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From: Arjan van de Ven <arjan@infradead.org>
To: Mark Underwood <basicmark@yahoo.com>
Cc: David Brownell <david-b@pacbell.net>,
	linux-kernel@vger.kernel.org, dpervushin@ru.mvista.com
Subject: Re: [RFC][PATCH] SPI subsystem
Date: Mon, 03 Oct 2005 13:07:36 +0200	[thread overview]
Message-ID: <1128337656.17024.10.camel@laptopd505.fenrus.org> (raw)
In-Reply-To: <20051003105748.213.qmail@web33014.mail.mud.yahoo.com>

On Mon, 2005-10-03 at 11:57 +0100, Mark Underwood wrote:

> > > > > Hmm, using local variables for messages, so DMA adapter drivers have
> > > > > to check if this is non-kmalloc'ed space (how?)
> > > > 
> > > > They can't check that.  It turns out that most current Linuxes
> > > > have no issues DMAing a few bytes from the stack.
> > >
> > > Will the DMA remapping calls work with data from the stack?
> > 
> > On "most current Linuxes" yes.  All I know about, in fact.
> > But it's not guaranteed.
> 
> OK. Thanks

please NEVER EVER do dma from or to a stack variable. It's not allowed
on all architectures and it is really really bad practice in general
anyway. 


  reply	other threads:[~2005-10-03 11:07 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-09-03 10:13 Mark Underwood
2005-09-09 21:39 ` David Brownell
2005-09-10 11:17   ` Mark Underwood
2005-09-15  0:08     ` David Brownell
2005-09-15 19:24       ` Mark Underwood
2005-09-15 22:14         ` David Brownell
2005-09-15 23:27           ` Mark Underwood
2005-09-16  3:25             ` David Brownell
2005-09-16 17:55               ` Mark Underwood
2005-09-16 18:43                 ` David Brownell
2005-09-18 14:45               ` Mark Underwood
2005-09-30  1:02                 ` David Brownell
2005-10-02 12:36                   ` Mark Underwood
2005-10-03  4:47                     ` David Brownell
2005-10-03 10:57                       ` Mark Underwood
2005-10-03 11:07                         ` Arjan van de Ven [this message]
2005-10-03 15:14                           ` David Brownell
2005-10-03 15:23                             ` Russell King
2005-10-03 15:40                               ` David Brownell
2005-09-10 10:55 ` Vital
2005-09-10 11:54   ` Mark Underwood
2005-09-10 21:20     ` Vital
2005-09-11  8:35       ` Mark Underwood
2005-09-15  0:14     ` David Brownell
2005-09-26 16:50       ` Vitaly Wool

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