Messages in this thread | | | Date | Tue, 11 Feb 2020 11:22:36 -0800 | From | Greg KH <> | Subject | Re: [PATCH v2 02/16] bus: mhi: core: Add support for registering MHI controllers |
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On Wed, Feb 12, 2020 at 12:41:47AM +0530, Manivannan Sadhasivam wrote: > Hi Greg, > > On Thu, Feb 06, 2020 at 05:56:06PM +0100, Greg KH wrote: > > On Fri, Jan 31, 2020 at 07:19:55PM +0530, Manivannan Sadhasivam wrote: > > > +static void mhi_release_device(struct device *dev) > > > +{ > > > + struct mhi_device *mhi_dev = to_mhi_device(dev); > > > + > > > + if (mhi_dev->ul_chan) > > > + mhi_dev->ul_chan->mhi_dev = NULL; > > > > That looks really odd. Why didn't you just drop the reference you > > should have grabbed here for this pointer? You did properly increment > > it when you saved it, right? :) > > > > Well, there is no reference count (kref) exist for mhi_dev.
Then something is wrong with your model :(
You can't save pointers off to things without reference counting, that is going to cause you real problems. See the coding style document for all the details.
> And we really needed to NULL the mhi_dev to avoid any dangling > reference to it.
Again, that's not how to do this correctly.
> The reason for not having kref is that, each mhi_dev will be used by > maximum of 2 channels only. So thought that refcounting is not needed. > Please correct me if I'm wrong.
Please read section 11 of Documentation/process/coding-style.rst
thanks,
greg k-h
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