Linux IOMMU Development
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From: Jens Axboe <axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
To: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
Cc: linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-block-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-ide-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
	"David S. Miller" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
Subject: Re: [PATCH 2/5] ide: kill ide_toggle_bounce
Date: Thu, 26 Apr 2018 09:11:21 -0600	[thread overview]
Message-ID: <682db9af-33bc-639d-8930-7a66c30bc644@kernel.dk> (raw)
In-Reply-To: <20180426072033.GA14700-jcswGhMUV9g@public.gmane.org>

On 4/26/18 1:20 AM, Christoph Hellwig wrote:
> On Tue, Apr 24, 2018 at 08:02:56PM -0600, Jens Axboe wrote:
>> On 4/24/18 12:16 PM, Christoph Hellwig wrote:
>>> ide_toggle_bounce did select various strange block bounce limits, including
>>> not bouncing at all as soon as an iommu is present in the system.  Given
>>> that the dma_map routines now handle any required bounce buffering except
>>> for ISA DMA, and the ide code already must handle either ISA DMA or highmem
>>> at least for iommu equipped systems we can get rid of the block layer
>>> bounce limit setting entirely.
>>
>> Pretty sure I was the one to add this code, when highmem page IO was
>> enabled about two decades ago...
>>
>> Outside of DMA, the issue was that the PIO code could not handle
>> highmem. That's not the case anymore, so this should be fine.
> 
> Yes, that is the rationale.  Any chance to you could look over the
> other patches as well?  Except for the networking one for which I'd
> really like to see a review from Dave all the users of the interface
> are block related.

You can add my reviewed-by to 1-3, and 5. Looks good to me.

-- 
Jens Axboe

  parent reply	other threads:[~2018-04-26 15:11 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-24 18:16 remove PCI_DMA_BUS_IS_PHYS V2 Christoph Hellwig
     [not found] ` <20180424181625.22410-1-hch-jcswGhMUV9g@public.gmane.org>
2018-04-24 18:16   ` [PATCH 1/5] scsi: reduce use of block bounce buffers Christoph Hellwig
2018-04-24 18:16   ` [PATCH 2/5] ide: kill ide_toggle_bounce Christoph Hellwig
2018-04-25  2:02     ` Jens Axboe
     [not found]       ` <5aaca0d3-417f-57f3-969f-b4c777c3fd48-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>
2018-04-26  7:20         ` Christoph Hellwig
     [not found]           ` <20180426072033.GA14700-jcswGhMUV9g@public.gmane.org>
2018-04-26 15:11             ` Jens Axboe [this message]
2018-04-24 18:16   ` [PATCH 3/5] ide: remove the PCI_DMA_BUS_IS_PHYS check Christoph Hellwig
2018-04-24 18:16   ` [PATCH 4/5] net: remove the PCI_DMA_BUS_IS_PHYS check in illegal_highdma Christoph Hellwig
2018-04-24 18:16   ` [PATCH 5/5] PCI: remove PCI_DMA_BUS_IS_PHYS Christoph Hellwig
2018-04-24 18:23     ` Palmer Dabbelt

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