[PATCH] w1: reconnect feature.

I've created reconnect feature - if on start there are no registered families
all new devices will have defailt family, later when driver for appropriate
family is loaded, slaves, which were faound earlier, will still have defult
family instead of right one. Reconnect feature will force control thread to run
through all master devices and all slaves found and search for slaves with
default family id and try to reconnect them.

It does not store newly registered family and does not check only those slaves
which have reg_num.family the same as being registered one - all slaves with
default family are reconnected.

Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 53 insertions, 15 deletions

diff --git a/drivers/w1/w1.c b/drivers/w1/w1.c
index 0e6ccd46af0..b460927ec32 100644
--- a/drivers/w1/w1.c
+++ b/drivers/w1/w1.c
@@ -469,6 +469,8 @@ static void w1_slave_detach(struct w1_slave *sl)
 	device_unregister(&sl->dev);
 	w1_family_put(sl->family);
 
+	sl->master->slave_count--;
+
 	memcpy(&msg.id.id, &sl->reg_num, sizeof(msg.id.id));
 	msg.type = W1_SLAVE_REMOVE;
 	w1_netlink_send(sl->master, &msg);
@@ -492,6 +494,20 @@ static struct w1_master *w1_search_master(unsigned long data)
 	return (found)?dev:NULL;
 }
 
+void w1_reconnect_slaves(struct w1_family *f)
+{
+	struct w1_master *dev;
+
+	spin_lock_bh(&w1_mlock);
+	list_for_each_entry(dev, &w1_masters, w1_master_entry) {
+		dev_info(&dev->dev, "Reconnecting slaves in %s into new family %02x.\n",
+				dev->name, f->fid);
+		set_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
+	}
+	spin_unlock_bh(&w1_mlock);
+}
+
+
 static void w1_slave_found(unsigned long data, u64 rn)
 {
 	int slave_count;
@@ -637,7 +653,7 @@ static int w1_control(void *data)
 			flush_signals(current);
 
 		list_for_each_entry_safe(dev, n, &w1_masters, w1_master_entry) {
-			if (!control_needs_exit && !dev->need_exit)
+			if (!control_needs_exit && !dev->flags)
 				continue;
 			/*
 			 * Little race: we can create thread but not set the flag.
@@ -648,12 +664,8 @@ static int w1_control(void *data)
 				continue;
 			}
 
-			spin_lock_bh(&w1_mlock);
-			list_del(&dev->w1_master_entry);
-			spin_unlock_bh(&w1_mlock);
-
 			if (control_needs_exit) {
-				dev->need_exit = 1;
+				set_bit(W1_MASTER_NEED_EXIT, &dev->flags);
 
 				err = kill_proc(dev->kpid, SIGTERM, 1);
 				if (err)
@@ -662,16 +674,42 @@ static int w1_control(void *data)
 						 dev->kpid);
 			}
 
-			wait_for_completion(&dev->dev_exited);
+			if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
+				wait_for_completion(&dev->dev_exited);
+				spin_lock_bh(&w1_mlock);
+				list_del(&dev->w1_master_entry);
+				spin_unlock_bh(&w1_mlock);
+
+				list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
+					list_del(&sl->w1_slave_entry);
+
+					w1_slave_detach(sl);
+					kfree(sl);
+				}
+				w1_destroy_master_attributes(dev);
+				atomic_dec(&dev->refcnt);
+				continue;
+			}
+
+			if (test_bit(W1_MASTER_NEED_RECONNECT, &dev->flags)) {
+				dev_info(&dev->dev, "Reconnecting slaves in device %s.\n", dev->name);
+				down(&dev->mutex);
+				list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
+					if (sl->family->fid == W1_FAMILY_DEFAULT) {
+						struct w1_reg_num rn;
+						list_del(&sl->w1_slave_entry);
+						w1_slave_detach(sl);
+
+						memcpy(&rn, &sl->reg_num, sizeof(rn));
 
-			list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) {
-				list_del(&sl->w1_slave_entry);
+						kfree(sl);
 
-				w1_slave_detach(sl);
-				kfree(sl);
+						w1_attach_slave_device(dev, &rn);
+					}
+				}
+				clear_bit(W1_MASTER_NEED_RECONNECT, &dev->flags);
+				up(&dev->mutex);
 			}
-			w1_destroy_master_attributes(dev);
-			atomic_dec(&dev->refcnt);
 		}
 	}
 
@@ -686,14 +724,14 @@ int w1_process(void *data)
 	daemonize("%s", dev->name);
 	allow_signal(SIGTERM);
 
-	while (!dev->need_exit) {
+	while (!test_bit(W1_MASTER_NEED_EXIT, &dev->flags)) {
 		try_to_freeze(PF_FREEZE);
 		msleep_interruptible(w1_timeout * 1000);
 
 		if (signal_pending(current))
 			flush_signals(current);
 
-		if (dev->need_exit)
+		if (test_bit(W1_MASTER_NEED_EXIT, &dev->flags))
 			break;
 
 		if (!dev->initialized)