dm: use fsleep() instead of msleep() for deterministic sleep duration

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

drivers/md/dm-init.c

@@ -296,7 +296,7 @@ static int __init dm_init_init(void)
 		if (waitfor[i]) {
 			DMINFO("waiting for device %s ...", waitfor[i]);
 			while (!dm_get_dev_t(waitfor[i]))
-				msleep(5);
+				fsleep(5000);
 		}
 	}
 

drivers/md/dm-kcopyd.c

@@ -110,7 +110,7 @@ static DEFINE_SPINLOCK(throttle_spinlock);
  * The reason for this is unknown but possibly due to jiffies rounding errors
  * or read/write cache inside the disk.
  */
-#define SLEEP_MSEC			100
+#define SLEEP_USEC			100000
 
 /*
  * Maximum number of sleep events. There is a theoretical livelock if more
@@ -158,7 +158,7 @@ static void io_job_start(struct dm_kcopyd_throttle *t)
 	if (unlikely(skew > 0) && slept < MAX_SLEEPS) {
 		slept++;
 		spin_unlock_irq(&throttle_spinlock);
-		msleep(SLEEP_MSEC);
+		fsleep(SLEEP_USEC);
 		goto try_again;
 	}
 

drivers/md/dm-snap.c

@@ -298,12 +298,12 @@ static int __chunk_is_tracked(struct dm_snapshot *s, chunk_t chunk)
 
 /*
  * This conflicting I/O is extremely improbable in the caller,
- * so msleep(1) is sufficient and there is no need for a wait queue.
+ * so fsleep(1000) is sufficient and there is no need for a wait queue.
  */
 static void __check_for_conflicting_io(struct dm_snapshot *s, chunk_t chunk)
 {
 	while (__chunk_is_tracked(s, chunk))
-		msleep(1);
+		fsleep(1000);
 }
 
 /*
@@ -1494,7 +1494,7 @@ static void snapshot_dtr(struct dm_target *ti)
 	unregister_snapshot(s);
 
 	while (atomic_read(&s->pending_exceptions_count))
-		msleep(1);
+		fsleep(1000);
 	/*
 	 * Ensure instructions in mempool_exit aren't reordered
 	 * before atomic_read.

drivers/md/dm.c

@@ -436,7 +436,7 @@ static int dm_prepare_ioctl(struct mapped_device *md, int *srcu_idx,
 	r = ti->type->prepare_ioctl(ti, bdev);
 	if (r == -ENOTCONN && !fatal_signal_pending(current)) {
 		dm_put_live_table(md, *srcu_idx);
-		msleep(10);
+		fsleep(10000);
 		goto retry;
 	}
 
@@ -2455,7 +2455,7 @@ static void __dm_destroy(struct mapped_device *md, bool wait)
 		set_bit(DMF_POST_SUSPENDING, &md->flags);
 		dm_table_postsuspend_targets(map);
 	}
-	/* dm_put_live_table must be before msleep, otherwise deadlock is possible */
+	/* dm_put_live_table must be before fsleep, otherwise deadlock is possible */
 	dm_put_live_table(md, srcu_idx);
 	mutex_unlock(&md->suspend_lock);
 
@@ -2467,7 +2467,7 @@ static void __dm_destroy(struct mapped_device *md, bool wait)
 	 */
 	if (wait)
 		while (atomic_read(&md->holders))
-			msleep(1);
+			fsleep(1000);
 	else if (atomic_read(&md->holders))
 		DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)",
 		       dm_device_name(md), atomic_read(&md->holders));
@@ -2544,7 +2544,7 @@ static int dm_wait_for_completion(struct mapped_device *md, unsigned int task_st
 			break;
 		}
 
-		msleep(5);
+		fsleep(5000);
 	}
 
 	return r;