On Wed, Aug 24, 2022 at 01:14:40PM -0700, Keith Busch wrote:
>
> -static bool __sbq_wake_up(struct sbitmap_queue *sbq)
> +static bool __sbq_wake_up(struct sbitmap_queue *sbq, int *nr)
> {
> struct sbq_wait_state *ws;
> - unsigned int wake_batch;
> - int wait_cnt;
> + int wake_batch, wait_cnt, sub, cur;
>
> ws = sbq_wake_ptr(sbq);
> if (!ws)
> return false;
>
> - wait_cnt = atomic_dec_return(&ws->wait_cnt);
> + wake_batch = READ_ONCE(sbq->wake_batch);
> + do {
> + cur = atomic_read(&ws->wait_cnt);
I think the above statement is not needed if we use atomic_try_cmpxchg
as the old value is updated in that function itself.
https://docs.kernel.org/staging/index.html?highlight=atomic_try_cmpxchg#atomic-types
> + sub = min3(wake_batch, *nr, cur);
> + wait_cnt = cur - sub;
> + } while (!atomic_try_cmpxchg(&ws->wait_cnt, &cur, wait_cnt));
> +
> + *nr -= sub;
> +
> /*
--
Pankaj Raghav
