On Mon, Apr 28, 2014 at 03:09:01PM -0700, Davidlohr Bueso wrote:
> +static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem)
> +{
> + int retval;
And yet the return value is bool.
> + struct task_struct *owner;
> +
> + rcu_read_lock();
> + owner = ACCESS_ONCE(sem->owner);
> +
> + /* Spin only if active writer running */
> + if (owner)
> + retval = owner->on_cpu;
> + else {
> + /*
> + * When the owner is not set, the sem owner may have just
> + * acquired it and not set the owner yet, or the sem has
> + * been released, or reader active.
> + */
> + retval = false;
> + }
And if you init the retval to false, you can leave this entire branch
out.
> + rcu_read_unlock();
> +
> + return retval;
> +}
Which yields the much shorter:
static inline bool rwsem_can_spin_on_owner(struct rw_semaphore *sem)
{
struct task_struct *owner;
bool on_cpu = false;
rcu_read_lock();
owner = ACCESS_ONCE(sem->owner);
if (owner)
on_cpu = owner->on_cpu;
rcu_read_unlock();
return on_cpu;
}
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
