Commit 937f1ba5 authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt Committed by David S. Miller
Browse files

net: Add init_dummy_netdev() and fix EMAC driver using it 



This adds an init_dummy_netdev() function that gets a network device
structure (allocation and lifetime entirely under caller's control) and
initialize the minimum amount of fields so it can be used to schedule
NAPI polls without registering a full blown interface. This is to be
used by drivers that need to tie several hardware interfaces to a single
NAPI poll scheduler due to HW limitations.

It also updates the ibm_newemac driver to use that, this fixing the
oops on 2.6.29 due to passing NULL as "dev" to netif_napi_add()

Symbol is exported GPL only a I don't think we want binary drivers doing
that sort of acrobatics (if we want them at all).

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: default avatarGeert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2950e952

drivers/net/ibm_newemac/mal.c

+3 −1
Original line number Diff line number Diff line
@@ -613,7 +613,9 @@ static int __devinit mal_probe(struct of_device *ofdev, 
	INIT_LIST_HEAD(&mal->list);

	spin_lock_init(&mal->lock);



	netif_napi_add(NULL, &mal->napi, mal_poll,

	init_dummy_netdev(&mal->dummy_dev);



	netif_napi_add(&mal->dummy_dev, &mal->napi, mal_poll,

		       CONFIG_IBM_NEW_EMAC_POLL_WEIGHT);



	/* Load power-on reset defaults */

drivers/net/ibm_newemac/mal.h

+2 −0
Original line number Diff line number Diff line
@@ -214,6 +214,8 @@ struct mal_instance { 
	int			index;

	spinlock_t		lock;



	struct net_device	dummy_dev;



	unsigned int features;

};

include/linux/netdevice.h

+3 −0
Original line number Diff line number Diff line
@@ -795,6 +795,7 @@ struct net_device 
	       NETREG_UNREGISTERING,	/* called unregister_netdevice */

	       NETREG_UNREGISTERED,	/* completed unregister todo */

	       NETREG_RELEASED,		/* called free_netdev */

	       NETREG_DUMMY,		/* dummy device for NAPI poll */

	} reg_state;



	/* Called from unregister, can be used to call free_netdev */
@@ -1077,6 +1078,8 @@ extern void free_netdev(struct net_device *dev); 
extern void		synchronize_net(void);

extern int 		register_netdevice_notifier(struct notifier_block *nb);

extern int		unregister_netdevice_notifier(struct notifier_block *nb);

extern int		init_dummy_netdev(struct net_device *dev);



extern int call_netdevice_notifiers(unsigned long val, struct net_device *dev);

extern struct net_device	*dev_get_by_index(struct net *net, int ifindex);

extern struct net_device	*__dev_get_by_index(struct net *net, int ifindex);

net/core/dev.c

+39 −0
Original line number Diff line number Diff line
@@ -4430,6 +4430,45 @@ err_uninit: 
	goto out;

}



/**

 *	init_dummy_netdev	- init a dummy network device for NAPI

 *	@dev: device to init

 *

 *	This takes a network device structure and initialize the minimum

 *	amount of fields so it can be used to schedule NAPI polls without

 *	registering a full blown interface. This is to be used by drivers

 *	that need to tie several hardware interfaces to a single NAPI

 *	poll scheduler due to HW limitations.

 */

int init_dummy_netdev(struct net_device *dev)

{

	/* Clear everything. Note we don't initialize spinlocks

	 * are they aren't supposed to be taken by any of the

	 * NAPI code and this dummy netdev is supposed to be

	 * only ever used for NAPI polls

	 */

	memset(dev, 0, sizeof(struct net_device));



	/* make sure we BUG if trying to hit standard

	 * register/unregister code path

	 */

	dev->reg_state = NETREG_DUMMY;



	/* initialize the ref count */

	atomic_set(&dev->refcnt, 1);



	/* NAPI wants this */

	INIT_LIST_HEAD(&dev->napi_list);



	/* a dummy interface is started by default */

	set_bit(__LINK_STATE_PRESENT, &dev->state);

	set_bit(__LINK_STATE_START, &dev->state);



	return 0;

}

EXPORT_SYMBOL_GPL(init_dummy_netdev);





/**

 *	register_netdev	- register a network device

 *	@dev: device to register

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