Messages in this thread | | | Date | Tue, 7 Mar 2006 17:33:04 -0800 | From | Greg KH <> | Subject | Re: [PATCH] EDAC: core EDAC support code |
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On Tue, Mar 07, 2006 at 08:03:41PM -0500, Dmitry Torokhov wrote: > On Tuesday 07 March 2006 12:04, Greg KH wrote: > > On Tue, Mar 07, 2006 at 08:47:44AM -0800, Dave Peterson wrote: > > > Ok, how does this sound: > > > > > > - Modify EDAC so it uses kmalloc() to create the kobject. > > > - Eliminate edac_memctrl_master_release(). Instead, use kfree() as > > > the release method for the kobject. Here, it's important to use a > > > function -outside- of EDAC as the release method since the core > > > EDAC module may have been unloaded by the time the release method > > > is called. > > > > No, if this happens then you are using the kobject incorrectly. How > > could it be held if your module is unloaded? Don't you have the module > > reference counting logic correct? > > > > It is pretty hard to implement kobject handling correctly. Consider the > following: > > rmmod device_driver < /sys/devices/pci0000:00/...../power/state > > for a driver that creates/destroys device objects.
I agree, that's one reason I really hate the "default" attributes :(
To do this "right" we need to make the attributes dynamically created and the owner set to the proper module. I did that for the module core code and it's on my todo list for the driver core too.
> Opening 'state' attribute will pin device structure into memory but will > not increase _your_ module's refcount. It is nice if you have a subsystem > core split from drivers code - then you can keep core module reference > until device objects are gone and allow individual drivers be unloaded > freely. But for single-module system it is pretty hard, that's why > platform devices are popular.
They are popular for when you don't have a "bus", and rightfully so.
thanks,
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