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| author | Trond Myklebust | 2012-03-01 23:00:56 +0100 |
|---|---|---|
| committer | Trond Myklebust | 2012-03-02 21:36:38 +0100 |
| commit | 2446ab6070861aba2dd9229463ffbc40016a9f33 (patch) | |
| tree | 2e366c3236788936b9f4f58c0787ae01c265f4a4 /fs/nfs/nfs4state.c | |
| parent | NFS: Add debugging messages to NFSv4's CLOSE procedure (diff) | |
| download | kernel-qcow2-linux-2446ab6070861aba2dd9229463ffbc40016a9f33.tar.gz kernel-qcow2-linux-2446ab6070861aba2dd9229463ffbc40016a9f33.tar.xz kernel-qcow2-linux-2446ab6070861aba2dd9229463ffbc40016a9f33.zip | |
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/nfs4state.c')
| -rw-r--r-- | fs/nfs/nfs4state.c | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c index c1111a37dc14..bae959e294cd 100644 --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -1037,19 +1037,28 @@ static void nfs4_clear_state_manager_bit(struct nfs_client *clp) void nfs4_schedule_state_manager(struct nfs_client *clp) { struct task_struct *task; + char buf[INET6_ADDRSTRLEN + sizeof("-manager") + 1]; if (test_and_set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state) != 0) return; __module_get(THIS_MODULE); atomic_inc(&clp->cl_count); - task = kthread_run(nfs4_run_state_manager, clp, "%s-manager", - rpc_peeraddr2str(clp->cl_rpcclient, - RPC_DISPLAY_ADDR)); - if (!IS_ERR(task)) - return; - nfs4_clear_state_manager_bit(clp); - nfs_put_client(clp); - module_put(THIS_MODULE); + + /* The rcu_read_lock() is not strictly necessary, as the state + * manager is the only thread that ever changes the rpc_xprt + * after it's initialized. At this point, we're single threaded. */ + rcu_read_lock(); + snprintf(buf, sizeof(buf), "%s-manager", + rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_ADDR)); + rcu_read_unlock(); + task = kthread_run(nfs4_run_state_manager, clp, buf); + if (IS_ERR(task)) { + printk(KERN_ERR "%s: kthread_run: %ld\n", + __func__, PTR_ERR(task)); + nfs4_clear_state_manager_bit(clp); + nfs_put_client(clp); + module_put(THIS_MODULE); + } } /* |