1 files changed, 26 insertions, 10 deletions

diff --git a/drivers/net/slip/slip.c b/drivers/net/slip/slip.c
index ad4a94e9ff57..87526443841f 100644
--- a/drivers/net/slip/slip.c
+++ b/drivers/net/slip/slip.c
@@ -83,6 +83,7 @@
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/slab.h>
+#include <linux/workqueue.h>
 #include "slip.h"
 #ifdef CONFIG_INET
 #include <linux/ip.h>
@@ -416,36 +417,46 @@ static void sl_encaps(struct slip *sl, unsigned char *icp, int len)
 #endif
 }
 
-/*
- * Called by the driver when there's room for more data.  If we have
- * more packets to send, we send them here.
- */
-static void slip_write_wakeup(struct tty_struct *tty)
+/* Write out any remaining transmit buffer. Scheduled when tty is writable */
+static void slip_transmit(struct work_struct *work)
 {
+        struct slip *sl = container_of(work, struct slip, tx_work);
         int actual;
-        struct slip *sl = tty->disc_data;
 
+        spin_lock_bh(&sl->lock);
         /* First make sure we're connected. */
-        if (!sl || sl->magic != SLIP_MAGIC || !netif_running(sl->dev))
+        if (!sl->tty || sl->magic != SLIP_MAGIC || !netif_running(sl->dev)) {
+                spin_unlock_bh(&sl->lock);
                 return;
+        }
 
-        spin_lock_bh(&sl->lock);
         if (sl->xleft <= 0)  {
                 /* Now serial buffer is almost free & we can start
                  * transmission of another packet */
                 sl->dev->stats.tx_packets++;
-                clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+                clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
                 spin_unlock_bh(&sl->lock);
                 sl_unlock(sl);
                 return;
         }
 
-        actual = tty->ops->write(tty, sl->xhead, sl->xleft);
+        actual = sl->tty->ops->write(sl->tty, sl->xhead, sl->xleft);
         sl->xleft -= actual;
         sl->xhead += actual;
         spin_unlock_bh(&sl->lock);
 }
 
+/*
+ * Called by the driver when there's room for more data.
+ * Schedule the transmit.
+ */
+static void slip_write_wakeup(struct tty_struct *tty)
+{
+        struct slip *sl = tty->disc_data;
+
+        schedule_work(&sl->tx_work);
+}
+
 static void sl_tx_timeout(struct net_device *dev)
 {
         struct slip *sl = netdev_priv(dev);
@@ -749,6 +760,7 @@ static struct slip *sl_alloc(dev_t line)
         sl->magic       = SLIP_MAGIC;
         sl->dev         = dev;
         spin_lock_init(&sl->lock);
+        INIT_WORK(&sl->tx_work, slip_transmit);
         sl->mode        = SL_MODE_DEFAULT;
 #ifdef CONFIG_SLIP_SMART
         /* initialize timer_list struct */
@@ -872,8 +884,12 @@ static void slip_close(struct tty_struct *tty)
         if (!sl || sl->magic != SLIP_MAGIC || sl->tty != tty)
                 return;
 
+        spin_lock_bh(&sl->lock);
         tty->disc_data = NULL;
         sl->tty = NULL;
+        spin_unlock_bh(&sl->lock);
+
+        flush_work(&sl->tx_work);
 
         /* VSV = very important to remove timers */
 #ifdef CONFIG_SLIP_SMART