Re: [PATCH 2/5] btrfs: add helpers to get inode from page/folio pointers

[Johannes Thumshirn <Johannes.Thumshirn@wdc.com>]

On 30.01.24 20:29, David Sterba wrote:
> On Tue, Jan 30, 2024 at 11:42:30AM +0000, Johannes Thumshirn wrote:
>> On 29.01.24 19:33, David Sterba wrote:
>>> diff --git a/fs/btrfs/misc.h b/fs/btrfs/misc.h
>>> index 40f2d9f1a17a..8be09234c575 100644
>>> --- a/fs/btrfs/misc.h
>>> +++ b/fs/btrfs/misc.h
>>> @@ -8,6 +8,9 @@
>>>    #include <linux/math64.h>
>>>    #include <linux/rbtree.h>
>>>    
>>> +#define page_to_inode(page)	BTRFS_I((page)->mapping->host)
>>> +#define folio_to_inode(folio)	BTRFS_I((folio)->mapping->host)
>>> +
>>
>> Why are you using a macro instead of an inline function here?
> 
> As said in the changelog so we don't have to include headers with full
> definitions of page, folio, fs_info, ...
> 
>> Shouldn't inline function give us a bit more type safety, or are
>> compilers smart enough nowadays?
> 
> Yes type safety would be good but then it can't be an inline without
> bloating misc.h (and the making include cycles).

I personally would've put them into fs.h anyways.

> 
> I could do a type check in the macro using _Generic.
>