Re: [PATCH v2 1/2] spi: spidev: fix a race condition when accessing spidev->spi

[Bartosz Golaszewski]

On Fri, Jan 6, 2023 at 5:16 PM Mark Brown <broonie@xxxxxxxxxx> wrote:
>
> On Fri, Jan 06, 2023 at 03:27:57PM +0100, Bartosz Golaszewski wrote:
>
> > IMO the complication of using an RW semaphore is insignificant and
> > maybe a comment next to its declaration in struct spidev would
> > suffice?
>
> The complication is using a semaphore at all, it's a pretty unusual
> locking construct and the whole up/down thing isn't clear to people
> who aren't familiar with it.  Given that there's no clounting being
> used rwlock would be a much more obvious choice if the microseconds
> of extra concurrency is meaningful somehow.

I don't have any numbers, it's just that in this case the rwsem feels
more correct. My opinion is not very strong so you can apply v2.

Bart