linux-kernel - [PATCH] Documentation: fix wrong value in md.txt

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <2b0cf4c2.21fa.1555c03d3e9.Coremail.kernelpatch@126.com>
Date:	Fri, 17 Jun 2016 09:40:02 +0800 (CST)
From:	"Tiezhu Yang" <kernelpatch@....com>
To:	corbet@....net, shli@...nel.org
Cc:	linux-doc@...r.kernel.org, linux-raid@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] Documentation: fix wrong value in md.txt

In the current Documentation/md.txt, the lower limit value of
stripe_cache_size is 16 and the default value is 128, but when
I update kernel to the latest mainline version and RAID5 array
is created by mdadm, then execute the following commands, it
shows an error and a difference respectively.

1) set stripe_cache_size to 16
[root@...alhost ~]# echo 16 > /sys/block/md0/md/stripe_cache_size
bash: echo: write error: Invalid argument
2) read the default value of stripe_cache_size
[root@...alhost ~]# cat /sys/block/md0/md/stripe_cache_size
256

I read drivers/md/raid5.c and find the following related code:
1) in function 'raid5_set_cache_size':
if (size <= 16 || size > 32768)
	return -EINVAL;
2) #define NR_STRIPES		256

So the lower limit value of stripe_cache_size should be 17 and
the default value should be 256.

Signed-off-by: Tiezhu Yang <kernelpatch@....com>
---
 Documentation/md.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/md.txt b/Documentation/md.txt
index 1a2ada4..d6e2fcf 100644
--- a/Documentation/md.txt
+++ b/Documentation/md.txt
@@ -602,7 +602,7 @@ These currently include
 
   stripe_cache_size  (currently raid5 only)
       number of entries in the stripe cache.  This is writable, but
-      there are upper and lower limits (32768, 16).  Default is 128.
+      there are upper and lower limits (32768, 17).  Default is 256.
   strip_cache_active (currently raid5 only)
       number of active entries in the stripe cache
   preread_bypass_threshold (currently raid5 only)
-- 
1.8.3.1