[AX25] ax25_route: make ax25_route_lock BH safe

> =================================
> [ INFO: inconsistent lock state ]
> 2.6.24-dg8ngn-p02 #1
> ---------------------------------
> inconsistent {softirq-on-W} -> {in-softirq-R} usage.
> linuxnet/3046 [HC0[0]:SC1[2]:HE1:SE0] takes:
>  (ax25_route_lock){--.+}, at: [<f8a0cfb7>] ax25_get_route+0x18/0xb7 [ax25]
> {softirq-on-W} state was registered at:
...

This lockdep report shows that ax25_route_lock is taken for reading in
softirq context, and for writing in process context with BHs enabled.
So, to make this safe, all write_locks in ax25_route.c are changed to
_bh versions.

Reported-by: Jann Traschewski <jann@gmx.de>,
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ax25/ax25_route.c b/net/ax25/ax25_route.c
index 38c7f3087ec3d17c1fc8a5ff48be10cb9dedda60..8672cd84fdf905990afb5810a70c505bc94bded8 100644 (file)
--- a/net/ax25/ax25_route.c
+++ b/net/ax25/ax25_route.c
@@ -45,7 +45,7 @@ void ax25_rt_device_down(struct net_device *dev)
 {
        ax25_route *s, *t, *ax25_rt;
 
-       write_lock(&ax25_route_lock);
+       write_lock_bh(&ax25_route_lock);
        ax25_rt = ax25_route_list;
        while (ax25_rt != NULL) {
                s       = ax25_rt;
@@ -68,7 +68,7 @@ void ax25_rt_device_down(struct net_device *dev)
                        }
                }
        }
-       write_unlock(&ax25_route_lock);
+       write_unlock_bh(&ax25_route_lock);
 }
 
 static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
@@ -82,7 +82,7 @@ static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
        if (route->digi_count > AX25_MAX_DIGIS)
                return -EINVAL;
 
-       write_lock(&ax25_route_lock);
+       write_lock_bh(&ax25_route_lock);
 
        ax25_rt = ax25_route_list;
        while (ax25_rt != NULL) {
@@ -92,7 +92,7 @@ static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
                        ax25_rt->digipeat = NULL;
                        if (route->digi_count != 0) {
                                if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
-                                       write_unlock(&ax25_route_lock);
+                                       write_unlock_bh(&ax25_route_lock);
                                        return -ENOMEM;
                                }
                                ax25_rt->digipeat->lastrepeat = -1;
@@ -102,14 +102,14 @@ static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
                                        ax25_rt->digipeat->calls[i]    = route->digi_addr[i];
                                }
                        }
-                       write_unlock(&ax25_route_lock);
+                       write_unlock_bh(&ax25_route_lock);
                        return 0;
                }
                ax25_rt = ax25_rt->next;
        }
 
        if ((ax25_rt = kmalloc(sizeof(ax25_route), GFP_ATOMIC)) == NULL) {
-               write_unlock(&ax25_route_lock);
+               write_unlock_bh(&ax25_route_lock);
                return -ENOMEM;
        }
 
@@ -120,7 +120,7 @@ static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
        ax25_rt->ip_mode      = ' ';
        if (route->digi_count != 0) {
                if ((ax25_rt->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
-                       write_unlock(&ax25_route_lock);
+                       write_unlock_bh(&ax25_route_lock);
                        kfree(ax25_rt);
                        return -ENOMEM;
                }
@@ -133,7 +133,7 @@ static int __must_check ax25_rt_add(struct ax25_routes_struct *route)
        }
        ax25_rt->next   = ax25_route_list;
        ax25_route_list = ax25_rt;
-       write_unlock(&ax25_route_lock);
+       write_unlock_bh(&ax25_route_lock);
 
        return 0;
 }
@@ -152,7 +152,7 @@ static int ax25_rt_del(struct ax25_routes_struct *route)
        if ((ax25_dev = ax25_addr_ax25dev(&route->port_addr)) == NULL)
                return -EINVAL;
 
-       write_lock(&ax25_route_lock);
+       write_lock_bh(&ax25_route_lock);
 
        ax25_rt = ax25_route_list;
        while (ax25_rt != NULL) {
@@ -174,7 +174,7 @@ static int ax25_rt_del(struct ax25_routes_struct *route)
                        }
                }
        }
-       write_unlock(&ax25_route_lock);
+       write_unlock_bh(&ax25_route_lock);
 
        return 0;
 }
@@ -188,7 +188,7 @@ static int ax25_rt_opt(struct ax25_route_opt_struct *rt_option)
        if ((ax25_dev = ax25_addr_ax25dev(&rt_option->port_addr)) == NULL)
                return -EINVAL;
 
-       write_lock(&ax25_route_lock);
+       write_lock_bh(&ax25_route_lock);
 
        ax25_rt = ax25_route_list;
        while (ax25_rt != NULL) {
@@ -216,7 +216,7 @@ static int ax25_rt_opt(struct ax25_route_opt_struct *rt_option)
        }
 
 out:
-       write_unlock(&ax25_route_lock);
+       write_unlock_bh(&ax25_route_lock);
        return err;
 }
 
@@ -492,7 +492,7 @@ void __exit ax25_rt_free(void)
 {
        ax25_route *s, *ax25_rt = ax25_route_list;
 
-       write_lock(&ax25_route_lock);
+       write_lock_bh(&ax25_route_lock);
        while (ax25_rt != NULL) {
                s       = ax25_rt;
                ax25_rt = ax25_rt->next;
@@ -500,5 +500,5 @@ void __exit ax25_rt_free(void)
                kfree(s->digipeat);
                kfree(s);
        }
-       write_unlock(&ax25_route_lock);
+       write_unlock_bh(&ax25_route_lock);
 }