From: liuxiang <liuxiang_1...@126.com> Date: Wed, 18 Apr 2018 21:48:22 +0800 (CST)
> Because the timeout task gets the main spinlock and disable the > current cpu's irq, there is no other task on the same cpu can run, > and tasks on the other cpus can not enter the dm9000_timeout() > again. So in the whole dm9000_timeout() routine, db->timeout_cpu can > not be changed by other tasks. Although smp_processor_id() may > change after preempt_enable(), these tasks always get the false > result when call dm9000_current_in_timeout. Only the timeout task > get the true result. And if there is no timeout, all the tasks that > want to do asynchronous phy operation get the false result. So I > think this can avoid racy. This is a very shaky foundation upon which to base the correctness of your driver's synchronization in my opinion.
