[PATCH 2/7] staging: erofs: code cleanup for option parsing of fault_injection

[Chao Yu]

On 2018/9/13 13:46, cgxu519 wrote:
> On 09/13/2018 10:15 AM, Chao Yu wrote:
>> On 2018/9/12 13:10, Chengguang Xu wrote:
>>> Define a dummpy function of erofs_build_fault_attr() when macro
>>> CONFIG_EROFS_FAULT_INJECTION is disabled, so that we don't have to
>>> check the macro in calling place. Based on above adjustment,
>>> do proper code cleanup for option parsing of fault_injection.
>>>
>>> Signed-off-by: Chengguang Xu <cgxu519 at gmx.com>
>>> ---
>>>   drivers/staging/erofs/super.c | 33 ++++++++++++++++++++++-----------
>>>   1 file changed, 22 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/drivers/staging/erofs/super.c b/drivers/staging/erofs/super.c
>>> index 1aec509c805f..14dbb6517b8d 100644
>>> --- a/drivers/staging/erofs/super.c
>>> +++ b/drivers/staging/erofs/super.c
>>> @@ -144,18 +144,33 @@ char *erofs_fault_name[FAULT_MAX] = {
>>>       [FAULT_KMALLOC]        = "kmalloc",
>>>   };
>>>   -static void erofs_build_fault_attr(struct erofs_sb_info *sbi,
>>> -                        unsigned int rate)
>>> +static int erofs_build_fault_attr(struct erofs_sb_info *sbi,
>>> +                    substring_t *args)
>>>   {
>>>       struct erofs_fault_info *ffi = &sbi->fault_info;
>>> +    int rate = 0;
>>> +
>>> +    if (args->from && match_int(args, &rate))
>>> +        return -EINVAL;
>>>         if (rate) {
>>>           atomic_set(&ffi->inject_ops, 0);
>>>           ffi->inject_rate = rate;
>>>           ffi->inject_type = (1 << FAULT_MAX) - 1;
>>> +        set_opt(sbi, FAULT_INJECTION);
>>>       } else {
>>>           memset(ffi, 0, sizeof(struct erofs_fault_info));
>>> +        clear_opt(sbi, FAULT_INJECTION);
>> Hmmm, if user mounts/remounts image with -o fault_injection=0, user can not
>> check such info in anywhere, as we skip showing this option due to lack of
>> EROFS_MOUNT_FAULT_INJECTION bit. How about keeping this bit?
>>
> 
> IIUC, the purpose of fault_injection=0 is for disabling fault injection function,
> so isn't it the same as default? Should we distinguish explicit setting value 0

IMO, if user set fault_injection=0 during mount, it means user want to enable
this feature but currently user want to set the rate to zero, later user may
change it to non-zero. And with EROFS_MOUNT_FAULT_INJECTION being set, user can
check current rate value via ->show_options.

Thanks,

> and default value 0?
> 
> Thanks,
> Chengguang
> 
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