xfrm: state: don't use lock anymore unless acquire operation is needed

push the lock down, after earlier patches we can rely on rcu to
make sure state struct won't go away.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 53e7867f9254..1a15b658a79e 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -799,7 +799,7 @@ xfrm_state_find(const xfrm_address_t *daddr, const xfrm_address_t *saddr,
 
         sequence = read_seqcount_begin(&xfrm_state_hash_generation);
 
-        spin_lock_bh(&net->xfrm.xfrm_state_lock);
+        rcu_read_lock();
         h = xfrm_dst_hash(net, daddr, saddr, tmpl->reqid, encap_family);
         hlist_for_each_entry_rcu(x, net->xfrm.state_bydst + h, bydst) {
                 if (x->props.family == encap_family &&
@@ -870,6 +870,7 @@ found:
                 }
 
                 if (km_query(x, tmpl, pol) == 0) {
+                        spin_lock_bh(&net->xfrm.xfrm_state_lock);
                         x->km.state = XFRM_STATE_ACQ;
                         list_add(&x->km.all, &net->xfrm.state_all);
                         hlist_add_head_rcu(&x->bydst, net->xfrm.state_bydst + h);
@@ -883,6 +884,7 @@ found:
                         tasklet_hrtimer_start(&x->mtimer, ktime_set(net->xfrm.sysctl_acq_expires, 0), HRTIMER_MODE_REL);
                         net->xfrm.state_num++;
                         xfrm_hash_grow_check(net, x->bydst.next != NULL);
+                        spin_unlock_bh(&net->xfrm.xfrm_state_lock);
                 } else {
                         x->km.state = XFRM_STATE_DEAD;
                         to_put = x;
@@ -899,7 +901,7 @@ out:
         } else {
                 *err = acquire_in_progress ? -EAGAIN : error;
         }
-        spin_unlock_bh(&net->xfrm.xfrm_state_lock);
+        rcu_read_unlock();
         if (to_put)
                 xfrm_state_put(to_put);