From: Christoph Hellwig <hch@infradead.org>
To: Tom Murphy <murphyt7@tcd.ie>
Cc: intel-gfx@lists.freedesktop.org,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Jani Nikula <jani.nikula@linux.intel.com>,
Christoph Hellwig <hch@infradead.org>,
iommu@lists.linux-foundation.org,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH V2 5/5] DO NOT MERGE: iommu: disable list appending in dma-iommu
Date: Tue, 8 Sep 2020 06:55:10 +0100 [thread overview]
Message-ID: <20200908055510.GA19078@infradead.org> (raw)
In-Reply-To: <20200908053619.GA15418@infradead.org>
On Tue, Sep 08, 2020 at 06:36:19AM +0100, Christoph Hellwig wrote:
> On Mon, Sep 07, 2020 at 09:18:50PM +0100, Tom Murphy wrote:
> > Yeah we talked about passing an attr to map_sg to disable merging at
> > the following microconfernce:
> > https://linuxplumbersconf.org/event/7/contributions/846/
> > As far as I can remember everyone seemed happy with that solution. I
> > won't be working on this though as I don't have any more time to
> > dedicate to this. It seems Lu Baolu will take over this.
>
> I'm absolutely again passing a flag. Tha just invites further
> abuse. We need a PCI ID based quirk or something else that can't
> be as easily abused.
Also, I looked at i915 and there are just three dma_map_sg callers.
The two dmabuf related ones are fixed by Marek in his series, leaving
just the one in i915_gem_gtt_prepare_pages, which does indeed look
very fishy. But if that one is so hard to fix it can just be replaced
by an open coded for_each_sg loop that contains manual dma_map_page
calls.
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next prev parent reply other threads:[~2020-09-08 5:55 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-03 20:18 [PATCH V2 0/5] Convert the intel iommu driver to the dma-iommu api Tom Murphy
2020-09-03 20:18 ` [PATCH V2 1/5] iommu: Handle freelists when using deferred flushing in iommu drivers Tom Murphy
2020-09-03 20:18 ` [PATCH V2 2/5] iommu: Add iommu_dma_free_cpu_cached_iovas function Tom Murphy
2020-09-09 0:45 ` Lu Baolu
2020-09-09 7:05 ` Christoph Hellwig
2020-09-12 2:55 ` Lu Baolu
2020-09-03 20:18 ` [PATCH V2 3/5] iommu: allow the dma-iommu api to use bounce buffers Tom Murphy
2020-09-09 1:34 ` Lu Baolu
2020-09-03 20:18 ` [PATCH V2 4/5] iommu/vt-d: Convert intel iommu driver to the iommu ops Tom Murphy
2020-09-09 1:59 ` Lu Baolu
2020-09-03 20:18 ` [PATCH V2 5/5] DO NOT MERGE: iommu: disable list appending in dma-iommu Tom Murphy
2020-09-07 7:00 ` Christoph Hellwig
2020-09-07 20:18 ` Tom Murphy
2020-09-08 5:36 ` Christoph Hellwig
2020-09-08 5:55 ` Christoph Hellwig [this message]
2020-09-08 6:04 ` Lu Baolu
2020-09-08 6:23 ` Christoph Hellwig
2020-09-08 9:07 ` Lu Baolu
2020-09-09 1:43 ` Lu Baolu
2020-09-09 7:06 ` Christoph Hellwig
2020-09-12 3:13 ` Lu Baolu
2020-09-04 10:03 ` [PATCH V2 0/5] Convert the intel iommu driver to the dma-iommu api Joerg Roedel
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