From: Andrew Morton <akpm@linux-foundation.org>
To: Oleg Verych <olecom@flower.upol.cz>
Cc: NeilBrown <neilb@suse.de>,
linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 006 of 6] md: Add support for reshape of a raid6
Date: Wed, 21 Feb 2007 15:58:20 -0800 [thread overview]
Message-ID: <20070221155820.de9f2f16.akpm@linux-foundation.org> (raw)
In-Reply-To: <E1HK10Y-0001MY-CB@flower>
On Thu, 22 Feb 2007 00:36:22 +0100
Oleg Verych <olecom@flower.upol.cz> wrote:
> > From: Andrew Morton
> > Newsgroups: gmane.linux.raid,gmane.linux.kernel
> > Subject: Re: [PATCH 006 of 6] md: Add support for reshape of a raid6
> > Date: Wed, 21 Feb 2007 14:48:06 -0800
>
> Hallo.
>
> > On Tue, 20 Feb 2007 17:35:16 +1100
> > NeilBrown <neilb@suse.de> wrote:
> >
> >> + for (i = conf->raid_disks ; i-- ; ) {
> >
> > That statement should be dragged out, shot, stomped on then ceremonially
> > incinerated.
> >
> > What's wrong with doing
> >
> > for (i = 0; i < conf->raid_disks; i++) {
> >
> > in a manner which can be understood without alcoholic fortification?
> >
> > ho hum.
>
> In case someone likes to do job, GCC usually ought to do, i would
> suggest something like this instead:
>
> if (expanded && test_bit(STRIPE_EXPANDING, &sh->state)) {
> /* Need to write out all blocks after computing P&Q */
> - sh->disks = conf->raid_disks;
> + i = conf->raid_disks;
> + sh->disks = i;
> - sh->pd_idx = stripe_to_pdidx(sh->sector, conf,
> - conf->raid_disks);
> + sh->pd_idx = stripe_to_pdidx(sh->sector, conf, i);
>
> compute_parity6(sh, RECONSTRUCT_WRITE);
> - for (i = conf->raid_disks ; i-- ; ) {
> + do {
> set_bit(R5_LOCKED, &sh->dev[i].flags);
> locked++;
> set_bit(R5_Wantwrite, &sh->dev[i].flags);
> - }
> + } while (--i);
>
> clear_bit(STRIPE_EXPANDING, &sh->state);
> } else if (expanded) {
>
> In any case this is subject of scripts/bloat-o-meter.
This:
--- a/drivers/md/raid5.c~a
+++ a/drivers/md/raid5.c
@@ -2364,7 +2364,7 @@ static void handle_stripe6(struct stripe
sh->pd_idx = stripe_to_pdidx(sh->sector, conf,
conf->raid_disks);
compute_parity6(sh, RECONSTRUCT_WRITE);
- for (i = conf->raid_disks ; i-- ; ) {
+ for (i = 0; i < conf->raid_disks; ++) {
set_bit(R5_LOCKED, &sh->dev[i].flags);
locked++;
set_bit(R5_Wantwrite, &sh->dev[i].flags);
_
reduces the size of drivers/md/raid5.o's .text by two bytes.
next prev parent reply other threads:[~2007-02-21 23:58 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-20 6:34 [PATCH 000 of 6] md: Assorted fixes and features for md for 2.6.21 NeilBrown
2007-02-20 6:34 ` [PATCH 001 of 6] md: Fix raid10 recovery problem NeilBrown
2007-02-20 6:34 ` [PATCH 002 of 6] md: RAID6: clean up CPUID and FPU enter/exit code NeilBrown
2007-02-20 6:35 ` [PATCH 003 of 6] md: Move warning about creating a raid array on partitions of the one device NeilBrown
2007-02-20 6:35 ` [PATCH 004 of 6] md: Clean out unplug and other queue function on md shutdown NeilBrown
2007-02-20 6:35 ` [PATCH 005 of 6] md: Restart a (raid5) reshape that has been aborted due to a read/write error NeilBrown
2007-02-20 6:35 ` [PATCH 006 of 6] md: Add support for reshape of a raid6 NeilBrown
2007-02-21 22:48 ` Andrew Morton
2007-02-21 23:36 ` Oleg Verych
2007-02-21 23:58 ` Andrew Morton [this message]
2007-02-21 23:57 ` Rafael J. Wysocki
2007-02-22 2:39 ` Neil Brown
2007-02-22 2:57 ` Andrew Morton
2007-02-23 12:15 ` Helge Hafting
2007-02-23 15:52 ` Bill Davidsen
2007-02-20 23:22 ` [PATCH 000 of 6] md: Assorted fixes and features for md for 2.6.21 Bill Davidsen
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