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W1: fix deadlocks and remove w1_control_thread

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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>
This commit is contained in:
David Fries
2008-10-15 22:04:38 -07:00
committed by Linus Torvalds
parent dd78c9439f
commit c30c9b1518
7 changed files with 71 additions and 122 deletions
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19
drivers/w1/w1.h
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@ -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 *);