Re: [RFC PATCH] net/core: support runtime PM on net_device

---
 net/core/dev.c       |   83 +++++++++++++++++++++++++++++++-------------------
 net/core/ethtool.c   |    9 ++++--
 net/core/net-sysfs.c |    4 +++
 3 files changed, 63 insertions(+), 33 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index de2bad7..d46d4ed 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c

@@ -135,6 +135,7 @@
 #include <linux/net_tstamp.h>
 #include <linux/static_key.h>
 #include <net/flow_keys.h>
+#include <linux/pm_runtime.h>
 
 #include "net-sysfs.h"
 

@@ -4966,39 +4967,24 @@ static int dev_ifsioc_locked(struct net *net, struct ifreq *ifr, unsigned int cm
 /*
  *	Perform the SIOCxIFxxx calls, inside rtnl_lock()
  */
-static int dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd)
+static int __dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd)
 {
 	int err;
 	struct net_device *dev = __dev_get_by_name(net, ifr->ifr_name);
 	const struct net_device_ops *ops;
 
-	if (!dev)
-		return -ENODEV;
-
 	ops = dev->netdev_ops;
 
 	switch (cmd) {
 	case SIOCSIFFLAGS:	/* Set interface flags */
 		return dev_change_flags(dev, ifr->ifr_flags);
 
-	case SIOCSIFMETRIC:	/* Set the metric on the interface
-				   (currently unused) */
-		return -EOPNOTSUPP;
-
 	case SIOCSIFMTU:	/* Set the MTU of a device */
 		return dev_set_mtu(dev, ifr->ifr_mtu);
 
 	case SIOCSIFHWADDR:
 		return dev_set_mac_address(dev, &ifr->ifr_hwaddr);
 
-	case SIOCSIFHWBROADCAST:
-		if (ifr->ifr_hwaddr.sa_family != dev->type)
-			return -EINVAL;
-		memcpy(dev->broadcast, ifr->ifr_hwaddr.sa_data,
-		       min(sizeof ifr->ifr_hwaddr.sa_data, (size_t) dev->addr_len));
-		call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
-		return 0;
-
 	case SIOCSIFMAP:
 		if (ops->ndo_set_config) {
 			if (!netif_device_present(dev))

@@ -5022,21 +5008,6 @@ static int dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd)
 		if (!netif_device_present(dev))
 			return -ENODEV;
 		return dev_mc_del_global(dev, ifr->ifr_hwaddr.sa_data);
-
-	case SIOCSIFTXQLEN:
-		if (ifr->ifr_qlen < 0)
-			return -EINVAL;
-		dev->tx_queue_len = ifr->ifr_qlen;
-		return 0;
-
-	case SIOCSIFNAME:
-		ifr->ifr_newname[IFNAMSIZ-1] = '\0';
-		return dev_change_name(dev, ifr->ifr_newname);
-
-	case SIOCSHWTSTAMP:
-		err = net_hwtstamp_validate(ifr);
-		if (err)
-			return err;
 		/* fall through */
 
 	/*

@@ -5072,6 +5043,56 @@ static int dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd)
 	return err;
 }
 
+static int dev_ifsioc(struct net *net, struct ifreq *ifr, unsigned int cmd)
+{
+	int err;
+	struct net_device *dev = __dev_get_by_name(net, ifr->ifr_name);
+	const struct net_device_ops *ops;
+
+	if (!dev)
+		return -ENODEV;
+
+	ops = dev->netdev_ops;
+
+	switch (cmd) {
+	case SIOCSIFMETRIC:	/* Set the metric on the interface
+				   (currently unused) */
+		return -EOPNOTSUPP;
+
+	case SIOCSIFHWBROADCAST:
+		if (ifr->ifr_hwaddr.sa_family != dev->type)
+			return -EINVAL;
+		memcpy(dev->broadcast, ifr->ifr_hwaddr.sa_data,
+		       min(sizeof ifr->ifr_hwaddr.sa_data, (size_t) dev->addr_len));
+		call_netdevice_notifiers(NETDEV_CHANGEADDR, dev);
+		return 0;
+
+	case SIOCSIFTXQLEN:
+		if (ifr->ifr_qlen < 0)
+			return -EINVAL;
+		dev->tx_queue_len = ifr->ifr_qlen;
+		return 0;
+
+	case SIOCSIFNAME:
+		ifr->ifr_newname[IFNAMSIZ-1] = '\0';
+		return dev_change_name(dev, ifr->ifr_newname);
+
+	case SIOCSHWTSTAMP:
+		err = net_hwtstamp_validate(ifr);
+		if (err)
+			return err;
+	}
+
+	if (pm_runtime_get_sync(&dev->dev) < 0)
+		return -ENODEV;
+
+	err = __dev_ifsioc(net, ifr, cmd);
+
+	pm_runtime_put(&dev->dev);
+
+	return err;
+}
+
 /*
  *	This function handles all "interface"-type I/O control requests. The actual
  *	'doing' part of this is dev_ifsioc above.

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 4d64cc2..2dc43da 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c

@@ -25,6 +25,7 @@
 #include <linux/slab.h>
 #include <linux/rtnetlink.h>
 #include <linux/sched.h>
+#include <linux/pm_runtime.h>
 
 /*
  * Some useful ethtool_ops methods that're device independent.

@@ -1464,10 +1465,13 @@ int dev_ethtool(struct net *net, struct ifreq *ifr)
 			return -EPERM;
 	}
 
+	if ((ret = pm_runtime_get_sync(&dev->dev)) < 0)
+		return -ENODEV;
+
 	if (dev->ethtool_ops->begin) {
 		rc = dev->ethtool_ops->begin(dev);
 		if (rc  < 0)
-			return rc;
+			goto exit;
 	}
 	old_features = dev->features;
 

@@ -1648,6 +1652,7 @@ int dev_ethtool(struct net *net, struct ifreq *ifr)
 
 	if (old_features != dev->features)
 		netdev_features_change(dev);
-
+exit:
+	pm_runtime_put(&dev->dev);
 	return rc;
 }

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index bcf02f6..c9adb89 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c

@@ -23,6 +23,7 @@
 #include <linux/export.h>
 #include <linux/jiffies.h>
 #include <net/wext.h>
+#include <linux/pm_runtime.h>
 
 #include "net-sysfs.h"
 

@@ -1415,6 +1416,9 @@ int netdev_register_kobject(struct net_device *net)
 	if (error)
 		return error;
 
+	pm_runtime_no_callbacks(dev);
+	pm_runtime_enable(dev);
+
 	error = register_queue_kobjects(net);
 	if (error) {
 		device_del(dev);