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>
diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
index a4c62e9..e3d12b4 100644
--- a/include/linux/sunrpc/clnt.h
+++ b/include/linux/sunrpc/clnt.h
@@ -35,7 +35,7 @@
struct list_head cl_clients; /* Global list of clients */
struct list_head cl_tasks; /* List of tasks */
spinlock_t cl_lock; /* spinlock */
- struct rpc_xprt * cl_xprt; /* transport */
+ struct rpc_xprt __rcu * cl_xprt; /* transport */
struct rpc_procinfo * cl_procinfo; /* procedure info */
u32 cl_prog, /* RPC program number */
cl_vers, /* RPC version number */
@@ -156,6 +156,8 @@
int rpc_restart_call_prepare(struct rpc_task *);
int rpc_restart_call(struct rpc_task *);
void rpc_setbufsize(struct rpc_clnt *, unsigned int, unsigned int);
+int rpc_protocol(struct rpc_clnt *);
+struct net * rpc_net_ns(struct rpc_clnt *);
size_t rpc_max_payload(struct rpc_clnt *);
void rpc_force_rebind(struct rpc_clnt *);
size_t rpc_peeraddr(struct rpc_clnt *, struct sockaddr *, size_t);
diff --git a/include/linux/sunrpc/debug.h b/include/linux/sunrpc/debug.h
index b506936..6cb2517 100644
--- a/include/linux/sunrpc/debug.h
+++ b/include/linux/sunrpc/debug.h
@@ -50,19 +50,32 @@
#endif
#define dprintk(args...) dfprintk(FACILITY, ## args)
+#define dprintk_rcu(args...) dfprintk_rcu(FACILITY, ## args)
#undef ifdebug
#ifdef RPC_DEBUG
# define ifdebug(fac) if (unlikely(rpc_debug & RPCDBG_##fac))
+
# define dfprintk(fac, args...) \
do { \
ifdebug(fac) \
printk(KERN_DEFAULT args); \
} while (0)
+
+# define dfprintk_rcu(fac, args...) \
+ do { \
+ ifdebug(fac) { \
+ rcu_read_lock(); \
+ printk(KERN_DEFAULT args); \
+ rcu_read_unlock(); \
+ } \
+ } while (0)
+
# define RPC_IFDEBUG(x) x
#else
# define ifdebug(fac) if (0)
# define dfprintk(fac, args...) do ; while (0)
+# define dfprintk_rcu(fac, args...) do ; while (0)
# define RPC_IFDEBUG(x)
#endif