0100, Peter Zijlstra wrote:
> > On Tue, Oct 29, 2019 at 03:11:04PM +0530, Saurav Girepunje wrote:
> > > Use true/false for bool type "dbg" in mmu.c
> > >
> > > Signed-off-by: Saurav Girepunje <[email protected]>
> > > ---
> > > arch/x86/kvm/mmu.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> > > index 24c23c66b226..c0b1df69ce0f 100644
> > > --- a/arch/x86/kvm/mmu.c
> > > +++ b/arch/x86/kvm/mmu.c
> > > @@ -68,7 +68,7 @@ enum {
> > > #undef MMU_DEBUG
> > >
> > > #ifdef MMU_DEBUG
> > > -static bool dbg = 0;
> > > +static bool dbg = true;
> >
> > You're actually changing the value from false to true. Please, if you
> > don't know C, don't touch things.
> Hi,
>
> Thanks for your review.
> I accept that I have given wrong value "true" to debug variable. It's my bad my typo mistake.
> I will make sure that I will not touch your exclusive C code where we can assign 0/1 to a bool variable,
> As you have given me a free advice, I also request you to please don't review such small patches from newbie to discourage them.

I will most certainly review whatever I want, and clearly it is needed.

2019-10-31 07:00:19

by Saurav Girepunje

[permalink] [raw]
Subject: Re: [PATCH] arch: x86: kvm: mmu.c: use true/false for bool type

On Tue, Oct 29, 2019 at 04:44:23PM +0100, Peter Zijlstra wrote:
> On Tue, Oct 29, 2019 at 07:12:46PM +0530, SAURAV GIREPUNJE wrote:
> > On Tue, Oct 29, 2019 at 11:13:00AM +0100, Peter Zijlstra wrote:
> > > On Tue, Oct 29, 2019 at 03:11:04PM +0530, Saurav Girepunje wrote:
> > > > Use true/false for bool type "dbg" in mmu.c
> > > >
> > > > Signed-off-by: Saurav Girepunje <[email protected]>
> > > > ---
> > > > arch/x86/kvm/mmu.c | 2 +-
> > > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > > >
> > > > diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> > > > index 24c23c66b226..c0b1df69ce0f 100644
> > > > --- a/arch/x86/kvm/mmu.c
> > > > +++ b/arch/x86/kvm/mmu.c
> > > > @@ -68,7 +68,7 @@ enum {
> > > > #undef MMU_DEBUG
> > > >
> > > > #ifdef MMU_DEBUG
> > > > -static bool dbg = 0;
> > > > +static bool dbg = true;
> > >
> > > You're actually changing the value from false to true. Please, if you
> > > don't know C, don't touch things.
> > Hi,
> >
> > Thanks for your review.
> > I accept that I have given wrong value "true" to debug variable. It's my bad my typo mistake.
> > I will make sure that I will not touch your exclusive C code where we can assign 0/1 to a bool variable,
> > As you have given me a free advice, I also request you to please don't review such small patches from newbie to discourage them.
>
> I will most certainly review whatever I want, and clearly it is needed.
Do you want me to discard this patch or resend ?

2019-10-31 10:14:05

by Paolo Bonzini

[permalink] [raw]
Subject: Re: [PATCH] arch: x86: kvm: mmu.c: use true/false for bool type

On 31/10/19 07:57, SAURAV GIREPUNJE wrote:
> On Tue, Oct 29, 2019 at 04:44:23PM +0100, Peter Zijlstra wrote:
>> On Tue, Oct 29, 2019 at 07:12:46PM +0530, SAURAV GIREPUNJE wrote:
>>> On Tue, Oct 29, 2019 at 11:13:00AM +0100, Peter Zijlstra wrote:
>>>> On Tue, Oct 29, 2019 at 03:11:04PM +0530, Saurav Girepunje wrote:
>>>>> Use true/false for bool type "dbg" in mmu.c
>>>>>
>>>>> Signed-off-by: Saurav Girepunje <[email protected]>
>>>>> ---
>>>>> arch/x86/kvm/mmu.c | 2 +-
>>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
>>>>> index 24c23c66b226..c0b1df69ce0f 100644
>>>>> --- a/arch/x86/kvm/mmu.c
>>>>> +++ b/arch/x86/kvm/mmu.c
>>>>> @@ -68,7 +68,7 @@ enum {
>>>>> #undef MMU_DEBUG
>>>>>
>>>>> #ifdef MMU_DEBUG
>>>>> -static bool dbg = 0;
>>>>> +static bool dbg = true;
>>>>
>>>> You're actually changing the value from false to true. Please, if you
>>>> don't know C, don't touch things.
>>> Hi,
>>>
>>> Thanks for your review.
>>> I accept that I have given wrong value "true" to debug variable. It's my bad my typo mistake.
>>> I will make sure that I will not touch your exclusive C code where we can assign 0/1 to a bool variable,
>>> As you have given me a free advice, I also request you to please don't review such small patches from newbie to discourage them.
>>
>> I will most certainly review whatever I want, and clearly it is needed.
> Do you want me to discard this patch or resend ?
>

Hi Saurav,

In general I would be happy with replacing 0/1 with false/true, but not
in this particular case. Despite working on KVM for quite some time I
have never found MMU_DEBUG particularly useful, therefore it is going to
go away soon and will be replaced with kernel tracepoints; see for
example commit 335e192a3fa4 ("KVM: x86: add tracepoints around
__direct_map and FNAME(fetch)", 2019-07-05). Therefore, even such a
simple change would be very short lived.

Regarding this patch, I for one am happy that Peter caught the problem
in your patch. His message was perhaps blunt but also honest;
contributing to the kernel requires a very good discipline. I don't
want to discourage you from contributing, but I suggest that you look
into how you developed the patch (from the idea down to sending it) and
figure out how your mistake managed to slip.

Thanks,

Paolo