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From: Robin Murphy <robin.murphy@arm.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Joerg Roedel <joro@8bytes.org>, Will Deacon <will.deacon@arm.com>,
	linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 02/19] dma-iommu: cleanup dma-iommu.h
Date: Wed, 6 Feb 2019 15:08:26 +0000	[thread overview]
Message-ID: <5bf081c2-2b8c-d3d1-c93e-468c8f3cef67@arm.com> (raw)
In-Reply-To: <20190201161305.GI6532@lst.de>

On 01/02/2019 16:13, Christoph Hellwig wrote:
> 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..

Other than dma-iommu.c itself, none of them *require* it - only 
arch/arm64 selects it (the one from MTK_IOMMU is just bogus), and a lot 
of the drivers also build for at least one other architecture (and/or 
arm64 with !IOMMU_API).

Either way, I have no vehement objection to the change, I just don't see 
any positive value in it.

Robin.

  reply	other threads:[~2019-02-06 15:08 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-14  9:41 implement generic dma_map_ops for IOMMUs Christoph Hellwig
2019-01-14  9:41 ` [PATCH 01/19] dma-mapping: add a Kconfig symbol to indicated arch_dma_prep_coherent presence Christoph Hellwig
2019-02-01 14:22   ` Robin Murphy
2019-02-01 16:12     ` Christoph Hellwig
2019-01-14  9:41 ` [PATCH 02/19] dma-iommu: cleanup dma-iommu.h Christoph Hellwig
2019-02-01 14:47   ` Robin Murphy
2019-02-01 16:13     ` Christoph Hellwig
2019-02-06 15:08       ` Robin Murphy [this message]
2019-02-11 15:59         ` Christoph Hellwig
2019-01-14  9:41 ` [PATCH 03/19] dma-iommu: don't use a scatterlist in iommu_dma_alloc Christoph Hellwig
2019-02-01 15:24   ` Robin Murphy
2019-02-01 16:16     ` Christoph Hellwig
2019-02-06 15:28       ` Robin Murphy
2019-02-11 16:00         ` Christoph Hellwig
2019-01-14  9:41 ` [PATCH 04/19] dma-iommu: remove the flush_page callback Christoph Hellwig
2019-02-01 15:28   ` Robin Murphy
2019-01-14  9:41 ` [PATCH 05/19] dma-iommu: move the arm64 wrappers to common code Christoph Hellwig
2019-01-14  9:41 ` [PATCH 06/19] dma-iommu: fix and refactor iommu_dma_mmap Christoph Hellwig
2019-02-05 15:02   ` Robin Murphy
2019-02-11 16:03     ` Christoph Hellwig
2019-01-14  9:41 ` [PATCH 07/19] dma-iommu: fix and refactor iommu_dma_get_sgtable Christoph Hellwig
2019-01-14  9:41 ` [PATCH 08/19] dma-iommu: move __iommu_dma_map Christoph Hellwig
2019-01-14  9:41 ` [PATCH 09/19] dma-iommu: refactor page array remap helpers Christoph Hellwig
2019-01-14  9:41 ` [PATCH 10/19] dma-iommu: factor atomic pool allocations into helpers Christoph Hellwig
2019-01-14  9:41 ` [PATCH 11/19] dma-iommu: factor contiguous " Christoph Hellwig
2019-01-14  9:41 ` [PATCH 12/19] dma-iommu: refactor iommu_dma_free Christoph Hellwig
2019-01-14  9:41 ` [PATCH 13/19] dma-iommu: don't remap contiguous allocations for coherent devices Christoph Hellwig
2019-01-14  9:41 ` [PATCH 14/19] dma-iommu: factor contiguous remapped allocations into helpers Christoph Hellwig
2019-01-14  9:41 ` [PATCH 15/19] dma-iommu: refactor iommu_dma_alloc Christoph Hellwig
2019-01-14  9:41 ` [PATCH 16/19] dma-iommu: don't depend on CONFIG_DMA_DIRECT_REMAP Christoph Hellwig
2019-02-06 11:55   ` Robin Murphy
2019-02-11 16:39     ` Christoph Hellwig
2019-01-14  9:41 ` [PATCH 17/19] dma-iommu: switch copyright boilerplace to SPDX Christoph Hellwig
2019-02-06 11:57   ` Robin Murphy
2019-01-14  9:41 ` [PATCH 18/19] arm64: switch copyright boilerplace to SPDX in dma-mapping.c Christoph Hellwig
2019-02-06 12:19   ` Robin Murphy
2019-01-14  9:41 ` [PATCH 19/19] arm64: trim includes " Christoph Hellwig
2019-01-28  7:53 ` implement generic dma_map_ops for IOMMUs Christoph Hellwig

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