From mboxrd@z Thu Jan  1 00:00:00 1970
From: Francois Romieu <romieu@fr.zoreil.com>
Subject: Re: [PATCH] r8169: fix invalid register dump
Date: Thu, 15 Aug 2013 00:47:36 +0200
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Cc: netdev@vger.kernel.org, nic_swsd@realtek.com
To: Peter Wu <lekensteyn@gmail.com>
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Peter Wu <lekensteyn@gmail.com> :
[...]
> Checklist:
> 1. super large regs->len: won't be greater than R8169_REGS_SIZE (256)
> 2. regs->len == 0: 0 < 0 is false, nothing is copied
> 3. regs->len is 1, 2 or 3: i = 0, at most 3 bytes will be copied
> 4. regs->len is 4, i < 4 - 4, skip loop, 0 < regs->len, copy 4
> 5. regs->len is 5, i < 5 - 4, copy; 4 < regs->len, copy 1

Spartan implementation:

	u32 __iomem *ioaddr = tp->mmio_addr;
	u32 *dw = p;
	int i;

	...

	for (i = regs->len; i > 0; i -= 4)
		memcpy_fromio(dw++, ioaddr++, min(i, 4));

or (min() verges on gluttony):

	for (i = regs->len; i >= 4; i -= 4)
		memcpy_fromio(dw++, ioaddr++, 4);

	if (i > 0)
		memcpy_fromio(dw, ioaddr, i);

-- 
Ueimor