Re: [PATCH 02/19] dma-iommu: cleanup dma-iommu.h

[Christoph Hellwig]

On Fri, Feb 01, 2019 at 02:47:17PM +0000, Robin Murphy wrote:
> On 14/01/2019 09:41, Christoph Hellwig wrote:
>> No need for a __KERNEL__ guard outside uapi, make sure we pull in the
>> includes unconditionally so users can rely on it, and add a missing
>> comment describing the #else cpp statement.  Last but not least include
>> <linux/errno.h> instead of the asm version, which is frowned upon.
>
> I think the __KERNEL__ and asm/errno.h slip-ups are things I cargo-culted 
> from the arch code as a fresh-faced noob yet to learn the finer details, so 
> ack for those parts. The forward-declarations, though, were a deliberate 
> effort to minimise header dependencies and compilation bloat for includers 
> who absolutely wouldn't care, and specifically to try to avoid setting 
> transitive include expectations since they always seem to end up breaking 
> someone's config somewhere down the line. Admittedly this little backwater 
> is hardly comparable to the likes of the sched.h business, but I'm still 
> somewhat on the fence about that change :/

As far as I can tell almost all users of linux/dma-iommu.h require
CONFIG_DMA_IOMMU to be enabled anyway..