[PATCH] usbcore: Improve endpoint sysfs file handling

This revised patch (as587b) improves the implementation of USB endpoint
sysfs files.  Instead of storing a whole bunch of attributes for every
single endpoint, each endpoint now gets its own kobject and they can
share a static list of attributes.  The number of extra fields added to
struct usb_host_endpoint has been reduced from 4 to 1.

The bEndpointAddress field is retained even though it is redundant (it
repeats the same information as the attributes' directory name).  The
code avoids calling kobject_register, to prevent generating unwanted
hotplug events.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 124 insertions, 95 deletions

diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index 4bdbc9df6e03..f18317fb49ee 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -23,43 +23,56 @@
 #include "usb.h"
 
 /* endpoint stuff */
-struct endpoint_attribute {
-        struct device_attribute dev_attr;
-        struct usb_endpoint_descriptor *endpoint;
+struct ep_object {
+        struct usb_endpoint_descriptor *desc;
         struct usb_device *udev;
+        struct kobject kobj;
 };
-#define to_endpoint_attr(_dev_attr) \
-        container_of(_dev_attr, struct endpoint_attribute, dev_attr)
-
-#define usb_ep_attr(field, format_string)                                       \
-static ssize_t show_ep_##field(struct device *dev, struct device_attribute *attr,       \
-                            char *buf)                                          \
-{                                                                               \
-        struct endpoint_attribute *endpoint_attr = to_endpoint_attr(attr);      \
-                                                                                \
-        return sprintf(buf, format_string, endpoint_attr->endpoint->field);     \
-}
+#define to_ep_object(_kobj) \
+        container_of(_kobj, struct ep_object, kobj)
+
+struct ep_attribute {
+        struct attribute attr;
+        ssize_t (*show)(struct usb_device *,
+                        struct usb_endpoint_descriptor *, char *);
+};
+#define to_ep_attribute(_attr) \
+        container_of(_attr, struct ep_attribute, attr)
+
+#define EP_ATTR(_name)                                          \
+struct ep_attribute ep_##_name = {                              \
+        .attr = {.name = #_name, .owner = THIS_MODULE,          \
+                        .mode = S_IRUGO},                       \
+        .show = show_ep_##_name}
+
+#define usb_ep_attr(field, format_string)                       \
+static ssize_t show_ep_##field(struct usb_device *udev,         \
+                struct usb_endpoint_descriptor *desc,           \
+                char *buf)                                      \
+{                                                               \
+        return sprintf(buf, format_string, desc->field);        \
+}                                                               \
+static EP_ATTR(field);
+
 usb_ep_attr(bLength, "%02x\n")
-usb_ep_attr(bDescriptorType, "%02x\n")
 usb_ep_attr(bEndpointAddress, "%02x\n")
 usb_ep_attr(bmAttributes, "%02x\n")
 usb_ep_attr(bInterval, "%02x\n")
 
-static ssize_t show_ep_wMaxPacketSize(struct device *dev,
-                                      struct device_attribute *attr, char *buf)
+static ssize_t show_ep_wMaxPacketSize(struct usb_device *udev,
+                struct usb_endpoint_descriptor *desc, char *buf)
 {
-        struct endpoint_attribute *endpoint_attr = to_endpoint_attr(attr);
-
         return sprintf(buf, "%04x\n",
-                      le16_to_cpu(endpoint_attr->endpoint->wMaxPacketSize) & 0x07ff);
+                        le16_to_cpu(desc->wMaxPacketSize) & 0x07ff);
 }
+static EP_ATTR(wMaxPacketSize);
 
-static ssize_t show_ep_type(struct device *dev, struct device_attribute *attr, char *buf)
+static ssize_t show_ep_type(struct usb_device *udev,
+                struct usb_endpoint_descriptor *desc, char *buf)
 {
-        struct endpoint_attribute *endpoint_attr = to_endpoint_attr(attr);
         char *type = "unknown";
 
-        switch (endpoint_attr->endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) {
+        switch (desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) {
         case USB_ENDPOINT_XFER_CONTROL:
                 type = "Control";
                 break;
@@ -75,35 +88,34 @@ static ssize_t show_ep_type(struct device *dev, struct device_attribute *attr, c
         }
         return sprintf(buf, "%s\n", type);
 }
+static EP_ATTR(type);
 
-static ssize_t show_ep_interval(struct device *dev, struct device_attribute *attr, char *buf)
+static ssize_t show_ep_interval(struct usb_device *udev,
+                struct usb_endpoint_descriptor *desc, char *buf)
 {
-        struct endpoint_attribute *endpoint_attr = to_endpoint_attr(attr);
-        struct usb_device *udev = endpoint_attr->udev;
-        struct usb_endpoint_descriptor *endpoint = endpoint_attr->endpoint;
         char unit;
         unsigned interval = 0;
         unsigned in;
 
-        in = (endpoint->bEndpointAddress & USB_DIR_IN);
+        in = (desc->bEndpointAddress & USB_DIR_IN);
 
