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Commit 44e4909e authored by Alan Cox's avatar Alan Cox Committed by Greg Kroah-Hartman
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tty: tty_port: Change the buffer allocator locking 



We want to be able to do this without regard for the activate/own open
method being used which causes a problem using port->mutex. Add another
mutex for now. Once everything uses port_open to do buffer allocs we can
kill it back off

Signed-off-by: default avatarAlan Cox <alan@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 1f100b32

drivers/char/tty_port.c

+5 −4
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ void tty_port_init(struct tty_port *port) 
	init_waitqueue_head(&port->close_wait);

	init_waitqueue_head(&port->delta_msr_wait);

	mutex_init(&port->mutex);

	mutex_init(&port->buf_mutex);

	spin_lock_init(&port->lock);

	port->close_delay = (50 * HZ) / 100;

	port->closing_wait = (3000 * HZ) / 100;
@@ -34,10 +35,10 @@ EXPORT_SYMBOL(tty_port_init); 
int tty_port_alloc_xmit_buf(struct tty_port *port)

{

	/* We may sleep in get_zeroed_page() */

	mutex_lock(&port->mutex);

	mutex_lock(&port->buf_mutex);

	if (port->xmit_buf == NULL)

		port->xmit_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL);

	mutex_unlock(&port->mutex);

	mutex_unlock(&port->buf_mutex);

	if (port->xmit_buf == NULL)

		return -ENOMEM;

	return 0;
@@ -46,12 +47,12 @@ EXPORT_SYMBOL(tty_port_alloc_xmit_buf); 


void tty_port_free_xmit_buf(struct tty_port *port)

{

	mutex_lock(&port->mutex);

	mutex_lock(&port->buf_mutex);

	if (port->xmit_buf != NULL) {

		free_page((unsigned long)port->xmit_buf);

		port->xmit_buf = NULL;

	}

	mutex_unlock(&port->mutex);

	mutex_unlock(&port->buf_mutex);

}

EXPORT_SYMBOL(tty_port_free_xmit_buf);

include/linux/tty.h

+1 −0
Original line number Diff line number Diff line
@@ -212,6 +212,7 @@ struct tty_port { 
	wait_queue_head_t	delta_msr_wait;	/* Modem status change */

	unsigned long		flags;		/* TTY flags ASY_*/

	struct mutex		mutex;		/* Locking */

	struct mutex		buf_mutex;	/* Buffer alloc lock */

	unsigned char		*xmit_buf;	/* Optional buffer */

	unsigned int		close_delay;	/* Close port delay */

	unsigned int		closing_wait;	/* Delay for output */