From c30c9b15187e977ab5928f7276e9dfcd8d6f9460 Mon Sep 17 00:00:00 2001 From: David Fries Date: Wed, 15 Oct 2008 22:04:38 -0700 Subject: W1: fix deadlocks and remove w1_control_thread w1_control_thread was removed which would wake up every second and process newly registered family codes and complete some final cleanup for a removed master. Those routines were moved to the threads that were previously requesting those operations. A new function w1_reconnect_slaves takes care of reconnecting existing slave devices when a new family code is registered or removed. The removal case was missing and would cause a deadlock waiting for the family code reference count to decrease, which will now happen. A problem with registering a family code was fixed. A slave device would be unattached if it wasn't yet claimed, then attached at the end of the list, two unclaimed slaves would cause an infinite loop. The struct w1_bus_master.search now takes a pointer to the struct w1_master device to avoid searching for it, which would have caused a lock ordering deadlock with the removal of w1_control_thread. Signed-off-by: David Fries Signed-off-by: Evgeniy Polyakov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/w1/w1_int.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'drivers/w1/w1_int.c') diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c index 6840dfebe4d..ed3228017da 100644 --- a/drivers/w1/w1_int.c +++ b/drivers/w1/w1_int.c @@ -148,10 +148,22 @@ err_out_free_dev: void __w1_remove_master_device(struct w1_master *dev) { struct w1_netlink_msg msg; + struct w1_slave *sl, *sln; set_bit(W1_MASTER_NEED_EXIT, &dev->flags); kthread_stop(dev->thread); + mutex_lock(&w1_mlock); + list_del(&dev->w1_master_entry); + mutex_unlock(&w1_mlock); + + mutex_lock(&dev->mutex); + list_for_each_entry_safe(sl, sln, &dev->slist, w1_slave_entry) + w1_slave_detach(sl); + w1_destroy_master_attributes(dev); + mutex_unlock(&dev->mutex); + atomic_dec(&dev->refcnt); + while (atomic_read(&dev->refcnt)) { dev_info(&dev->dev, "Waiting for %s to become free: refcnt=%d.\n", dev->name, atomic_read(&dev->refcnt)); -- cgit v1.2.3