tty: Introduce a tty_port common structure
Every tty driver has its own concept of a port structure and because
they all differ we cannot extract commonality. Begin fixing this by
creating a structure drivers can elect to use so that over time we can
push fields into this and create commonality and then introduce common
methods.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 54c4ada..739c9c5 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -2088,6 +2088,40 @@
return tty_write(file, buf, count, ppos);
}
+void tty_port_init(struct tty_port *port)
+{
+ memset(port, 0, sizeof(*port));
+ init_waitqueue_head(&port->open_wait);
+ init_waitqueue_head(&port->close_wait);
+ mutex_init(&port->mutex);
+}
+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);
+ if (port->xmit_buf == NULL)
+ port->xmit_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL);
+ mutex_unlock(&port->mutex);
+ if (port->xmit_buf == NULL)
+ return -ENOMEM;
+ return 0;
+}
+EXPORT_SYMBOL(tty_port_alloc_xmit_buf);
+
+void tty_port_free_xmit_buf(struct tty_port *port)
+{
+ mutex_lock(&port->mutex);
+ if (port->xmit_buf != NULL) {
+ free_page((unsigned long)port->xmit_buf);
+ port->xmit_buf = NULL;
+ }
+ mutex_unlock(&port->mutex);
+}
+EXPORT_SYMBOL(tty_port_free_xmit_buf);
+
+
static char ptychar[] = "pqrstuvwxyzabcde";
/**