Re: [PATCH v3 6/6] usb: gadget: f_fs: show instance name in debug message

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Wed, Mar 29, 2023 at 03:42:08PM +0800, Linyu Yuan wrote:
> 
> On 3/29/2023 3:37 PM, Greg Kroah-Hartman wrote:
> > On Wed, Mar 29, 2023 at 03:11:14PM +0800, Linyu Yuan wrote:
> > > On 3/29/2023 2:54 PM, Greg Kroah-Hartman wrote:
> > > > On Mon, Mar 27, 2023 at 06:12:20PM +0800, Linyu Yuan wrote:
> > > > > show ffs->dev_name in all possible debug message.
> > > > > 
> > > > > Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
> > > > > ---
> > > > > v3: change according comments
> > > > > v2: split to several changes according to v1 comments
> > > > > v1: https://lore.kernel.org/linux-usb/1679481369-30094-1-git-send-email-quic_linyyuan@quicinc.com/
> > > > > 
> > > > >    drivers/usb/gadget/function/f_fs.c | 141 ++++++++++++++++++++-----------------
> > > > >    1 file changed, 75 insertions(+), 66 deletions(-)
> > > > > 
> > > > > diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
> > > > > index 0761eaa..383343d 100644
> > > > > --- a/drivers/usb/gadget/function/f_fs.c
> > > > > +++ b/drivers/usb/gadget/function/f_fs.c
> > > > > @@ -317,12 +317,12 @@ static int __ffs_ep0_queue_wait(struct ffs_data *ffs, char *data, size_t len)
> > > > >    static int __ffs_ep0_stall(struct ffs_data *ffs)
> > > > >    {
> > > > >    	if (ffs->ev.can_stall) {
> > > > > -		dev_vdbg(ffs->dev, "ep0 stall\n");
> > > > > +		dev_vdbg(ffs->dev, "%s: ep0 stall\n", ffs->dev_name);
> > > > You already have the name here, it's in the usb-gadget structure, why do
> > > > you need to print it out again?
> > > > 
> > > > What is the before and after output of this change?  I think it should
> > > > have the same information already in it.
> > > 
> > > you have wrong understanding of usb_gadget->dev and ffs->dev_name,
> > > 
> > > this is output example,
> > > 
> > > [11.046519] configfs-gadget.g1 gadget.0: adb: interface descriptor
> > > 
> > > usb_gadget->dev is gadget.0,
> > > 
> > > but ffs->dev_name is adb.
> > Isn't there some mapping of gadget name to "dev_name" somewhere else in
> > the logs?  And what sets dev_name, why isn't that part of the gadget
> > name already?
> 
> 
> ffs->dev_name should be different from gadget name,
> 
> as we can create multiple ffs instances (adb, MTP, PTP ...) which work on
> one gadget device (gadget.0).

Shouldn't all of those instances have their own struct device pointer?

thanks,

greg k-h