Putting USB gadgets on a new bus of their own encounters a problem
when multiple gadgets are present: They all have the same name! The
driver core fails with a "sys: cannot create duplicate filename" error
when creating any of the /sys/bus/gadget/devices/<gadget-name>
symbolic links after the first.
This patch fixes the problem by adding a ".N" suffix to each gadget's
name when the gadget is registered (where N is a unique ID number),
thus making the names distinct.
Reported-and-tested-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Fixes: fc274c1e9973 ("USB: gadget: Add a new bus for gadgets")
---
[as1980]
drivers/usb/gadget/udc/core.c | 16 ++++++++++++++--
include/linux/usb/gadget.h | 2 ++
2 files changed, 16 insertions(+), 2 deletions(-)
Index: usb-devel/drivers/usb/gadget/udc/core.c
===================================================================
--- usb-devel.orig/drivers/usb/gadget/udc/core.c
+++ usb-devel/drivers/usb/gadget/udc/core.c
@@ -12,6 +12,7 @@
#include <linux/module.h>
#include <linux/device.h>
#include <linux/list.h>
+#include <linux/idr.h>
#include <linux/err.h>
#include <linux/dma-mapping.h>
#include <linux/sched/task_stack.h>
@@ -23,6 +24,8 @@
#include "trace.h"
+static DEFINE_IDA(gadget_id_numbers);
+
static struct bus_type gadget_bus_type;
/**
@@ -1248,7 +1251,6 @@ static void usb_udc_nop_release(struct d
void usb_initialize_gadget(struct device *parent, struct usb_gadget *gadget,
void (*release)(struct device *dev))
{
- dev_set_name(&gadget->dev, "gadget");
INIT_WORK(&gadget->work, usb_gadget_state_work);
gadget->dev.parent = parent;
@@ -1304,12 +1306,21 @@ int usb_add_gadget(struct usb_gadget *ga
usb_gadget_set_state(gadget, USB_STATE_NOTATTACHED);
udc->vbus = true;
+ ret = ida_alloc(&gadget_id_numbers, GFP_KERNEL);
+ if (ret < 0)
+ goto err_del_udc;
+ gadget->id_number = ret;
+ dev_set_name(&gadget->dev, "gadget.%d", ret);
+
ret = device_add(&gadget->dev);
if (ret)
- goto err_del_udc;
+ goto err_free_id;
return 0;
+ err_free_id:
+ ida_free(&gadget_id_numbers, gadget->id_number);
+
err_del_udc:
flush_work(&gadget->work);
device_del(&udc->dev);
@@ -1417,6 +1428,7 @@ void usb_del_gadget(struct usb_gadget *g
kobject_uevent(&udc->dev.kobj, KOBJ_REMOVE);
flush_work(&gadget->work);
device_del(&gadget->dev);
+ ida_free(&gadget_id_numbers, gadget->id_number);
device_unregister(&udc->dev);
}
EXPORT_SYMBOL_GPL(usb_del_gadget);
Index: usb-devel/include/linux/usb/gadget.h
===================================================================
--- usb-devel.orig/include/linux/usb/gadget.h
+++ usb-devel/include/linux/usb/gadget.h
@@ -386,6 +386,7 @@ struct usb_gadget_ops {
* @lpm_capable: If the gadget max_speed is FULL or HIGH, this flag
* indicates that it supports LPM as per the LPM ECN & errata.
* @irq: the interrupt number for device controller.
+ * @id_number: a unique ID number for ensuring that gadget names are distinct
*
* Gadgets have a mostly-portable "gadget driver" implementing device
* functions, handling all usb configurations and interfaces. Gadget
@@ -446,6 +447,7 @@ struct usb_gadget {
unsigned connected:1;
unsigned lpm_capable:1;
int irq;
+ int id_number;
};
#define work_to_gadget(w) (container_of((w), struct usb_gadget, work))
