netdev - [PATCH net-next v2] net: core: change bool members of struct net

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Date:   Mon, 8 Oct 2018 22:17:45 +0200
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     David Miller <davem@...emloft.net>
Cc:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: [PATCH net-next v2] net: core: change bool members of struct
 net_device to bitfield members

bool is good as parameter type or function return type, but if used
for struct members it consumes more memory than needed.
Changing the bool members of struct net_device to bitfield members
allows to decrease the memory footprint of this struct.

Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
v2:
- Change Counter to Flag in description of uc_promisc
---
 include/linux/netdevice.h | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 76603ee13..3d7b8df2e 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1651,10 +1651,6 @@ enum netdev_priv_flags {
  * 	@dev_port:		Used to differentiate devices that share
  * 				the same function
  *	@addr_list_lock:	XXX: need comments on this one
- *	@uc_promisc:		Counter that indicates promiscuous mode
- *				has been enabled due to the need to listen to
- *				additional unicast addresses in a device that
- *				does not implement ndo_set_rx_mode()
  *	@uc:			unicast mac addresses
  *	@mc:			multicast mac addresses
  *	@dev_addrs:		list of device hw addresses
@@ -1714,11 +1710,9 @@ enum netdev_priv_flags {
  *	@link_watch_list:	XXX: need comments on this one
  *
  *	@reg_state:		Register/unregister state machine
- *	@dismantle:		Device is going to be freed
  *	@rtnl_link_state:	This enum represents the phases of creating
  *				a new link
  *
- *	@needs_free_netdev:	Should unregister perform free_netdev?
  *	@priv_destructor:	Called from unregister
  *	@npinfo:		XXX: need comments on this one
  * 	@nd_net:		Network namespace this network device is inside
@@ -1758,6 +1752,15 @@ enum netdev_priv_flags {
  *	@qdisc_tx_busylock: lockdep class annotating Qdisc->busylock spinlock
  *	@qdisc_running_key: lockdep class annotating Qdisc->running seqcount
  *
+ *	@uc_promisc:	Flag that indicates promiscuous mode
+ *			has been enabled due to the need to listen to
+ *			additional unicast addresses in a device that
+ *			does not implement ndo_set_rx_mode()
+ *
+ *	@dismantle:	Device is going to be freed
+ *
+ *	@needs_free_netdev:	Should unregister perform free_netdev?
+ *
  *	@proto_down:	protocol port state information can be sent to the
  *			switch driver and used to set the phys state of the
  *			switch port.
@@ -1879,7 +1882,6 @@ struct net_device {
 	unsigned short          dev_port;
 	spinlock_t		addr_list_lock;
 	unsigned char		name_assign_type;
-	bool			uc_promisc;
 	struct netdev_hw_addr_list	uc;
 	struct netdev_hw_addr_list	mc;
 	struct netdev_hw_addr_list	dev_addrs;
@@ -1986,14 +1988,11 @@ struct net_device {
 	       NETREG_DUMMY,		/* dummy device for NAPI poll */
 	} reg_state:8;
 
-	bool dismantle;
-
 	enum {
 		RTNL_LINK_INITIALIZED,
 		RTNL_LINK_INITIALIZING,
 	} rtnl_link_state:16;
 
-	bool needs_free_netdev;
 	void (*priv_destructor)(struct net_device *dev);
 
 #ifdef CONFIG_NETPOLL
@@ -2046,7 +2045,10 @@ struct net_device {
 	struct sfp_bus		*sfp_bus;
 	struct lock_class_key	*qdisc_tx_busylock;
 	struct lock_class_key	*qdisc_running_key;
-	bool			proto_down;
+	unsigned		uc_promisc:1;
+	unsigned		dismantle:1;
+	unsigned		needs_free_netdev:1;
+	unsigned		proto_down:1;
 	unsigned		wol_enabled:1;
 };
 #define to_net_dev(d) container_of(d, struct net_device, dev)
-- 
2.19.1