Define a kfifo inside struct tty_port. We use DECLARE_KFIFO_PTR and let
the preexisting tty_port::xmit_buf be also the buffer for the kfifo.
And handle the initialization/decomissioning along with xmit_buf, i.e.
in tty_port_alloc_xmit_buf() and tty_port_free_xmit_buf(), respectively.
This allows for kfifo use in drivers which opt-in, while others still
may use the old xmit_buf. mxser will be the first user in the next
few patches.
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
drivers/tty/tty_port.c | 6 +++++-
include/linux/tty_port.h | 3 +++
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index 7709ce655f44..7644834640f1 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -225,8 +225,11 @@ int tty_port_alloc_xmit_buf(struct tty_port *port)
{
/* We may sleep in get_zeroed_page() */
mutex_lock(&port->buf_mutex);
- if (port->xmit_buf == NULL)
+ if (port->xmit_buf == NULL) {
port->xmit_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL);
+ if (port->xmit_buf)
+ kfifo_init(&port->xmit_fifo, port->xmit_buf, PAGE_SIZE);
+ }
mutex_unlock(&port->buf_mutex);
if (port->xmit_buf == NULL)
return -ENOMEM;
@@ -240,6 +243,7 @@ void tty_port_free_xmit_buf(struct tty_port *port)
if (port->xmit_buf != NULL) {
free_page((unsigned long)port->xmit_buf);
port->xmit_buf = NULL;
+ INIT_KFIFO(port->xmit_fifo);
}
mutex_unlock(&port->buf_mutex);
}
diff --git a/include/linux/tty_port.h b/include/linux/tty_port.h
index d3ea9ed0b98e..58e9619116b7 100644
--- a/include/linux/tty_port.h
+++ b/include/linux/tty_port.h
@@ -2,6 +2,7 @@
#ifndef _LINUX_TTY_PORT_H
#define _LINUX_TTY_PORT_H
+#include <linux/kfifo.h>
#include <linux/kref.h>
#include <linux/mutex.h>
#include <linux/tty_buffer.h>
@@ -67,6 +68,7 @@ extern const struct tty_port_client_operations tty_port_default_client_ops;
* @mutex: locking, for open, shutdown and other port operations
* @buf_mutex: @xmit_buf alloc lock
* @xmit_buf: optional xmit buffer used by some drivers
+ * @xmit_fifo: optional xmit buffer used by some drivers
* @close_delay: delay in jiffies to wait when closing the port
* @closing_wait: delay in jiffies for output to be sent before closing
* @drain_delay: set to zero if no pure time based drain is needed else set to
@@ -110,6 +112,7 @@ struct tty_port {
struct mutex mutex;
struct mutex buf_mutex;
unsigned char *xmit_buf;
+ DECLARE_KFIFO_PTR(xmit_fifo, unsigned char);
unsigned int close_delay;
unsigned int closing_wait;
int drain_delay;
--
2.34.1
