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>

1 files changed, 7 insertions, 1 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 4790c83d78d..deeac4b4417 100644
--- 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;