ipv6: get rid of ipip6_prl_lock

As noticed by Julia Lawall, ipip6_tunnel_add_prl() incorrectly calls
kzallloc(..., GFP_KERNEL) while a spinlock is held. She provided
a patch to use GFP_ATOMIC instead.

One possibility would be to convert this spinlock to a mutex, or
preallocate the thing before taking the lock.

After RCU conversion, it appears we dont need this lock, since
caller already holds RTNL

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index e51e650..702c532 100644 (file)
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -249,8 +249,6 @@ failed:
        return NULL;
 }
 
-static DEFINE_SPINLOCK(ipip6_prl_lock);
-
 #define for_each_prl_rcu(start)                        \
        for (prl = rcu_dereference(start);      \
             prl;                               \
@@ -340,7 +338,7 @@ ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
        if (a->addr == htonl(INADDR_ANY))
                return -EINVAL;
 
-       spin_lock(&ipip6_prl_lock);
+       ASSERT_RTNL();
 
        for (p = t->prl; p; p = p->next) {
                if (p->addr == a->addr) {
@@ -370,7 +368,6 @@ ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
        t->prl_count++;
        rcu_assign_pointer(t->prl, p);
 out:
-       spin_unlock(&ipip6_prl_lock);
        return err;
 }
 
@@ -397,7 +394,7 @@ ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
        struct ip_tunnel_prl_entry *x, **p;
        int err = 0;
 
-       spin_lock(&ipip6_prl_lock);
+       ASSERT_RTNL();
 
        if (a && a->addr != htonl(INADDR_ANY)) {
                for (p = &t->prl; *p; p = &(*p)->next) {
@@ -419,7 +416,6 @@ ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
                }
        }
 out:
-       spin_unlock(&ipip6_prl_lock);
        return err;
 }