ipv6: Re-arrange code in rt6_probe()

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@fb.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Julian Anastasov <ja@ssi.bg>
Cc: YOSHIFUJI Hideaki <hideaki.yoshifuji@miraclelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index c9b2b9f..0ef5262 100644 (file)
--- 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