[PATCH] Calgary: allow compiling Calgary in but not using it by default

This patch makes it possible to compile Calgary in but not use it by
default. In this mode, use 'iommu=calgary' to activate it.

Signed-off-by: Muli Ben-Yehuda <muli@il.ibm.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
Signed-off-by: Andi Kleen <ak@suse.de>
diff --git a/arch/x86_64/kernel/pci-dma.c b/arch/x86_64/kernel/pci-dma.c
index f8d8574..683b7a5 100644
--- a/arch/x86_64/kernel/pci-dma.c
+++ b/arch/x86_64/kernel/pci-dma.c
@@ -296,6 +296,11 @@
 		gart_parse_options(p);
 #endif
 
+#ifdef CONFIG_CALGARY_IOMMU
+		if (!strncmp(p, "calgary", 7))
+			use_calgary = 1;
+#endif /* CONFIG_CALGARY_IOMMU */
+
 		p += strcspn(p, ",");
 		if (*p == ',')
 			++p;