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Message-ID: <55B6C7B9.5000000@miraclelinux.com>
Date: Tue, 28 Jul 2015 09:07:21 +0900
From: YOSHIFUJI Hideaki/吉藤英明
<hideaki.yoshifuji@...aclelinux.com>
To: Martin KaFai Lau <kafai@...com>, netdev <netdev@...r.kernel.org>
CC: hideaki.yoshifuji@...aclelinux.com,
Kernel Team <kernel-team@...com>,
Hannes Frederic Sowa <hannes@...essinduktion.org>,
Julian Anastasov <ja@....bg>
Subject: Re: [PATCH net-next v2 1/2] ipv6: Re-arrange code in rt6_probe()
Martin KaFai Lau wrote:
> It is a prep work for the next patch to remove write_lock
> from rt6_probe().
>
> 1. Reduce the number of if(neigh) check. From 4 to 1.
> 2. Bring the write_(un)lock() closer to the operations that the
> lock is protecting.
>
> Hopefully, the above make rt6_probe() more readable.
>
> Signed-off-by: Martin KaFai Lau <kafai@...com>
> Cc: Hannes Frederic Sowa <hannes@...essinduktion.org>
> Cc: Julian Anastasov <ja@....bg>
> Cc: YOSHIFUJI Hideaki <hideaki.yoshifuji@...aclelinux.com>
Acked-by: YOSHIFUJI Hideaki <hideaki.yoshifuji@...aclelinux.com>
--yoshfuji
> ---
> net/ipv6/route.c | 44 ++++++++++++++++++++------------------------
> 1 file changed, 20 insertions(+), 24 deletions(-)
>
> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
> index 7f2214f..6d503db 100644
> --- a/net/ipv6/route.c
> +++ b/net/ipv6/route.c
> @@ -545,6 +545,7 @@ static void rt6_probe_deferred(struct work_struct *w)
>
> static void rt6_probe(struct rt6_info *rt)
> {
> + struct __rt6_probe_work *work;
> struct neighbour *neigh;
> /*
> * Okay, this does not seem to be appropriate
> @@ -559,34 +560,29 @@ static void rt6_probe(struct rt6_info *rt)
> rcu_read_lock_bh();
> neigh = __ipv6_neigh_lookup_noref(rt->dst.dev, &rt->rt6i_gateway);
> if (neigh) {
> + work = NULL;
> write_lock(&neigh->lock);
> - if (neigh->nud_state & NUD_VALID)
> - goto out;
> - }
> -
> - if (!neigh ||
> - time_after(jiffies, neigh->updated + rt->rt6i_idev->cnf.rtr_probe_interval)) {
> - struct __rt6_probe_work *work;
> -
> - work = kmalloc(sizeof(*work), GFP_ATOMIC);
> -
> - if (neigh && work)
> - __neigh_set_probe_once(neigh);
> -
> - if (neigh)
> - write_unlock(&neigh->lock);
> -
> - if (work) {
> - INIT_WORK(&work->work, rt6_probe_deferred);
> - work->target = rt->rt6i_gateway;
> - dev_hold(rt->dst.dev);
> - work->dev = rt->dst.dev;
> - schedule_work(&work->work);
> + if (!(neigh->nud_state & NUD_VALID) &&
> + time_after(jiffies,
> + neigh->updated +
> + rt->rt6i_idev->cnf.rtr_probe_interval)) {
> + work = kmalloc(sizeof(*work), GFP_ATOMIC);
> + if (work)
> + __neigh_set_probe_once(neigh);
> }
> - } else {
> -out:
> write_unlock(&neigh->lock);
> + } else {
> + work = kmalloc(sizeof(*work), GFP_ATOMIC);
> + }
> +
> + if (work) {
> + INIT_WORK(&work->work, rt6_probe_deferred);
> + work->target = rt->rt6i_gateway;
> + dev_hold(rt->dst.dev);
> + work->dev = rt->dst.dev;
> + schedule_work(&work->work);
> }
> +
> rcu_read_unlock_bh();
> }
> #else
>
--
吉藤英明 <hideaki.yoshifuji@...aclelinux.com>
ミラクル・リナックス株式会社 技術本部 サポート部
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