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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/sunrpc/stats.c
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/sunrpc/stats.c')
-rw-r--r--net/sunrpc/stats.c6
1 files changed, 5 insertions, 1 deletions
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++) {