From a6a5349d17f2a5c37079826f1a1474c3d08c6b53 Mon Sep 17 00:00:00 2001 From: Sage Weil Date: Tue, 13 Apr 2010 14:07:07 -0700 Subject: [PATCH] ceph: use separate class for ceph sockets' sk_lock Use a separate class for ceph sockets to prevent lockdep confusion. Because ceph sockets only get passed kernel pointers, there is no dependency from sk_lock -> mmap_sem. If we share the same class as other sockets, lockdep detects a circular dependency from mmap_sem (page fault) -> fs mutex -> sk_lock -> mmap_sem because dependencies are noted from both ceph and user contexts. Using a separate class prevents the sk_lock(ceph) -> mmap_sem dependency and makes lockdep happy. Signed-off-by: Sage Weil --- fs/ceph/messenger.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/ceph/messenger.c b/fs/ceph/messenger.c index f35b4945a9c3..5c75d5d32b27 100644 --- a/fs/ceph/messenger.c +++ b/fs/ceph/messenger.c @@ -29,6 +29,10 @@ static char tag_msg = CEPH_MSGR_TAG_MSG; static char tag_ack = CEPH_MSGR_TAG_ACK; static char tag_keepalive = CEPH_MSGR_TAG_KEEPALIVE; +#ifdef CONFIG_LOCKDEP +static struct lock_class_key socket_class; +#endif + static void queue_con(struct ceph_connection *con); static void con_work(struct work_struct *); @@ -227,6 +231,10 @@ static struct socket *ceph_tcp_connect(struct ceph_connection *con) con->sock = sock; sock->sk->sk_allocation = GFP_NOFS; +#ifdef CONFIG_LOCKDEP + lockdep_set_class(&sock->sk->sk_lock, &socket_class); +#endif + set_sock_callbacks(sock, con); dout("connect %s\n", pr_addr(&con->peer_addr.in_addr)); -- 2.30.2