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USB: serial core should respect driver requirements
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This patch (as997) fixes a bug in the USB serial core.  The core needs
to pay attention to drivers' requirements regarding the number and
type of endpoints a device has.

At the same time, the patch changes the NUM_DONT_CARE constant (which
is stored in a single-byte field) from -1 to a safer, unsigned value.
It also improves the kerneldoc for several fields in the
usb_serial_driver structure.

Finally, the patch replaces a list_for_each() with list_for_each_entry().

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Alan Stern authored and Greg Kroah-Hartman committed Oct 12, 2007
1 parent cd38c1e commit 063a2da
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Showing 2 changed files with 35 additions and 16 deletions.
31 changes: 22 additions & 9 deletions drivers/usb/serial/usb-serial.c
Original file line number Diff line number Diff line change
Expand Up @@ -662,16 +662,14 @@ static const struct usb_device_id *get_iface_id(struct usb_serial_driver *drv,

static struct usb_serial_driver *search_serial_device(struct usb_interface *iface)
{
struct list_head *p;
const struct usb_device_id *id;
struct usb_serial_driver *t;
struct usb_serial_driver *drv;

/* Check if the usb id matches a known device */
list_for_each(p, &usb_serial_driver_list) {
t = list_entry(p, struct usb_serial_driver, driver_list);
id = get_iface_id(t, iface);
list_for_each_entry(drv, &usb_serial_driver_list, driver_list) {
id = get_iface_id(drv, iface);
if (id)
return t;
return drv;
}

return NULL;
Expand Down Expand Up @@ -811,9 +809,6 @@ int usb_serial_probe(struct usb_interface *interface,
/* END HORRIBLE HACK FOR PL2303 */
#endif

/* found all that we need */
dev_info(&interface->dev, "%s converter detected\n", type->description);

#ifdef CONFIG_USB_SERIAL_GENERIC
if (type == &usb_serial_generic_device) {
num_ports = num_bulk_out;
Expand Down Expand Up @@ -847,6 +842,24 @@ int usb_serial_probe(struct usb_interface *interface,
serial->num_interrupt_in = num_interrupt_in;
serial->num_interrupt_out = num_interrupt_out;

/* check that the device meets the driver's requirements */
if ((type->num_interrupt_in != NUM_DONT_CARE &&
type->num_interrupt_in != num_interrupt_in)
|| (type->num_interrupt_out != NUM_DONT_CARE &&
type->num_interrupt_out != num_interrupt_out)
|| (type->num_bulk_in != NUM_DONT_CARE &&
type->num_bulk_in != num_bulk_in)
|| (type->num_bulk_out != NUM_DONT_CARE &&
type->num_bulk_out != num_bulk_out)) {
dbg("wrong number of endpoints");
kfree(serial);
return -EIO;
}

/* found all that we need */
dev_info(&interface->dev, "%s converter detected\n",
type->description);

/* create our ports, we need as many as the max endpoints */
/* we don't use num_ports here cauz some devices have more endpoint pairs than ports */
max_endpoints = max(num_bulk_in, num_bulk_out);
Expand Down
20 changes: 13 additions & 7 deletions include/linux/usb/serial.h
Original file line number Diff line number Diff line change
Expand Up @@ -141,7 +141,7 @@ struct usb_serial {
};
#define to_usb_serial(d) container_of(d, struct usb_serial, kref)

#define NUM_DONT_CARE (-1)
#define NUM_DONT_CARE 99

/* get and set the serial private data pointer helper functions */
static inline void *usb_get_serial_data (struct usb_serial *serial)
Expand All @@ -160,12 +160,18 @@ static inline void usb_set_serial_data (struct usb_serial *serial, void *data)
* in the syslog messages when a device is inserted or removed.
* @id_table: pointer to a list of usb_device_id structures that define all
* of the devices this structure can support.
* @num_interrupt_in: the number of interrupt in endpoints this device will
* have.
* @num_interrupt_out: the number of interrupt out endpoints this device will
* have.
* @num_bulk_in: the number of bulk in endpoints this device will have.
* @num_bulk_out: the number of bulk out endpoints this device will have.
* @num_interrupt_in: If a device doesn't have this many interrupt-in
* endpoints, it won't be sent to the driver's attach() method.
* (But it might still be sent to the probe() method.)
* @num_interrupt_out: If a device doesn't have this many interrupt-out
* endpoints, it won't be sent to the driver's attach() method.
* (But it might still be sent to the probe() method.)
* @num_bulk_in: If a device doesn't have this many bulk-in
* endpoints, it won't be sent to the driver's attach() method.
* (But it might still be sent to the probe() method.)
* @num_bulk_out: If a device doesn't have this many bulk-out
* endpoints, it won't be sent to the driver's attach() method.
* (But it might still be sent to the probe() method.)
* @num_ports: the number of different ports this device will have.
* @calc_num_ports: pointer to a function to determine how many ports this
* device has dynamically. It will be called after the probe()
Expand Down

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