Messages in this thread | | | Date | Wed, 22 Feb 2023 14:52:07 -0800 | Subject | Re: [PATCH v10 08/26] gunyah: rsc_mgr: Add resource manager RPC core | From | Elliot Berman <> |
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On 2/16/2023 11:37 PM, Greg Kroah-Hartman wrote: > On Thu, Feb 16, 2023 at 09:40:52AM -0800, Elliot Berman wrote: >> >> >> On 2/15/2023 10:43 PM, Greg Kroah-Hartman wrote: >>> On Tue, Feb 14, 2023 at 01:23:25PM -0800, Elliot Berman wrote: >>>> +struct gh_rm { >>>> + struct device *dev; >>> >>> What device does this point to? >>> >> >> The platform device. > > What platform device? And why a platform device? >
This will be used for the dev_printk. It's presently also used for the reference counting. From your comments below, I'll switch the reference counting away from this platform device.
>>>> + struct gunyah_resource tx_ghrsc, rx_ghrsc; >>>> + struct gh_msgq msgq; >>>> + struct mbox_client msgq_client; >>>> + struct gh_rm_connection *active_rx_connection; >>>> + int last_tx_ret; >>>> + >>>> + struct idr call_idr; >>>> + struct mutex call_idr_lock; >>>> + >>>> + struct kmem_cache *cache; >>>> + struct mutex send_lock; >>>> + struct blocking_notifier_head nh; >>>> +}; >>> >>> This obviously is the "device" that your system works on, so what are >>> the lifetime rules of it? Why isn't is just a real 'struct device' in >>> the system instead of a random memory blob with a pointer to a device? >>> >>> What controls the lifetime of this structure and where is the reference >>> counting logic for it? >>> >> >> The lifetime of the structure is bound by the platform device that above >> struct device *dev points to. get_gh_rm and put_gh_rm increments the device >> ref counter and ensures lifetime of the struct is also extended. > > But this really is "your" device, not the platform device. So make it a > real one please as that is how the kernel's driver model works. Don't > hang "magic structures" off of a random struct device and have them > control the lifetime rules of the parent without actually being a device > themself. This should make things simpler overall, not more complex, > and allow you to expose things to userspace properly (right now your > data is totally hidden.)
The "real" device I create here is the miscdev, so I think the recommendation here is to do refcounting off that miscdev. Is this the approach you were thinking of?
Thanks, Elliot
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