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From: Christoph Hellwig <hch@infradead.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	iommu@lists.linux-foundation.org, will@kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2] iommu: Streamline iommu_iova_to_phys()
Date: Fri, 16 Jul 2021 07:19:13 +0100	[thread overview]
Message-ID: <YPEk4bZKOZntylOI@infradead.org> (raw)
In-Reply-To: <d4eb3346-2152-8a7c-619f-b8d5ee222410@arm.com>

On Thu, Jul 15, 2021 at 03:16:08PM +0100, Robin Murphy wrote:
> On 2021-07-15 15:07, Christoph Hellwig wrote:
> > On Thu, Jul 15, 2021 at 02:04:24PM +0100, Robin Murphy wrote:
> > > If people are going to insist on calling iommu_iova_to_phys()
> > > pointlessly and expecting it to work,
> > 
> > Maybe we need to fix that?
> 
> Feel free to try, but we didn't have much luck pushing back on it
> previously, so playing whack-a-mole against netdev now is a game I'm
> personally happy to stay away from ;)

One thing I've done with symbols I want people to not use it to
unexport them.  But what about vfio?

While we're talking about iommu_iova_to_phys: __iommu_dma_unmap_swiotlb
calls it unconditionally, despite only needed ing the physical address.
Can we optimize that somehow by splitting out the bounce buffering case
out?
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iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	iommu@lists.linux-foundation.org, will@kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2] iommu: Streamline iommu_iova_to_phys()
Date: Fri, 16 Jul 2021 07:19:13 +0100	[thread overview]
Message-ID: <YPEk4bZKOZntylOI@infradead.org> (raw)
In-Reply-To: <d4eb3346-2152-8a7c-619f-b8d5ee222410@arm.com>

On Thu, Jul 15, 2021 at 03:16:08PM +0100, Robin Murphy wrote:
> On 2021-07-15 15:07, Christoph Hellwig wrote:
> > On Thu, Jul 15, 2021 at 02:04:24PM +0100, Robin Murphy wrote:
> > > If people are going to insist on calling iommu_iova_to_phys()
> > > pointlessly and expecting it to work,
> > 
> > Maybe we need to fix that?
> 
> Feel free to try, but we didn't have much luck pushing back on it
> previously, so playing whack-a-mole against netdev now is a game I'm
> personally happy to stay away from ;)

One thing I've done with symbols I want people to not use it to
unexport them.  But what about vfio?

While we're talking about iommu_iova_to_phys: __iommu_dma_unmap_swiotlb
calls it unconditionally, despite only needed ing the physical address.
Can we optimize that somehow by splitting out the bounce buffering case
out?

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2021-07-16  6:20 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-15 13:04 [PATCH v2] iommu: Streamline iommu_iova_to_phys() Robin Murphy
2021-07-15 13:04 ` Robin Murphy
2021-07-15 14:07 ` Christoph Hellwig
2021-07-15 14:07   ` Christoph Hellwig
2021-07-15 14:16   ` Robin Murphy
2021-07-15 14:16     ` Robin Murphy
2021-07-16  6:19     ` Christoph Hellwig [this message]
2021-07-16  6:19       ` Christoph Hellwig
2021-07-16 12:01       ` Robin Murphy
2021-07-16 12:01         ` Robin Murphy
2021-07-26 11:38 ` Joerg Roedel
2021-07-26 11:38   ` Joerg Roedel

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