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 <david@fries.net>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/w1/masters/ds1wm.c b/drivers/w1/masters/ds1wm.c
index 10211e493001..ea894bf18113 100644
--- a/drivers/w1/masters/ds1wm.c
+++ b/drivers/w1/masters/ds1wm.c
@@ -274,8 +274,8 @@ static u8 ds1wm_reset_bus(void *data)
         return 0;
 }
 
-static void ds1wm_search(void *data, u8 search_type,
-                         w1_slave_found_callback slave_found)
+static void ds1wm_search(void *data, struct w1_master *master_dev,
+                        u8 search_type, w1_slave_found_callback slave_found)
 {
         struct ds1wm_data *ds1wm_data = data;
         int i;
@@ -313,7 +313,7 @@ static void ds1wm_search(void *data, u8 search_type,
         ds1wm_write_register(ds1wm_data, DS1WM_CMD, ~DS1WM_CMD_SRA);
         ds1wm_reset(ds1wm_data);
 
-        slave_found(ds1wm_data, rom_id);
+        slave_found(master_dev, rom_id);
 }
 
 /* --------------------------------------------------------------------- */