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, 15 insertions, 4 deletions

diff --git a/drivers/w1/w1.h b/drivers/w1/w1.h
index f1df534..13e0ea8 100644
--- a/drivers/w1/w1.h
+++ b/drivers/w1/w1.h
@@ -77,7 +77,7 @@ struct w1_slave
 	struct completion	released;
 };
 
-typedef void (* w1_slave_found_callback)(void *, u64);
+typedef void (*w1_slave_found_callback)(struct w1_master *, u64);
 
 
 /**
@@ -142,12 +142,14 @@ struct w1_bus_master
 	 */
 	u8		(*reset_bus)(void *);
 
-	/** Really nice hardware can handles the different types of ROM search */
-	void		(*search)(void *, u8, w1_slave_found_callback);
+	/** Really nice hardware can handles the different types of ROM search
+	 *  w1_master* is passed to the slave found callback.
+	 */
+	void		(*search)(void *, struct w1_master *,
+		u8, w1_slave_found_callback);
 };
 
 #define W1_MASTER_NEED_EXIT		0
-#define W1_MASTER_NEED_RECONNECT	1
 
 struct w1_master
 {
@@ -181,12 +183,21 @@ struct w1_master
 };
 
 int w1_create_master_attributes(struct w1_master *);
+void w1_destroy_master_attributes(struct w1_master *master);
 void w1_search(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb);
 void w1_search_devices(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb);
 struct w1_slave *w1_search_slave(struct w1_reg_num *id);
 void w1_search_process(struct w1_master *dev, u8 search_type);
 struct w1_master *w1_search_master_id(u32 id);
 
+/* Disconnect and reconnect devices in the given family.  Used for finding
+ * unclaimed devices after a family has been registered or releasing devices
+ * after a family has been unregistered.  Set attach to 1 when a new family
+ * has just been registered, to 0 when it has been unregistered.
+ */
+void w1_reconnect_slaves(struct w1_family *f, int attach);
+void w1_slave_detach(struct w1_slave *sl);
+
 u8 w1_triplet(struct w1_master *dev, int bdir);
 void w1_write_8(struct w1_master *, u8);
 int w1_reset_bus(struct w1_master *);