On Thu, Jul 30, 2015 at 01:01:21AM +0200, Rafael J. Wysocki wrote:
On Wednesday, July 29, 2015 02:19:16 PM Greg KH wrote:
On Fri, Jun 26, 2015 at 02:32:47PM +0530, Viresh Kumar wrote:
->add_dev() may fail and the error returned from it can be useful for the caller.
For example, if some of the resources aren't ready yet and -EPROBE_DEFER is returned from ->add_dev(), then the owner of 'struct subsys_interface' may want to try probing again at a later point of time. And that requires a proper return value from ->add_dev().
Also, if we hit an error while registering subsys_interface, then we should stop proceeding further and rollback whatever has been done until then. Break part of subsys_interface_unregister() into another routine, which lets us call ->remove_dev() for all devices for which ->add_dev() is already called.
Cc: 3.3+ stable@vger.kernel.org # 3.3+ Fixes: ca22e56debc5 ("driver-core: implement 'sysdev' functionality for regular devices and buses")
I don't see how this is a stable bug fix, what is resolved by it that doesn't work today? Is there some code that is expecting this functionality that has never been present?
I'll go queue it up, but I don't think it is -stable material, but feel free to change my mind.
There is a small problem with it that I've already pointed out to Viresh.
Namely, while changing subsys_interface_(un)register() to handle return values from ->add_dev(), it doesn't do the same thing in bus_probe_device() which I believe it should for consistency at least.
Oops, sorry, missed that response. I'll go drop this patch then, thanks for letting me know.
But then, the question is whether or not the probing should fail and what if device_attach() returns 0 and one of the ->add_dev() callbacks returns an error.
That's a total mess...
Given that there are almost no uses of this api, I think people should work it out before any more start to pop up :)
thanks,
greg k-h