6.11-stable review patch. If anyone has any objections, please let me know.
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From: Dmitry Torokhov dmitry.torokhov@gmail.com
[ Upstream commit 071b24b54d2d05fbf39ddbb27dee08abd1d713f3 ]
Commit d469647bafd9 ("Input: simplify event handling logic") introduced code that would set handler->events() method to either input_handler_events_filter() or input_handler_events_default() or input_handler_events_null(), depending on the kind of input handler (a filter or a regular one) we are dealing with. Unfortunately this breaks cases when we try to re-register the same filter (as is the case with sysrq handler): after initial registration the handler will have 2 event handling methods defined, and will run afoul of the check in input_handler_check_methods():
input: input_handler_check_methods: only one event processing method can be defined (sysrq) sysrq: Failed to register input handler, error -22
Fix this by adding handle_events() method to input_handle structure and setting it up when registering a new input handle according to event handling methods defined in associated input_handler structure, thus avoiding modifying the input_handler structure.
Reported-by: "Ned T. Crigler" crigler@gmail.com Reported-by: Christian Heusel christian@heusel.eu Tested-by: "Ned T. Crigler" crigler@gmail.com Tested-by: Peter Seiderer ps.report@gmx.net Fixes: d469647bafd9 ("Input: simplify event handling logic") Link: https://lore.kernel.org/r/Zx2iQp6csn42PJA7@xavtug Cc: stable@vger.kernel.org Signed-off-by: Dmitry Torokhov dmitry.torokhov@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/input/input.c | 134 +++++++++++++++++++++++------------------- include/linux/input.h | 10 +++- 2 files changed, 82 insertions(+), 62 deletions(-)
diff --git a/drivers/input/input.c b/drivers/input/input.c index 54c57b267b25f..865d3f8e97a66 100644 --- a/drivers/input/input.c +++ b/drivers/input/input.c @@ -119,12 +119,12 @@ static void input_pass_values(struct input_dev *dev,
handle = rcu_dereference(dev->grab); if (handle) { - count = handle->handler->events(handle, vals, count); + count = handle->handle_events(handle, vals, count); } else { list_for_each_entry_rcu(handle, &dev->h_list, d_node) if (handle->open) { - count = handle->handler->events(handle, vals, - count); + count = handle->handle_events(handle, vals, + count); if (!count) break; } @@ -2537,57 +2537,6 @@ static int input_handler_check_methods(const struct input_handler *handler) return 0; }
-/* - * An implementation of input_handler's events() method that simply - * invokes handler->event() method for each event one by one. - */ -static unsigned int input_handler_events_default(struct input_handle *handle, - struct input_value *vals, - unsigned int count) -{ - struct input_handler *handler = handle->handler; - struct input_value *v; - - for (v = vals; v != vals + count; v++) - handler->event(handle, v->type, v->code, v->value); - - return count; -} - -/* - * An implementation of input_handler's events() method that invokes - * handler->filter() method for each event one by one and removes events - * that were filtered out from the "vals" array. - */ -static unsigned int input_handler_events_filter(struct input_handle *handle, - struct input_value *vals, - unsigned int count) -{ - struct input_handler *handler = handle->handler; - struct input_value *end = vals; - struct input_value *v; - - for (v = vals; v != vals + count; v++) { - if (handler->filter(handle, v->type, v->code, v->value)) - continue; - if (end != v) - *end = *v; - end++; - } - - return end - vals; -} - -/* - * An implementation of input_handler's events() method that does nothing. - */ -static unsigned int input_handler_events_null(struct input_handle *handle, - struct input_value *vals, - unsigned int count) -{ - return count; -} - /** * input_register_handler - register a new input handler * @handler: handler to be registered @@ -2607,13 +2556,6 @@ int input_register_handler(struct input_handler *handler)
INIT_LIST_HEAD(&handler->h_list);
- if (handler->filter) - handler->events = input_handler_events_filter; - else if (handler->event) - handler->events = input_handler_events_default; - else if (!handler->events) - handler->events = input_handler_events_null; - error = mutex_lock_interruptible(&input_mutex); if (error) return error; @@ -2687,6 +2629,75 @@ int input_handler_for_each_handle(struct input_handler *handler, void *data, } EXPORT_SYMBOL(input_handler_for_each_handle);
+/* + * An implementation of input_handle's handle_events() method that simply + * invokes handler->event() method for each event one by one. + */ +static unsigned int input_handle_events_default(struct input_handle *handle, + struct input_value *vals, + unsigned int count) +{ + struct input_handler *handler = handle->handler; + struct input_value *v; + + for (v = vals; v != vals + count; v++) + handler->event(handle, v->type, v->code, v->value); + + return count; +} + +/* + * An implementation of input_handle's handle_events() method that invokes + * handler->filter() method for each event one by one and removes events + * that were filtered out from the "vals" array. + */ +static unsigned int input_handle_events_filter(struct input_handle *handle, + struct input_value *vals, + unsigned int count) +{ + struct input_handler *handler = handle->handler; + struct input_value *end = vals; + struct input_value *v; + + for (v = vals; v != vals + count; v++) { + if (handler->filter(handle, v->type, v->code, v->value)) + continue; + if (end != v) + *end = *v; + end++; + } + + return end - vals; +} + +/* + * An implementation of input_handle's handle_events() method that does nothing. + */ +static unsigned int input_handle_events_null(struct input_handle *handle, + struct input_value *vals, + unsigned int count) +{ + return count; +} + +/* + * Sets up appropriate handle->event_handler based on the input_handler + * associated with the handle. + */ +static void input_handle_setup_event_handler(struct input_handle *handle) +{ + struct input_handler *handler = handle->handler; + + if (handler->filter) + handle->handle_events = input_handle_events_filter; + else if (handler->event) + handle->handle_events = input_handle_events_default; + else if (handler->events) + handle->handle_events = handler->events; + else + handle->handle_events = input_handle_events_null; +} + /** * input_register_handle - register a new input handle * @handle: handle to register @@ -2704,6 +2715,7 @@ int input_register_handle(struct input_handle *handle) struct input_dev *dev = handle->dev; int error;
+ input_handle_setup_event_handler(handle); /* * We take dev->mutex here to prevent race with * input_release_device(). diff --git a/include/linux/input.h b/include/linux/input.h index 89a0be6ee0e23..cd866b020a01d 100644 --- a/include/linux/input.h +++ b/include/linux/input.h @@ -339,12 +339,16 @@ struct input_handler { * @name: name given to the handle by handler that created it * @dev: input device the handle is attached to * @handler: handler that works with the device through this handle + * @handle_events: event sequence handler. It is set up by the input core + * according to event handling method specified in the @handler. See + * input_handle_setup_event_handler(). + * This method is being called by the input core with interrupts disabled + * and dev->event_lock spinlock held and so it may not sleep. * @d_node: used to put the handle on device's list of attached handles * @h_node: used to put the handle on handler's list of handles from which * it gets events */ struct input_handle { - void *private;
int open; @@ -353,6 +357,10 @@ struct input_handle { struct input_dev *dev; struct input_handler *handler;
+ unsigned int (*handle_events)(struct input_handle *handle, + struct input_value *vals, + unsigned int count); + struct list_head d_node; struct list_head h_node; };