From: Jonathan Brassow <jbrassow@redhat.com>
To: linux-raid@vger.kernel.org
Cc: neilb@suse.de, agk@redhat.com, jbrassow@redhat.com
Subject: Re: [PATCH] DM RAID: Ensure the bitmap region_size is a power of 2
Date: Wed, 12 Dec 2012 08:53:32 -0600 [thread overview]
Message-ID: <1355324012.26828.9.camel@f16> (raw)
In-Reply-To: <1355261825.26828.6.camel@f16>
This is probably a better way to do it...
brassow
DM RAID: Ensure the bitmap region_size is a power of 2
If the user does not supply a region_size, a reasonable size is computed
automatically. However, region_size needs to be a power of 2 and the
code was not properly ensuring that.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Index: linux-upstream/drivers/md/dm-raid.c
===================================================================
--- linux-upstream.orig/drivers/md/dm-raid.c
+++ linux-upstream/drivers/md/dm-raid.c
@@ -295,9 +295,11 @@ static int validate_region_size(struct r
* Choose a reasonable default. All figures in sectors.
*/
if (min_region_size > (1 << 13)) {
+ /* If not a power of 2, make it the next power of 2 */
+ if (min_region_size & (min_region_size - 1))
+ region_size = 1 << fls(region_size);
DMINFO("Choosing default region size of %lu sectors",
region_size);
- region_size = min_region_size;
} else {
DMINFO("Choosing default region size of 4MiB");
region_size = 1 << 13; /* sectors */
next prev parent reply other threads:[~2012-12-12 14:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-11 21:37 [PATCH] DM RAID: Ensure the bitmap region_size is a power of 2 Jonathan Brassow
2012-12-11 21:49 ` Alasdair G Kergon
2012-12-12 14:53 ` Jonathan Brassow [this message]
2012-12-12 16:10 ` Alasdair G Kergon
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