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Message-Id: <1481683756-29276-1-git-send-email-hejianet@gmail.com>
Date: Wed, 14 Dec 2016 10:49:14 +0800
From: Jia He <hejianet@...il.com>
To: linux-kernel@...r.kernel.org, linux-nfs@...r.kernel.org
Cc: "Eric W. Biederman" <ebiederm@...ssion.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Dmitry Torokhov <dmitry.torokhov@...il.com>,
Serge Hallyn <serge@...lyn.com>,
"David S. Miller" <davem@...emloft.net>,
Alexey Dobriyan <adobriyan@...il.com>,
Subash Abhinov Kasiviswanathan <subashab@...eaurora.org>,
Arnaldo Carvalho de Melo <acme@...hat.com>,
Al Viro <viro@...iv.linux.org.uk>,
Mel Gorman <mgorman@...hsingularity.net>,
Kees Cook <keescook@...omium.org>,
Hugh Dickins <hughd@...gle.com>,
Daniel Bristot de Oliveira <bristot@...hat.com>,
Daniel Cashman <dcashman@...gle.com>,
Arnd Bergmann <arnd@...db.de>,
"J. Bruce Fields" <bfields@...ldses.org>,
Jeff Layton <jlayton@...chiereds.net>,
Trond Myklebust <trond.myklebust@...marydata.com>,
Anna Schumaker <anna.schumaker@...app.com>,
Jia He <hejianet@...il.com>
Subject: [RESEND PATCH v4 0/2] change the proc handler for nsm_use_hostnames
Resend the v4 since I didn't add --to=linux-kernel@...r.kernel.org,sorry about
it
nsm_use_hostnames is a module parameter and it will be exported to sysctl
procfs. This is to let user sometimes change it from userspace. But the
minimal unit for sysctl procfs read/write it sizeof(int).
In big endian system, the converting from/to bool to/from int will cause
error for proc items.
This patch introduces a new proc handler proc_dobool for nsm_use_hostnames.
Changes:
v4: Change (u8 *) to (bool *)
v3: Introduce a new proc handler proc_dou8vec(suggested by Xinhui Pan)
v2: Change extern type in lockd.h
The test case I used:
/***************************************************************/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sysctl.h>
bool __read_mostly nsm_use_hostnames;
module_param(nsm_use_hostnames, bool, 0644);
static struct ctl_table my_sysctl[] = {
{
.procname = "nsm_use_hostnames",
.data = &nsm_use_hostnames,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = &proc_dointvec,
},
{}
};
static struct ctl_table my_root[] = {
{
.procname = "mysysctl",
.mode = 0555,
.child = my_sysctl,
},
{}
};
static struct ctl_table_header * my_ctl_header;
static int __init sysctl_exam_init(void)
{
my_ctl_header = register_sysctl_table(&my_root);
if (my_ctl_header == NULL)
printk("error regiester sysctl");
return 0;
}
static void __exit sysctl_exam_exit(void)
{
unregister_sysctl_table(my_ctl_header);
}
module_init(sysctl_exam_init);
module_exit(sysctl_exam_exit);
MODULE_LICENSE("GPL");
/****************************************************************/
[root@...endian my]# insmod -f /root/my/hello.ko nsm_use_hostnames=1
[root@...endian my]# cat /proc/sys/mysysctl/nsm_use_hostnames
16777216
After I change the proc_dointvec to new handler proc_dou8vec with the
patch:
[root@...endian my]# insmod -f /root/my/hello.ko nsm_use_hostnames=1
[root@...endian my]# cat /proc/sys/mysysctl/nsm_use_hostnames
1
In little endian system, there is no such issue.
Already tested v4 in both of big and little endian(ppc64 and ppc64le)
Jia He (2):
sysctl: introduce new proc handler proc_dobool
lockd: change the proc_handler for nsm_use_hostnames
fs/lockd/svc.c | 2 +-
include/linux/sysctl.h | 2 ++
kernel/sysctl.c | 35 +++++++++++++++++++++++++++++++++++
3 files changed, 38 insertions(+), 1 deletion(-)
--
2.5.5
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