Re: [PATCH 3/3] bitops.h: set_mask_bits() to return old value

[Anthony Yznaga]

On 1/10/19 4:26 PM, Vineet Gupta wrote:
> | > Also, set_mask_bits is used in fs quite a bit and we can possibly come up
> | > with a generic llsc based implementation (w/o the cmpxchg loop)
> |
> | May I also suggest changing the return value of set_mask_bits() to old.
> |
> | You can compute the new value given old, but you cannot compute the old
> | value given new, therefore old is the better return value. Also, no
> | current user seems to use the return value, so changing it is without
> | risk.
>
> Link: http://lkml.kernel.org/g/20150807110955.GH16853@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Miklos Szeredi <mszeredi@xxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Will Deacon <will.deacon@xxxxxxx>
> Signed-off-by: Vineet Gupta <vgupta@xxxxxxxxxxxx>
>

Reviewed-by: Anthony Yznaga <anthony.yznaga@xxxxxxxxxx>