[ide] add ide_drive_t.sleeping

ide_drive_t.sleeping field added.  0 in sleep field used to
indicate inactive sleeping but because 0 is a valid jiffy
value, though slim, there's a chance that something can go
weird.  And while at it, explicit jiffy comparisons are
converted to use time_before() macros.
Signed-off-by: Tejun Heo <tj@home-tj.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

drivers/ide/ide-io.c

@@ -933,6 +933,7 @@ void ide_stall_queue (ide_drive_t *drive, unsigned long timeout)
 	if (timeout > WAIT_WORSTCASE)
 		timeout = WAIT_WORSTCASE;
 	drive->sleep = timeout + jiffies;
+	drive->sleeping = 1;
 }
 
 EXPORT_SYMBOL(ide_stall_queue);
@@ -972,18 +973,18 @@ static inline ide_drive_t *choose_drive (ide_hwgroup_t *hwgroup)
 	}
 
 	do {
-		if ((!drive->sleep || time_after_eq(jiffies, drive->sleep))
+		if ((!drive->sleeping || time_after_eq(jiffies, drive->sleep))
 		    && !elv_queue_empty(drive->queue)) {
 			if (!best
-			 || (drive->sleep && (!best->sleep || 0 < (signed long)(best->sleep - drive->sleep)))
-			 || (!best->sleep && 0 < (signed long)(WAKEUP(best) - WAKEUP(drive))))
+			 || (drive->sleeping && (!best->sleeping || time_before(drive->sleep, best->sleep)))
+			 || (!best->sleeping && time_before(WAKEUP(drive), WAKEUP(best))))
 			{
 				if (!blk_queue_plugged(drive->queue))
 					best = drive;
 			}
 		}
 	} while ((drive = drive->next) != hwgroup->drive);
-	if (best && best->nice1 && !best->sleep && best != hwgroup->drive && best->service_time > WAIT_MIN_SLEEP) {
+	if (best && best->nice1 && !best->sleeping && best != hwgroup->drive && best->service_time > WAIT_MIN_SLEEP) {
 		long t = (signed long)(WAKEUP(best) - jiffies);
 		if (t >= WAIT_MIN_SLEEP) {
 		/*
@@ -992,10 +993,9 @@ static inline ide_drive_t *choose_drive (ide_hwgroup_t *hwgroup)
 		 */
 			drive = best->next;
 			do {
-				if (!drive->sleep
-				/* FIXME: use time_before */
-				 && 0 < (signed long)(WAKEUP(drive) - (jiffies - best->service_time))
-				 && 0 < (signed long)((jiffies + t) - WAKEUP(drive)))
+				if (!drive->sleeping
+				 && 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;
@@ -1058,14 +1058,17 @@ static void ide_do_request (ide_hwgroup_t *hwgroup, int masked_irq)
 		hwgroup->busy = 1;
 		drive = choose_drive(hwgroup);
 		if (drive == NULL) {
-			unsigned long sleep = 0;
+			int sleeping = 0;
+			unsigned long sleep = 0; /* shut up, gcc */
 			hwgroup->rq = NULL;
 			drive = hwgroup->drive;
 			do {
-				if (drive->sleep && (!sleep || 0 < (signed long)(sleep - drive->sleep)))
+				if (drive->sleeping && (!sleeping || time_before(drive->sleep, sleep))) {
+					sleeping = 1;
 					sleep = drive->sleep;
+				}
 			} while ((drive = drive->next) != hwgroup->drive);
-			if (sleep) {
+			if (sleeping) {
 		/*
 		 * Take a short snooze, and then wake up this hwgroup again.
 		 * This gives other hwgroups on the same a chance to
@@ -1105,7 +1108,7 @@ static void ide_do_request (ide_hwgroup_t *hwgroup, int masked_irq)
 		}
 		hwgroup->hwif = hwif;
 		hwgroup->drive = drive;
-		drive->sleep = 0;
+		drive->sleeping = 0;
 		drive->service_start = jiffies;
 
 		if (blk_queue_plugged(drive->queue)) {

include/linux/ide.h

@@ -717,6 +717,7 @@ typedef struct ide_drive_s {
 					 *  3=64-bit
 					 */
 	unsigned scsi		: 1;	/* 0=default, 1=ide-scsi emulation */
+	unsigned sleeping	: 1;	/* 1=sleeping & sleep field valid */
 
         u8	quirk_list;	/* considered quirky, set for a specific host */
         u8	init_speed;	/* transfer rate set at boot */