/*
* padata_get_next - Get the next object that needs serialization.
*
* Return values are:
*
* A pointer to the control struct of the next object that needs
* serialization, if present in one of the percpu reorder queues.
*
* -EINPROGRESS, if the next object that needs serialization will
* be parallel processed by another cpu and is not yet present in
* the cpu's reorder queue.
*
* -ENODATA, if this cpu has to do the parallel processing for
* the next object.
*/
static struct padata_priv *padata_get_next(struct parallel_data *pd)
{
int cpu, num_cpus;
unsigned int next_nr, next_index;
struct padata_parallel_queue *next_queue;
struct padata_priv *padata;
struct padata_list *reorder;
num_cpus = cpumask_weight(pd->cpumask.pcpu);
/*
* Calculate the percpu reorder queue and the sequence
* number of the next object.
*/
next_nr = pd->processed;
next_index = next_nr % num_cpus;
cpu = padata_index_to_cpu(pd, next_index);
next_queue = per_cpu_ptr(pd->pqueue, cpu);
reorder = &next_queue->reorder;
spin_lock(&reorder->lock);
if (!list_empty(&reorder->list)) {
padata = list_entry(reorder->list.next,
struct padata_priv, list);
list_del_init(&padata->list);
atomic_dec(&pd->reorder_objects);
pd->processed++;
spin_unlock(&reorder->lock);
goto out;
}
static int padata_cpu_hash(struct parallel_data *pd)
{
int cpu_index;
spin_lock(&pd->seq_lock);
cpu_index = pd->seq_nr % cpumask_weight(pd->cpumask.pcpu);
pd->seq_nr++;
spin_unlock(&pd->seq_lock);
return padata_index_to_cpu(pd, cpu_index);
}
static int padata_cpu_hash(struct padata_priv *padata)
{
int cpu_index;
struct parallel_data *pd;
pd = padata->pd;
/*
* Hash the sequence numbers to the cpus by taking
* seq_nr mod. number of cpus in use.
*/
cpu_index = padata->seq_nr % cpumask_weight(pd->cpumask.pcpu);
return padata_index_to_cpu(pd, cpu_index);
}
static int padata_cpu_hash(struct parallel_data *pd)
{
unsigned int seq_nr;
int cpu_index;
/*
* Hash the sequence numbers to the cpus by taking
* seq_nr mod. number of cpus in use.
*/
seq_nr = atomic_inc_return(&pd->seq_nr);
cpu_index = seq_nr % cpumask_weight(pd->cpumask.pcpu);
return padata_index_to_cpu(pd, cpu_index);
}
static int padata_cpu_hash(struct parallel_data *pd)
{
int cpu_index;
/*
* Hash the sequence numbers to the cpus by taking
* seq_nr mod. number of cpus in use.
*/
spin_lock(&pd->seq_lock);
cpu_index = pd->seq_nr % cpumask_weight(pd->cpumask.pcpu);
pd->seq_nr++;
spin_unlock(&pd->seq_lock);
return padata_index_to_cpu(pd, cpu_index);
}
