Re: Re: [PATCH] btrfs: Simplify offset calculation method for ctree.h

[Zhaolei <zhaolei@cn.fujitsu.com>]

sniper wrote:
> No, many pointers in btrfs function arguments are not pointing to an
> absolute address, but relative to the start address of extent.
> Take following function as example, argument inode_item is an offset
> value to the beginning of leaf. So we can't reach its member with
> &inode_item->xxx

Notice that we are not reach its member, we are getting pointer of its
member with &inode_item->mtime.
This operation have same effect as old one.

Thanks
Zhaolei

> 
>>  static inline struct btrfs_timespec *
>>  btrfs_inode_mtime(struct btrfs_inode_item *inode_item)
>>  {
>> -       unsigned long ptr = (unsigned long)inode_item;
>> -       ptr += offsetof(struct btrfs_inode_item, mtime);
>> -       return (struct btrfs_timespec *)ptr;
>> +       return &inode_item->mtime;
>>  }