SUNRPC: Don't allocate a full sockaddr_storage for tracing

BugLink: http://bugs.launchpad.net/bugs/1615620

commit db1bb44c upstream.

We're always tracing IPv4 or IPv6 addresses, so we can save a lot
of space on the ringbuffer by allocating the correct sockaddr size.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Fixes: 83a712e0 "sunrpc: add some tracepoints around ..."
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

include/trace/events/sunrpc.h

@@ -529,20 +529,27 @@ TRACE_EVENT(svc_xprt_do_enqueue,
 
 	TP_STRUCT__entry(
 		__field(struct svc_xprt *, xprt)
-		__field_struct(struct sockaddr_storage, ss)
 		__field(int, pid)
 		__field(unsigned long, flags)
+		__dynamic_array(unsigned char, addr, xprt != NULL ?
+			xprt->xpt_remotelen : 0)
 	),
 
 	TP_fast_assign(
 		__entry->xprt = xprt;
-		xprt ? memcpy(&__entry->ss, &xprt->xpt_remote, sizeof(__entry->ss)) : memset(&__entry->ss, 0, sizeof(__entry->ss));
 		__entry->pid = rqst? rqst->rq_task->pid : 0;
-		__entry->flags = xprt ? xprt->xpt_flags : 0;
+		if (xprt) {
+			memcpy(__get_dynamic_array(addr),
+				&xprt->xpt_remote,
+				xprt->xpt_remotelen);
+			__entry->flags = xprt->xpt_flags;
+		} else
+			__entry->flags = 0;
 	),
 
 	TP_printk("xprt=0x%p addr=%pIScp pid=%d flags=%s", __entry->xprt,
-		(struct sockaddr *)&__entry->ss,
+		__get_dynamic_array_len(addr) != 0 ?
+			(struct sockaddr *)__get_dynamic_array(addr) : NULL,
 		__entry->pid, show_svc_xprt_flags(__entry->flags))
 );
 
@@ -553,18 +560,25 @@ TRACE_EVENT(svc_xprt_dequeue,
 
 	TP_STRUCT__entry(
 		__field(struct svc_xprt *, xprt)
-		__field_struct(struct sockaddr_storage, ss)
 		__field(unsigned long, flags)
+		__dynamic_array(unsigned char, addr, xprt != NULL ?
+			xprt->xpt_remotelen : 0)
 	),
 
 	TP_fast_assign(
-		__entry->xprt = xprt,
-		xprt ? memcpy(&__entry->ss, &xprt->xpt_remote, sizeof(__entry->ss)) : memset(&__entry->ss, 0, sizeof(__entry->ss));
-		__entry->flags = xprt ? xprt->xpt_flags : 0;
+		__entry->xprt = xprt;
+		if (xprt) {
+			memcpy(__get_dynamic_array(addr),
+					&xprt->xpt_remote,
+					xprt->xpt_remotelen);
+			__entry->flags = xprt->xpt_flags;
+		} else
+			__entry->flags = 0;
 	),
 
 	TP_printk("xprt=0x%p addr=%pIScp flags=%s", __entry->xprt,
-		(struct sockaddr *)&__entry->ss,
+		__get_dynamic_array_len(addr) != 0 ?
+			(struct sockaddr *)__get_dynamic_array(addr) : NULL,
 		show_svc_xprt_flags(__entry->flags))
 );
 
@@ -592,19 +606,26 @@ TRACE_EVENT(svc_handle_xprt,
 	TP_STRUCT__entry(
 		__field(struct svc_xprt *, xprt)
 		__field(int, len)
-		__field_struct(struct sockaddr_storage, ss)
 		__field(unsigned long, flags)
+		__dynamic_array(unsigned char, addr, xprt != NULL ?
+			xprt->xpt_remotelen : 0)
 	),
 
 	TP_fast_assign(
 		__entry->xprt = xprt;
-		xprt ? memcpy(&__entry->ss, &xprt->xpt_remote, sizeof(__entry->ss)) : memset(&__entry->ss, 0, sizeof(__entry->ss));
 		__entry->len = len;
-		__entry->flags = xprt ? xprt->xpt_flags : 0;
+		if (xprt) {
+			memcpy(__get_dynamic_array(addr),
+					&xprt->xpt_remote,
+					xprt->xpt_remotelen);
+			__entry->flags = xprt->xpt_flags;
+		} else
+			__entry->flags = 0;
 	),
 
 	TP_printk("xprt=0x%p addr=%pIScp len=%d flags=%s", __entry->xprt,
-		(struct sockaddr *)&__entry->ss,
+		__get_dynamic_array_len(addr) != 0 ?
+			(struct sockaddr *)__get_dynamic_array(addr) : NULL,
 		__entry->len, show_svc_xprt_flags(__entry->flags))
 );
 #endif /* _TRACE_SUNRPC_H */