Re: [PATCH v3 0/2] btrfs: re-define btrfs_raid_types

[David Sterba <dsterba@suse.cz>]

On Wed, Apr 20, 2022 at 04:08:26PM +0800, Qu Wenruo wrote:
> [CHANGELOG]
> Changelog:
> v2:
> - Fix the start value of BTRFS_RAID_RAID0
> 
> v3:
> - Introduce more static sanity checks
>   They are kinda overkilled, but they are only compile time checks, it
>   should be fine.
> 
> - Keep btrfs_bg_flags_to_raid_index() as regular function
> 
> By the nature of BTRFS_BLOCK_GROUP_* profiles, converting the flag into
> an index should only need one bits AND, one if () check for SINGLE
> profile, one right shift to align the values, one ilog2() call which is
> normally converted into ffs() assembly code.
> 
> But we're using a lot of if () branches to do the convert.
> 
> This patch will re-define btrfs_raid_types by:
> 
> - Move it to volumes.h
>   btrfs_raid_types are only used internally, no need to be exposed
>   through UAPI.
> 
> - Re-order btrfs_raid_types
>   To make them match their value order.
> 
> - Use ilog2() to convert them into index
> 
> - Extra static_assert()s to make sure RAID0 is always the least
>   significant bit in PROFILE_MASK
> 
> 
> Qu Wenruo (2):
>   btrfs: move definition of btrfs_raid_types to volumes.h
>   btrfs: use ilog2() to replace if () branches for
>     btrfs_bg_flags_to_raid_index()

I've added the patches to for-next as it looks good as it is now, feel
free to send an update, either an incremental fixup or full resend.