driver core: synchronize device shutdown
driver core: synchronize device shutdown

A patch series to make .shutdown execute asynchronously.  Some drivers's
shutdown can take a lot of time.  The patches can help save some shutdown
time.  The patches use Arjan's async API.


This patch:

synchronize all tasks submitted by .shutdown

Signed-off-by: Shaohua Li <cb3904095a5bc20edc93ba3dfa3e7d27d981b654@intel.com>
Cc: Arjan van de Ven <9043bf4b08f6c93a2cb55d98c3494b123858348f@infradead.org>
Cc: Dmitry Torokhov <10a8c465cefc9bdd6c925e26964d23c90f1141cc@mail.ru>
Cc: James Bottomley <407b36959ca09543ccda8f8e06721c791bc53435@HansenPartnership.com>
Signed-off-by: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@suse.de>


KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs