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From: "Roedel, Joerg" <Joerg.Roedel@amd.com>
To: Neil Horman <nhorman@tuxdriver.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Divy LeRay <divy@chelsio.com>,
	Stanislaw Gruszka <sgruszka@redhat.com>,
	Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH] dma-debug: hash_bucket_find needs to allow for offsets within an entry (v2)
Date: Wed, 10 Aug 2011 15:31:59 +0200	[thread overview]
Message-ID: <20110810133158.GB7598@amd.com> (raw)
In-Reply-To: <20110808191354.GA22117@hmsreliant.think-freely.org>

On Mon, Aug 08, 2011 at 03:13:54PM -0400, Neil Horman wrote:
> dma-debug: hash_bucket_find needs to allow for offsets within an entry (v2)
> 
> Summary:
> Users of the pci_dma_sync_single_* api allow users to sync address ranges within
> the range of a mapped entry (i.e. you can dma map address X to dma_addr_t A and
> then pci_dma_sync_single on dma_addr_t A+1.  The dma-debug library however
> assume dma syncs will always occur using the base address of a mapped region,
> and uses that assumption to find entries in its hash table.  Since thats often
> (but not always the case), the dma debug library can give us false errors about
> missing entries, which are reported as syncing of memory not allocated by the
> driver.  This was noted in the cxgb3 driver as this error:

Hi Neil,

thanks for your patch. Im out-of-office this week and traveling next
week. So it may take a couple of days until I can take an in-depth look
at it. But I get to it as soon as I can :-)

Regards,

	Joerg

-- 
AMD Operating System Research Center

Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach
General Managers: Alberto Bozzo, Andrew Bowd
Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632


  reply	other threads:[~2011-08-10 13:32 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-07-19 17:41 [PATCH] dma-debug: hash_bucket_find needs to allow for offsets within an entry Neil Horman
2011-07-20 10:38 ` Roedel, Joerg
2011-07-20 11:11   ` Neil Horman
2011-07-20 13:29     ` Roedel, Joerg
2011-07-20 14:32       ` Neil Horman
2011-07-20 14:59         ` Roedel, Joerg
2011-07-20 15:12           ` Neil Horman
2011-08-08 19:13 ` [PATCH] dma-debug: hash_bucket_find needs to allow for offsets within an entry (v2) Neil Horman
2011-08-10 13:31   ` Roedel, Joerg [this message]
2011-08-10 14:47     ` Neil Horman
2011-08-22 10:46     ` Neil Horman
2011-08-22 12:44       ` Roedel, Joerg
2011-08-22 13:20         ` Neil Horman
2011-08-22 16:46   ` Roedel, Joerg
2011-08-22 17:23     ` Neil Horman

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