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From: "David S. Miller" <davem@redhat.com>
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
Date: Mon, 5 Jan 2004 11:28:00 -0800	[thread overview]
Message-ID: <20040105112800.7a9f240b.davem@redhat.com> (raw)
In-Reply-To: <200401051929.i05JTsM0000014248@mudpuddle.cs.wustl.edu>

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.

WARNING: multiple messages have this Message-ID (diff)
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
Date: Mon, 5 Jan 2004 11:28:00 -0800	[thread overview]
Message-ID: <20040105112800.7a9f240b.davem@redhat.com> (raw)
In-Reply-To: <200401051929.i05JTsM0000014248@mudpuddle.cs.wustl.edu>

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.

  reply	other threads:[~2004-01-05 19:33 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-01-05 19:29 [BUG] x86_64 pci_map_sg modifies sg list - fails multiple map/unmaps Berkley Shands
2004-01-05 19:28 ` David S. Miller [this message]
2004-01-05 19:28   ` David S. Miller
  -- strict thread matches above, loose matches on Subject: below --
2004-01-07 16:33 Berkley Shands
2004-01-07 15:35 Berkley Shands
2004-01-07 19:19 ` badari
     [not found] <200401051929.i05JTsM0000014248@mudpuddle.cs.wustl.edu.suse.lists.linux.kernel>
     [not found] ` <20040105112800.7a9f240b.davem@redhat.com.suse.lists.linux.kernel>
2004-01-05 21:02   ` Andi Kleen
2004-01-05 21:01     ` David S. Miller
2004-01-05 21:01       ` David S. Miller
2004-01-05 21:31       ` Andi Kleen
2004-01-05 21:31         ` Andi Kleen
2004-01-06  0:05         ` James Bottomley
2004-01-06  0:05           ` James Bottomley
2004-01-06  3:06           ` Andi Kleen
2004-01-06  3:06             ` Andi Kleen
2004-01-06  3:04             ` David S. Miller
2004-01-06  3:04               ` David S. Miller
2004-01-06  3:14               ` James Bottomley
2004-01-06  3:14                 ` James Bottomley
     [not found] <2938942704.1073325455@aslan.btc.adaptec.com.suse.lists.linux.kernel>
     [not found] ` <m3brpi41q0.fsf@averell.firstfloor.org.suse.lists.linux.kernel>
     [not found]   ` <2997092704.1073333041@aslan.btc.adaptec.com.suse.lists.linux.kernel>
2004-01-05 20:58     ` Andi Kleen
2004-01-05 20:00 Berkley Shands
2004-01-05 17:57 Justin T. Gibbs
2004-01-05 19:22 ` David S. Miller
2004-01-05 19:41 ` Badari Pulavarty
2004-01-05 19:47 ` Andi Kleen
2004-01-05 20:04   ` Justin T. Gibbs
2004-01-05 20:35   ` David S. Miller
2004-01-05 21:10     ` Andi Kleen

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