-        switch (endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) {
+        switch (desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) {
         case USB_ENDPOINT_XFER_CONTROL:
                 if (udev->speed == USB_SPEED_HIGH)      /* uframes per NAK */
-                        interval = endpoint->bInterval;
+                        interval = desc->bInterval;
                 break;
         case USB_ENDPOINT_XFER_ISOC:
-                interval = 1 << (endpoint->bInterval - 1);
+                interval = 1 << (desc->bInterval - 1);
                 break;
         case USB_ENDPOINT_XFER_BULK:
-                if (udev->speed == USB_SPEED_HIGH && !in)       /* uframes per NAK */
-                        interval = endpoint->bInterval;
+                if (udev->speed == USB_SPEED_HIGH && !in) /* uframes per NAK */
+                        interval = desc->bInterval;
                 break;
         case USB_ENDPOINT_XFER_INT:
-                if (udev->speed == USB_SPEED_HIGH) {
-                        interval = 1 << (endpoint->bInterval - 1);
-                } else
-                        interval = endpoint->bInterval;
+                if (udev->speed == USB_SPEED_HIGH)
+                        interval = 1 << (desc->bInterval - 1);
+                else
+                        interval = desc->bInterval;
                 break;
         }
         interval *= (udev->speed == USB_SPEED_HIGH) ? 125 : 1000;
@@ -116,78 +128,95 @@ static ssize_t show_ep_interval(struct device *dev, struct device_attribute *att
 
         return sprintf(buf, "%d%cs\n", interval, unit);
 }
+static EP_ATTR(interval);
 
-static ssize_t show_ep_direction(struct device *dev, struct device_attribute *attr, char *buf)
+static ssize_t show_ep_direction(struct usb_device *udev,
+                struct usb_endpoint_descriptor *desc, char *buf)
 {
-        struct endpoint_attribute *endpoint_attr = to_endpoint_attr(attr);
         char *direction;
 
-        if ((endpoint_attr->endpoint->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
-            USB_ENDPOINT_XFER_CONTROL)
+        if ((desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
+                        USB_ENDPOINT_XFER_CONTROL)
                 direction = "both";
-        else if (endpoint_attr->endpoint->bEndpointAddress & USB_DIR_IN)
+        else if (desc->bEndpointAddress & USB_DIR_IN)
                 direction = "in";
         else
                 direction = "out";
         return sprintf(buf, "%s\n", direction);
 }
+static EP_ATTR(direction);
+
+static struct attribute *ep_attrs[] = {
+        &ep_bLength.attr,
+        &ep_bEndpointAddress.attr,
+        &ep_bmAttributes.attr,
+        &ep_bInterval.attr,
+        &ep_wMaxPacketSize.attr,
+        &ep_type.attr,
+        &ep_interval.attr,
+        &ep_direction.attr,
+        NULL,
+};
 
-static struct endpoint_attribute *create_ep_attr(struct usb_endpoint_descriptor *endpoint,
-                                                 struct usb_device *udev, char *name,
-                ssize_t (*show)(struct device *dev, struct device_attribute *attr, char *buf))
+static void ep_object_release(struct kobject *kobj)
 {
-        struct endpoint_attribute *ep_attr;
-
-        ep_attr = kzalloc(sizeof(*ep_attr), GFP_KERNEL);
-        if (ep_attr) {
-                ep_attr->endpoint = endpoint;
-                ep_attr->udev = udev;
-                ep_attr->dev_attr.attr.name = name;
-                ep_attr->dev_attr.attr.mode = 0444;
-                ep_attr->dev_attr.attr.owner = THIS_MODULE;
-                ep_attr->dev_attr.show = show;
-        }
-        return ep_attr;
+        kfree(to_ep_object(kobj));
 }
 
