[PATCH] usbcore: Fix handling of sysfs strings and other attributes
This patch (as592) makes a few small improvements to the way device
strings are handled, and it fixes some bugs in a couple of other sysfs
attribute routines. (Look at show_configuration_string() to see what I
mean.)
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 3519f31..644a3d4 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -787,6 +787,31 @@
return err;
}
+/**
+ * usb_cache_string - read a string descriptor and cache it for later use
+ * @udev: the device whose string descriptor is being read
+ * @index: the descriptor index
+ *
+ * Returns a pointer to a kmalloc'ed buffer containing the descriptor string,
+ * or NULL if the index is 0 or the string could not be read.
+ */
+char *usb_cache_string(struct usb_device *udev, int index)
+{
+ char *buf;
+ char *smallbuf = NULL;
+ int len;
+
+ if (index > 0 && (buf = kmalloc(256, GFP_KERNEL)) != NULL) {
+ if ((len = usb_string(udev, index, buf, 256)) > 0) {
+ if ((smallbuf = kmalloc(++len, GFP_KERNEL)) == NULL)
+ return buf;
+ memcpy(smallbuf, buf, len);
+ }
+ kfree(buf);
+ }
+ return smallbuf;
+}
+
/*
* usb_get_device_descriptor - (re)reads the device descriptor (usbcore)
* @dev: the device whose device descriptor is being updated
@@ -1008,8 +1033,6 @@
dev_dbg (&dev->dev, "unregistering interface %s\n",
interface->dev.bus_id);
usb_remove_sysfs_intf_files(interface);
- kfree(interface->cur_altsetting->string);
- interface->cur_altsetting->string = NULL;
device_del (&interface->dev);
}
@@ -1422,12 +1445,9 @@
}
kfree(new_interfaces);
- if ((cp->desc.iConfiguration) &&
- (cp->string == NULL)) {
- cp->string = kmalloc(256, GFP_KERNEL);
- if (cp->string)
- usb_string(dev, cp->desc.iConfiguration, cp->string, 256);
- }
+ if (cp->string == NULL)
+ cp->string = usb_cache_string(dev,
+ cp->desc.iConfiguration);
/* Now that all the interfaces are set up, register them
* to trigger binding of drivers to interfaces. probe()
@@ -1437,13 +1457,12 @@
*/
for (i = 0; i < nintf; ++i) {
struct usb_interface *intf = cp->interface[i];
- struct usb_interface_descriptor *desc;
+ struct usb_host_interface *alt = intf->cur_altsetting;
- desc = &intf->altsetting [0].desc;
dev_dbg (&dev->dev,
"adding %s (config #%d, interface %d)\n",
intf->dev.bus_id, configuration,
- desc->bInterfaceNumber);
+ alt->desc.bInterfaceNumber);
ret = device_add (&intf->dev);
if (ret != 0) {
dev_err(&dev->dev,
@@ -1452,13 +1471,6 @@
ret);
continue;
}
- if ((intf->cur_altsetting->desc.iInterface) &&
- (intf->cur_altsetting->string == NULL)) {
- intf->cur_altsetting->string = kmalloc(256, GFP_KERNEL);
- if (intf->cur_altsetting->string)
- usb_string(dev, intf->cur_altsetting->desc.iInterface,
- intf->cur_altsetting->string, 256);
- }
usb_create_sysfs_intf_files (intf);
}
}