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From: Roland Dreier <rdreier@cisco.com>
To: Arjan van de Ven <arjan@infradead.org>
Cc: "Bryan O'Sullivan" <bos@pathscale.com>,
	openib-general@openib.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5 of 13] ipath - use proper address translation routine
Date: Mon, 01 May 2006 12:00:00 -0700	[thread overview]
Message-ID: <aday7xltvtb.fsf@cisco.com> (raw)
In-Reply-To: <1146509646.20760.63.camel@laptopd505.fenrus.org> (Arjan van de Ven's message of "Mon, 01 May 2006 20:54:06 +0200")

    Arjan> do you really NEED the vaddr?  (most of the time linux
    Arjan> drivers don't need it, while other OSes do) If you really
    Arjan> need it you should grab it at dma_map time ...  (and
    Arjan> realize that it's not kernel addressable per se ;)

Yes, they need some kind of vaddr.

It's kind of a layering problem.  The IB stack assumes that IB devices
have a DMA engine that deals with bus addresses.  But the ipath driver
has to simulate this by using a memcpy on the CPU to move data to the
PCI device.

I really don't know what the right solution is.  Maybe having some way
to override the dma mapping operations so that the ipath driver can
keep the info it needs?

 - R.

  reply	other threads:[~2006-05-01 19:00 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-04-24 21:22 [PATCH 0 of 13] ipath - various fixes and cleanups Bryan O'Sullivan
2006-04-24 21:22 ` [PATCH 1 of 13] ipath - fix race with exposing reset file Bryan O'Sullivan
2006-04-24 21:22 ` [PATCH 2 of 13] ipath - set up 32-bit DMA mask if 64-bit setup fails Bryan O'Sullivan
2006-05-01 18:47   ` Roland Dreier
2006-05-01 19:56     ` Segher Boessenkool
2006-05-01 21:41       ` Roland Dreier
2006-05-01 23:13         ` Segher Boessenkool
2006-05-01 23:27           ` [openib-general] " Roland Dreier
2006-05-02  0:13             ` Segher Boessenkool
2006-05-02  0:18               ` Roland Dreier
2006-04-24 21:22 ` [PATCH 3 of 13] ipath - iterate over correct number of ports during reset Bryan O'Sullivan
2006-04-24 21:23 ` [PATCH 4 of 13] ipath - change handling of PIO buffers Bryan O'Sullivan
2006-04-25  9:32   ` Segher Boessenkool
2006-04-24 21:23 ` [PATCH 5 of 13] ipath - use proper address translation routine Bryan O'Sullivan
2006-05-01 18:50   ` Roland Dreier
2006-05-01 18:54     ` Arjan van de Ven
2006-05-01 19:00       ` Roland Dreier [this message]
2006-05-01 19:20         ` Arjan van de Ven
2006-05-01 19:28           ` Roland Dreier
2006-05-02 13:35         ` Christoph Hellwig
2006-05-02 14:24           ` Roland Dreier
2006-05-02 14:27             ` Christoph Hellwig
2006-05-02 14:55             ` Alan Cox
2006-05-02 14:58               ` Roland Dreier
2006-05-01 19:03     ` Bryan O'Sullivan
2006-04-24 21:23 ` [PATCH 6 of 13] ipath - fix verbs registration Bryan O'Sullivan
2006-04-24 21:23 ` [PATCH 7 of 13] ipath - prevent hardware from being accessed during reset Bryan O'Sullivan
2006-04-24 21:23 ` [PATCH 8 of 13] ipath - fix a number of RC protocol bugs Bryan O'Sullivan
2006-04-25  7:56   ` Andrew Morton
2006-05-01 17:22     ` Roland Dreier
2006-05-01 17:34       ` Bryan O'Sullivan
2006-04-24 21:23 ` [PATCH 9 of 13] ipath - simplify RC send posting Bryan O'Sullivan
2006-04-24 21:23 ` [PATCH 10 of 13] ipath - simplify IB timer usage Bryan O'Sullivan
2006-04-24 21:23 ` [PATCH 11 of 13] ipath - improve sparse annotation Bryan O'Sullivan
2006-04-24 21:23 ` [PATCH 12 of 13] ipath - fix label name in interrupt handler Bryan O'Sullivan
2006-04-24 21:23 ` [PATCH 13 of 13] ipath - tidy up white space in a few files Bryan O'Sullivan
2006-05-01 19:17   ` Roland Dreier

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