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authorTrond Myklebust <Trond.Myklebust@netapp.com>2012-03-01 17:00:56 -0500
committerTrond Myklebust <Trond.Myklebust@netapp.com>2012-03-02 15:36:38 -0500
commit2446ab6070861aba2dd9229463ffbc40016a9f33 (patch)
tree2e366c3236788936b9f4f58c0787ae01c265f4a4 /net
parenta3ca5651cb5eebe2e56e510bbf5cd60abc301c9f (diff)
downloadlinux-2446ab6070861aba2dd9229463ffbc40016a9f33.tar.gz
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 'net')
-rw-r--r--net/sunrpc/auth_gss/auth_gss.c4
-rw-r--r--net/sunrpc/clnt.c110
-rw-r--r--net/sunrpc/rpc_pipe.c3
-rw-r--r--net/sunrpc/rpcb_clnt.c15
-rw-r--r--net/sunrpc/stats.c6
5 files changed, 110 insertions, 28 deletions
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index cb2e5645274..d3ad81f8da5 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -799,7 +799,7 @@ err_unlink_pipe_1:
static void gss_pipes_dentries_destroy_net(struct rpc_clnt *clnt,
struct rpc_auth *auth)
{
- struct net *net = clnt->cl_xprt->xprt_net;
+ struct net *net = rpc_net_ns(clnt);
struct super_block *sb;
sb = rpc_get_sb_net(net);
@@ -813,7 +813,7 @@ static void gss_pipes_dentries_destroy_net(struct rpc_clnt *clnt,
static int gss_pipes_dentries_create_net(struct rpc_clnt *clnt,
struct rpc_auth *auth)
{
- struct net *net = clnt->cl_xprt->xprt_net;
+ struct net *net = rpc_net_ns(clnt);
struct super_block *sb;
int err = 0;
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index 25c3da53fb6..7783fc0e726 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -31,6 +31,7 @@
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/un.h>
+#include <linux/rcupdate.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/rpc_pipe_fs.h>
@@ -81,7 +82,8 @@ static int rpc_ping(struct rpc_clnt *clnt);
static void rpc_register_client(struct rpc_clnt *clnt)
{
- struct sunrpc_net *sn = net_generic(clnt->cl_xprt->xprt_net, sunrpc_net_id);
+ struct net *net = rpc_net_ns(clnt);
+ struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
spin_lock(&sn->rpc_client_lock);
list_add(&clnt->cl_clients, &sn->all_clients);
@@ -90,7 +92,8 @@ static void rpc_register_client(struct rpc_clnt *clnt)
static void rpc_unregister_client(struct rpc_clnt *clnt)
{
- struct sunrpc_net *sn = net_generic(clnt->cl_xprt->xprt_net, sunrpc_net_id);
+ struct net *net = rpc_net_ns(clnt);
+ struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
spin_lock(&sn->rpc_client_lock);
list_del(&clnt->cl_clients);
@@ -109,12 +112,13 @@ static void __rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
static void rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
{
+ struct net *net = rpc_net_ns(clnt);
struct super_block *pipefs_sb;
- pipefs_sb = rpc_get_sb_net(clnt->cl_xprt->xprt_net);
+ pipefs_sb = rpc_get_sb_net(net);
if (pipefs_sb) {
__rpc_clnt_remove_pipedir(clnt);
- rpc_put_sb_net(clnt->cl_xprt->xprt_net);
+ rpc_put_sb_net(net);
}
}
@@ -155,17 +159,18 @@ static struct dentry *rpc_setup_pipedir_sb(struct super_block *sb,
static int
rpc_setup_pipedir(struct rpc_clnt *clnt, const char *dir_name)
