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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-01-14 21:05:05 -0800
committerDavid S. Miller <davem@davemloft.net>2009-01-14 21:05:05 -0800
commit937f1ba56b4be37d9e2ad77412f95048662058d2 (patch)
tree154e0c5ce11b5afe25816d667c76b19ac679d530
parent2950e952920811be465ec95c6b56f03dc66a05c0 (diff)
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 <benh@kernel.crashing.org> Tested-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/ibm_newemac/mal.c4
-rw-r--r--drivers/net/ibm_newemac/mal.h2
-rw-r--r--include/linux/netdevice.h3
-rw-r--r--net/core/dev.c39
4 files changed, 47 insertions, 1 deletions
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
@@ -4431,6 +4431,45 @@ err_uninit:
}
/**
+ * 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
*