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: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/char/tty_port.c b/drivers/char/tty_port.c
index dd471d6..3ef644a 100644
--- a/drivers/char/tty_port.c
+++ b/drivers/char/tty_port.c
@@ -25,6 +25,7 @@
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 @@
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 @@
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);
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 6352ac2..e9269ca 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -212,6 +212,7 @@
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 */