From: James Bottomley <James.Bottomley@SteelEye.com>
To: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
Alessandro Rubini <rubini@vision.unipv.it>,
linuxppc-dev@ozlabs.org, Paul Mackerras <paulus@samba.org>,
Jens Axboe <jens.axboe@oracle.com>
Subject: Re: [patch 5/6] ps3: BD/DVD/CD-ROM Storage Driver
Date: Fri, 13 Jul 2007 09:34:30 -0400 [thread overview]
Message-ID: <1184333670.3402.17.camel@localhost.localdomain> (raw)
In-Reply-To: <Pine.LNX.4.62.0707131518120.18802@pademelon.sonytel.be>
On Fri, 2007-07-13 at 15:25 +0200, Geert Uytterhoeven wrote:
> kmap() just returns page_address() on ppc64, as there's no highmem.
> kunmap() is a no-op.
> So technically I could just use page_address() directly, but Christoph
> wanted
> me to keep the kmap()/kunmap() sequence because it's considered a good
> practice.
The point isn't what kmap and kunmap do ... it's the addresses they
return. By and large, a kernel virtual address for a page is different
from the user virtual address. If the cache is virtually indexed you
get different cache lines for the same page ... and that sets you up
with aliases you need to resolve. parisc is the same ... our
kmap/kunmap are nops as well, but our kernel virtual addresses are still
different from the user virtual ones.
James
next prev parent reply other threads:[~2007-07-13 13:34 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-04 13:22 [patch 0/6] PS3 Storage Drivers for 2.6.23, take 4 Geert Uytterhoeven
2007-07-04 13:22 ` [patch 1/6] ps3: Preallocate bootmem memory for the PS3 FLASH ROM storage driver Geert Uytterhoeven
2007-07-04 13:22 ` [patch 2/6] ps3: Storage Driver Core Geert Uytterhoeven
2007-07-04 13:22 ` [patch 3/6] ps3: Storage device registration routines Geert Uytterhoeven
2007-07-04 13:22 ` [patch 4/6] ps3: Disk Storage Driver Geert Uytterhoeven
2007-07-04 13:22 ` [patch 5/6] ps3: BD/DVD/CD-ROM " Geert Uytterhoeven
2007-07-13 13:02 ` James Bottomley
2007-07-13 13:05 ` Jens Axboe
2007-07-13 13:25 ` Geert Uytterhoeven
2007-07-13 13:34 ` James Bottomley [this message]
2007-07-13 13:45 ` Geert Uytterhoeven
2007-07-13 14:02 ` James Bottomley
2007-07-13 14:19 ` Arnd Bergmann
2007-07-13 15:10 ` Geert Uytterhoeven
2007-07-13 15:28 ` James Bottomley
2007-07-13 20:13 ` Geert Uytterhoeven
2007-07-16 11:43 ` Geert Uytterhoeven
2007-07-16 12:16 ` Jens Axboe
2007-07-16 12:59 ` Geert Uytterhoeven
2007-07-16 13:04 ` Jens Axboe
2007-07-16 13:24 ` Geert Uytterhoeven
2007-07-16 13:33 ` Jens Axboe
2007-07-16 21:38 ` Benjamin Herrenschmidt
2007-07-16 13:47 ` James Bottomley
2007-07-16 14:38 ` Jens Axboe
2007-07-16 14:59 ` Geert Uytterhoeven
2007-07-16 21:40 ` Benjamin Herrenschmidt
2007-07-16 21:49 ` Benjamin Herrenschmidt
2007-07-16 22:03 ` James Bottomley
2007-07-16 22:12 ` Benjamin Herrenschmidt
2007-07-13 16:35 ` Jens Axboe
2007-07-13 23:12 ` Benjamin Herrenschmidt
2007-07-16 12:08 ` Segher Boessenkool
2007-07-13 14:51 ` Jens Axboe
2007-07-13 23:06 ` Benjamin Herrenschmidt
2007-07-04 13:22 ` [patch 6/6] ps3: FLASH ROM " Geert Uytterhoeven
2007-07-10 7:45 ` [patch 0/6] PS3 Storage Drivers for 2.6.23, take 4 Geert Uytterhoeven
2007-07-10 7:55 ` Jens Axboe
2007-07-10 8:01 ` Paul Mackerras
2007-07-10 8:32 ` Jens Axboe
2007-07-13 9:31 ` Geert Uytterhoeven
2007-07-13 12:27 ` PS3 Storage Driver O_DIRECT issue Olaf Hering
2007-07-13 13:34 ` Geert Uytterhoeven
2007-07-17 16:40 ` Geoff Levand
2007-07-18 16:12 ` Geert Uytterhoeven
2007-07-18 17:57 ` Jens Axboe
-- strict thread matches above, loose matches on Subject: below --
2007-06-21 14:14 [patch 0/6] PS3 Storage Drivers for 2.6.23, take 3 Geert Uytterhoeven
2007-06-21 14:14 ` [patch 5/6] ps3: BD/DVD/CD-ROM Storage Driver Geert Uytterhoeven
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