Re: [RFC/PATCH 2/7] iommu-api: Add map_range/unmap_range functions

From: Olav Haugan <ohaugan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
To: Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
Cc: linux-arm-msm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	will.deacon-5wv7dgnIgG8@public.gmane.org,
	iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
	thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org,
	vgandhi-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [RFC/PATCH 2/7] iommu-api: Add map_range/unmap_range functions
Date: Mon, 14 Jul 2014 18:13:40 -0700	[thread overview]
Message-ID: <53C48044.5020007@codeaurora.org> (raw)
In-Reply-To: <20140711102053.GB1958-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>

On 7/11/2014 3:20 AM, Joerg Roedel wrote:
> On Mon, Jun 30, 2014 at 09:51:51AM -0700, Olav Haugan wrote:
>> +int iommu_map_range(struct iommu_domain *domain, unsigned int iova,
>> +		    struct scatterlist *sg, unsigned int len, int prot)
>> +{
>> +	if (unlikely(domain->ops->map_range == NULL))
>> +		return -ENODEV;
>> +
>> +	BUG_ON(iova & (~PAGE_MASK));
>> +
>> +	return domain->ops->map_range(domain, iova, sg, len, prot);
>> +}
>> +EXPORT_SYMBOL_GPL(iommu_map_range);
>> +
>> +int iommu_unmap_range(struct iommu_domain *domain, unsigned int iova,
>> +		      unsigned int len)
>> +{
>> +	if (unlikely(domain->ops->unmap_range == NULL))
>> +		return -ENODEV;
>> +
>> +	BUG_ON(iova & (~PAGE_MASK));
>> +
>> +	return domain->ops->unmap_range(domain, iova, len);
>> +}
>> +EXPORT_SYMBOL_GPL(iommu_unmap_range);
> 
> Before introducing these new API functions there should be a fall-back
> for IOMMU drivers that do (not yet) implement the map_range and
> unmap_range call-backs.
> 
> The last thing we want is this kind of functional partitioning between
> different IOMMU drivers.

Yes, I can definitely add a fallback instead of returning -ENODEV.

Thanks,

Olav

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