From: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
To: Jens Axboe <axboe@suse.de>
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 14:20:35 +0200 (MET DST) [thread overview]
Message-ID: <Pine.SOL.4.30.0305081406310.12362-100000@mion.elka.pw.edu.pl> (raw)
In-Reply-To: <20030508115950.GQ823@suse.de>
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);
> > > > > Patch also misses updates for many uses of drive->addressing
> > > > > (in ide.c, ide-io.c, icside.c, ide-tcq.c and even in ide-taskfile.c).
> > > >
> > > > Hmm bad grep, weird.
> > >
> > > ide.c: ide_dump_status(). this is an ugly one, but to me it already
> > > looks correct. we are not throwing away any info by not reading the high
> > > bits.
> >
> > It should check for rq_lba48(rq) || task->addressing.
> > After taskfile IO switch it will be checking for task->addressing only.
>
> This is really ugly, but it has to look like that until you make the
> global taskfile changes...
Yep.
> > > ide-io.c, ide-tcq.c, icside.c: indeed, missed these.
> > >
> > > > > Jens, I like the general idea of the patch, but it needs some more work.
> > > > > Linus, please don't apply for now.
> > > >
> > > > Agree, I'll update the patch to suit your concerns tomorrow.
> > >
> > > Apart from the pdc202xx_old part, I think I've addressed all of your
> > > concerns in this patch.
> >
> > Nope ;-), please move setting of hwif->rqsize from setup-pci.c to where
> > it belongs, ide_init_queue() in ide-probe.c.
>
> So how's this?
Looks good.
Now test/review it for some time, we don't want any bugs to slip in.
:-)
--
Bartlomiej
next prev parent reply other threads:[~2003-05-08 12:08 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 [this message]
2003-05-08 12:26 ` Jens Axboe
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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