[IrDA]: Calling ppp_unregister_channel() from process context

We need to call ppp_unregister_channel() when IrNET disconnects, and this
must be done from a process context.

Bug reported and patch tested by Guennadi Liakhovetski.
Signed-off-by: Samuel Ortiz <samuel@sortiz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/irda/irnet/irnet.h

@@ -419,7 +419,7 @@ typedef struct irnet_socket
   u32			raccm;		/* to please pppd - dummy) */
   unsigned int		flags;		/* PPP flags (compression, ...) */
   unsigned int		rbits;		/* Unused receive flags ??? */
-
+  struct work_struct disconnect_work;   /* Process context disconnection */
   /* ------------------------ IrTTP part ------------------------ */
   /* We create a pseudo "socket" over the IrDA tranport */
   unsigned long		ttp_open;	/* Set when IrTTP is ready */

net/irda/irnet/irnet_irda.c

@@ -10,6 +10,27 @@
 
 #include "irnet_irda.h"		/* Private header */
 
+/*
+ * PPP disconnect work: we need to make sure we're in
+ * process context when calling ppp_unregister_channel().
+ */
+static void irnet_ppp_disconnect(struct work_struct *work)
+{
+	irnet_socket * self =
+		container_of(work, irnet_socket, disconnect_work);
+
+	if (self == NULL)
+		return;
+	/*
+	 * If we were connected, cleanup & close the PPP
+	 * channel, which will kill pppd (hangup) and the rest.
+	 */
+	if (self->ppp_open && !self->ttp_open && !self->ttp_connect) {
+		ppp_unregister_channel(&self->chan);
+		self->ppp_open = 0;
+	}
+}
+
 /************************* CONTROL CHANNEL *************************/
 /*
  * When ppp is not active, /dev/irnet act as a control channel.
@@ -499,6 +520,8 @@ irda_irnet_create(irnet_socket *	self)
 #endif /* DISCOVERY_NOMASK */
   self->tx_flow = FLOW_START;	/* Flow control from IrTTP */
 
+  INIT_WORK(&self->disconnect_work, irnet_ppp_disconnect);
+
   DEXIT(IRDA_SOCK_TRACE, "\n");
   return(0);
 }
@@ -1134,15 +1157,8 @@ irnet_disconnect_indication(void *	instance,
     {
       if(test_open)
 	{
-#ifdef MISSING_PPP_API
-	  /* ppp_unregister_channel() wants a user context, which we
-	   * are guaranteed to NOT have here. What are we supposed
-	   * to do here ? Jean II */
-	  /* If we were connected, cleanup & close the PPP channel,
-	   * which will kill pppd (hangup) and the rest */
-	  ppp_unregister_channel(&self->chan);
-	  self->ppp_open = 0;
-#endif
+	  /* ppp_unregister_channel() wants a user context. */
+	  schedule_work(&self->disconnect_work);
 	}
       else
 	{