Re: [RFC][PATCH v2 1/2] printk: Make printk() completely async

[Tetsuo Handa]

Sergey Senozhatsky wrote:
> such usage is quite possible.
> 
> problems that I have with console_lock()/console_unlock() is that
> these functions serve a double purpose: exclusive printk() lock and a
> console_drivers list lock.

Yes, I don't like it too.

> 
> **** I haven't really thought about it yet, but I want to split it. ****
> 

Since writing to console does not call schedule(), I think
rcu_read_lock()/rcu_read_unlock()/synchronize_rcu() (or synchronize_rcu_*() ?)
can manage it without using
read_lock_console()/read_unlock_console()/write_lock_console()/write_unlock_console().

Replacing console_lock()/console_unlock() for protecting console_drivers list
with RCU might be helpful.