ide: add ide_[un]lock_hwgroup() helpers

Add ide_[un]lock_hwgroup() inline helpers for obtaining exclusive
access to the given hwgroup and update the core code accordingly.

[ This change besides making code saner results in more efficient
  use of ide_{get,release}_lock(). ]

Cc: Michael Schmitz <schmitz@biophys.uni-duesseldorf.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Elias Oltmanns <eo@nebensachen.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide-io.c

@@ -790,10 +790,7 @@ void do_ide_request(struct request_queue *q)
 	/* caller must own hwgroup->lock */
 	BUG_ON(!irqs_disabled());
 
-	while (!hwgroup->busy) {
-		hwgroup->busy = 1;
-		/* for atari only */
-		ide_get_lock(ide_intr, hwgroup);
+	while (!ide_lock_hwgroup(hwgroup)) {
 		drive = choose_drive(hwgroup);
 		if (drive == NULL) {
 			int sleeping = 0;
@@ -825,17 +822,10 @@ void do_ide_request(struct request_queue *q)
 				hwgroup->sleeping = 1;
 				hwgroup->req_gen_timer = hwgroup->req_gen;
 				mod_timer(&hwgroup->timer, sleep);
-				/* we purposely leave hwgroup->busy==1
+				/* we purposely leave hwgroup locked
 				 * while sleeping */
-			} else {
-				/* Ugly, but how can we sleep for the lock
-				 * otherwise? perhaps from tq_disk?
-				 */
-
-				/* for atari only */
-				ide_release_lock();
-				hwgroup->busy = 0;
-			}
+			} else
+				ide_unlock_hwgroup(hwgroup);
 
 			/* no more work for this hwgroup (for now) */
 			goto plug_device;
@@ -865,7 +855,7 @@ void do_ide_request(struct request_queue *q)
 		 */
 		rq = elv_next_request(drive->queue);
 		if (!rq) {
-			hwgroup->busy = 0;
+			ide_unlock_hwgroup(hwgroup);
 			break;
 		}
 
@@ -885,8 +875,8 @@ void do_ide_request(struct request_queue *q)
 		if ((drive->dev_flags & IDE_DFLAG_BLOCKED) &&
 		    blk_pm_request(rq) == 0 &&
 		    (rq->cmd_flags & REQ_PREEMPT) == 0) {
-			/* We clear busy, there should be no pending ATA command at this point. */
-			hwgroup->busy = 0;
+			/* there should be no pending command at this point */
+			ide_unlock_hwgroup(hwgroup);
 			goto plug_device;
 		}
 
@@ -897,7 +887,7 @@ void do_ide_request(struct request_queue *q)
 		spin_lock_irq(&hwgroup->lock);
 
 		if (startstop == ide_stopped) {
-			hwgroup->busy = 0;
+			ide_unlock_hwgroup(hwgroup);
 			if (!elv_queue_empty(orig_drive->queue))
 				blk_plug_device(orig_drive->queue);
 		}
@@ -1001,7 +991,7 @@ void ide_timer_expiry (unsigned long data)
 		 */
 		if (hwgroup->sleeping) {
 			hwgroup->sleeping = 0;
-			hwgroup->busy = 0;
+			ide_unlock_hwgroup(hwgroup);
 		}
 	} else {
 		ide_drive_t *drive = hwgroup->drive;
@@ -1056,7 +1046,7 @@ void ide_timer_expiry (unsigned long data)
 			spin_lock_irq(&hwgroup->lock);
 			enable_irq(hwif->irq);
 			if (startstop == ide_stopped) {
-				hwgroup->busy = 0;
+				ide_unlock_hwgroup(hwgroup);
 				if (!elv_queue_empty(drive->queue))
 					blk_plug_device(drive->queue);
 			}
@@ -1249,7 +1239,7 @@ irqreturn_t ide_intr (int irq, void *dev_id)
 	drive->service_time = jiffies - drive->service_start;
 	if (startstop == ide_stopped) {
 		if (hwgroup->handler == NULL) {	/* paranoia */
-			hwgroup->busy = 0;
+			ide_unlock_hwgroup(hwgroup);
 			if (!elv_queue_empty(drive->queue))
 				blk_plug_device(drive->queue);
 		} else

drivers/ide/ide-park.c

@@ -22,7 +22,7 @@ static void issue_park_cmd(ide_drive_t *drive, unsigned long timeout)
 		if (reset_timer && hwgroup->sleeping &&
 		    del_timer(&hwgroup->timer)) {
 			hwgroup->sleeping = 0;
-			hwgroup->busy = 0;
+			ide_unlock_hwgroup(hwgroup);
 			blk_start_queueing(q);
 		}
 		spin_unlock_irq(&hwgroup->lock);

include/linux/ide.h

@@ -1280,6 +1280,26 @@ extern void ide_stall_queue(ide_drive_t *drive, unsigned long timeout);
 
 extern void ide_timer_expiry(unsigned long);
 extern irqreturn_t ide_intr(int irq, void *dev_id);
+
+static inline int ide_lock_hwgroup(ide_hwgroup_t *hwgroup)
+{
+	if (hwgroup->busy)
+		return 1;
+
+	hwgroup->busy = 1;
+	/* for atari only */
+	ide_get_lock(ide_intr, hwgroup);
+
+	return 0;
+}
+
+static inline void ide_unlock_hwgroup(ide_hwgroup_t *hwgroup)
+{
+	/* for atari only */
+	ide_release_lock();
+	hwgroup->busy = 0;
+}
+
 extern void do_ide_request(struct request_queue *);
 
 void ide_init_disk(struct gendisk *, ide_drive_t *);