Re: [PATCH] Revert "seqlock: lockdep assert non-preemptibility on seqcount_t write"

Valdis Klētnieks
2020-08-19T07:34:17Z

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On Wed, 19 Aug 2020 09:00:22 +0200, Sebastian Andrzej Siewior said:
> On 2020-08-18 17:56:49 [-0700], Guenter Roeck wrote:
> > Nice catch. FWIW, there is no obvious reason why this would need to be atomic.
> > The calling code does not set a lock, meaning there can be two (or more)
> > callers entering this code. Weird, especially since the code looks like it
> > would actually need a mutex to work correctly. It might be interesting to
> > see what happens if there are, say, half a dozen scripts/processes trying
> > to read the hwmon attribute introduced by this patch at the same time.
>
> => https://lkml.kernel.org/r/20200818161439.3dkf6jzp3vuwmvvh@linutronix.de

Looks reasonable to me, though I've not verified that it's preemptible at that
point...

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