Date: Mon, 5 Jan 2004 11:28:00 -0800
From: "David S. Miller" <davem@redhat.com>
To: Berkley Shands <berkley@cs.wustl.edu>
Cc: gibbs@scsiguy.com, berkley@cs.wustl.edu, linux-kernel@vger.kernel.org,
       linux-scsi@vger.kernel.org
Subject: Re: [BUG] x86_64 pci_map_sg modifies sg list - fails multiple
 map/unmaps
Message-Id: <20040105112800.7a9f240b.davem@redhat.com>
In-Reply-To: <200401051929.i05JTsM0000014248@mudpuddle.cs.wustl.edu>
References: <200401051929.i05JTsM0000014248@mudpuddle.cs.wustl.edu>
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On Mon, 5 Jan 2004 13:29:54 -0600 (CST)
Berkley Shands <berkley@cs.wustl.edu> wrote:

> 	The pci layer is modifying the sg list, and then placing a zero
> in the length field. pci-gart.c at line 453 (2.6.0 sources) checks this length field
> after a retry, sees that it is zero, and bughalts.

Oh that's a bug.  It is allowed to modify the dma_length field but not
the physical length field.

I imagine x86_64 is doing this so that there need not be a seperate dma_length
field in the scatter_gather struct defined for that platform, and that's too bad it will
definitely need such a seperate field if it wants to implement coalescing.
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