[PATCH] net/core: use net_device dev_id to indicate port number

[PATCH] net/core: use net_device dev_id to indicate port number

[Eli Cohen]

Today, there are no means to know which port of a hardware device a netdev
interface uses. struct net_device conatins a field, dev_id, that can be used
for that. This patch adds a new macro, SET_NETDEV_DEV_ID(), to provide a
standard way to set the value of this field.
Also also make use of this feature in the mlx4_en driver to set the port
number; port numbers are zero based.

Signed-off-by: Eli Cohen <eli@mellanox.co.il>
---
 drivers/net/mlx4/en_netdev.c |    1 +
 include/linux/netdevice.h    |    5 +++++
 2 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/drivers/net/mlx4/en_netdev.c b/drivers/net/mlx4/en_netdev.c
index 6c2b15b..612df1e 100644
--- a/drivers/net/mlx4/en_netdev.c
+++ b/drivers/net/mlx4/en_netdev.c
@@ -978,6 +978,7 @@ int mlx4_en_init_netdev(struct mlx4_en_dev *mdev, int port,
 	}
 
 	SET_NETDEV_DEV(dev, &mdev->dev->pdev->dev);
+	SET_NETDEV_DEV_ID(dev, port - 1);
 
 	/*
 	 * Initialize driver private data
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 3857517..8d5f2c7 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1080,6 +1080,11 @@ static inline void *netdev_priv(const struct net_device *dev)
  */
 #define SET_NETDEV_DEVTYPE(net, devtype)	((net)->dev.type = (devtype))
 
+/*
+ * Set the port number of the physical device that this port net device uses
+ */
+#define SET_NETDEV_DEV_ID(net, devid)	((net)->dev_id = (devid))
+
 /**
  *	netif_napi_add - initialize a napi context
  *	@dev:  network device
-- 
1.7.1

Re: [PATCH] net/core: use net_device dev_id to indicate port number

[Stephen Hemminger]

On Wed, 26 May 2010 12:52:00 +0300
Eli Cohen <eli-VPRAkNaXOzVS1MOuV/RT9w@public.gmane.org> wrote:

> Today, there are no means to know which port of a hardware device a netdev
> interface uses. struct net_device conatins a field, dev_id, that can be used
> for that. This patch adds a new macro, SET_NETDEV_DEV_ID(), to provide a
> standard way to set the value of this field.
> Also also make use of this feature in the mlx4_en driver to set the port
> number; port numbers are zero based.

Why is a macro wrapper needed?

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Re: [PATCH] net/core: use net_device dev_id to indicate port number

[Eli Cohen]

On Wed, May 26, 2010 at 08:23:06AM -0700, Stephen Hemminger wrote:
> On Wed, 26 May 2010 12:52:00 +0300
> Eli Cohen <eli@mellanox.co.il> wrote:
> 
> > Today, there are no means to know which port of a hardware device a netdev
> > interface uses. struct net_device conatins a field, dev_id, that can be used
> > for that. This patch adds a new macro, SET_NETDEV_DEV_ID(), to provide a
> > standard way to set the value of this field.
> > Also also make use of this feature in the mlx4_en driver to set the port
> > number; port numbers are zero based.
> 
> Why is a macro wrapper needed?
> 

I guess for the same reason we use SET_NETDEV_DEV - to provide a
consistent interface for setting this value...

Re: [PATCH] net/core: use net_device dev_id to indicate port number

[Stephen Hemminger]

On Wed, 26 May 2010 18:27:30 +0300
Eli Cohen <eli@dev.mellanox.co.il> wrote:

> On Wed, May 26, 2010 at 08:23:06AM -0700, Stephen Hemminger wrote:
> > On Wed, 26 May 2010 12:52:00 +0300
> > Eli Cohen <eli@mellanox.co.il> wrote:
> > 
> > > Today, there are no means to know which port of a hardware device a netdev
> > > interface uses. struct net_device conatins a field, dev_id, that can be used
> > > for that. This patch adds a new macro, SET_NETDEV_DEV_ID(), to provide a
> > > standard way to set the value of this field.
> > > Also also make use of this feature in the mlx4_en driver to set the port
> > > number; port numbers are zero based.
> > 
> > Why is a macro wrapper needed?
> > 
> 
> I guess for the same reason we use SET_NETDEV_DEV - to provide a
> consistent interface for setting this value...

SET_NETDEV_DEV macro exists because at the time 2.5 kernel was being developed
it was important to be able to maintain source compatibility between 2.4 and
2.6 (nee 2.5) drivers. Since 2.4 did not have sysfs, the macro was a mechanism
to allow the same code to run on both kernel versions.

Your situation is different, just use dev_id and update documentation if
you need to.

-- 

Re: [PATCH] net/core: use net_device dev_id to indicate port number

[Eli Cohen]

On Wed, May 26, 2010 at 08:33:18AM -0700, Stephen Hemminger wrote:
> 
> SET_NETDEV_DEV macro exists because at the time 2.5 kernel was being developed
> it was important to be able to maintain source compatibility between 2.4 and
> 2.6 (nee 2.5) drivers. Since 2.4 did not have sysfs, the macro was a mechanism
> to allow the same code to run on both kernel versions.
> 
> Your situation is different, just use dev_id and update documentation if
> you need to.
> 

OK, great. Things get much much simpler :-)
I'll send another patch for mlx4_en only.
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