From: Russell King <rmk@arm.linux.org.uk>
To: Andrew Morton <akpm@digeo.com>
Cc: Hugh Dickins <hugh@veritas.com>,
LW@KARO-electronics.de, linux-kernel@vger.kernel.org
Subject: Re: [patch] cache flush bug in mm/filemap.c (all kernels >= 2.5.30(at least))
Date: Fri, 23 May 2003 19:34:58 +0100 [thread overview]
Message-ID: <20030523193458.B4584@flint.arm.linux.org.uk> (raw)
In-Reply-To: <20030523112926.7c864263.akpm@digeo.com>; from akpm@digeo.com on Fri, May 23, 2003 at 11:29:26AM -0700
On Fri, May 23, 2003 at 11:29:26AM -0700, Andrew Morton wrote:
> Vague statement of principle: The device driver layer takes care of these
> issues for DMA transfers, and hence should also take care of them for PIO.
> Is this sensible and/or possible?
I'd err on the side of caution about extending this principle. The
device driver layer's issue for DMA transfers seems to cover the device <->
kernel cache consistency, not the device <-> user space or kernel <->
user space cache consistency.
The kernel <-> user space consistency issue seems to be one for the MM
layer to deal with. There are other situations where this view can go
out of sync - for instance, when you have a page of a file mmap'd, and
you use sys_write() to that page of file. This is the issue which
flush_dcache_page() seems to be addressing, and it's the same issue
with PIO from IDE.
So no, I don't think it is a device driver issue at all.
DaveM?
--
Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux
http://www.arm.linux.org.uk/personal/aboutme.html
next prev parent reply other threads:[~2003-05-23 18:21 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-22 12:34 [patch] cache flush bug in mm/filemap.c (all kernels >= 2.5.30(at least)) LW
2003-05-22 14:03 ` Russell King
2003-05-22 14:11 ` Russell King
2003-05-23 8:02 ` David S. Miller
2003-05-23 9:12 ` Andrew Morton
2003-05-23 9:49 ` David S. Miller
2003-05-23 10:04 ` Andrew Morton
2003-05-23 10:15 ` David S. Miller
2003-05-23 8:20 ` Lothar Wassmann
2003-05-23 9:24 ` Andrew Morton
2003-05-23 10:04 ` Lothar Wassmann
2003-05-23 10:45 ` Andrew Morton
2003-05-23 11:22 ` Paul Mackerras
2003-05-23 16:54 ` Russell King
2003-05-23 17:31 ` Hugh Dickins
2003-05-23 18:29 ` Andrew Morton
2003-05-23 18:34 ` Russell King [this message]
2003-05-26 3:19 ` David S. Miller
2003-05-26 5:07 ` Mika Penttilä
2003-05-26 5:08 ` David S. Miller
2003-05-26 5:36 ` Mika Penttilä
2003-05-26 5:36 ` David S. Miller
2003-05-26 13:18 ` Roman Zippel
2003-05-26 22:34 ` David S. Miller
2003-05-27 10:53 ` Roman Zippel
2003-05-27 21:22 ` David S. Miller
2003-05-28 16:35 ` Roman Zippel
2003-05-28 22:47 ` David S. Miller
2003-05-29 0:12 ` Roman Zippel
2003-05-29 1:37 ` David S. Miller
2003-05-29 7:13 ` Russell King
2003-05-29 7:15 ` David S. Miller
2003-05-29 17:49 ` Roman Zippel
2003-05-29 21:09 ` David S. Miller
2003-05-26 8:55 ` Russell King
2003-05-26 13:08 ` Lothar Wassmann
2003-05-26 22:19 ` Russell King
2003-05-26 13:25 ` Jens Axboe
2003-05-26 22:35 ` David S. Miller
2003-05-26 3:20 ` David S. Miller
2003-05-23 11:13 ` Russell King
2003-05-23 12:46 ` Lothar Wassmann
2003-05-23 15:42 ` Hugh Dickins
2003-05-25 17:10 ` David Woodhouse
2003-05-26 11:44 ` Lothar Wassmann
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