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[PATCH v2] USB: gadget: Add ID numbers to configfs-gadget driver names

Chanh Nguyen posted 1 patch 2 years, 8 months ago
There is a newer version of this series
drivers/usb/gadget/configfs.c | 25 ++++++++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)
[PATCH v2] USB: gadget: Add ID numbers to configfs-gadget driver names
Posted by Chanh Nguyen 2 years, 8 months ago 
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

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@os.amperecomputing.com>

---
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);
+	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);
-- 
2.17.1
Re: [PATCH v2] USB: gadget: Add ID numbers to configfs-gadget driver names
Posted by Andrzej Pietrasiewicz 2 years, 8 months ago 
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@os.amperecomputing.com>
> 
> ---
> 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);
Re: [PATCH v2] USB: gadget: Add ID numbers to configfs-gadget driver names
Posted by Chanh Nguyen 2 years, 8 months ago 

On 22/12/2022 22:20, Andrzej Pietrasiewicz wrote:
> 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?
> 

Yes, I'd like to have more active gadgets. For example, mass_storage and 
ecm usb, ...

>> 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@os.amperecomputing.com>
>>
>> ---
>> 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
> 

Thanks, Andrzej! I'll update that in patch v3

>> +    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);
>
RE: [EXT] Re: [PATCH v2] USB: gadget: Add ID numbers to configfs-gadget driver names
Posted by Frank Li 2 years, 8 months ago 
> 
> 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).

I vote this ways. 

Best regards
Frank Li

> 
> Regards,
> 
> Andrzej
>

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