md: Don't wait UNINTERRUPTIBLE for other resync to finish

When two md arrays share some block device (e.g each uses different
partitions on the one device), a resync of one array will wait for
the resync on the other to finish.

This can be a long time and as it currently waits TASK_UNINTERRUPTIBLE,
the softlockup code notices and complains.

So use TASK_INTERRUPTIBLE instead and make sure to flush signals
before calling schedule.

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

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 4790c83d78d0cd52adbfb4d4c394eb9d7ec4c691..deeac4b44173d959b2fca6ca7f9abf57aa419f55 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5761,7 +5761,11 @@ void md_do_sync(mddev_t *mddev)
                                         * time 'round when curr_resync == 2
                                         */
                                        continue;
-                               prepare_to_wait(&resync_wait, &wq, TASK_UNINTERRUPTIBLE);
+                               /* We need to wait 'interruptible' so as not to
+                                * contribute to the load average, and not to
+                                * be caught by 'softlockup'
+                                */
+                               prepare_to_wait(&resync_wait, &wq, TASK_INTERRUPTIBLE);
                                if (!kthread_should_stop() &&
                                    mddev2->curr_resync >= mddev->curr_resync) {
                                        printk(KERN_INFO "md: delaying %s of %s"
@@ -5769,6 +5773,8 @@ void md_do_sync(mddev_t *mddev)
                                               " share one or more physical units)\n",
                                               desc, mdname(mddev), mdname(mddev2));
                                        mddev_put(mddev2);
+                                       if (signal_pending(current))
+                                               flush_signals(current);
                                        schedule();
                                        finish_wait(&resync_wait, &wq);
                                        goto try_again;