* [PATCH] Add init_dummy_netdev() and fix EMAC driver using it
@ 2009-01-14 4:14 Benjamin Herrenschmidt
2009-01-14 10:00 ` Geert Uytterhoeven
0 siblings, 1 reply; 3+ messages in thread
From: Benjamin Herrenschmidt @ 2009-01-14 4:14 UTC (permalink / raw)
To: netdev; +Cc: linuxppc-dev list
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>
---
Index: linux-work/include/linux/netdevice.h
===================================================================
--- linux-work.orig/include/linux/netdevice.h 2009-01-13 16:13:41.000000000 +1100
+++ linux-work/include/linux/netdevice.h 2009-01-14 14:13:24.000000000 +1100
@@ -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_devi
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);
Index: linux-work/net/core/dev.c
===================================================================
--- linux-work.orig/net/core/dev.c 2009-01-13 16:17:52.000000000 +1100
+++ linux-work/net/core/dev.c 2009-01-14 14:24:03.000000000 +1100
@@ -4434,6 +4434,45 @@ 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
*
Index: linux-work/drivers/net/ibm_newemac/mal.c
===================================================================
--- linux-work.orig/drivers/net/ibm_newemac/mal.c 2009-01-14 14:25:10.000000000 +1100
+++ linux-work/drivers/net/ibm_newemac/mal.c 2009-01-14 14:25:30.000000000 +1100
@@ -613,7 +613,9 @@ static int __devinit mal_probe(struct of
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 */
Index: linux-work/drivers/net/ibm_newemac/mal.h
===================================================================
--- linux-work.orig/drivers/net/ibm_newemac/mal.h 2009-01-14 14:24:40.000000000 +1100
+++ linux-work/drivers/net/ibm_newemac/mal.h 2009-01-14 14:24:58.000000000 +1100
@@ -214,6 +214,8 @@ struct mal_instance {
int index;
spinlock_t lock;
+ struct net_device dummy_dev;
+
unsigned int features;
};
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] Add init_dummy_netdev() and fix EMAC driver using it
2009-01-14 4:14 [PATCH] Add init_dummy_netdev() and fix EMAC driver using it Benjamin Herrenschmidt
@ 2009-01-14 10:00 ` Geert Uytterhoeven
2009-01-15 5:05 ` David Miller
0 siblings, 1 reply; 3+ messages in thread
From: Geert Uytterhoeven @ 2009-01-14 10:00 UTC (permalink / raw)
To: Benjamin Herrenschmidt; +Cc: netdev, linuxppc-dev list
On Wed, 14 Jan 2009, Benjamin Herrenschmidt wrote:
> 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>
Thanks, this fixed my Sequoia!
Tested-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
> --- linux-work.orig/include/linux/netdevice.h 2009-01-13 16:13:41.000000000 +1100
> +++ linux-work/include/linux/netdevice.h 2009-01-14 14:13:24.000000000 +1100
> @@ -4434,6 +4434,45 @@ 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
^^^^^^^^^^
initializes
> + * 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
^^^
as
> + * NAPI code and this dummy netdev is supposed to be
> + * only ever used for NAPI polls
> + */
With kind regards,
Geert Uytterhoeven
Software Architect
Sony Techsoft Centre Europe
The Corporate Village · Da Vincilaan 7-D1 · B-1935 Zaventem · Belgium
Phone: +32 (0)2 700 8453
Fax: +32 (0)2 700 8622
E-mail: Geert.Uytterhoeven@sonycom.com
Internet: http://www.sony-europe.com/
A division of Sony Europe (Belgium) N.V.
VAT BE 0413.825.160 · RPR Brussels
Fortis · BIC GEBABEBB · IBAN BE41293037680010
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] Add init_dummy_netdev() and fix EMAC driver using it
2009-01-14 10:00 ` Geert Uytterhoeven
@ 2009-01-15 5:05 ` David Miller
0 siblings, 0 replies; 3+ messages in thread
From: David Miller @ 2009-01-15 5:05 UTC (permalink / raw)
To: Geert.Uytterhoeven; +Cc: linuxppc-dev, netdev
From: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Date: Wed, 14 Jan 2009 11:00:05 +0100 (CET)
> On Wed, 14 Jan 2009, Benjamin Herrenschmidt wrote:
> > 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>
>
> Thanks, this fixed my Sequoia!
>
> Tested-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Applied, thanks everyone.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2009-01-14 4:14 [PATCH] Add init_dummy_netdev() and fix EMAC driver using it Benjamin Herrenschmidt
2009-01-14 10:00 ` Geert Uytterhoeven
2009-01-15 5:05 ` David Miller
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