From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [RFC] r8169 DMA failure with iommu=off
Date: Fri, 01 May 2015 21:46:06 -0400 (EDT)
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From: Stephen Hemminger <shemming@brocade.com>
Date: Wed, 29 Apr 2015 16:58:13 -0700

> In either case since this is a receive DMA buffer, it should set
> the appropriate GFP_DMA since that may matter on some platforms.

Plain GFP_DMA is really only appropriate when used for ISA DMA
situations where we must have 24-bit addresses or whatever that
restriction was.

Anyways, it is dma_map_single()'s job to restrict DMA addressing if
necessary.  Otherwise, the transmit path would not work at all.