[PATCH] 2.6 Altix: console fix for CONFIG_DEBUG_SHIRQ usage

The sn console driver was snagged by the use of CONFIG_DEBUG_SHIRQ!

The request_irq() immediate call to the interrupt handler caused
another attempt to lock the port lock - deadlock.

This is a patch to fix that.

Signed-off-by: Patrick Gefre <pfg@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 35 deletions

diff --git a/drivers/serial/sn_console.c b/drivers/serial/sn_console.c
index 253ceb895ca7..a27e9e92cb5e 100644
--- a/drivers/serial/sn_console.c
+++ b/drivers/serial/sn_console.c
@@ -636,25 +636,6 @@ static irqreturn_t sn_sal_interrupt(int irq, void *dev_id)
 }
 
 /**
- * sn_sal_connect_interrupt - Request interrupt, handled by sn_sal_interrupt
- * @port: Our sn_cons_port (which contains the uart port)
- *
- * returns the console irq if interrupt is successfully registered, else 0
- *
- */
-static int sn_sal_connect_interrupt(struct sn_cons_port *port)
-{
-        if (request_irq(SGI_UART_VECTOR, sn_sal_interrupt,
-                        IRQF_DISABLED | IRQF_SHARED,
-                        "SAL console driver", port) >= 0) {
-                return SGI_UART_VECTOR;
-        }
-
-        printk(KERN_INFO "sn_console: console proceeding in polled mode\n");
-        return 0;
-}
-
-/**
  * sn_sal_timer_poll - this function handles polled console mode
  * @data: A pointer to our sn_cons_port (which contains the uart port)
  *
@@ -746,30 +727,31 @@ static void __init sn_sal_switch_to_asynch(struct sn_cons_port *port)
  * mode.  We were previously in asynch/polling mode (using init_timer).
  *
  * We attempt to switch to interrupt mode here by calling
- * sn_sal_connect_interrupt.  If that works out, we enable receive interrupts.
+ * request_irq.  If that works out, we enable receive interrupts.
  */
 static void __init sn_sal_switch_to_interrupts(struct sn_cons_port *port)
 {
-        int irq;
         unsigned long flags;
 
-        if (!port)
-                return;
-
-        DPRINTF("sn_console: switching to interrupt driven console\n");
-
-        spin_lock_irqsave(&port->sc_port.lock, flags);
+        if (port) {
+                DPRINTF("sn_console: switching to interrupt driven console\n");
 
-        irq = sn_sal_connect_interrupt(port);
+                if (request_irq(SGI_UART_VECTOR, sn_sal_interrupt,
+                                IRQF_DISABLED | IRQF_SHARED,
+                                "SAL console driver", port) >= 0) {
+                        spin_lock_irqsave(&port->sc_port.lock, flags);
+                        port->sc_port.irq = SGI_UART_VECTOR;
+                        port->sc_ops = &intr_ops;
 
-        if (irq) {
-                port->sc_port.irq = irq;
-                port->sc_ops = &intr_ops;
-
-                /* turn on receive interrupts */
-                ia64_sn_console_intr_enable(SAL_CONSOLE_INTR_RECV);
+                        /* turn on receive interrupts */
+                        ia64_sn_console_intr_enable(SAL_CONSOLE_INTR_RECV);
+                        spin_unlock_irqrestore(&port->sc_port.lock, flags);
+                }
+                else {
+                        printk(KERN_INFO
+                            "sn_console: console proceeding in polled mode\n");
+                }
         }
-        spin_unlock_irqrestore(&port->sc_port.lock, flags);
 }
 
 /*