Re: [PATCH v8 4/8] smp: add func to IPI cpus based on parameter func

[Gilad Ben-Yossef <gilad@benyossef.com>]

On Thu, Feb 9, 2012 at 2:03 AM, Andrew Morton <akpm@linux-foundation.org> wrote:
> On Wed, 08 Feb 2012 10:30:51 +0100
> "Michal Nazarewicz" <mina86@mina86.com> wrote:
>
>> >     } while (0)
>> > +/*
>> > + * Preemption is disabled here to make sure the
>> > + * cond_func is called under the same condtions in UP
>> > + * and SMP.
>> > + */
>> > +#define on_each_cpu_cond(cond_func, func, info, wait, gfp_flags) \
>> > +   do {                                            \
>>
>> How about:
>>
>>               void *__info = (info);
>>
>> as to avoid double execution.
>
> Yup.  How does this look?
>
>
> From: Andrew Morton <akpm@linux-foundation.org>
> Subject: smp-add-func-to-ipi-cpus-based-on-parameter-func-update-fix
>
> - avoid double-evaluation of `info' (per Michal)
> - parenthesise evaluation of `cond_func'
>
> Cc: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
> Cc: Gilad Ben-Yossef <gilad@benyossef.com>
> Cc: Michal Nazarewicz <mina86@mina86.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>
>  include/linux/smp.h |    5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> --- a/include/linux/smp.h~smp-add-func-to-ipi-cpus-based-on-parameter-func-update-fix
> +++ a/include/linux/smp.h
> @@ -168,10 +168,11 @@ static inline int up_smp_call_function(s
>  */
>  #define on_each_cpu_cond(cond_func, func, info, wait, gfp_flags)\
>        do {                                                    \
> +               void *__info = (info);                          \
>                preempt_disable();                              \
> -               if (cond_func(0, info)) {                       \
> +               if ((cond_func)(0, __info)) {                   \
>                        local_irq_disable();                    \
> -                       (func)(info);                           \
> +                       (func)(__info);                         \
>                        local_irq_enable();                     \
>                }                                               \
>                preempt_enable();                               \
> _
>

Right, I missed that. I hate macros.

As I was requested to correct some comments I'll send a re-spin.
I folded your patch into the original one (and kept the Signed-off-by,
I hope it's OK).

BTW -  I used a macro since I imitated the rest of the code in smp.h
but is there any
reason not to use an inline macro here?

Thanks!
Gilad

-- 
Gilad Ben-Yossef
Chief Coffee Drinker
gilad@benyossef.com
Israel Cell: +972-52-8260388
US Cell: +1-973-8260388
http://benyossef.com

"If you take a class in large-scale robotics, can you end up in a
situation where the homework eats your dog?"
 -- Jean-Baptiste Queru

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