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 <Trond.Myklebust@netapp.com>
[ 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 <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust
2012-03-01 17:00:56 -05:00
parent a3ca5651cb
commit 2446ab6070
13 changed files with 175 additions and 50 deletions

View File

@@ -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);
}