Revert "ide: improve handling of Power Management requests"

This reverts commit a1317f714af7aed60ddc182d0122477cbe36ee9b.

1 files changed, 32 insertions, 22 deletions

diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c
index d5f3c77beadd..db96138fefcd 100644
--- a/drivers/ide/ide-io.c
+++ b/drivers/ide/ide-io.c
@@ -466,14 +466,10 @@ void do_ide_request(struct request_queue *q)
 
         if (!ide_lock_port(hwif)) {
                 ide_hwif_t *prev_port;
+
+                WARN_ON_ONCE(hwif->rq);
 repeat:
                 prev_port = hwif->host->cur_port;
-
-                if (drive->dev_flags & IDE_DFLAG_BLOCKED)
-                        rq = hwif->rq;
-                else
-                        WARN_ON_ONCE(hwif->rq);
-
                 if (drive->dev_flags & IDE_DFLAG_SLEEPING &&
                     time_after(drive->sleep, jiffies)) {
                         ide_unlock_port(hwif);
@@ -500,29 +496,43 @@ repeat:
                 hwif->cur_dev = drive;
                 drive->dev_flags &= ~(IDE_DFLAG_SLEEPING | IDE_DFLAG_PARKED);
 
-                if (rq == NULL) {
-                        spin_unlock_irq(&hwif->lock);
-                        spin_lock_irq(q->queue_lock);
-                        /*
-                         * we know that the queue isn't empty, but this can
-                         * happen if ->prep_rq_fn() decides to kill a request
-                         */
+                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
+                 */
+                if (!rq)
                         rq = blk_fetch_request(drive->queue);
-                        spin_unlock_irq(q->queue_lock);
-                        spin_lock_irq(&hwif->lock);
 
-                        if (rq == NULL) {
-                                ide_unlock_port(hwif);
-                                goto out;
-                        }
+                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.
+                 * if we are currently power managed. This is very important as
+                 * blk_stop_queue() doesn't prevent the blk_fetch_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.
                  */
-                BUG_ON((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
-                       blk_pm_request(rq) == 0);
+                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;