On Wed, Mar 01, 2017 at 11:37:14AM +0100, Michał Kępień wrote: > > On Tue, Feb 28, 2017 at 10:45:25AM +0100, Michał Kępień wrote: > > > Some platform drivers use devm_input_allocate_device() together with > > > sparse_keymap_setup() in their .probe callbacks. While using the former > > > simplifies error handling, using the latter necessitates calling > > > sparse_keymap_free() in the error path and upon module unloading to > > > avoid leaking the copy of the keymap allocated by sparse_keymap_setup(). > > > > > > To help prevent such leaks and enable simpler error handling in these > > > drivers, add a new function which allows automatic freeing of the keymap > > > copy upon probe failure and on driver detach. > > > > > > As devm_input_allocate_device() adds its devres to the device owning the > > > input device, we do the same for managed input devices to ensure freeing > > > the keymap copy is properly slotted in the devres stack. > > > > > > The new function can also be used by non-managed input devices, though > > > in this case the devres is attached to the struct device embedded inside > > > the input device itself. > > > > This is wrong and does not work as input devices are never probed and > > never unbound, so the cleanup will never happen. > > > > Either pass device explicitly, or always take input's parent. > > Thank you for taking a look, Dmitry. I may be missing something, but > please bear with me. AFAICT, in the non-managed input device case the > devres release callback is called when the last reference to that input > device is dropped, i.e. after input_unregister_device() is called. > Setting devres.log=1 confirms this, so does putting a WARN_ON() inside > devm_sparse_keymap_free(). Could you please elaborate? Perhaps I am > misunderstanding your argument. Ah, I missed the fact that we drop devres resources when we destroy the device. OK, in this case why don't we make sparse keymap always use devm-allocated memory and make sparse_keymap_free() a noop for the time being? Once we remove it from all the drivers we can kill the stub. Thanks. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
