[PATCH 1/7] media: aspeed: fix a kernel warning on clk control

Eddie James eajames at linux.vnet.ibm.com
Fri May 10 01:19:49 AEST 2019


On 5/8/19 9:16 PM, Benjamin Herrenschmidt wrote:
> On Wed, 2019-05-08 at 18:19 -0700, Jae Hyun Yoo wrote:
>> I changed that from a bool because the maintainer of this code, Eddie
>> doesn't like adding of an additional flag. I'll change it back with
>> codes in the first submit:
>> https://www.spinics.net/lists/linux-media/msg148955.html
>>
>> Eddie,
>> Please let me know if you have any objection on that.


Thats fine with me. I merely thought it was more conventional to use 
flags rather than bools, but I may be mistaken.

Thanks!

Eddie


> Ok, so random flags ... ugh.
>
> Well, you can approach it either way. Have them all be bitops or all be
> bool.
>
> The tricky thing however is that if they are bitops you need to ensure
> that they are *all* manipulated under the same lock. If not you have to
> use the atomic bitops variants.
>
> The reason I don't like that is that experience shows that most uses of
> such atomic variants in drivers usually are failed attempts at papering
> over broken locking.
>
> If everything is covered by a lock, then using the non-atomic versions
> is more efficient, but so is using bool (optionally with :1 bitfield
> qualifiers to avoid wasting memory), which from a pure C language
> perspective I think is more expressive of what you are doing and more
> readable.
>
> Cheers,
> Ben.
>



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