staging: comedi: use attach_lock semaphore during attach and detach

Acquire the `attach_lock` semaphore in the `struct comedi_device` while
modifying the `attached` flag.  This is a "write" acquire.  Note that
the main mutex in the `struct comedi_device` is also held at this time.
Tasks wishing to check the device is attached will need to either
acquire the main mutex, or "read" acquire the `attach_lock` semaphore,
or both in that order.

Signed-off-by: Ian Abbott <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

0 files changed, 0 insertions, 0 deletions