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authorTrond Myklebust <Trond.Myklebust@netapp.com>2012-03-02 02:00:56 +0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2012-03-03 00:36:38 +0400
commit2446ab6070861aba2dd9229463ffbc40016a9f33 (patch)
tree2e366c3236788936b9f4f58c0787ae01c265f4a4 /fs/nfs/nfs4proc.c
parenta3ca5651cb5eebe2e56e510bbf5cd60abc301c9f (diff)
downloadlinux-2446ab6070861aba2dd9229463ffbc40016a9f33.tar.xz
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>
Diffstat (limited to 'fs/nfs/nfs4proc.c')
-rw-r--r--fs/nfs/nfs4proc.c13
1 files changed, 10 insertions, 3 deletions
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);
}