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Date: Thu, 15 Dec 2011 11:12:01 -0600
From: Timur Tabi <timur@freescale.com>
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To: Andy Fleming <afleming@freescale.com>
Subject: Re: [PATCH] phylib: update mdiobus_alloc() to allocate extra private
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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;

This can be replaced with:

	bus = mdiobus_alloc(sizeof(*priv));
	if (bus == NULL)
		return -ENOMEM;

So the benefit is in simplifying memory management.  Now you have only one allocation to manage, instead of two.

fbdev does the same thing, which is where I got the idea from.  See framebuffer_alloc().

-- 
Timur Tabi
Linux kernel developer at Freescale