X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Firq%2Fmanage.c;h=1f314221d534be091d809628b39f12ccba4e997e;hb=85b161a826f1954e9605deb3e6faa4be4d285a34;hp=80eab7a0420597ec0c27fe7eaefe12a5868674b9;hpb=81f8320f624a785d77443ace83391d0fdee695f6;p=linux-2.6

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 80eab7a042..1f314221d5 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -29,12 +29,28 @@
 void synchronize_irq(unsigned int irq)
 {
 	struct irq_desc *desc = irq_desc + irq;
+	unsigned int status;
 
 	if (irq >= NR_IRQS)
 		return;
 
-	while (desc->status & IRQ_INPROGRESS)
-		cpu_relax();
+	do {
+		unsigned long flags;
+
+		/*
+		 * Wait until we're out of the critical section.  This might
+		 * give the wrong answer due to the lack of memory barriers.
+		 */
+		while (desc->status & IRQ_INPROGRESS)
+			cpu_relax();
+
+		/* Ok, that indicated we're done: double-check carefully. */
+		spin_lock_irqsave(&desc->lock, flags);
+		status = desc->status;
+		spin_unlock_irqrestore(&desc->lock, flags);
+
+		/* Oops, that failed? */
+	} while (status & IRQ_INPROGRESS);
 }
 EXPORT_SYMBOL(synchronize_irq);