sunrpc: provide showing transport's state info in the sysfs directory

In preparation of being able to change the xprt's state, add a way
to show currect state of the transport.
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

net/sunrpc/sysfs.c

@@ -111,6 +111,49 @@ static ssize_t rpc_sysfs_xprt_info_show(struct kobject *kobj,
 	return ret + 1;
 }
 
+static ssize_t rpc_sysfs_xprt_state_show(struct kobject *kobj,
+					 struct kobj_attribute *attr,
+					 char *buf)
+{
+	struct rpc_xprt *xprt = rpc_sysfs_xprt_kobj_get_xprt(kobj);
+	ssize_t ret;
+	int locked, connected, connecting, close_wait, bound, binding,
+	    closing, congested, cwnd_wait, write_space;
+
+	if (!xprt)
+		return 0;
+
+	if (!xprt->state) {
+		ret = sprintf(buf, "state=CLOSED\n");
+	} else {
+		locked = test_bit(XPRT_LOCKED, &xprt->state);
+		connected = test_bit(XPRT_CONNECTED, &xprt->state);
+		connecting = test_bit(XPRT_CONNECTING, &xprt->state);
+		close_wait = test_bit(XPRT_CLOSE_WAIT, &xprt->state);
+		bound = test_bit(XPRT_BOUND, &xprt->state);
+		binding = test_bit(XPRT_BINDING, &xprt->state);
+		closing = test_bit(XPRT_CLOSING, &xprt->state);
+		congested = test_bit(XPRT_CONGESTED, &xprt->state);
+		cwnd_wait = test_bit(XPRT_CWND_WAIT, &xprt->state);
+		write_space = test_bit(XPRT_WRITE_SPACE, &xprt->state);
+
+		ret = sprintf(buf, "state=%s %s %s %s %s %s %s %s %s %s\n",
+			      locked ? "LOCKED" : "",
+			      connected ? "CONNECTED" : "",
+			      connecting ? "CONNECTING" : "",
+			      close_wait ? "CLOSE_WAIT" : "",
+			      bound ? "BOUND" : "",
+			      binding ? "BOUNDING" : "",
+			      closing ? "CLOSING" : "",
+			      congested ? "CONGESTED" : "",
+			      cwnd_wait ? "CWND_WAIT" : "",
+			      write_space ? "WRITE_SPACE" : "");
+	}
+
+	xprt_put(xprt);
+	return ret + 1;
+}
+
 static ssize_t rpc_sysfs_xprt_switch_info_show(struct kobject *kobj,
 					       struct kobj_attribute *attr,
 					       char *buf)
@@ -255,9 +298,13 @@ static struct kobj_attribute rpc_sysfs_xprt_dstaddr = __ATTR(dstaddr,
 static struct kobj_attribute rpc_sysfs_xprt_info = __ATTR(xprt_info,
 	0444, rpc_sysfs_xprt_info_show, NULL);
 
+static struct kobj_attribute rpc_sysfs_xprt_change_state = __ATTR(xprt_state,
+	0644, rpc_sysfs_xprt_state_show, NULL);
+
 static struct attribute *rpc_sysfs_xprt_attrs[] = {
 	&rpc_sysfs_xprt_dstaddr.attr,
 	&rpc_sysfs_xprt_info.attr,
+	&rpc_sysfs_xprt_change_state.attr,
 	NULL,
 };