Re: [PATCH V4 1/3] usb: gadget: configfs: add UDC trace entry

[Felipe Balbi <balbi@kernel.org>]

Hi again,

Felipe Balbi <balbi@kernel.org> writes:
> Linyu Yuan <quic_linyyuan@quicinc.com> writes:
>> add trace in function gadget_dev_desc_UDC_store()
>> will show when user space enable/disable the gadget.
>>
>> Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
>> ---
>>  drivers/usb/gadget/Makefile         |  1 +
>>  drivers/usb/gadget/configfs.c       |  3 +++
>>  drivers/usb/gadget/configfs_trace.c |  7 +++++++
>>  drivers/usb/gadget/configfs_trace.h | 39 +++++++++++++++++++++++++++++++++++++
>>  4 files changed, 50 insertions(+)
>>  create mode 100644 drivers/usb/gadget/configfs_trace.c
>>  create mode 100644 drivers/usb/gadget/configfs_trace.h
>>
>> diff --git a/drivers/usb/gadget/Makefile b/drivers/usb/gadget/Makefile
>> index 130dad7..8e9c2b8 100644
>> --- a/drivers/usb/gadget/Makefile
>> +++ b/drivers/usb/gadget/Makefile
>> @@ -9,5 +9,6 @@ ccflags-y				+= -I$(srctree)/drivers/usb/gadget/udc
>>  obj-$(CONFIG_USB_LIBCOMPOSITE)	+= libcomposite.o
>>  libcomposite-y			:= usbstring.o config.o epautoconf.o
>>  libcomposite-y			+= composite.o functions.o configfs.o u_f.o
>> +libcomposite-y			+= configfs_trace.o
>>  
>>  obj-$(CONFIG_USB_GADGET)	+= udc/ function/ legacy/
>> diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
>> index 477e72a..f7f3af8 100644
>> --- a/drivers/usb/gadget/configfs.c
>> +++ b/drivers/usb/gadget/configfs.c
>> @@ -9,6 +9,7 @@
>>  #include "configfs.h"
>>  #include "u_f.h"
>>  #include "u_os_desc.h"
>> +#include "configfs_trace.h"
>>  
>>  int check_user_usb_string(const char *name,
>>  		struct usb_gadget_strings *stringtab_dev)
>> @@ -270,6 +271,8 @@ static ssize_t gadget_dev_desc_UDC_store(struct config_item *item,
>>  	if (name[len - 1] == '\n')
>>  		name[len - 1] = '\0';
>>  
>> +	trace_gadget_dev_desc_UDC_store(config_item_name(item), name);
>
> why tracing only the names? This gives us no insight into whatever bug
> may happen and we may want to use trace events to debug. Rather, try to
> think of trace events as tracking the lifetime of the UDC and
> gadget. Trace values that may change over time.
>
> I also think that all three patches could be combined into a single
> commit, but that's up to discussion.

nevermind this last paragraph, just saw that Greg asked you to split ;-)

The first paragraph remains valid, though

-- 
balbi