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To: timur@freescale.com
Subject: Re: [PATCH] phylib: update mdiobus_alloc() to allocate extra
 private space
From: David Miller <davem@davemloft.net>
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From: Timur Tabi <timur@freescale.com>
Date: Thu, 15 Dec 2011 11:12:01 -0600

> Andy Fleming wrote:
>> Why? Doesn't this just obfuscate things a little, while providing no immediate benefit?
> 
> I see code like this frequently:
> 
> 	bus = mdiobus_alloc();
> 	if (bus == NULL)
> 		return -ENOMEM;
> 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> 	if (priv == NULL) {
> 		err = -ENOMEM;
> 		goto out_free;
> 	}
> 	bus->priv = priv;

Where "frequently", all of the mdiobus_alloc() call sites in your patch just
get translated to pass "0" for the private size.

Make the change how I suggested, where mdiobus_alloc() retains it's current
function signature and semantics.  Then you can edit drivers as needed rather
than from the beginning.