On Thu, 11 Jan 2018 13:03:41 +0100 Petr Mladek <pmla...@suse.com> wrote:
> > > +static DEFINE_RAW_SPINLOCK(console_owner_lock); > > > +static struct task_struct *console_owner; > > > +static bool console_waiter; > > > + > > > +/** > > > + * console_lock_spinning_enable - mark beginning of code where another > > > + * thread might safely busy wait > > > + * > > > + * This might be called in sections where the current console_lock owner > > > > > > > > > "might be"? It has to be called in sections where the current > > console_lock owner can not sleep. It's basically saying "console lock is > > now acting like a spinlock". > > I am afraid that both explanations are confusing. Your one sounds like > it must be called every time we enter non-preemptive context in > console_unlock. What about the following? > > * This is basically saying that "console lock is now acting like > * a spinlock". It can be called _only_ in sections where the current > * console_lock owner could not sleep. Also it must be ready to hand > * over the lock at the end of the section. I would reword the above: * This basically converts console_lock into a spinlock. This marks * the section where the console_lock owner can not sleep, because * there may be a waiter spinning (like a spinlock). Also it must be * ready to hand over the lock at the end of the section. > > > > + * cannot sleep. It is a signal that another thread might start busy > > > + * waiting for console_lock. > > > + */ > > All the other changes look good to me. I will use them in the next version. Great. -- Steve
