GitHub-Mirror/Star64_linux
2
0
Fork 0
mirror of https://github.com/Fishwaldo/Star64_linux.git synced 2025-06-29 10:01:25 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

net: fix lock_sock_bh/unlock_sock_bh

Browse source 
This new sock lock primitive was introduced to speedup some user context
socket manipulation. But it is unsafe to protect two threads, one using
regular lock_sock/release_sock, one using lock_sock_bh/unlock_sock_bh

This patch changes lock_sock_bh to be careful against 'owned' state.
If owned is found to be set, we must take the slow path.
lock_sock_bh() now returns a boolean to say if the slow path was taken,
and this boolean is used at unlock_sock_bh time to call the appropriate
unlock function.

After this change, BH are either disabled or enabled during the
lock_sock_bh/unlock_sock_bh protected section. This might be misleading,
so we rename these functions to lock_sock_fast()/unlock_sock_fast().

Reported-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Tested-by: Anton Blanchard <anton@samba.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2010-05-26 19:20:18 +00:00 • committed by David S. Miller
parent a56635a56f
commit 8a74ad60a5
5 changed files with 62 additions and 16 deletions
Download patch file Download diff file Expand all files Collapse all files

14
net/ipv4/udp.c
View file

@ -1063,10 +1063,11 @@ static unsigned int first_packet_length(struct sock *sk)
spin_unlock_bh(&rcvq->lock);
if (!skb_queue_empty(&list_kill)) {
lock_sock_bh(sk);
bool slow = lock_sock_fast(sk);
__skb_queue_purge(&list_kill);
sk_mem_reclaim_partial(sk);
unlock_sock_bh(sk);
unlock_sock_fast(sk, slow);
}
return res;
}
@ -1123,6 +1124,7 @@ int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
int peeked;
int err;
int is_udplite = IS_UDPLITE(sk);
bool slow;
/*
* Check any passed addresses
@ -1197,10 +1199,10 @@ out:
return err;
csum_copy_err:
lock_sock_bh(sk);
slow = lock_sock_fast(sk);
if (!skb_kill_datagram(sk, skb, flags))
UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
unlock_sock_bh(sk);
unlock_sock_fast(sk, slow);
if (noblock)
return -EAGAIN;
@ -1625,9 +1627,9 @@ int udp_rcv(struct sk_buff *skb)
void udp_destroy_sock(struct sock *sk)
{
lock_sock_bh(sk);
bool slow = lock_sock_fast(sk);
udp_flush_pending_frames(sk);
unlock_sock_bh(sk);
unlock_sock_fast(sk, slow);
}
/*