From 2446ab6070861aba2dd9229463ffbc40016a9f33 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Thu, 1 Mar 2012 17:00:56 -0500 Subject: SUNRPC: Use RCU to dereference the rpc_clnt.cl_xprt field A migration event will replace the rpc_xprt used by an rpc_clnt. To ensure this can be done safely, all references to cl_xprt must now use a form of rcu_dereference(). Special care is taken with rpc_peeraddr2str(), which returns a pointer to memory whose lifetime is the same as the rpc_xprt. Signed-off-by: Trond Myklebust [ cel: fix lockdep splats and layering violations ] [ cel: forward ported to 3.4 ] [ cel: remove rpc_max_reqs(), add rpc_net_ns() ] Signed-off-by: Chuck Lever Signed-off-by: Trond Myklebust --- fs/nfs/nfs4proc.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'fs/nfs/nfs4proc.c') diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index 6c8e170e2e6b..671510cc14c0 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -3833,6 +3833,7 @@ int nfs4_proc_setclientid(struct nfs_client *clp, u32 program, *p = htonl((u32)clp->cl_boot_time.tv_nsec); for(;;) { + rcu_read_lock(); setclientid.sc_name_len = scnprintf(setclientid.sc_name, sizeof(setclientid.sc_name), "%s/%s %s %s %u", clp->cl_ipaddr, @@ -3849,6 +3850,7 @@ int nfs4_proc_setclientid(struct nfs_client *clp, u32 program, setclientid.sc_uaddr_len = scnprintf(setclientid.sc_uaddr, sizeof(setclientid.sc_uaddr), "%s.%u.%u", clp->cl_ipaddr, port >> 8, port & 255); + rcu_read_unlock(); status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT); if (status != -NFS4ERR_CLID_INUSE) @@ -5244,11 +5246,16 @@ struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp) void nfs4_destroy_session(struct nfs4_session *session) { + struct rpc_xprt *xprt; + nfs4_proc_destroy_session(session); + + rcu_read_lock(); + xprt = rcu_dereference(session->clp->cl_rpcclient->cl_xprt); + rcu_read_unlock(); dprintk("%s Destroy backchannel for xprt %p\n", - __func__, session->clp->cl_rpcclient->cl_xprt); - xprt_destroy_backchannel(session->clp->cl_rpcclient->cl_xprt, - NFS41_BC_MIN_CALLBACKS); + __func__, xprt); + xprt_destroy_backchannel(xprt, NFS41_BC_MIN_CALLBACKS); nfs4_destroy_slot_tables(session); kfree(session); } -- cgit v1.2.3