{
+ struct net *net = rpc_net_ns(clnt);
struct super_block *pipefs_sb;
struct dentry *dentry;
clnt->cl_dentry = NULL;
if (dir_name == NULL)
return 0;
- pipefs_sb = rpc_get_sb_net(clnt->cl_xprt->xprt_net);
+ pipefs_sb = rpc_get_sb_net(net);
if (!pipefs_sb)
return 0;
dentry = rpc_setup_pipedir_sb(pipefs_sb, clnt, dir_name);
- rpc_put_sb_net(clnt->cl_xprt->xprt_net);
+ rpc_put_sb_net(net);
if (IS_ERR(dentry))
return PTR_ERR(dentry);
clnt->cl_dentry = dentry;
@@ -295,7 +300,7 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, stru
if (clnt->cl_server == NULL)
goto out_no_server;
- clnt->cl_xprt = xprt;
+ rcu_assign_pointer(clnt->cl_xprt, xprt);
clnt->cl_procinfo = version->procs;
clnt->cl_maxproc = version->nrprocs;
clnt->cl_protname = program->name;
@@ -310,7 +315,7 @@ static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, stru
INIT_LIST_HEAD(&clnt->cl_tasks);
spin_lock_init(&clnt->cl_lock);
- if (!xprt_bound(clnt->cl_xprt))
+ if (!xprt_bound(xprt))
clnt->cl_autobind = 1;
clnt->cl_timeout = xprt->timeout;
@@ -477,6 +482,7 @@ struct rpc_clnt *
rpc_clone_client(struct rpc_clnt *clnt)
{
struct rpc_clnt *new;
+ struct rpc_xprt *xprt;
int err = -ENOMEM;
new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
@@ -499,18 +505,25 @@ rpc_clone_client(struct rpc_clnt *clnt)
if (new->cl_principal == NULL)
goto out_no_principal;
}
+ rcu_read_lock();
+ xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
+ rcu_read_unlock();
+ if (xprt == NULL)
+ goto out_no_transport;
+ rcu_assign_pointer(new->cl_xprt, xprt);
atomic_set(&new->cl_count, 1);
err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
if (err != 0)
goto out_no_path;
if (new->cl_auth)
atomic_inc(&new->cl_auth->au_count);
- xprt_get(clnt->cl_xprt);
atomic_inc(&clnt->cl_count);
rpc_register_client(new);
rpciod_up();
return new;
out_no_path:
+ xprt_put(xprt);
+out_no_transport:
kfree(new->cl_principal);
out_no_principal:
rpc_free_iostats(new->cl_metrics);
@@ -590,7 +603,7 @@ rpc_free_client(struct rpc_clnt *clnt)
rpc_free_iostats(clnt->cl_metrics);
kfree(clnt->cl_principal);
clnt->cl_metrics = NULL;
- xprt_put(clnt->cl_xprt);
+ xprt_put(rcu_dereference_raw(clnt->cl_xprt));
rpciod_down();
kfree(clnt);
}
@@ -879,13 +892,18 @@ EXPORT_SYMBOL_GPL(rpc_call_start);
size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
{
size_t bytes;
- struct rpc_xprt *xprt = clnt->cl_xprt;
+ struct rpc_xprt *xprt;
+
+ rcu_read_lock();
+ xprt = rcu_dereference(clnt->cl_xprt);
- bytes = sizeof(xprt->addr);
+ bytes = xprt->addrlen;
if (bytes > bufsize)
bytes = bufsize;
- memcpy(buf, &clnt->cl_xprt->addr, bytes);
- return xprt->addrlen;
+ memcpy(buf, &xprt->addr, bytes);
+ rcu_read_unlock();
+
+ return bytes;
}
EXPORT_SYMBOL_GPL(rpc_peeraddr);
@@ -894,11 +912,16 @@ EXPORT_SYMBOL_GPL(rpc_peeraddr);
* @clnt: RPC client structure
* @format: address format
*
+ * NB: the lifetime of the memory referenced by the returned pointer is
+ * the same as the rpc_xprt itself. As long as the caller uses this
+ * pointer, it must hold the RCU read lock.
