[PATCH] PCI: Add sysfs file to map PCI busses to cpus

Add sysfs file to map PCI busses to cpus

Export the information from pcibus_to_cpumask() to sysfs. This
is useful for some user space programs who want to optimize their IO
using O_DIRECT.

There was some indecision on whether it's more useful to report
cpus or nodes here. In the end cpus was chosen because that is
what the existing macros report.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/pci/pci-sysfs.c

@@ -19,6 +19,7 @@
 #include <linux/kernel.h>
 #include <linux/pci.h>
 #include <linux/stat.h>
+#include <linux/topology.h>
 
 #include "pci.h"
 
@@ -42,6 +43,15 @@ pci_config_attr(subsystem_device, "0x%04x\n");
 pci_config_attr(class, "0x%06x\n");
 pci_config_attr(irq, "%u\n");
 
+static ssize_t local_cpus_show(struct device *dev, char *buf)
+{		
+	struct pci_dev *pdev = to_pci_dev(dev);
+	cpumask_t mask = pcibus_to_cpumask(pdev->bus->number);
+	int len = cpumask_scnprintf(buf, PAGE_SIZE-2, mask);
+	strcat(buf,"\n"); 
+	return 1+len;
+}
+
 /* show resources */
 static ssize_t
 resource_show(struct device * dev, char * buf)
@@ -71,6 +81,7 @@ struct device_attribute pci_dev_attrs[] = {
 	__ATTR_RO(subsystem_device),
 	__ATTR_RO(class),
 	__ATTR_RO(irq),
+	__ATTR_RO(local_cpus),
 	__ATTR_NULL,
 };