The sysfs `state` attribute is not protected against race conditions.
If multiple processes perform a device state transition on the same
device in parallel, unexpected behaviors might occur.

For transitioning the device state, adf_sysfs.c calls the functions
adf_dev_init(), adf_dev_start(), adf_dev_stop() and adf_dev_shutdown()
which are unprotected and interdependent on each other. To perform a
state transition, these functions needs to be called in a specific
order:
  * device up:   adf_dev_init() -> adf_dev_start()
  * device down: adf_dev_stop() -> adf_dev_shutdown()

This change introduces the functions adf_dev_up() and adf_dev_down()
which wrap the state machine functions and protect them with a
per-device lock. These are then used in adf_sysfs.c instead of the
individual state transition functions.

Fixes: 5ee52118 ("crypto: qat - expose device state through sysfs for 4xxx")
Signed-off-by: Shashank Gupta <shashank.gupta@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>