[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>

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index b311005..a523c8f 100644 (file)
--- 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 fcfda21..39e6b61 100644 (file)
--- 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 27575e6..e59d1bd 100644 (file)
--- 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 */