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SubjectRe: [PATCH v2 1/1] lockd: Change nsm_use_hostnames from bool to u32
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hi, jia
nice catch!
However I think we should fix it totally.
This is because do_proc_dointvec_conv() try to get a int value from a bool *.

something like below might help. pls. ignore the code style and this is tested :)

diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index fc4084e..7eeaee4 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -519,6 +519,8 @@ EXPORT_SYMBOL_GPL(lockd_down);
* Sysctl parameters (same as module parameters, different interface).
*/

+int proc_dou8vec(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos);
static struct ctl_table nlm_sysctls[] = {
{
.procname = "nlm_grace_period",
@@ -561,7 +563,7 @@ static struct ctl_table nlm_sysctls[] = {
.data = &nsm_use_hostnames,
.maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = proc_dointvec,
+ .proc_handler = proc_dou8vec,
},
{
.procname = "nsm_local_state",
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 706309f..6307737 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -2112,6 +2112,30 @@ static int proc_put_char(void __user **buf, size_t *size, char c)
return 0;
}

+
+static int do_proc_dou8vec_conv(bool *negp, unsigned long *lvalp,
+ u8 *valp,
+ int write, void *data)
+{
+ if (write) {
+ if (*negp) {
+ *valp = -*lvalp;
+ } else {
+ *valp = *lvalp;
+ }
+ } else {
+ int val = *valp;
+ if (val < 0) {
+ *negp = true;
+ *lvalp = -(unsigned long)val;
+ } else {
+ *negp = false;
+ *lvalp = (unsigned long)val;
+ }
+ }
+ return 0;
+}
+
static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
int *valp,
int write, void *data)
@@ -2296,6 +2320,14 @@ int proc_douintvec(struct ctl_table *table, int write,
do_proc_douintvec_conv, NULL);
}

+int proc_dou8vec(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_dou8vec_conv, NULL);
+}
+
+

在 2016/12/11 23:36, Jia He 写道:
> nsm_use_hostnames is a module paramter 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 changes the type definition of nsm_use_hostnames.
>
> V2: Changes extern type in lockd.h
> Signed-off-by: Jia He <hejianet@gmail.com>
> ---
> fs/lockd/mon.c | 2 +-
> fs/lockd/svc.c | 2 +-
> include/linux/lockd/lockd.h | 2 +-
> 3 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
> index 19166d4..3e7ff4d 100644
> --- a/fs/lockd/mon.c
> +++ b/fs/lockd/mon.c
> @@ -57,7 +57,7 @@ static DEFINE_SPINLOCK(nsm_lock);
> * Local NSM state
> */
> u32 __read_mostly nsm_local_state;
> -bool __read_mostly nsm_use_hostnames;
> +u32 __read_mostly nsm_use_hostnames;
>
> static inline struct sockaddr *nsm_addr(const struct nsm_handle *nsm)
> {
> diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
> index fc4084e..308033d 100644
> --- a/fs/lockd/svc.c
> +++ b/fs/lockd/svc.c
> @@ -658,7 +658,7 @@ module_param_call(nlm_udpport, param_set_port, param_get_int,
> &nlm_udpport, 0644);
> module_param_call(nlm_tcpport, param_set_port, param_get_int,
> &nlm_tcpport, 0644);
> -module_param(nsm_use_hostnames, bool, 0644);
> +module_param(nsm_use_hostnames, u32, 0644);
> module_param(nlm_max_connections, uint, 0644);
>
> static int lockd_init_net(struct net *net)
> diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
> index c153738..db52152 100644
> --- a/include/linux/lockd/lockd.h
> +++ b/include/linux/lockd/lockd.h
> @@ -196,7 +196,7 @@ extern struct svc_procedure nlmsvc_procedures4[];
> #endif
> extern int nlmsvc_grace_period;
> extern unsigned long nlmsvc_timeout;
> -extern bool nsm_use_hostnames;
> +extern u32 nsm_use_hostnames;
> extern u32 nsm_local_state;
>
> /*
>

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