*/
const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
enum rpc_display_format_t format)
{
- struct rpc_xprt *xprt = clnt->cl_xprt;
+ struct rpc_xprt *xprt;
+
+ xprt = rcu_dereference(clnt->cl_xprt);
if (xprt->address_strings[format] != NULL)
return xprt->address_strings[format];
@@ -910,14 +933,51 @@ EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
void
rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
{
- struct rpc_xprt *xprt = clnt->cl_xprt;
+ struct rpc_xprt *xprt;
+
+ rcu_read_lock();
+ xprt = rcu_dereference(clnt->cl_xprt);
if (xprt->ops->set_buffer_size)
xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
+ rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(rpc_setbufsize);
-/*
- * Return size of largest payload RPC client can support, in bytes
+/**
+ * rpc_protocol - Get transport protocol number for an RPC client
+ * @clnt: RPC client to query
+ *
+ */
+int rpc_protocol(struct rpc_clnt *clnt)
+{
+ int protocol;
+
+ rcu_read_lock();
+ protocol = rcu_dereference(clnt->cl_xprt)->prot;
+ rcu_read_unlock();
+ return protocol;
+}
+EXPORT_SYMBOL_GPL(rpc_protocol);
+
+/**
+ * rpc_net_ns - Get the network namespace for this RPC client
+ * @clnt: RPC client to query
+ *
+ */
+struct net *rpc_net_ns(struct rpc_clnt *clnt)
+{
+ struct net *ret;
+
+ rcu_read_lock();
+ ret = rcu_dereference(clnt->cl_xprt)->xprt_net;
+ rcu_read_unlock();
+ return ret;
+}
+EXPORT_SYMBOL_GPL(rpc_net_ns);
+
+/**
+ * rpc_max_payload - Get maximum payload size for a transport, in bytes
+ * @clnt: RPC client to query
*
* For stream transports, this is one RPC record fragment (see RFC
* 1831), as we don't support multi-record requests yet. For datagram
@@ -926,7 +986,12 @@ EXPORT_SYMBOL_GPL(rpc_setbufsize);
*/
size_t rpc_max_payload(struct rpc_clnt *clnt)
{
- return clnt->cl_xprt->max_payload;
+ size_t ret;
+
+ rcu_read_lock();
+ ret = rcu_dereference(clnt->cl_xprt)->max_payload;
+ rcu_read_unlock();
+ return ret;
}
EXPORT_SYMBOL_GPL(rpc_max_payload);
@@ -937,8 +1002,11 @@ EXPORT_SYMBOL_GPL(rpc_max_payload);
*/
void rpc_force_rebind(struct rpc_clnt *clnt)
{
- if (clnt->cl_autobind)
- xprt_clear_bound(clnt->cl_xprt);
+ if (clnt->cl_autobind) {
+ rcu_read_lock();
+ xprt_clear_bound(rcu_dereference(clnt->cl_xprt));
+ rcu_read_unlock();
+ }
}
EXPORT_SYMBOL_GPL(rpc_force_rebind);
diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index ac9ee159073..3d30943ed6d 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -16,6 +16,7 @@
#include <linux/namei.h>
#include <linux/fsnotify.h>
#include <linux/kernel.h>
+#include <linux/rcupdate.h>
#include <asm/ioctls.h>
#include <linux/poll.h>
@@ -402,12 +403,14 @@ rpc_show_info(struct seq_file *m, void *v)
{
struct rpc_clnt *clnt = m->private;
+ rcu_read_lock();
seq_printf(m, "RPC server: %s\n", clnt->cl_server);
seq_printf(m, "service: %s (%d) version %d\n", clnt->cl_protname,
clnt->cl_prog, clnt->cl_vers);
