On Thu, 2 Nov 2017 13:06:05 -0400
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> + raw_spin_lock(&console_owner_lock);
> + waiter = console_waiter;
> + console_owner = NULL;
> + raw_spin_unlock(&console_owner_lock);
> +
> + /*
> + * If there is a waiter waiting for us, then pass the
> + * rest of the work load over to that waiter.
> + */
> + if (waiter)
> + break;
OK, the spin_unlock() wont let the load leak. Thus it is fine as is.
> + raw_spin_lock(&console_owner_lock);
> + owner = console_owner;
> + waiter = console_waiter;
> + if (!waiter && owner && owner != current) {
But Mathieu Desnoyers pointed out that usage of variables within a
spinlock may be an issue. Although, it shouldn't affect the code as is,
I think I'll add back READ/WRITE_ONCE() just to be on the safe side.
I may add the waiter = READ_ONCE(console_waiter) to the first one too,
more as documentation. It should cause any issues to add it.
-- Steve
> + console_waiter = true;
> + spin = true;
> + }
> + raw_spin_unlock(&console_owner_lock);
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
