Re: [PATCH v2 1/1] lockd: Change nsm_use_hostnames from bool to u32

[hejianet <hejianet@gmail.com>]

Hi Xinhui
Thanks, it really works.
Will send out V3 soon afterwards

B.R.
Jia

On 12/12/16 1:43 AM, Pan Xinhui wrote:
>
> 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;
>>
>>  /*
>>
>
>