Resend the v4 since I didn't add [email protected],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@bigendian my]# insmod -f /root/my/hello.ko nsm_use_hostnames=1
[root@bigendian my]# cat /proc/sys/mysysctl/nsm_use_hostnames
16777216
After I change the proc_dointvec to new handler proc_dou8vec with the
patch:
[root@bigendian my]# insmod -f /root/my/hello.ko nsm_use_hostnames=1
[root@bigendian 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
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 use a new proc_handler proc_dobool.
Signed-off-by: Jia He <[email protected]>
---
fs/lockd/svc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index fc4084e..bd6fcf9 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -561,7 +561,7 @@ static struct ctl_table nlm_sysctls[] = {
.data = &nsm_use_hostnames,
.maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dobool,
},
{
.procname = "nsm_local_state",
--
2.5.5
This is to let bool variable could be correctly displayed in
big/little endian sysctl procfs.
sizeof(bool) is arch dependent, proc_dobool should work in all
arches.
Suggested-by: Pan Xinhui <[email protected]>
Signed-off-by: Jia He <[email protected]>
---
include/linux/sysctl.h | 2 ++
kernel/sysctl.c | 35 +++++++++++++++++++++++++++++++++++
2 files changed, 37 insertions(+)
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index adf4e51..255a9c7 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -41,6 +41,8 @@ typedef int proc_handler (struct ctl_table *ctl, int write,
extern int proc_dostring(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
+extern int proc_dobool(struct ctl_table *, int,
+ void __user *, size_t *, loff_t *);
extern int proc_dointvec(struct ctl_table *, int,
void __user *, size_t *, loff_t *);
extern int proc_douintvec(struct ctl_table *, int,
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 706309f..69f93cd 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2112,6 +2112,20 @@ static int proc_put_char(void __user **buf, size_t *size, char c)
return 0;
}
+static int do_proc_dobool_conv(bool *negp, unsigned long *lvalp,
+ int *valp,
+ int write, void *data)
+{
+ if (write)
+ *(bool *)valp = *lvalp;
+ else {
+ int val = *(bool *)valp;
+
+ *lvalp = (unsigned long)val;
+ }
+ return 0;
+}
+
static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
int *valp,
int write, void *data)
@@ -2258,6 +2272,26 @@ static int do_proc_dointvec(struct ctl_table *table, int write,
}
/**
+ * proc_dobool - read/write a bool
+ * @table: the sysctl table
+ * @write: %TRUE if this is a write to the sysctl file
+ * @buffer: the user buffer
+ * @lenp: the size of the user buffer
+ * @ppos: file position
+ *
+ * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
+ * values from/to the user buffer, treated as an ASCII string.
+ *
+ * Returns 0 on success.
+ */
+int proc_dobool(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+ return do_proc_dointvec(table, write, buffer, lenp, ppos,
+ do_proc_dobool_conv, NULL);
+}
+
+/**
* proc_dointvec - read a vector of integers
* @table: the sysctl table
* @write: %TRUE if this is a write to the sysctl file
@@ -2941,6 +2975,7 @@ int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
* No sense putting this after each symbol definition, twice,
* exception granted :-)
*/
+EXPORT_SYMBOL(proc_dobool);
EXPORT_SYMBOL(proc_dointvec);
EXPORT_SYMBOL(proc_douintvec);
EXPORT_SYMBOL(proc_dointvec_jiffies);
--
2.5.5
Hi Jia,
[auto build test ERROR on linus/master]
[also build test ERROR on v4.9 next-20161214]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Jia-He/sysctl-introduce-new-proc-handler-proc_dobool/20161214-112656
config: x86_64-randconfig-n0-12141159 (attached as .config)
compiler: gcc-4.8 (Debian 4.8.4-1) 4.8.4
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64
All errors (new ones prefixed by >>):
>> kernel/built-in.o:(___ksymtab+proc_dobool+0x0): undefined reference to `proc_dobool'
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
Thanks, this error is caused by
# CONFIG_PROC_SYSCTL is not set
Will fixed in next version
Jia
B.R.
On 12/14/16 2:13 PM, kbuild test robot wrote:
> Hi Jia,
>
> [auto build test ERROR on linus/master]
> [also build test ERROR on v4.9 next-20161214]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>
> url: https://github.com/0day-ci/linux/commits/Jia-He/sysctl-introduce-new-proc-handler-proc_dobool/20161214-112656
> config: x86_64-randconfig-n0-12141159 (attached as .config)
> compiler: gcc-4.8 (Debian 4.8.4-1) 4.8.4
> reproduce:
> # save the attached .config to linux build tree
> make ARCH=x86_64
>
> All errors (new ones prefixed by >>):
>
>>> kernel/built-in.o:(___ksymtab+proc_dobool+0x0): undefined reference to `proc_dobool'
> ---
> 0-DAY kernel test infrastructure Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all Intel Corporation