This change ensures that concurrent device access including ramdisk
storage, protection info, and provisioning map by read, write, and
unmap commands are protected with atomic_rw spinlock.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: NDouglas Gilbert <dgilbert@interlog.com>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>