# HG changeset patch
# User root@mercury.spf.cl.nec.co.jp
# Node ID 1a29b07abc6303f016d828070a8e4327fe8f53e9
# Parent  161473836da3ccf922f44e910f8b5c01c709d1e6
Output VBD requests information into sysfs.

  Add group "statistics" under /sys/device/xen-backed/vbd-x-xxxx
  and output VBD statistics information -- oo_req, rd_req, and wr_req --
  into its group.

  Signed-off-by: Satoshi UCHIDA <s-uchida@ap.jp.nec.com>

diff -r 161473836da3 -r 1a29b07abc63 linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c
--- a/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c	Wed Jun 14 22:15:13 2006 +0100
+++ b/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c	Wed Jun 28 16:04:50 2006 +0900
@@ -43,6 +43,13 @@ static void backend_changed(struct xenbu
 static void backend_changed(struct xenbus_watch *, const char **,
 			    unsigned int);
 
+#ifdef CONFIG_SYSFS
+int xenvbd_sysfs_addif(struct xenbus_device *dev);
+void xenvbd_sysfs_delif(struct xenbus_device *dev);
+#else
+#define xenvbd_sysfs_addif(dev) (0)
+#define xenvbd_sysfs_delif(dev) do { } while(0)
+#endif
 
 static void update_blkif_status(blkif_t *blkif)
 { 
@@ -73,6 +80,66 @@ static void update_blkif_status(blkif_t 
 }
 
 
+
+/****************************************************************
+ *  sysfs interface for VBD I/O requests
+ */
+
+#ifdef CONFIG_SYSFS
+
+#define VBD_SHOW(name, field, format_string)				\
+	static ssize_t show_##name(struct device *_dev,			\
+				   struct device_attribute *attr,	\
+				   char *buf)				\
+	{								\
+		struct xenbus_device *dev = to_xenbus_device(_dev);	\
+		struct backend_info *be = dev->dev.driver_data;		\
+									\
+		return sprintf(buf, format_string, be->field);		\
+	}								\
+	DEVICE_ATTR(name, S_IRUGO, show_##name, NULL);
+
+VBD_SHOW(oo_req, blkif->st_oo_req, "%d\n");
+VBD_SHOW(rd_req, blkif->st_rd_req, "%d\n");
+VBD_SHOW(wr_req, blkif->st_wr_req, "%d\n");
+
+static struct attribute *vbdstat_attrs[] = {
+	&dev_attr_oo_req.attr,
+	&dev_attr_rd_req.attr,
+	&dev_attr_wr_req.attr,
+	NULL
+};
+
+static struct attribute_group vbdstat_group = {
+	.name = "statistics",
+	.attrs = vbdstat_attrs,
+};
+
+int xenvbd_sysfs_addif(struct xenbus_device *dev)
+{
+	int error = 0;
+	
+	error = sysfs_create_group(&dev->dev.kobj,
+				   &vbdstat_group);
+	if (error)
+		goto fail;
+	
+	return 0;
+	
+fail:
+	sysfs_remove_group(&dev->dev.kobj,
+			   &vbdstat_group);
+	return error;
+}
+
+void xenvbd_sysfs_delif(struct xenbus_device *dev)
+{
+       	sysfs_remove_group(&dev->dev.kobj,
+			   &vbdstat_group);
+}
+
+#endif /* CONFIG_SYSFS */
+
 static ssize_t show_physical_device(struct device *_dev,
 				    struct device_attribute *attr, char *buf)
 {
@@ -114,6 +181,7 @@ static int blkback_remove(struct xenbus_
 
 	device_remove_file(&dev->dev, &dev_attr_physical_device);
 	device_remove_file(&dev->dev, &dev_attr_mode);
+	xenvbd_sysfs_delif(dev);
 
 	kfree(be);
 	dev->dev.driver_data = NULL;
@@ -236,6 +304,7 @@ static void backend_changed(struct xenbu
 
 		device_create_file(&dev->dev, &dev_attr_physical_device);
 		device_create_file(&dev->dev, &dev_attr_mode);
+		xenvbd_sysfs_addif(dev);
 
 		/* We're potentially connected now */
 		update_blkif_status(be->blkif);