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Date: Wed, 28 Mar 2018 13:57:03 +0200
From: Christoph Hellwig <hch@lst.de>
To: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>,
        Jesper Nilsson <jesper.nilsson@axis.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        linux-kernel@vger.kernel.org
Subject: Re: dma_zalloc_coherent broken with
        57bf5a8963f80fb3828c46c3e3a5b2dd790e09a7
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On Tue, Mar 27, 2018 at 07:04:51PM +0200, Sebastian Ott wrote:
> What was wrong with the old behavior (let the caller decide - the same
> as with memory allocations)?

The old behavior on most (all?) mainstream architectures is that we
always zero the return value.  On x86/i386 this goes back to at least
Linux 2.4.  So common drivers simply expect this to happen.