On 03/02, Lai Jiangshan wrote:
>
> +void lg_rwlock_local_read_unlock(struct lgrwlock *lgrw)
> +{
> + switch (__this_cpu_read(*lgrw->reader_refcnt)) {
> + case 1:
> + __this_cpu_write(*lgrw->reader_refcnt, 0);
> + lg_local_unlock(&lgrw->lglock);
> + return;
> + case FALLBACK_BASE:
> + __this_cpu_write(*lgrw->reader_refcnt, 0);
> + read_unlock(&lgrw->fallback_rwlock);
> + rwlock_release(&lg->lock_dep_map, 1, _RET_IP_);
I guess "case 1:" should do rwlock_release() too.
Otherwise, at first glance looks correct...
However, I still think that FALLBACK_BASE only adds the unnecessary
complications. But even if I am right this is subjective of course, please
feel free to ignore.
And btw, I am not sure about lg->lock_dep_map, perhaps we should use
fallback_rwlock->dep_map ?
We need rwlock_acquire_read() even in the fast-path, and this acquire_read
should be paired with rwlock_acquire() in _write_lock(), but it does
spin_acquire(lg->lock_dep_map). Yes, currently this is the same (afaics)
but perhaps fallback_rwlock->dep_map would be more clean.
Oleg.
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