On Tue, Nov 13, 2012 at 09:52:09AM +0800, Shan Wei wrote:
> From: Shan Wei <davids...@tencent.com>
>
Please add a proper commit message, explaining why you do this change.
>
> Signed-off-by: Shan Wei <davids...@tencent.com>
> ---
> v4:
> derefrence pointer before reading to avoid compile warning.
> ---
> net/xfrm/xfrm_ipcomp.c | 8 +++-----
> 1 files changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/net/xfrm/xfrm_ipcomp.c b/net/xfrm/xfrm_ipcomp.c
> index e5246fb..2906d52 100644
> --- a/net/xfrm/xfrm_ipcomp.c
> +++ b/net/xfrm/xfrm_ipcomp.c
> @@ -276,18 +276,16 @@ static struct crypto_comp * __percpu
> *ipcomp_alloc_tfms(const char *alg_name)
> struct crypto_comp * __percpu *tfms;
> int cpu;
>
> - /* This can be any valid CPU ID so we don't need locking. */
> - cpu = raw_smp_processor_id();
>
> list_for_each_entry(pos, &ipcomp_tfms_list, list) {
> struct crypto_comp *tfm;
>
> - tfms = pos->tfms;
> - tfm = *per_cpu_ptr(tfms, cpu);
> + /* This can be any valid CPU ID so we don't need locking. */
> + tfm = __this_cpu_read(*pos->tfms);
This should just fetch the tfm pointer, so why exactly __this_cpu_read
is better than __this_cpu_ptr? Please keep in mind that performance is
not the most important thing here. It's much more important that it
works in any case.
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