Re: [PATCH v15 00/13] mux controller abstraction and iio/i2c muxes

[Luc Van Oostenryck]

On Sat, Jun 3, 2017 at 12:26 PM, Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> On Sun, May 14, 2017 at 09:51:03PM +0200, Peter Rosin wrote:
>> From: Peter Rosin <peda@xxxxxxxxxx>
>>
>> Hi Greg,
>>
>> Philipp found problems in v14 with using a mutex for locking that was
>> the outcome of the review for v13, so I'm now using a semaphore instead
>> of the rwsem that was in v13. That at least got rid of the scary call
>> to downgrade_write. However, I'm still unsure about what you actually
>> meant with your comment about lack of sparse markings [1]. I did add
>> __must_check to the funcs that selects the mux, but I've got this
>> feeling that this is not what you meant?
>
> I thought there was a way to mark a function as requiring a lock be held
> when it is being called.  Does sparse not support that anymore?

sparse still support these annotations, of course.
In this case, I suppose you're talking about '__must_hold()' which
*must* be used instead of a pair of '__releases()' + '__acquires()'
when the lock is help on function entry and exit.

Cheers,
-- Luc Van Oostenryck