[PATCH] lockdep: core, add enable/disable_irq_irqsave/irqrestore() APIs

Introduce the disable_irq_nosync_lockdep_irqsave() and
enable_irq_lockdep_irqrestore() APIs.  These are needed for NE2000; basically
NE2000 calls disable_irq and enable_irq as locking against the IRQ handler,
but both in cases where interrupts are on and off.  This means that lockdep
needs to track the old state of the virtual irq flags on disable_irq, and
restore these at enable_irq time.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/net/8390.c

@@ -299,7 +299,7 @@ static int ei_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	 *	Slow phase with lock held.
 	 */
 
-	disable_irq_nosync_lockdep(dev->irq);
+	disable_irq_nosync_lockdep_irqsave(dev->irq, &flags);
 
 	spin_lock(&ei_local->page_lock);
 
@@ -338,7 +338,7 @@ static int ei_start_xmit(struct sk_buff *skb, struct net_device *dev)
 		netif_stop_queue(dev);
 		outb_p(ENISR_ALL, e8390_base + EN0_IMR);
 		spin_unlock(&ei_local->page_lock);
-		enable_irq_lockdep(dev->irq);
+		enable_irq_lockdep_irqrestore(dev->irq, &flags);
 		ei_local->stat.tx_errors++;
 		return 1;
 	}
@@ -379,7 +379,7 @@ static int ei_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	outb_p(ENISR_ALL, e8390_base + EN0_IMR);
 
 	spin_unlock(&ei_local->page_lock);
-	enable_irq_lockdep(dev->irq);
+	enable_irq_lockdep_irqrestore(dev->irq, &flags);
 
 	dev_kfree_skb (skb);
 	ei_local->stat.tx_bytes += send_length;

include/linux/interrupt.h

@@ -123,6 +123,14 @@ static inline void disable_irq_nosync_lockdep(unsigned int irq)
 #endif
 }
 
+static inline void disable_irq_nosync_lockdep_irqsave(unsigned int irq, unsigned long *flags)
+{
+	disable_irq_nosync(irq);
+#ifdef CONFIG_LOCKDEP
+	local_irq_save(*flags);
+#endif
+}
+
 static inline void disable_irq_lockdep(unsigned int irq)
 {
 	disable_irq(irq);
@@ -139,6 +147,14 @@ static inline void enable_irq_lockdep(unsigned int irq)
 	enable_irq(irq);
 }
 
+static inline void enable_irq_lockdep_irqrestore(unsigned int irq, unsigned long *flags)
+{
+#ifdef CONFIG_LOCKDEP
+	local_irq_restore(*flags);
+#endif
+	enable_irq(irq);
+}
+
 /* IRQ wakeup (PM) control: */
 extern int set_irq_wake(unsigned int irq, unsigned int on);