Hi Vinod, On 05/02/2020 13.31, Vinod Koul wrote: >> Looking at the commit which added it and I still don't get the point. >> If any of the channel is in use then we should not allow the DMA driver >> to go away at all. > > Not really, if the device is already gone, we cant do much about it. We > have to handle that gracefully rather than oopsing Ah, I have not thought about that. True. > The important part is that the device is gone. Think about a device on > PCI card which is yanked off or a USB device unplugged. Device is > already gone, you can't communicate with it anymore. So all we can do is > handle the condition and exit, hence the new method to let driver know. But for most devices this is not applicable, I also wondered what should I do in order to silence the print. Just add an empty device_release? >> Imho there should be a function to check if we can proceed with the >> .remove of the driver and fail it if any of the channels are in use. >> >> Hrm, base/dd.c __device_release_driver() does not check the .remove's >> return value, so it can not fail. >> >> What is expected if the .remove returns with OK but we still have >> channels in use? >> >> After the remove all sorts of things got yanked which might makes the >> still in use channels cause issues down the road. >> >> I'm curious why it is a good thing to remotely try to support unbind >> when the driver is in use. >> It is like one wants to support ext4 removal even when your rootfs is ext4. >> >> I think krefing the DMA driver for channel request/release is just fine, >> if user wants to break the system we should not assist... >> >>>> It's not limited to that driver, but actually all I'm maintaining. >>>> >>>> Users are not happy! >>>> >>>> -- >>>> With Best Regards, >>>> Andy Shevchenko >>> >> >> - Péter >> >> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. >> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki > - Péter Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
