On Tue, Jan 23, 2018 at 04:47:11PM +0000, Bart Van Assche wrote: > On Wed, 2018-01-24 at 00:41 +0800, Ming Lei wrote: > > Could you explain where to call call_rcu()? call_rcu() can't be used in > > IO path at all. > > Can you explain what makes you think that call_rcu() can't be used in the > I/O path? As you know call_rcu() invokes a function asynchronously. From > Documentation/RCU/Design/Requirements/Requirements.html: > > The <tt>call_rcu()</tt> function may be used in a number of > situations where neither <tt>synchronize_rcu()</tt> nor > <tt>synchronize_rcu_expedited()</tt> would be legal, > including within preempt-disable code, <tt>local_bh_disable()</tt> code, > interrupt-disable code, and interrupt handlers. OK, suppose it is true, do you want to change most of STS_RESOURCE in all drivers to this way? Why can't we use the generic and simple approach in this patch? -- Ming
