Hi Dan,

On 2018/8/13 20:00, Dan Carpenter wrote:
> On Sun, Aug 12, 2018 at 10:01:46PM +0800, Chao Yu wrote:
>> From: Gao Xiang <gaoxian...@huawei.com>
>>
>> This patch introduces 'struct z_erofs_vle_work_finder' to clean up
>> arguments of z_erofs_vle_work_lookup and z_erofs_vle_work_register.
>>
>> Signed-off-by: Gao Xiang <gaoxian...@huawei.com>
>> Reviewed-by: Chao Yu <yuch...@huawei.com>
>> Signed-off-by: Chao Yu <yuch...@huawei.com>
>> ---
>>  drivers/staging/erofs/unzip_vle.c | 89 ++++++++++++++++---------------
>>  1 file changed, 47 insertions(+), 42 deletions(-)
>>
>> diff --git a/drivers/staging/erofs/unzip_vle.c 
>> b/drivers/staging/erofs/unzip_vle.c
>> index b2e05e2b4116..5032b3b05de1 100644
>> --- a/drivers/staging/erofs/unzip_vle.c
>> +++ b/drivers/staging/erofs/unzip_vle.c
>> @@ -271,36 +271,42 @@ static inline bool try_to_claim_workgroup(
>>      return true;    /* lucky, I am the followee :) */
>>  }
>>  
>> +struct z_erofs_vle_work_finder {
>> +    struct super_block *sb;
>> +    pgoff_t idx;
>> +    unsigned pageofs;
>> +
>> +    struct z_erofs_vle_workgroup **grp_ret;
>> +    enum z_erofs_vle_work_role *role;
>> +    z_erofs_vle_owned_workgrp_t *owned_head;
>> +    bool *hosted;
>> +};
>> +
>>  static struct z_erofs_vle_work *
>> -z_erofs_vle_work_lookup(struct super_block *sb,
>> -                    pgoff_t idx, unsigned pageofs,
>> -                    struct z_erofs_vle_workgroup **grp_ret,
>> -                    enum z_erofs_vle_work_role *role,
>> -                    z_erofs_vle_owned_workgrp_t *owned_head,
>> -                    bool *hosted)
>> +z_erofs_vle_work_lookup(const struct z_erofs_vle_work_finder *f)
>>  {
>>      bool tag, primary;
>>      struct erofs_workgroup *egrp;
>>      struct z_erofs_vle_workgroup *grp;
>>      struct z_erofs_vle_work *work;
>>  
>> -    egrp = erofs_find_workgroup(sb, idx, &tag);
>> +    egrp = erofs_find_workgroup(f->sb, f->idx, &tag);
>>      if (egrp == NULL) {
>> -            *grp_ret = NULL;
>> +            *f->grp_ret = NULL;
> 
> All these pointers to pointer seem a bit messy.  Just do this:
> 
>       struct z_erofs_vle_workgroup *grp;
> 
> Then replace "grp" in z_erofs_vle_work_iter_begin() with finder.grp;
> 

I wrote this because I am not sure of all compiler behaviors.

Notice that the struct `struct z_erofs_vle_work_finder' has been all marked as 
const.

If I use `struct z_erofs_vle_workgroup *grp;' and drop the `const' decorator,
compilers could do some re-read operations bacause its value could potentially 
change by its caller at the same time.

Thanks,
Gao Xiang

> regards,
> dan carpenter
> 

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