md: use MD_RECOVERY_INTR instead of kthread_should_stop in resync thread.

We currently use kthread_should_stop() in various places in the
sync/reshape code to abort early.
However some places set MD_RECOVERY_INTR but don't immediately call
md_reap_sync_thread() (and we will shortly get another one).
When this happens we are relying on md_check_recovery() to reap the
thread and that only happen when it finishes normally.
So MD_RECOVERY_INTR must lead to a normal finish without the
kthread_should_stop() test.

So replace all relevant tests, and be more careful when the thread is
interrupted not to acknowledge that latest step in a reshape as it may
not be fully committed yet.

Also add a test on MD_RECOVERY_INTR in the 'is_mddev_idle' loop
so we don't wait have to wait for the speed to drop before we can abort.

Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 14 insertions, 26 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 1ca47b0f4779..a74045df7bab 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -7410,9 +7410,6 @@ void md_do_sync(struct md_thread *thread)
 		mddev->curr_resync = 2;
 
 	try_again:
-		if (kthread_should_stop())
-			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
-
 		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
 			goto skip;
 		for_each_mddev(mddev2, tmp) {
@@ -7437,7 +7434,7 @@ void md_do_sync(struct md_thread *thread)
 				 * be caught by 'softlockup'
 				 */
 				prepare_to_wait(&resync_wait, &wq, TASK_INTERRUPTIBLE);
-				if (!kthread_should_stop() &&
+				if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery) &&
 				    mddev2->curr_resync >= mddev->curr_resync) {
 					printk(KERN_INFO "md: delaying %s of %s"
 					       " until %s has finished (they"
@@ -7513,7 +7510,7 @@ void md_do_sync(struct md_thread *thread)
 	last_check = 0;
 
 	if (j>2) {
-		printk(KERN_INFO 
+		printk(KERN_INFO
 		       "md: resuming %s of %s from checkpoint.\n",
 		       desc, mdname(mddev));
 		mddev->curr_resync = j;
@@ -7550,7 +7547,8 @@ void md_do_sync(struct md_thread *thread)
 			sysfs_notify(&mddev->kobj, NULL, "sync_completed");
 		}
 
-		while (j >= mddev->resync_max && !kthread_should_stop()) {
+		while (j >= mddev->resync_max &&
+		       !test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
 			/* As this condition is controlled by user-space,
 			 * we can block indefinitely, so use '_interruptible'
 			 * to avoid triggering warnings.
@@ -7558,17 +7556,18 @@ void md_do_sync(struct md_thread *thread)
 			flush_signals(current); /* just in case */
 			wait_event_interruptible(mddev->recovery_wait,
 						 mddev->resync_max > j
-						 || kthread_should_stop());
+						 || test_bit(MD_RECOVERY_INTR,
+							     &mddev->recovery));
 		}
 
-		if (kthread_should_stop())
-			goto interrupted;
+		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
+			break;
 
 		sectors = mddev->pers->sync_request(mddev, j, &skipped,
 						  currspeed < speed_min(mddev));
 		if (sectors == 0) {
 			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
-			goto out;
+			break;
 		}
 
 		if (!skipped) { /* actual IO requested */
@@ -7605,10 +7604,8 @@ void md_do_sync(struct md_thread *thread)
 			last_mark = next;
 		}
 
-
-		if (kthread_should_stop())
-			goto interrupted;
-
+		if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
+			break;
 
 		/*
 		 * this loop exits only if either when we are slower than
@@ -7631,11 +7628,12 @@ void md_do_sync(struct md_thread *thread)
 			}
 		}
 	}
-	printk(KERN_INFO "md: %s: %s done.\n",mdname(mddev), desc);
+	printk(KERN_INFO "md: %s: %s %s.\n",mdname(mddev), desc,
+	       test_bit(MD_RECOVERY_INTR, &mddev->recovery)
+	       ? "interrupted" : "done");
 	/*
 	 * this also signals 'finished resyncing' to md_stop
 	 */
- out:
 	blk_finish_plug(&plug);
 	wait_event(mddev->recovery_wait, !atomic_read(&mddev->recovery_active));
 
@@ -7689,16 +7687,6 @@ void md_do_sync(struct md_thread *thread)
 	set_bit(MD_RECOVERY_DONE, &mddev->recovery);
 	md_wakeup_thread(mddev->thread);
 	return;
-
- interrupted:
-	/*
-	 * got a signal, exit.
-	 */
-	printk(KERN_INFO
-	       "md: md_do_sync() got signal ... exiting\n");
-	set_bit(MD_RECOVERY_INTR, &mddev->recovery);
-	goto out;
-
 }
 EXPORT_SYMBOL_GPL(md_do_sync);