Hi,
W dniu 21.12.2022 o 10:13, Chanh Nguyen pisze:
It is unable to use configfs to attach more than one gadget. When
attaching the second gadget, it always fails and the kernel message
prints out:
Error: Driver 'configfs-gadget' is already registered, aborting...
UDC core: g1: driver registration failed: -16
I assume you are interested in a scenario where there is more than one
UDC available which means you can have more than one active gadget?
This commit fixes the problem by a ".N" suffix added to each
configfs_gadget's driver name (where N is a unique ID number),
thus making the names distinct.
Fixes: fc274c1e9973 ("USB: gadget: Add a new bus for gadgets")
Signed-off-by: Chanh Nguyen <chanh@xxxxxxxxxxxxxxxxxxxxxx>
---
Changes in v2:
- Replace scnprintf() by kasprintf() to simplify the code [CJ]
- Move the clean up code from gadgets_drop() to
gadget_info_attr_release() [Frank Li]
- Correct the resource free up in gadges_make() [Alan Stern]
- Remove the unnecessary variable in gadgets_make() [Chanh]
- Fixes minor grammar issue in commit message [Chanh]
---
drivers/usb/gadget/configfs.c | 25 ++++++++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index 96121d1c8df4..7faf68bfa716 100644
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -3,6 +3,7 @@
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/device.h>
+#include <linux/idr.h>
#include <linux/kstrtox.h>
#include <linux/nls.h>
#include <linux/usb/composite.h>
@@ -11,6 +12,8 @@
#include "u_f.h"
#include "u_os_desc.h"
+static DEFINE_IDA(driver_id_numbers);
+
int check_user_usb_string(const char *name,
struct usb_gadget_strings *stringtab_dev)
{
@@ -52,6 +55,9 @@ struct gadget_info {
char qw_sign[OS_STRING_QW_SIGN_LEN];
spinlock_t spinlock;
bool unbind;
+
+ /* Make driver names unique */
+ int driver_id_number;
};
static inline struct gadget_info *to_gadget_info(struct config_item *item)
@@ -393,6 +399,8 @@ static void gadget_info_attr_release(struct config_item *item)
WARN_ON(!list_empty(&gi->string_list));
WARN_ON(!list_empty(&gi->available_func));
kfree(gi->composite.gadget_driver.function);
+ kfree(gi->composite.gadget_driver.driver.name);
+ ida_free(&driver_id_numbers, gi->driver_id_number);
kfree(gi);
}
@@ -1623,13 +1631,28 @@ static struct config_group *gadgets_make(
gi->composite.gadget_driver = configfs_driver_template;
+ gi->driver_id_number = ida_alloc(&driver_id_numbers, GFP_KERNEL);
+ if (gi->driver_id_number < 0)
+ goto err;
+
+ gi->composite.gadget_driver.driver.name = kasprintf(GFP_KERNEL,
+ "configfs-gadget.%d",
+ gi->driver_id_number);
I'm wondering if it maybe makes more sense to use the gadget name as a suffix
instead?
gi->composite.gadget_driver.driver.name =
kasprintf(GFP_KERNEL, "configfs-gadget.%s" name);
So that when you
mkdir g1
you will ultimately see /sys/bus/gadget/drivers/configfs-gadget.g1
instead of /sys/bus/gadget/drivers/configfs-gadget.0
Gadget names are guaranteed to be unique because they are created
as sibling subdirectories in configfs. Your patch would then be greatly
simplified (no need for ida).
Regards,
Andrzej
+ if (!gi->composite.gadget_driver.driver.name)
+ goto out_free_driver_id_number;
+
gi->composite.gadget_driver.function = kstrdup(name, GFP_KERNEL);
gi->composite.name = gi->composite.gadget_driver.function;
if (!gi->composite.gadget_driver.function)
- goto err;
+ goto out_free_driver_name;
return &gi->group;
+
+out_free_driver_name:
+ kfree(gi->composite.gadget_driver.driver.name);
+out_free_driver_id_number:
+ ida_free(&driver_id_numbers, gi->driver_id_number);
err:
kfree(gi);
return ERR_PTR(-ENOMEM);
