Re: [PATCH] tty/serial_core: Introduce lock mechanism for RS485
From: One Thousand Gnomes <hidden>
Date: 2014-10-13 13:52:48
Also in:
lkml
quoted hunk ↗ jump to hunk
@@ -1154,8 +1154,16 @@ static int uart_get_icount(struct tty_struct *tty, static int uart_get_rs485_config(struct uart_port *port, struct serial_rs485 __user *rs485) { - if (copy_to_user(rs485, &port->rs485, sizeof(port->rs485))) + unsigned long flags; + int ret; + + spin_lock_irqsave(&port->lock, flags); + ret = copy_to_user(rs485, &port->rs485, sizeof(port->rs485)); + spin_unlock_irqrestore(&port->lock, flags);
Looks good apart from this bit.. The copy needs to go to a temporary before the lock is taken otherwise we may sleep on a pagefault with irqs off Alan