| Message ID | 20221221091317.19380-1-chanh@os.amperecomputing.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] USB: gadget: Add ID numbers to configfs-gadget driver names | expand |
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);
> > 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 >
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);
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(-)