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[PATCH] Serial: Adjust serial locking

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This patch changes the way serial ports are locked when getting modem
status.  This change is necessary because we will need to atomically
read the modem status and take action depending on the CTS status.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King
2005-06-29 09:42:38 +01:00
committed by Russell King
parent a839688362
commit c5f4644e6c
12 changed files with 29 additions and 41 deletions
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11
drivers/serial/serial_core.c
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@ -828,7 +828,10 @@ static int uart_tiocmget(struct tty_struct *tty, struct file *file)
if ((!file || !tty_hung_up_p(file)) &&
!(tty->flags & (1 << TTY_IO_ERROR))) {
result = port->mctrl;
spin_lock_irq(&port->lock);
result |= port->ops->get_mctrl(port);
spin_unlock_irq(&port->lock);
}
up(&state->sem);
@ -1369,6 +1372,7 @@ uart_block_til_ready(struct file *filp, struct uart_state *state)
DECLARE_WAITQUEUE(wait, current);
struct uart_info *info = state->info;
struct uart_port *port = state->port;
unsigned int mctrl;
info->blocked_open++;
state->count--;
@ -1416,7 +1420,10 @@ uart_block_til_ready(struct file *filp, struct uart_state *state)
* and wait for the carrier to indicate that the
* modem is ready for us.
*/
if (port->ops->get_mctrl(port) & TIOCM_CAR)
spin_lock_irq(&port->lock);
mctrl = port->ops->get_mctrl(port);
spin_unlock_irq(&port->lock);
if (mctrl & TIOCM_CAR)
break;
up(&state->sem);
@ -1618,7 +1625,9 @@ static int uart_line_info(char *buf, struct uart_driver *drv, int i)
if(capable(CAP_SYS_ADMIN))
{
spin_lock_irq(&port->lock);
status = port->ops->get_mctrl(port);
spin_unlock_irq(&port->lock);
ret += sprintf(buf + ret, " tx:%d rx:%d",
port->icount.tx, port->icount.rx);