seq_printf(m, "address: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
seq_printf(m, "protocol: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PROTO));
seq_printf(m, "port: %s\n", rpc_peeraddr2str(clnt, RPC_DISPLAY_PORT));
+ rcu_read_unlock();
return 0;
}
diff --git a/net/sunrpc/rpcb_clnt.c b/net/sunrpc/rpcb_clnt.c
index b1f08bd6788..4f8af63798a 100644
--- a/net/sunrpc/rpcb_clnt.c
+++ b/net/sunrpc/rpcb_clnt.c
@@ -620,9 +620,10 @@ static struct rpc_task *rpcb_call_async(struct rpc_clnt *rpcb_clnt, struct rpcbi
static struct rpc_clnt *rpcb_find_transport_owner(struct rpc_clnt *clnt)
{
struct rpc_clnt *parent = clnt->cl_parent;
+ struct rpc_xprt *xprt = rcu_dereference(clnt->cl_xprt);
while (parent != clnt) {
- if (parent->cl_xprt != clnt->cl_xprt)
+ if (rcu_dereference(parent->cl_xprt) != xprt)
break;
if (clnt->cl_autobind)
break;
@@ -653,8 +654,12 @@ void rpcb_getport_async(struct rpc_task *task)
size_t salen;
int status;
- clnt = rpcb_find_transport_owner(task->tk_client);
- xprt = clnt->cl_xprt;
+ rcu_read_lock();
+ do {
+ clnt = rpcb_find_transport_owner(task->tk_client);
+ xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
+ } while (xprt == NULL);
+ rcu_read_unlock();
dprintk("RPC: %5u %s(%s, %u, %u, %d)\n",
task->tk_pid, __func__,
@@ -667,6 +672,7 @@ void rpcb_getport_async(struct rpc_task *task)
if (xprt_test_and_set_binding(xprt)) {
dprintk("RPC: %5u %s: waiting for another binder\n",
task->tk_pid, __func__);
+ xprt_put(xprt);
return;
}
@@ -734,7 +740,7 @@ void rpcb_getport_async(struct rpc_task *task)
switch (bind_version) {
case RPCBVERS_4:
case RPCBVERS_3:
- map->r_netid = rpc_peeraddr2str(clnt, RPC_DISPLAY_NETID);
+ map->r_netid = xprt->address_strings[RPC_DISPLAY_NETID];
map->r_addr = rpc_sockaddr2uaddr(sap, GFP_ATOMIC);
map->r_owner = "";
break;
@@ -763,6 +769,7 @@ bailout_release_client:
bailout_nofree:
rpcb_wake_rpcbind_waiters(xprt, status);
task->tk_status = status;
+ xprt_put(xprt);
}
EXPORT_SYMBOL_GPL(rpcb_getport_async);
diff --git a/net/sunrpc/stats.c b/net/sunrpc/stats.c
index 1eb3304bc10..bc2068ee795 100644
--- a/net/sunrpc/stats.c
+++ b/net/sunrpc/stats.c
@@ -22,6 +22,7 @@
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/metrics.h>
+#include <linux/rcupdate.h>
#include "netns.h"
@@ -179,7 +180,7 @@ static void _print_name(struct seq_file *seq, unsigned int op,
void rpc_print_iostats(struct seq_file *seq, struct rpc_clnt *clnt)
{
struct rpc_iostats *stats = clnt->cl_metrics;
- struct rpc_xprt *xprt = clnt->cl_xprt;
+ struct rpc_xprt *xprt;
unsigned int op, maxproc = clnt->cl_maxproc;
if (!stats)
@@ -189,8 +190,11 @@ void rpc_print_iostats(struct seq_file *seq, struct rpc_clnt *clnt)
seq_printf(seq, "p/v: %u/%u (%s)\n",
clnt->cl_prog, clnt->cl_vers, clnt->cl_protname);
+ rcu_read_lock();
+ xprt = rcu_dereference(clnt->cl_xprt);
if (xprt)
xprt->ops->print_stats(xprt, seq);
+ rcu_read_unlock();
seq_printf(seq, "\tper-op statistics\n");
for (op = 0; op < maxproc; op++) {