/*
* row_dispatch_requests() - selects the next request to dispatch
* @q: requests queue
* @force: flag indicating if forced dispatch
*
* Return 0 if no requests were moved to the dispatch queue.
* 1 otherwise
*
*/
static int row_dispatch_requests(struct request_queue *q, int force)
{
struct row_data *rd = (struct row_data *)q->elevator->elevator_data;
int ret = 0, currq, ioprio_class_to_serve, start_idx, end_idx;
if (force && hrtimer_active(&rd->rd_idle_data.hr_timer)) {
if (hrtimer_try_to_cancel(&rd->rd_idle_data.hr_timer) >= 0) {
row_log(rd->dispatch_queue,
"Canceled delayed work on %d - forced dispatch",
rd->rd_idle_data.idling_queue_idx);
rd->rd_idle_data.idling_queue_idx = ROWQ_MAX_PRIO;
}
}
if (rd->pending_urgent_rq) {
row_log(rd->dispatch_queue, "dispatching urgent request");
row_dispatch_insert(rd, rd->pending_urgent_rq);
ret = 1;
goto done;
}
ioprio_class_to_serve = row_get_ioprio_class_to_serve(rd, force);
row_log(rd->dispatch_queue, "Dispatching from %d priority class",
ioprio_class_to_serve);
switch (ioprio_class_to_serve) {
case IOPRIO_CLASS_NONE:
rd->last_served_ioprio_class = IOPRIO_CLASS_NONE;
goto done;
case IOPRIO_CLASS_RT:
start_idx = ROWQ_HIGH_PRIO_IDX;
end_idx = ROWQ_REG_PRIO_IDX;
break;
case IOPRIO_CLASS_BE:
start_idx = ROWQ_REG_PRIO_IDX;
end_idx = ROWQ_LOW_PRIO_IDX;
break;
case IOPRIO_CLASS_IDLE:
start_idx = ROWQ_LOW_PRIO_IDX;
end_idx = ROWQ_MAX_PRIO;
break;
default:
pr_err("%s(): Invalid I/O priority class", __func__);
goto done;
}
currq = row_get_next_queue(q, rd, start_idx, end_idx);
/* Dispatch */
if (currq >= 0) {
row_dispatch_insert(rd,
rq_entry_fifo(rd->row_queues[currq].fifo.next));
ret = 1;
}
done:
return ret;
}
/*
* row_choose_queue() - choose the next queue to dispatch from
* @rd: pointer to struct row_data
*
* Updates rd->curr_queue. Returns 1 if there are requests to
* dispatch, 0 if there are no requests in scheduler
*
*/
static int row_choose_queue(struct row_data *rd)
{
int prev_curr_queue = rd->curr_queue;
if (!(rd->nr_reqs[0] + rd->nr_reqs[1]))
return 0;
row_get_next_queue(rd);
/*
* Loop over all queues to find the next queue that is not empty.
* Stop when you get back to curr_queue
*/
while (list_empty(&rd->row_queues[rd->curr_queue].rqueue.fifo)
&& rd->curr_queue != prev_curr_queue) {
/* Mark rqueue as unserved */
row_mark_rowq_unserved(rd, rd->curr_queue);
row_get_next_queue(rd);
}
return 1;
}