Re: [PATCH] cpumask: kill loop in cpumask_next_and()

From: Sergey Senozhatsky
Date: Sat Jan 31 2015 - 06:39:06 EST


On (01/16/15 00:22), Sergey Senozhatsky wrote:
>
> cpumask_next_and() does cpumask_next() src1 in a loop and tests if found
> cpu is alsop present in src2. remove that loop and perform cpumask_and()
> of src1 and src2 first and use to find cpumask_next() intead.
>

Hello,

did you have any chance to review this patch? let me know
if you want me to resend (I made some nasty typos in the commit
message).

-ss

> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
> ---
> lib/cpumask.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/lib/cpumask.c b/lib/cpumask.c
> index b6513a9..5ab1553 100644
> --- a/lib/cpumask.c
> +++ b/lib/cpumask.c
> @@ -37,10 +37,11 @@ EXPORT_SYMBOL(__next_cpu_nr);
> int cpumask_next_and(int n, const struct cpumask *src1p,
> const struct cpumask *src2p)
> {
> - while ((n = cpumask_next(n, src1p)) < nr_cpu_ids)
> - if (cpumask_test_cpu(n, src2p))
> - break;
> - return n;
> + struct cpumask tmp;
> +
> + if (cpumask_and(&tmp, src1p, src2p))
> + return cpumask_next(n, &tmp);
> + return nr_cpu_ids;
> }
> EXPORT_SYMBOL(cpumask_next_and);
>
> --
> 2.2.2
>
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