Messages in this thread | | | Date | Wed, 4 Jan 2017 11:40:56 +0000 | From | Russell King - ARM Linux <> | Subject | Re: [PATCH v2 2/2] arm: perf: Mark as non-removable |
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On Wed, Jan 04, 2017 at 11:30:25AM +0000, Mark Rutland wrote: > On Wed, Jan 04, 2017 at 10:19:46AM +0100, Alexander Stein wrote: > > I'm not sure if the change above works with remove functions set in struct > > bus_type too. > > But on the other hand this would hide errors in drivers which are actually > > removable but do not cleanup properly which DEBUG_TEST_DRIVER_REMOVE tries to > > detect. > > By setting .suppress_bind_attrs = true explicitely you state "This > > driver cannot be removed!", so the remove callback is not missing by accident. > > I'm not sure I follow. If the remove callback is accidentally missing, > the driver is not "actually removable" today -- there's either no remove > code, or it's not been wired up (the latter of which will likely result > in a compiler warning about an unused function). > > Aborting the remove early in those cases is much safer than forcefully > removing a driver without a remove callback.
Drivers without a remove function may be removable - there's more layers than just the driver - there's the bus layer as well, which may or may not direct to a private-bus pointer.
There's no real way for the core driver model code to know whether the lack of the ->remove in the struct device_driver is something that prevents a driver being removed, or whether it's handled via some other method. Eg, platform drivers.
-- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.
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