Re: Linux 3.10-rc6

[David Daney <ddaney@caviumnetworks.com>]

On 06/17/2013 02:38 PM, Andrew Morton wrote:
> On Mon, 17 Jun 2013 14:26:01 -0700 David Daney <ddaney@caviumnetworks.com> wrote:
>
>> On 06/17/2013 02:13 PM, Andrew Morton wrote:
>>> On Mon, 17 Jun 2013 14:08:13 -0700 David Daney <ddaney@caviumnetworks.com> wrote:
>>>
>>>>>
>>>>> I think switch-back-to-a-macro is simplest and safest for now.  Perhaps
>>>>> you can queue a 3.11 patch which restores the C function and fixes up
>>>>> mn10300 and ia64?
>>>>>
>>>>
>>>> If the patch is reverted, I will do that.
>>>
>>> I'm not proposing that we revert f21afc25f9ed4.  Retain its
>>> functionality, but do it via a macro for 3.10.

FYI, these two commits:

c0691143dfe (mn10300: Fix include dependency in irqflags.h et al.)
f75773103d2 ([IA64] Fix include dependency in asm/irqflags.h)

... seem to fix all known breakage related to this issue.  So, the patch 
(to convert back to a macro) may not be necessary.

Sorry to create all this late -rc churn,
David Daney

>>>
>>
>> I misread your patch.  Your patch may be incorrect in that the flags
>> variable you introduce has name space collisions with code using the
>> macro.  Linus found this exact problem with the first version of my
>> patch (which was identical to your patch).
>
> Sigh.  Macros do so suck.
>
> --- a/include/linux/smp.h~include-linux-smph-on_each_cpu-switch-back-to-a-macro
> +++ a/include/linux/smp.h
> @@ -11,7 +11,6 @@
>   #include <linux/list.h>
>   #include <linux/cpumask.h>
>   #include <linux/init.h>
> -#include <linux/irqflags.h>
>
>   extern void cpu_idle(void);
>
> @@ -140,17 +139,14 @@ static inline int up_smp_call_function(s
>   }
>   #define smp_call_function(func, info, wait) \
>   			(up_smp_call_function(func, info))
> -
> -static inline int on_each_cpu(smp_call_func_t func, void *info, int wait)
> -{
> -	unsigned long flags;
> -
> -	local_irq_save(flags);
> -	func(info);
> -	local_irq_restore(flags);
> -	return 0;
> -}
> -
> +#define on_each_cpu(func, info, wait)		\
> +	({					\
> +		unsigned long __flags;		\
> +		local_irq_save(__flags);	\
> +		func(info);			\
> +		local_irq_restore(__flags);	\
> +		0;				\
> +	})
>   /*
>    * Note we still need to test the mask even for UP
>    * because we actually can get an empty mask from
> _
>
>> Once you fix the name of 'flags', I hope you don't run into the same
>> Include Hell on ia64 and mn10300 that I did.
>
> I build-tested ia64.  I don't have an mn10300 cross-compiler set up.
>
>