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From: Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
To: Tom Murphy <tmurphy-nzgTgzXrdUbQT0dZR+AlfA@public.gmane.org>
Cc: linux-samsung-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>,
	dima-nzgTgzXrdUbQT0dZR+AlfA@public.gmane.org,
	Marc Zyngier <marc.zyngier-5wv7dgnIgG8@public.gmane.org>,
	linux-arm-msm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Krzysztof Kozlowski
	<krzk-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	David Brown <david.brown-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
	Kukjin Kim <kgene-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	murphyt7-/Zw1syy4LHg@public.gmane.org,
	Andy Gross <andy.gross-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>,
	Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	Matthias Brugger
	<matthias.bgg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: [PATCH 1/9] iommu/dma-iommu: Add iommu_map_atomic
Date: Sun, 14 Apr 2019 23:30:58 -0700	[thread overview]
Message-ID: <20190415063058.GA1377@infradead.org> (raw)
In-Reply-To: <20190411184741.27540-2-tmurphy-nzgTgzXrdUbQT0dZR+AlfA@public.gmane.org>

On Thu, Apr 11, 2019 at 07:47:30PM +0100, Tom Murphy via iommu wrote:
> The iommu ops .map function (or the iommu_map function which calls it)
> was always supposed to be sleepable (according to Joerg's comment in
> this thread: https://lore.kernel.org/patchwork/patch/977520/ ) and so
> should probably have had a "might_sleep()" since it was written. However
> currently the dma-iommu api can call iommu_map in an atomic context,
> which it shouldn't do. This doesn't cause any problems because any iommu
> driver which uses the dma-iommu api uses gfp_atomic in it's iommu_ops
> .map function. But doing this wastes the memory allocators atomic pools.
> 
> Add a new function iommu_map_atomic, use it in the dma-iommu api and add
> “might_sleep()” to the iommu_map function.
> 
> After this change all drivers which use the dma-iommu api need to
> implement the new iommu ops .map_atomic function. For the moment just
> reuse the driver's iommus ops .map function for .map_atomic.

Instead of duplicating the callchain shouldn't we just pass down a flag
to indicate if the context can sleep or not?  Especially as all the
existing arm drivers already implement the atomic behavior, which is
a majority of struct iommu_ops based iommu drivers.

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  parent reply	other threads:[~2019-04-15  6:30 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-11 18:47 [PATCH 0/9] iommu/amd: Convert the AMD iommu driver to the dma-iommu api Tom Murphy
2019-04-11 18:47 ` [PATCH 1/9] iommu/dma-iommu: Add iommu_map_atomic Tom Murphy
     [not found]   ` <20190411184741.27540-2-tmurphy-nzgTgzXrdUbQT0dZR+AlfA@public.gmane.org>
2019-04-15  6:30     ` Christoph Hellwig [this message]
2019-04-11 18:47 ` [PATCH 2/9] iommu/dma-iommu: Add function to flush any cached not present IOTLB entries Tom Murphy
2019-04-16 14:00   ` Robin Murphy
     [not found]     ` <82ce70dc-b370-3bb0-bce8-2d32db4d6a0d-5wv7dgnIgG8@public.gmane.org>
2019-04-16 16:40       ` Tom Murphy via iommu
2019-04-11 18:47 ` [PATCH 3/9] iommu/dma-iommu: Add iommu_dma_copy_reserved_iova, iommu_dma_apply_resv_region to the dma-iommu api Tom Murphy
     [not found]   ` <20190411184741.27540-4-tmurphy-nzgTgzXrdUbQT0dZR+AlfA@public.gmane.org>
2019-04-15  6:31     ` Christoph Hellwig
2019-04-16 13:22       ` Tom Murphy
2019-04-16 13:37         ` Robin Murphy
2019-04-11 18:47 ` [PATCH 4/9] iommu/dma-iommu: Add iommu_dma_map_page_coherent Tom Murphy
2019-04-15  6:33   ` Christoph Hellwig
2019-04-11 18:47 ` [PATCH 5/9] iommu/amd: Implement .flush_np_cache Tom Murphy
     [not found]   ` <20190411184741.27540-6-tmurphy-nzgTgzXrdUbQT0dZR+AlfA@public.gmane.org>
2019-04-15  6:33     ` Christoph Hellwig
2019-04-15 18:18       ` Tom Murphy
2019-04-11 18:47 ` [PATCH 6/9] iommu/amd: Implement map_atomic Tom Murphy
2019-04-16 14:13   ` Robin Murphy
2019-04-11 18:47 ` [PATCH 7/9] iommu/amd: Use the dma-iommu api Tom Murphy
2019-04-11 18:47 ` [PATCH 8/9] iommu/amd: Clean up unused functions Tom Murphy
     [not found]   ` <20190411184741.27540-9-tmurphy-nzgTgzXrdUbQT0dZR+AlfA@public.gmane.org>
2019-04-15  6:22     ` Christoph Hellwig
2019-04-11 18:47 ` [PATCH 9/9] iommu/amd: Add allocated domain to global list earlier Tom Murphy
     [not found]   ` <20190411184741.27540-10-tmurphy-nzgTgzXrdUbQT0dZR+AlfA@public.gmane.org>
2019-04-15  6:23     ` Christoph Hellwig
2019-04-15 18:06       ` Tom Murphy
     [not found] ` <20190411184741.27540-1-tmurphy-nzgTgzXrdUbQT0dZR+AlfA@public.gmane.org>
2019-04-15  6:18   ` [PATCH 0/9] iommu/amd: Convert the AMD iommu driver to the dma-iommu api Christoph Hellwig

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