-static void usb_create_ep_files(struct kobject *kobj, struct usb_host_endpoint *endpoint, struct usb_device *udev)
+static ssize_t ep_object_show(struct kobject *kobj, struct attribute *attr,
+                char *buf)
 {
-        struct usb_endpoint_descriptor *ep;
-
-        ep = &endpoint->desc;
-
-        endpoint->attrs = kzalloc(sizeof(struct attribute *) * 10, GFP_KERNEL);
-        endpoint->attrs[0] = &(create_ep_attr(ep, udev, "direction", show_ep_direction)->dev_attr.attr);
-        endpoint->attrs[1] = &(create_ep_attr(ep, udev, "type", show_ep_type)->dev_attr.attr);
-        endpoint->attrs[2] = &(create_ep_attr(ep, udev, "bLength", show_ep_bLength)->dev_attr.attr);
-        endpoint->attrs[3] = &(create_ep_attr(ep, udev, "bDescriptorType", show_ep_bDescriptorType)->dev_attr.attr);
-        endpoint->attrs[4] = &(create_ep_attr(ep, udev, "bEndpointAddress", show_ep_bEndpointAddress)->dev_attr.attr);
-        endpoint->attrs[5] = &(create_ep_attr(ep, udev, "bmAttributes", show_ep_bmAttributes)->dev_attr.attr);
-        endpoint->attrs[6] = &(create_ep_attr(ep, udev, "wMaxPacketSize", show_ep_wMaxPacketSize)->dev_attr.attr);
-        endpoint->attrs[7] = &(create_ep_attr(ep, udev, "bInterval", show_ep_bInterval)->dev_attr.attr);
-        endpoint->attrs[8] = &(create_ep_attr(ep, udev, "interval", show_ep_interval)->dev_attr.attr);
-        endpoint->attrs[9] = NULL;
-        endpoint->num_attrs = 9;
-
-        endpoint->attr_group = kzalloc(sizeof(*endpoint->attr_group), GFP_KERNEL);
-        endpoint->attr_name = kzalloc(10, GFP_KERNEL);
-        sprintf(endpoint->attr_name, "ep_%02x", endpoint->desc.bEndpointAddress);
-
-        endpoint->attr_group->attrs = endpoint->attrs;
-        endpoint->attr_group->name = endpoint->attr_name;
-        sysfs_create_group(kobj, endpoint->attr_group);
+        struct ep_object *ep_obj = to_ep_object(kobj);
+        struct ep_attribute *ep_attr = to_ep_attribute(attr);
+
+        return (ep_attr->show)(ep_obj->udev, ep_obj->desc, buf);
 }
 
-static void usb_remove_ep_files(struct kobject *kobj, struct usb_host_endpoint *endpoint)
+static struct sysfs_ops ep_object_sysfs_ops = {
+        .show =                 ep_object_show,
+};
+
+static struct kobj_type ep_object_ktype = {
+        .release =              ep_object_release,
+        .sysfs_ops =            &ep_object_sysfs_ops,
+        .default_attrs =        ep_attrs,
+};
+
+static void usb_create_ep_files(struct kobject *parent,
+                struct usb_host_endpoint *endpoint,
+                struct usb_device *udev)
 {
-        int i;
+        struct ep_object *ep_obj;
+        struct kobject *kobj;
+
+        ep_obj = kzalloc(sizeof(struct ep_object), GFP_KERNEL);
+        if (!ep_obj)
+                return;
 
-        sysfs_remove_group(kobj, endpoint->attr_group);
-        kfree(endpoint->attr_group);
-        kfree(endpoint->attr_name);
-        for (i = 0; i < endpoint->num_attrs; ++i)
-                kfree(endpoint->attrs[i]);
-        kfree(endpoint->attrs);
+        ep_obj->desc = &endpoint->desc;
+        ep_obj->udev = udev;
+
+        kobj = &ep_obj->kobj;
+        kobject_set_name(kobj, "ep_%02x", endpoint->desc.bEndpointAddress);
+        kobj->parent = parent;
+        kobj->ktype = &ep_object_ktype;
+
+        /* Don't use kobject_register, because it generates a hotplug event */
+        kobject_init(kobj);
+        if (kobject_add(kobj) == 0)
+                endpoint->kobj = kobj;
+        else
+                kobject_put(kobj);
+}
+
+static void usb_remove_ep_files(struct usb_host_endpoint *endpoint)
+{
+
+        if (endpoint->kobj) {
+                kobject_del(endpoint->kobj);
+                kobject_put(endpoint->kobj);
+                endpoint->kobj = NULL;
+        }
 }
 
 /* Active configuration fields */
@@ -411,7 +440,7 @@ void usb_remove_sysfs_dev_files (struct usb_device *udev)
 {
         struct device *dev = &udev->dev;
 
-        usb_remove_ep_files(&dev->kobj, &udev->ep0);
+        usb_remove_ep_files(&udev->ep0);
         sysfs_remove_group(&dev->kobj, &dev_attr_grp);
 
         if (udev->descriptor.iManufacturer)
@@ -496,7 +525,7 @@ static struct attribute_group intf_attr_grp = {
         .attrs = intf_attrs,
 };
 
-static void usb_create_intf_ep_files(struct usb_interface *intf)
+static inline void usb_create_intf_ep_files(struct usb_interface *intf)
 {
         struct usb_host_interface *iface_desc;
         int i;
@@ -504,17 +533,17 @@ static void usb_create_intf_ep_files(struct usb_interface *intf)
         iface_desc = intf->cur_altsetting;
         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i)
                 usb_create_ep_files(&intf->dev.kobj, &iface_desc->endpoint[i],
-                                    interface_to_usbdev(intf));
+                                interface_to_usbdev(intf));
 }
 
-static void usb_remove_intf_ep_files(struct usb_interface *intf)
+static inline void usb_remove_intf_ep_files(struct usb_interface *intf)
 {
         struct usb_host_interface *iface_desc;
         int i;
 
         iface_desc = intf->cur_altsetting;
         for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i)
-                usb_remove_ep_files(&intf->dev.kobj, &iface_desc->endpoint[i]);
+                usb_remove_ep_files(&iface_desc->endpoint[i]);
 }
 
 void usb_create_sysfs_intf_files (struct usb_interface *intf)