NFS: include filelayout DS rpc stats in mountstats

Include RPC statistics from all data servers in /proc/self/mountstats for pNFS
filelayout mounts.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/sunrpc/metrics.h b/include/linux/sunrpc/metrics.h
index b6edbc0..1565bbe 100644
--- a/include/linux/sunrpc/metrics.h
+++ b/include/linux/sunrpc/metrics.h
@@ -74,14 +74,16 @@
 #ifdef CONFIG_PROC_FS
 
 struct rpc_iostats *	rpc_alloc_iostats(struct rpc_clnt *);
-void			rpc_count_iostats(struct rpc_task *);
+void			rpc_count_iostats(const struct rpc_task *,
+					  struct rpc_iostats *);
 void			rpc_print_iostats(struct seq_file *, struct rpc_clnt *);
 void			rpc_free_iostats(struct rpc_iostats *);
 
 #else  /*  CONFIG_PROC_FS  */
 
 static inline struct rpc_iostats *rpc_alloc_iostats(struct rpc_clnt *clnt) { return NULL; }
-static inline void rpc_count_iostats(struct rpc_task *task) {}
+static inline void rpc_count_iostats(const struct rpc_task *task,
+				     struct rpc_iostats *stats) {}
 static inline void rpc_print_iostats(struct seq_file *seq, struct rpc_clnt *clnt) {}
 static inline void rpc_free_iostats(struct rpc_iostats *stats) {}
 
diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index 22dfc24..dc0c3cc 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -103,6 +103,7 @@
 struct rpc_call_ops {
 	void (*rpc_call_prepare)(struct rpc_task *, void *);
 	void (*rpc_call_done)(struct rpc_task *, void *);
+	void (*rpc_count_stats)(struct rpc_task *, void *);
 	void (*rpc_release)(void *);
 };