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_family.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'drivers/w1/w1_family.c') diff --git a/drivers/w1/w1_family.c b/drivers/w1/w1_family.c index a3c95bd6890a..8c35f9ccb689 100644 --- a/drivers/w1/w1_family.c +++ b/drivers/w1/w1_family.c @@ -53,7 +53,8 @@ int w1_register_family(struct w1_family *newf) } spin_unlock(&w1_flock); - w1_reconnect_slaves(newf); + /* check default devices against the new set of drivers */ + w1_reconnect_slaves(newf, 1); return ret; } @@ -77,6 +78,9 @@ void w1_unregister_family(struct w1_family *fent) spin_unlock(&w1_flock); + /* deatch devices using this family code */ + w1_reconnect_slaves(fent, 0); + while (atomic_read(&fent->refcnt)) { printk(KERN_INFO "Waiting for family %u to become free: refcnt=%d.\n", fent->fid, atomic_read(&fent->refcnt)); -- cgit v1.2.3