From: Arnd Bergmann <arnd@arndb.de>
To: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: joerg.roedel@amd.com, torvalds@linux-foundation.org,
mingo@elte.hu, lethal@linux-sh.org, just.for.lkml@googlemail.com,
hancockrwd@gmail.com, jens.axboe@oracle.com,
bharrosh@panasas.com, linux-kernel@vger.kernel.org,
linux-scsi@vger.kernel.org
Subject: Re: [PATCH] dma-debug: disable DMA_API_DEBUG for now
Date: Fri, 5 Jun 2009 15:57:56 +0100 [thread overview]
Message-ID: <200906051557.58809.arnd@arndb.de> (raw)
In-Reply-To: <20090605203753K.fujita.tomonori@lab.ntt.co.jp>
On Friday 05 June 2009, FUJITA Tomonori wrote:
> I think that the better fix can handle both cases per device:
>
> - multiple identical dma addresses should not happen (with devices
> behind hardware IOMMU)
> - multiple identical dma addresses could happen
I guess you could also have the case where for a given range
of addresses, you use a linear mapping and the dma addresses
can be identical, while for other physical addresses you would
rely on address translation.
For example on PowerPC/Cell with infiniband adapters, you can get
linear mapping behavior for DMA_ATTR_WEAK_ORDERING but IOMMU
translation without that flag, for the same device and same
physical address.
Arnd <><
next prev parent reply other threads:[~2009-06-05 14:58 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-05 8:33 [PATCH] dma-debug: disable DMA_API_DEBUG for now FUJITA Tomonori
2009-06-05 10:41 ` Joerg Roedel
2009-06-05 10:41 ` Joerg Roedel
2009-06-05 11:38 ` FUJITA Tomonori
2009-06-05 11:38 ` FUJITA Tomonori
2009-06-05 12:44 ` Joerg Roedel
2009-06-05 12:44 ` Joerg Roedel
2009-06-05 14:57 ` Arnd Bergmann [this message]
2009-06-05 15:52 ` Torsten Kaiser
2009-06-05 15:52 ` Torsten Kaiser
2009-06-05 18:20 ` Joerg Roedel
2009-06-05 20:25 ` Torsten Kaiser
2009-06-05 22:11 ` Torsten Kaiser
2009-06-07 8:13 ` Ingo Molnar
2009-06-07 8:22 ` Torsten Kaiser
2009-06-07 10:45 ` FUJITA Tomonori
2009-06-07 10:22 ` [tip:core/iommu] dma-debug: change hash_bucket_find from first-fit to best-fit tip-bot for Joerg Roedel
2009-06-10 20:41 ` [PATCH] dma-debug: disable DMA_API_DEBUG for now Torsten Kaiser
2009-06-11 8:10 ` Joerg Roedel
2009-06-11 8:10 ` Joerg Roedel
2009-06-11 17:38 ` Torsten Kaiser
2009-06-12 7:50 ` Joerg Roedel
2009-06-12 7:50 ` Joerg Roedel
2009-06-12 14:13 ` Joerg Roedel
2009-06-12 14:51 ` Torsten Kaiser
2009-06-13 11:10 ` Joerg Roedel
2009-06-13 14:26 ` Torsten Kaiser
2009-06-13 17:34 ` Joerg Roedel
2009-06-13 17:08 ` Torsten Kaiser
2009-06-15 7:46 ` Joerg Roedel
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