From 937f1ba56b4be37d9e2ad77412f95048662058d2 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Wed, 14 Jan 2009 21:05:05 -0800 Subject: [PATCH] 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: Benjamin Herrenschmidt Tested-by: Geert Uytterhoeven Signed-off-by: David S. Miller --- drivers/net/ibm_newemac/mal.c | 4 +++- drivers/net/ibm_newemac/mal.h | 2 ++ include/linux/netdevice.h | 3 +++ net/core/dev.c | 39 +++++++++++++++++++++++++++++++++++ 4 files changed, 47 insertions(+), 1 deletion(-) diff --git a/drivers/net/ibm_newemac/mal.c b/drivers/net/ibm_newemac/mal.c index ecf9798987f..2a2fc17b287 100644 --- a/drivers/net/ibm_newemac/mal.c +++ b/drivers/net/ibm_newemac/mal.c @@ -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 */ diff --git a/drivers/net/ibm_newemac/mal.h b/drivers/net/ibm_newemac/mal.h index 2f0a8736084..9ededfbf072 100644 --- a/drivers/net/ibm_newemac/mal.h +++ b/drivers/net/ibm_newemac/mal.h @@ -214,6 +214,8 @@ struct mal_instance { int index; spinlock_t lock; + struct net_device dummy_dev; + unsigned int features; }; diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 4647604c7ca..ec54785d34f 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -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); diff --git a/net/core/dev.c b/net/core/dev.c index 60377b6c0a8..8d675975d85 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -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 -- 2.41.1