static inline ide_drive_t *choose_drive (ide_hwgroup_t *hwgroup)
{
ide_drive_t *drive, *best;
repeat:
best = NULL;
drive = hwgroup->drive;
/*
* drive is doing pre-flush, ordered write, post-flush sequence. even
* though that is 3 requests, it must be seen as a single transaction.
* we must not preempt this drive until that is complete
*/
if (blk_queue_flushing(drive->queue)) {
/*
* small race where queue could get replugged during
* the 3-request flush cycle, just yank the plug since
* we want it to finish asap
*/
blk_remove_plug(drive->queue);
return drive;
}
do {
u8 dev_s = !!(drive->dev_flags & IDE_DFLAG_SLEEPING);
u8 best_s = (best && !!(best->dev_flags & IDE_DFLAG_SLEEPING));
if ((dev_s == 0 || time_after_eq(jiffies, drive->sleep)) &&
!elv_queue_empty(drive->queue)) {
if (best == NULL ||
(dev_s && (best_s == 0 || time_before(drive->sleep, best->sleep))) ||
(best_s == 0 && time_before(WAKEUP(drive), WAKEUP(best)))) {
if (!blk_queue_plugged(drive->queue))
best = drive;
}
}
} while ((drive = drive->next) != hwgroup->drive);
if (best && (best->dev_flags & IDE_DFLAG_NICE1) &&
(best->dev_flags & IDE_DFLAG_SLEEPING) == 0 &&
best != hwgroup->drive && best->service_time > WAIT_MIN_SLEEP) {
long t = (signed long)(WAKEUP(best) - jiffies);
if (t >= WAIT_MIN_SLEEP) {
/*
* We *may* have some time to spare, but first let's see if
* someone can potentially benefit from our nice mood today..
*/
drive = best->next;
do {
if ((drive->dev_flags & IDE_DFLAG_SLEEPING) == 0
&& time_before(jiffies - best->service_time, WAKEUP(drive))
&& time_before(WAKEUP(drive), jiffies + t))
{
ide_stall_queue(best, min_t(long, t, 10 * WAIT_MIN_SLEEP));
goto repeat;
}
} while ((drive = drive->next) != best);
}
/*
* Issue a new request to a device.
*/
void do_ide_request(struct request_queue *q)
{
ide_drive_t *drive = q->queuedata;
ide_hwif_t *hwif = drive->hwif;
struct ide_host *host = hwif->host;
struct request *rq = NULL;
ide_startstop_t startstop;
/*
* drive is doing pre-flush, ordered write, post-flush sequence. even
* though that is 3 requests, it must be seen as a single transaction.
* we must not preempt this drive until that is complete
*/
if (blk_queue_flushing(q))
/*
* small race where queue could get replugged during
* the 3-request flush cycle, just yank the plug since
* we want it to finish asap
*/
blk_remove_plug(q);
spin_unlock_irq(q->queue_lock);
if (ide_lock_host(host, hwif))
goto plug_device_2;
spin_lock_irq(&hwif->lock);
if (!ide_lock_port(hwif)) {
ide_hwif_t *prev_port;
repeat:
prev_port = hwif->host->cur_port;
hwif->rq = NULL;
if (drive->dev_flags & IDE_DFLAG_SLEEPING) {
if (time_before(drive->sleep, jiffies)) {
ide_unlock_port(hwif);
goto plug_device;
}
}
if ((hwif->host->host_flags & IDE_HFLAG_SERIALIZE) &&
hwif != prev_port) {
/*
* set nIEN for previous port, drives in the
* quirk_list may not like intr setups/cleanups
*/
if (prev_port && prev_port->cur_dev->quirk_list == 0)
prev_port->tp_ops->set_irq(prev_port, 0);
hwif->host->cur_port = hwif;
}
hwif->cur_dev = drive;
drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);
spin_unlock_irq(&hwif->lock);
spin_lock_irq(q->queue_lock);
/*
* we know that the queue isn't empty, but this can happen
* if the q->prep_rq_fn() decides to kill a request
*/
rq = elv_next_request(drive->queue);
spin_unlock_irq(q->queue_lock);
spin_lock_irq(&hwif->lock);
if (!rq) {
ide_unlock_port(hwif);
goto out;
}
/*
* Sanity: don't accept a request that isn't a PM request
* if we are currently power managed. This is very important as
* blk_stop_queue() doesn't prevent the elv_next_request()
* above to return us whatever is in the queue. Since we call
* ide_do_request() ourselves, we end up taking requests while
* the queue is blocked...
*
* We let requests forced at head of queue with ide-preempt
* though. I hope that doesn't happen too much, hopefully not
* unless the subdriver triggers such a thing in its own PM
* state machine.
*/
if ((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
blk_pm_request(rq) == 0 &&
(rq->cmd_flags & REQ_PREEMPT) == 0) {
/* there should be no pending command at this point */
ide_unlock_port(hwif);
goto plug_device;
}
hwif->rq = rq;
spin_unlock_irq(&hwif->lock);
startstop = start_request(drive, rq);
spin_lock_irq(&hwif->lock);
if (startstop == ide_stopped)
goto repeat;
} else
goto plug_device;
out:
spin_unlock_irq(&hwif->lock);
if (rq == NULL)
ide_unlock_host(host);
spin_lock_irq(q->queue_lock);
return;
plug_device:
spin_unlock_irq(&hwif->lock);
ide_unlock_host(host);
plug_device_2:
spin_lock_irq(q->queue_lock);
if (!elv_queue_empty(q))
blk_plug_device(q);
}
