[PATCH 1/6] md: Revert "md: Don't register sync_thread for reshape directly"

[Xiao Ni <xni@redhat.com>]

This reverts commit ad39c08186f8a0f221337985036ba86731d6aafe.

Function stop_sync_thread only wakes up sync task. It also needs to
wake up sync thread. This problem will be fixed in the following
patch.

Signed-off-by: Xiao Ni <xni@redhat.com>
---
 drivers/md/md.c     |  5 +----
 drivers/md/raid10.c | 16 ++++++++++++++--
 drivers/md/raid5.c  | 29 +++++++++++++++++++++++++++--
 3 files changed, 42 insertions(+), 8 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 9e41a9aaba8b..db4743ba7f6c 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -9376,7 +9376,6 @@ static void md_start_sync(struct work_struct *ws)
 	struct mddev *mddev = container_of(ws, struct mddev, sync_work);
 	int spares = 0;
 	bool suspend = false;
-	char *name;
 
 	/*
 	 * If reshape is still in progress, spares won't be added or removed
@@ -9414,10 +9413,8 @@ static void md_start_sync(struct work_struct *ws)
 	if (spares)
 		md_bitmap_write_all(mddev->bitmap);
 
-	name = test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) ?
-			"reshape" : "resync";
 	rcu_assign_pointer(mddev->sync_thread,
-			   md_register_thread(md_do_sync, mddev, name));
+			   md_register_thread(md_do_sync, mddev, "resync"));
 	if (!mddev->sync_thread) {
 		pr_warn("%s: could not start resync thread...\n",
 			mdname(mddev));
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index a5f8419e2df1..7412066ea22c 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -4175,7 +4175,11 @@ static int raid10_run(struct mddev *mddev)
 		clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
 		clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
 		set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
-		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+		set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
+		rcu_assign_pointer(mddev->sync_thread,
+			md_register_thread(md_do_sync, mddev, "reshape"));
+		if (!mddev->sync_thread)
+			goto out_free_conf;
 	}
 
 	return 0;
@@ -4569,8 +4573,16 @@ static int raid10_start_reshape(struct mddev *mddev)
 	clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
 	clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
 	set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
-	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+	set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
+
+	rcu_assign_pointer(mddev->sync_thread,
+			   md_register_thread(md_do_sync, mddev, "reshape"));
+	if (!mddev->sync_thread) {
+		ret = -EAGAIN;
+		goto abort;
+	}
 	conf->reshape_checkpoint = jiffies;
+	md_wakeup_thread(mddev->sync_thread);
 	md_new_event();
 	return 0;
 
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 6a7a32f7fb91..8497880135ee 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -7936,7 +7936,11 @@ static int raid5_run(struct mddev *mddev)
 		clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
 		clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
 		set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
-		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+		set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
+		rcu_assign_pointer(mddev->sync_thread,
+			md_register_thread(md_do_sync, mddev, "reshape"));
+		if (!mddev->sync_thread)
+			goto abort;
 	}
 
 	/* Ok, everything is just fine now */
@@ -8502,8 +8506,29 @@ static int raid5_start_reshape(struct mddev *mddev)
 	clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
 	clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
 	set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
-	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+	set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
+	rcu_assign_pointer(mddev->sync_thread,
+			   md_register_thread(md_do_sync, mddev, "reshape"));
+	if (!mddev->sync_thread) {
+		mddev->recovery = 0;
+		spin_lock_irq(&conf->device_lock);
+		write_seqcount_begin(&conf->gen_lock);
+		mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
+		mddev->new_chunk_sectors =
+			conf->chunk_sectors = conf->prev_chunk_sectors;
+		mddev->new_layout = conf->algorithm = conf->prev_algo;
+		rdev_for_each(rdev, mddev)
+			rdev->new_data_offset = rdev->data_offset;
+		smp_wmb();
+		conf->generation--;
+		conf->reshape_progress = MaxSector;
+		mddev->reshape_position = MaxSector;
+		write_seqcount_end(&conf->gen_lock);
+		spin_unlock_irq(&conf->device_lock);
+		return -EAGAIN;
+	}
 	conf->reshape_checkpoint = jiffies;
+	md_wakeup_thread(mddev->sync_thread);
 	md_new_event();
 	return 0;
 }
-- 
2.32.0 (Apple Git-132)