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Revert "USB: Close usb_find_interface race"

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This reverts commit a2582bd478.

It turned out to be buggy and broke USB printers from working.

Cc: Russ Dill <Russ.Dill@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Greg Kroah-Hartman 2009-12-15 07:47:28 -08:00
parent 3ea6b3d0e6
commit ab7cd8c76c
1 changed files with 18 additions and 10 deletions
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28
drivers/usb/core/usb.c
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@ -167,17 +167,24 @@ struct usb_host_interface *usb_altnum_to_altsetting(
}
EXPORT_SYMBOL_GPL(usb_altnum_to_altsetting);
struct find_interface_arg {
int minor;
struct usb_interface *interface;
};
static int __find_interface(struct device *dev, void *data)
{
int *minor = data;
struct find_interface_arg *arg = data;
struct usb_interface *intf;
if (!is_usb_interface(dev))
return 0;
intf = to_usb_interface(dev);
if (intf->minor != -1 && intf->minor == *minor)
if (intf->minor != -1 && intf->minor == arg->minor) {
arg->interface = intf;
return 1;
}
return 0;
}
@ -186,20 +193,21 @@ static int __find_interface(struct device *dev, void *data)
* @drv: the driver whose current configuration is considered
* @minor: the minor number of the desired device
*
* This walks the bus device list and returns a pointer to the interface
* This walks the driver device list and returns a pointer to the interface
* with the matching minor. Note, this only works for devices that share the
* USB major number.
*/
struct usb_interface *usb_find_interface(struct usb_driver *drv, int minor)
{
struct device *dev;
struct find_interface_arg argb;
int retval;
dev = bus_find_device(&usb_bus_type, NULL, &minor, __find_interface);
/* Drop reference count from bus_find_device */
put_device(dev);
return dev ? to_usb_interface(dev) : NULL;
argb.minor = minor;
argb.interface = NULL;
/* eat the error, it will be in argb.interface */
retval = driver_for_each_device(&drv->drvwrap.driver, NULL, &argb,
__find_interface);
return argb.interface;
}
EXPORT_SYMBOL_GPL(usb_find_interface);