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/client.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) (limited to 'fs/nfs/client.c') diff --git a/fs/nfs/client.c b/fs/nfs/client.c index 1506adf4d4ed..d038dc5916e5 100644 --- a/fs/nfs/client.c +++ b/fs/nfs/client.c @@ -1284,16 +1284,18 @@ static int nfs4_init_callback(struct nfs_client *clp) int error; if (clp->rpc_ops->version == 4) { + struct rpc_xprt *xprt; + + xprt = rcu_dereference_raw(clp->cl_rpcclient->cl_xprt); + if (nfs4_has_session(clp)) { - error = xprt_setup_backchannel( - clp->cl_rpcclient->cl_xprt, + error = xprt_setup_backchannel(xprt, NFS41_BC_MIN_CALLBACKS); if (error < 0) return error; } - error = nfs_callback_up(clp->cl_mvops->minor_version, - clp->cl_rpcclient->cl_xprt); + error = nfs_callback_up(clp->cl_mvops->minor_version, xprt); if (error < 0) { dprintk("%s: failed to start callback. Error = %d\n", __func__, error); @@ -1678,7 +1680,7 @@ struct nfs_server *nfs4_create_referral_server(struct nfs_clone_mount *data, data->addrlen, parent_client->cl_ipaddr, data->authflavor, - parent_server->client->cl_xprt->prot, + rpc_protocol(parent_server->client), parent_server->client->cl_timeout, parent_client->cl_mvops->minor_version, parent_client->net); @@ -1905,12 +1907,14 @@ static int nfs_server_list_show(struct seq_file *m, void *v) if (clp->cl_cons_state != NFS_CS_READY) return 0; + rcu_read_lock(); seq_printf(m, "v%u %s %s %3d %s\n", clp->rpc_ops->version, rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR), rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_PORT), atomic_read(&clp->cl_count), clp->cl_hostname); + rcu_read_unlock(); return 0; } @@ -1993,6 +1997,7 @@ static int nfs_volume_list_show(struct seq_file *m, void *v) (unsigned long long) server->fsid.major, (unsigned long long) server->fsid.minor); + rcu_read_lock(); seq_printf(m, "v%u %s %s %-7s %-17s %s\n", clp->rpc_ops->version, rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR), @@ -2000,6 +2005,7 @@ static int nfs_volume_list_show(struct seq_file *m, void *v) dev, fsid, nfs_server_fscache_state(server)); + rcu_read_unlock(); return 0; } -- cgit v1.2.3-58-ga151