On Tue, Mar 07, 2017 at 04:35:37AM +0000, Ajay Kaher wrote: > > > > > On Fri, 3 Mar 2017, Ajay Kaher wrote: > > > > > > usb_class->kref is not accessible outside the file.c > > > > as usb_class is _static_ inside the file.c and > > > > pointer of usb_class->kref is not passed anywhere. > > > > > > > > Hence as you wanted, there are no references of usb_class->kref > > > > other than taken by init_usb_class() and released by destroy_usb_class(). > > > > > > Verified the code again, I hope my last comments clarifed the things > > > which came in your mind and helps you to accept the patch :) > > > > Your main point is that usb_class->kref is accessed from only two > > points, both of which are protected by the new mutex. This means there > > is no reason for the value to be a struct kref at all. You should > > change it to an int (and change its name). Leaving it as a kref will > > make readers wonder why it needs to be updated atomically. > > At many places in Linux kernel, instances of Kref have been used within > Mutex, SpinLock and don’t have any side effect. > > Making to int and handle (i.e. get/put) it within file.c seems > not good as we have Kref. Instead, we can have non_atomic version of kref. > We can discuss about non_atomic kref in another thread, if you are interested. > > > Also, why does destroy_usb_class() have that "if (usb_class) "test? > > Isn't it true that usb_class can never be NULL there? > > Removed in Patch v4. > > thanks, > ajay kaher > > > Signed-off-by: Ajay Kaher > Can you resend this in a format that I can apply it in? I suggest reading Documentation/SubmittingPatches. If you have any questions about the correct format, please let me know. Also add Alan's ack to it. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
