From: Jens Axboe <axboe@suse.de>
To: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
Cc: Linus Torvalds <torvalds@transmeta.com>,
Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] 2.5 ide 48-bit usage
Date: Thu, 8 May 2003 14:26:41 +0200 [thread overview]
Message-ID: <20030508122641.GW823@suse.de> (raw)
In-Reply-To: <Pine.SOL.4.30.0305081406310.12362-100000@mion.elka.pw.edu.pl>
On Thu, May 08 2003, Bartlomiej Zolnierkiewicz wrote:
>
> On Thu, 8 May 2003, Jens Axboe wrote:
>
> > On Thu, May 08 2003, Bartlomiej Zolnierkiewicz wrote:
> > >
> > > On Thu, 8 May 2003, Jens Axboe wrote:
> > > > On Wed, May 07 2003, Jens Axboe wrote:
> > > > > > Jens you your patch sets hwif->rqsize to 65535 in setup-pci.c for all
> > > > > > PCI hwifs which is simply wrong as not all of them supports LBA48.
> > > > > > You should check for hwif->addressing and if true set rqsize to 65536
> > > > > > (not 65535) and not in IDE PCI code but in ide_init_queue() in ide-probe.c.
> > > > >
> > > > > Yes you are right, that would be the best way of doing it. As it happens
> > > > > for that patch, it does not hurt or break anything. But it is certainly
> > > > > cleaner, I'll fix that up.
> > > >
> > > > That part is added, I still kept it at 65535 though akin to how we don't
> > > > use that last sector in 28-bit commands either. For 48-bit commands this
> > >
> > > No, ide_init_queue() sets it to 256, so I want 65536 too.
> >
> > Alright, I don't care enough about that 1 sector to argue.
> >
> > > Note that it should be done after setting queue max sectors to 256,
> > > because not only ide-disk depends on this code:
> > >
> > > max_sectors = 256;
> > >
> > > (...)
> > >
> > > /*
> > > * Added "< max_sectors" check for safety if it will
> > > * be called again later with rq->size = 65536.
> > > * I don't believe it ever is.
> > > */
> > > if (hwif->rqsize < max_sectors)
> > > max_sectors = hwif->rqsize;
> > > blk_queue_max_sectors(q, max_sectors);
> > > if (!hwif->rqsize)
> > > hwif->rqsize = hwif->addressing ? 65536 : 256;
> >
> > You have the logic reversed here, the hwif and drive addressing are
> > reversed. Yeah, it's convoluted, dunno who thought that logic up...
>
> Not me.
> Logic is to prevent some bugs and actually my comment "I don't believe it
> ever is." is totally wrong.
>
> ide_init_queue() is called for all drives on hwif.
>
> ie. failure scenario:
> 1st drive 48-bit: !rqsize -> max_sectors = 256, rqsize = 65536
> 2nd drive 28-bit: rqsize -> max_sectors = 65536 -> doh!
>
> so "< max_sectors" is really needed.
>
> It can look a bit saner:
>
> if (!hwif->rqsize)
> hwif->rqsize = hwif->addressing ? 65536 : 256;
> if (hwif->rqsize < max_sectors)
> max_sectors = hwif->rqsize;
> blk_queue_max_sectors(q, max_sectors);
Ugh yeah, that stinks. Your changed version looks better.
> Looks good.
> Now test/review it for some time, we don't want any bugs to slip in.
> :-)
I'll give it a test spin.
--
Jens Axboe
next prev parent reply other threads:[~2003-05-08 12:14 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-07 8:49 [PATCH] 2.5 ide 48-bit usage Jens Axboe
2003-05-07 16:28 ` Linus Torvalds
2003-05-07 16:46 ` Jens Axboe
2003-05-07 17:15 ` Linus Torvalds
2003-05-07 17:33 ` Jens Axboe
2003-05-07 17:42 ` Linus Torvalds
2003-05-07 17:50 ` Jens Axboe
2003-05-07 19:58 ` Bartlomiej Zolnierkiewicz
2003-05-07 20:19 ` Jens Axboe
2003-05-08 7:56 ` Jens Axboe
2003-05-08 11:01 ` Alan Cox
2003-05-08 12:01 ` Jens Axboe
2003-05-12 21:41 ` Mike Fedyk
2003-05-13 6:44 ` Jens Axboe
2003-05-08 11:34 ` Bartlomiej Zolnierkiewicz
2003-05-08 11:59 ` Jens Axboe
2003-05-08 12:20 ` Bartlomiej Zolnierkiewicz
2003-05-08 12:26 ` Jens Axboe [this message]
2003-05-08 12:36 ` Jens Axboe
2003-05-08 13:16 ` Bartlomiej Zolnierkiewicz
2003-05-08 13:23 ` Jens Axboe
2003-05-08 13:35 ` Bartlomiej Zolnierkiewicz
2003-05-08 13:37 ` Jens Axboe
2003-05-08 14:47 ` Jens Axboe
2003-05-08 14:51 ` Jens Axboe
2003-05-08 14:46 ` Alan Cox
2003-05-08 15:49 ` Bartlomiej Zolnierkiewicz
2003-05-08 16:16 ` Jens Axboe
2003-05-08 16:27 ` Linus Torvalds
2003-05-08 16:34 ` Jens Axboe
2003-05-08 16:59 ` Bartlomiej Zolnierkiewicz
2003-05-09 7:40 ` Jens Axboe
2003-05-08 22:06 ` Alan Cox
2003-05-09 7:06 ` Jens Axboe
2003-05-09 8:28 ` [PATCH][RFC] Sanitize hwif/drive addressing (was Re: [PATCH] 2.5 ide 48-bit usage) Jens Axboe
2003-05-09 11:07 ` Bartlomiej Zolnierkiewicz
2003-05-09 12:03 ` Jens Axboe
2003-05-07 21:45 ` [PATCH] 2.5 ide 48-bit usage Henning P. Schmiedehausen
2003-05-07 22:03 ` Alan Cox
2003-05-07 22:55 ` H. Peter Anvin
2003-05-07 18:29 ` Alan Cox
2003-05-07 19:30 ` Jens Axboe
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