[PATCH] USB: Store port number in usb_device

This patch (as610) adds a field to struct usb_device to store the device's
port number.  This allows us to remove several loops in the hub driver
(searching for a particular device among all the entries in the parent's
array of children).

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

3 files changed, 20 insertions, 61 deletions

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index b311005ff1a6..a523c8f20b5d 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -946,24 +946,21 @@ static int locktree(struct usb_device *udev)
         t = locktree(hdev);
         if (t < 0)
                 return t;
-        for (t = 0; t < hdev->maxchild; t++) {
-                if (hdev->children[t] == udev) {
-                        /* everything is fail-fast once disconnect
-                         * processing starts
-                         */
-                        if (udev->state == USB_STATE_NOTATTACHED)
-                                break;
 
-                        /* when everyone grabs locks top->bottom,
-                         * non-overlapping work may be concurrent
-                         */
-                        usb_lock_device(udev);
-                        usb_unlock_device(hdev);
-                        return t + 1;
-                }
+        /* everything is fail-fast once disconnect
+         * processing starts
+         */
+        if (udev->state == USB_STATE_NOTATTACHED) {
+                usb_unlock_device(hdev);
+                return -ENODEV;
         }
+
+        /* when everyone grabs locks top->bottom,
+         * non-overlapping work may be concurrent
+         */
+        usb_lock_device(udev);
         usb_unlock_device(hdev);
-        return -ENODEV;
+        return udev->portnum;
 }
 
 static void recursively_mark_NOTATTACHED(struct usb_device *udev)
@@ -1335,15 +1332,9 @@ int usb_new_device(struct usb_device *udev)
                                         le16_to_cpu(udev->config[0].desc.wTotalLength),
                                         USB_DT_OTG, (void **) &desc) == 0) {
                         if (desc->bmAttributes & USB_OTG_HNP) {
-                                unsigned                port1;
+                                unsigned                port1 = udev->portnum;
                                 struct usb_device       *root = udev->parent;
                                 
-                                for (port1 = 1; port1 <= root->maxchild;
-                                                port1++) {
-                                        if (root->children[port1-1] == udev)
-                                                break;
-                                }
-
                                 dev_info(&udev->dev,
                                         "Dual-Role OTG device on %sHNP port\n",
                                         (port1 == bus->otg_port)
@@ -1720,22 +1711,9 @@ static int __usb_suspend_device (struct usb_device *udev, int port1)
 int usb_suspend_device(struct usb_device *udev)
 {
 #ifdef  CONFIG_USB_SUSPEND
-        int     port1;
-
         if (udev->state == USB_STATE_NOTATTACHED)
                 return -ENODEV;
-        if (!udev->parent)
-                port1 = 0;
-        else {
-                for (port1 = udev->parent->maxchild; port1 > 0; --port1) {
-                        if (udev->parent->children[port1-1] == udev)
-                                break;
-                }
-                if (port1 == 0)
-                        return -ENODEV;
-        }
-
-        return __usb_suspend_device(udev, port1);
+        return __usb_suspend_device(udev, udev->portnum);
 #else
         /* NOTE:  udev->state unchanged, it's not lying ... */
         udev->dev.power.power_state = PMSG_SUSPEND;
@@ -1893,20 +1871,10 @@ hub_port_resume(struct usb_hub *hub, int port1, struct usb_device *udev)
  */
 int usb_resume_device(struct usb_device *udev)
 {
-        int     port1, status;
+        int     status;
 
         if (udev->state == USB_STATE_NOTATTACHED)
                 return -ENODEV;
-        if (!udev->parent)
-                port1 = 0;
-        else {
-                for (port1 = udev->parent->maxchild; port1 > 0; --port1) {
-                        if (udev->parent->children[port1-1] == udev)
-                                break;
-                }
-                if (port1 == 0)
-                        return -ENODEV;
-        }
 
 #ifdef  CONFIG_USB_SUSPEND
         /* selective resume of one downstream hub-to-device port */
@@ -1915,7 +1883,7 @@ int usb_resume_device(struct usb_device *udev)
                         // NOTE swsusp may bork us, device state being wrong...
                         // NOTE this fails if parent is also suspended...
                         status = hub_port_resume(hdev_to_hub(udev->parent),
-                                        port1, udev);
+                                        udev->portnum, udev);
                 } else
                         status = 0;
         } else
@@ -3029,7 +2997,8 @@ int usb_reset_device(struct usb_device *udev)
         struct usb_hub                  *parent_hub;
         struct usb_device_descriptor    descriptor = udev->descriptor;
         struct usb_hub                  *hub = NULL;
-        int                             i, ret = 0, port1 = -1;
+        int                             i, ret = 0;
+        int                             port1 = udev->portnum;
 
         if (udev->state == USB_STATE_NOTATTACHED ||
                         udev->state == USB_STATE_SUSPENDED) {
@@ -3043,18 +3012,6 @@ int usb_reset_device(struct usb_device *udev)
                 dev_dbg(&udev->dev, "%s for root hub!\n", __FUNCTION__);
                 return -EISDIR;
         }
-
-        for (i = 0; i < parent_hdev->maxchild; i++)
-                if (parent_hdev->children[i] == udev) {
-                        port1 = i + 1;
-                        break;
-                }
-
-        if (port1 < 0) {
-                /* If this ever happens, it's very bad */
-                dev_err(&udev->dev, "Can't locate device's port!\n");
-                return -ENOENT;
-        }
         parent_hub = hdev_to_hub(parent_hdev);
 
         /* If we're resetting an active hub, take some special actions */
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index fcfda21be499..39e6b61b898a 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -439,6 +439,7 @@ usb_alloc_dev(struct usb_device *parent, struct usb_bus *bus, unsigned port1)
                 /* hub driver sets up TT records */
         }
 
+        dev->portnum = port1;
         dev->bus = bus;
         dev->parent = parent;
         INIT_LIST_HEAD(&dev->filelist);
diff --git a/include/linux/usb.h b/include/linux/usb.h
index 27575e678a7c..e59d1bd52d4f 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -348,6 +348,7 @@ struct usb_device {
         char **rawdescriptors;          /* Raw descriptors for each config */
 
         unsigned short bus_mA;          /* Current available from the bus */
+        u8 portnum;                     /* Parent port number (origin 1) */
 
         int have_langid;                /* whether string_langid is valid */
         int string_langid;              /* language ID for strings */