Dave
This mail is a question mail more than patch mail.

In your commit "netdev: netdev_priv() can now be sane again.",

you said netdev_priv() != netdev->priv, because that time,

netdev->priv = ((char *)dev +((sizeof(struct net_device) +(sizeof(struct net_device_subqueue) *

		(queue_count - 1)) + NETDEV_ALIGN_CONST) & ~NETDEV_ALIGN_CONST))

But now, after you do TX multiqueue improvement.

netdev->priv == netdev_priv() again.
That make me think, what the use of netdev->priv?

We have netdev_priv() and use it flexibly. Why don't kill netdev->priv?
---

From be26ade29c6a3d0002492f7aab25258cb78ab597 Mon Sep 17 00:00:00 2001

From: Wang Chen <wangchen@cn.fujitsu.com>

Date: Fri, 1 Aug 2008 16:59:59 +0800

Subject: [PATCH] netdevice: Use netdev_priv()
dev->priv is now point to private data again.
Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com>

---

 net/core/dev.c |    7 ++-----

 1 files changed, 2 insertions(+), 5 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c

index 63d6bcd..9b73624 100644

--- a/net/core/dev.c

+++ b/net/core/dev.c

@@ -4255,11 +4255,8 @@ struct net_device *alloc_netdev_mq(int sizeof_priv, const char *name,

 	dev->num_tx_queues = queue_count;

 	dev->real_num_tx_queues = queue_count;
-	if (sizeof_priv) {

-		dev->priv = ((char *)dev +

-			     ((sizeof(struct net_device) + NETDEV_ALIGN_CONST)

-			      & ~NETDEV_ALIGN_CONST));

-	}

+	if (sizeof_priv)

+		dev->priv = netdev_priv(dev);
 	dev->gso_max_size = GSO_MAX_SIZE;
--

1.5.3.4
--

From: Wang Chen <wangchen@cn.fujitsu.com>
Way too many old drivers still reference netdev->priv directly.
Once we convert all of them to netdev_priv(), yes we can kill

netdev->priv

--

Thanks for the explanation.
Then next question comes.

We *have to* convert the drivers to use netdev_priv(), right?

Because, netdev->priv == netdev_priv() maybe change again in future,

just as before.
--

From: Wang Chen <wangchen@cn.fujitsu.com>
We will work to prevent that.  I should not have allowed it to happen

in the first place. :-)

--

How about add a comment to netdev->priv
void	*priv;	/* pointer to private data, referent me by netdev_priv()*/
--

From: Wang Chen <wangchen@cn.fujitsu.com>
Sure, but I'd much rather apply a patch that converts

all the direct references :-)

--

I just checked some drivers' source.

And, maybe some direct references of net_device->priv are needed.

For example:

init_one() of cxgb2 makes several net_device to share one private data.

For this purpose, direct reference is necessary.
--

From: Wang Chen <wangchen@cn.fujitsu.com>
It should use netdev->ml_priv which is created for this purpose.
Every direct netdev->priv usage is a bug.

--

cxgb3 was fixed in this regard, cxgb2 needs the same treatment ...
cheers,

Divy

--

Thanks Dave and Divy.

I am making the big patch for fixing all direct reference of netdev->priv.
--