[NET]: Conditionally use bh_lock_sock_nested in sk_receive_skb

Spotted by Ian McDonald, tentatively fixed by Gerrit Renker:

http://www.mail-archive.com/dccp%40vger.kernel.org/msg00599.html

Rewritten not to unroll sk_receive_skb, in the common case, i.e. no lock
debugging, its optimized away.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

6 files changed, 11 insertions, 7 deletions

diff --git a/drivers/net/pppoe.c b/drivers/net/pppoe.c
index 0adee733b761..315d5c3fc66a 100644
--- a/drivers/net/pppoe.c
+++ b/drivers/net/pppoe.c
@@ -393,7 +393,7 @@ static int pppoe_rcv(struct sk_buff *skb,
 
         po = get_item((unsigned long) ph->sid, eth_hdr(skb)->h_source);
         if (po != NULL)
-                return sk_receive_skb(sk_pppox(po), skb);
+                return sk_receive_skb(sk_pppox(po), skb, 0);
 drop:
         kfree_skb(skb);
 out:
diff --git a/include/net/sock.h b/include/net/sock.h
index dc4b92b8abea..26fc0b16bc0c 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -954,7 +954,8 @@ static inline void sock_put(struct sock *sk)
                 sk_free(sk);
 }
 
-extern int sk_receive_skb(struct sock *sk, struct sk_buff *skb);
+extern int sk_receive_skb(struct sock *sk, struct sk_buff *skb,
+                          const int nested);
 
 /* Detach socket from process context.
  * Announce socket dead, detach it from wait queue and inode.
diff --git a/net/core/sock.c b/net/core/sock.c
index 32ff1c551d69..ab8fafadb4ba 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -270,7 +270,7 @@ out:
 }
 EXPORT_SYMBOL(sock_queue_rcv_skb);
 
-int sk_receive_skb(struct sock *sk, struct sk_buff *skb)
+int sk_receive_skb(struct sock *sk, struct sk_buff *skb, const int nested)
 {
         int rc = NET_RX_SUCCESS;
 
@@ -279,7 +279,10 @@ int sk_receive_skb(struct sock *sk, struct sk_buff *skb)
 
         skb->dev = NULL;
 
-        bh_lock_sock(sk);
+        if (nested)
+                bh_lock_sock_nested(sk);
+        else
+                bh_lock_sock(sk);
         if (!sock_owned_by_user(sk)) {
                 /*
                  * trylock + unlock semantics:
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index a20eb71d45db..7114befe7d50 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -899,7 +899,7 @@ static int dccp_v4_rcv(struct sk_buff *skb)
                 goto discard_and_relse;
         nf_reset(skb);
 
-        return sk_receive_skb(sk, skb);
+        return sk_receive_skb(sk, skb, 1);
 
 no_dccp_socket:
         if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index 6eda430ae929..03bb8298250a 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -888,7 +888,7 @@ static int dccp_v6_rcv(struct sk_buff **pskb)
         if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
                 goto discard_and_relse;
 
-        return sk_receive_skb(sk, skb) ? -1 : 0;
+        return sk_receive_skb(sk, skb, 1) ? -1 : 0;
 
 no_dccp_socket:
         if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
diff --git a/net/decnet/dn_nsp_in.c b/net/decnet/dn_nsp_in.c
index 7683d4f754d2..39a6cf7fb566 100644
--- a/net/decnet/dn_nsp_in.c
+++ b/net/decnet/dn_nsp_in.c
@@ -804,7 +804,7 @@ got_it:
                                 goto free_out;
                 }
 
-                return sk_receive_skb(sk, skb);
+                return sk_receive_skb(sk, skb, 0);
         }
 
         return dn_nsp_no_socket(skb, reason);