From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christian Borntraeger <borntraeger@de.ibm.com>
Subject: Re: [PATCH 1/3] Provide simple noop dma ops
Date: Mon, 2 Nov 2015 17:01:47 +0100
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To: Joerg Roedel <jroedel@suse.de>
Cc: linux-s390 <linux-s390@vger.kernel.org>, KVM <kvm@vger.kernel.org>, Michael Tsirkin <mst@redhat.com>, benh@kernel.crashing.org, Sebastian Ott <sebott@linux.vnet.ibm.com>, virtualization@lists.linux-foundation.org, Martin Schwidefsky <schwidefsky@de.ibm.com>, Andy Lutomirski <luto@kernel.org>, Paolo Bonzini <pbonzini@redhat.com>, dwmw2@infradead.org, Christoph Hellwig <hch@lst.de>
List-Id: virtualization@lists.linuxfoundation.org

Am 02.11.2015 um 16:16 schrieb Joerg Roedel:
> On Fri, Oct 30, 2015 at 02:20:35PM +0100, Christian Borntraeger wrote:
>> +static void *dma_noop_alloc(struct device *dev, size_t size,
>> +			    dma_addr_t *dma_handle, gfp_t gfp,
>> +			    struct dma_attrs *attrs)
>> +{
>> +	void *ret;
>> +
>> +	ret = (void *)__get_free_pages(gfp, get_order(size));
>> +	if (ret) {
>> +		memset(ret, 0, size);
> 
> There is no need to zero out the memory here. If the user wants
> initialized memory it can call dma_zalloc_coherent. Having the memset
> here means to clear the memory twice in the dma_zalloc_coherent path.
> 
> Otherwise it looks good.

Thanks. Will fix.
In addition I will also make the compilation of dma-noop.o dependent 
on HAS_DMA.