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From: Christoph Hellwig <hch@infradead.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	murphyt7@tcd.ie, iommu@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Changing the AMD IOMMU API path to work in an atomic context which is necessary for any custom drivers using the IOMMU API while holding a spinlock.
Date: Sun, 26 Aug 2018 23:58:41 -0700	[thread overview]
Message-ID: <20180827065841.GA7053@infradead.org> (raw)
In-Reply-To: <24d3f04a-e6e2-ed8f-e2bd-b38144f33f26@arm.com>

On Fri, Aug 24, 2018 at 04:24:49PM +0100, Robin Murphy wrote:
> Although IIRC the AMD driver is in fact the only one whose map/unmap
> callbacks aren't already spinlock-safe (or at least it was last time I was
> looking). Stuff like iommu-dma is already relying on this in order to
> implement streaming DMA API calls (which may be in atomic context) on top of
> the corresponding IOMMU API operations.

True.  That should be mentioned in the spinlock, though - and once
it is done the calling conventions should be documented.

  reply	other threads:[~2018-08-27  6:58 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-24 14:28 [PATCH] Changing the AMD IOMMU API path to work in an atomic context which is necessary for any custom drivers using the IOMMU API while holding a spinlock murphyt7
2018-08-24 14:53 ` Christoph Hellwig
2018-08-24 15:24   ` Robin Murphy
2018-08-27  6:58     ` Christoph Hellwig [this message]
     [not found]     ` <CALQxJuuWqiygrGMVjZ0j-AxBZOskoNHfdYoHEwW4Zgigqjf7kg@mail.gmail.com>
     [not found]       ` <CALQxJutCDrg5A6Mhqq9Tkyd3siGrdY03LdmfEtV9v5vjYO+ZZQ@mail.gmail.com>
2018-08-27  7:07         ` Christoph Hellwig
2018-09-25  9:09 ` Joerg Roedel

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