[ 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>

Now that the input_dev->vals array is always there we can be assured
that input_pass_values() is always called with a non-0 number of
events. Remove the check.

Reviewed-by: Jeff LaBundy <jeff@labundy.com>
Reviewed-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240703213756.3375978-8-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Preallocate memory for holding event values (input_dev->vals) so that
there is no need to check if it was allocated or not in the event
processing code.

The amount of memory will be adjusted after input device has been fully
set up upon registering device with the input core.

Reviewed-by: Jeff LaBundy <jeff@labundy.com>
Reviewed-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240703213756.3375978-7-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

In preparation to have dev->vals memory pre-allocated rearrange
code in input_alloc_device() so that it allows handling multiple
points of failure.

Reviewed-by: Jeff LaBundy <jeff@labundy.com>
Reviewed-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240703213756.3375978-6-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Streamline event handling code by providing batch implementations for
filtering and event processing and using them in place of the main
event handler, as needed, instead of having complex branching logic
in the middle of the event processing code.

Reviewed-by: Jeff LaBundy <jeff@labundy.com>
Reviewed-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240703213756.3375978-5-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Input core expects input handlers to be either filters, or regular
handlers, but not both. Additionally, for regular handlers it does
not make sense to define both single event method and batch method.

Refuse registering handler if it defines more than one method.

Reviewed-by: Jeff LaBundy <jeff@labundy.com>
Reviewed-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240703213756.3375978-3-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

If an input device declares too many capability bits then modalias
string for such device may become too long and not fit into uevent
buffer, resulting in failure of sending said uevent. This, in turn,
may prevent userspace from recognizing existence of such devices.

This is typically not a concern for real hardware devices as they have
limited number of keys, but happen with synthetic devices such as
ones created by xen-kbdfront driver, which creates devices as being
capable of delivering all possible keys, since it doesn't know what
keys the backend may produce.

To deal with such devices input core will attempt to trim key data,
in the hope that the rest of modalias string will fit in the given
buffer. When trimming key data it will indicate that it is not
complete by placing "+," sign, resulting in conversions like this:

old: k71,72,73,74,78,7A,7B,7C,7D,8E,9E,A4,AD,E0,E1,E4,F8,174,
new: k71,72,73,74,78,7A,7B,7C,+,

This should allow existing udev rules continue to work with existing
devices, and will also allow writing more complex rules that would
recognize trimmed modalias and check input device characteristics by
other means (for example by parsing KEY= data in uevent or parsing
input device sysfs attributes).

Note that the driver core may try adding more uevent environment
variables once input core is done adding its own, so when forming
modalias we can not use the entire available buffer, so we reduce
it by somewhat an arbitrary amount (96 bytes).

Reported-by: Jason Andryuk <jandryuk@gmail.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Tested-by: Jason Andryuk <jandryuk@gmail.com>
Link: https://lore.kernel.org/r/ZjAWMQCJdrxZkvkB@google.com
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Since commit 43a7206b0963 ("driver core: class: make class_register() take
a const *"), the driver core allows for struct class to be in read-only
memory, so move the input_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Link: https://lore.kernel.org/r/20240305-class_cleanup-input-v1-1-0c3d950c25db@marliere.net
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

ida_alloc() and ida_free() should be preferred to the deprecated
ida_simple_get() and ida_simple_remove().

Note that the upper limit of ida_simple_get() is exclusive, but the one of
ida_alloc_range() is inclusive. So a -1 has been added when needed.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/a885de14beead2cc3c1c946f192b8b178dac696a.1705349930.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Replace calls to scnprintf() in the methods showing device attributes
with sysfs_emit() to simplify the code.

Signed-off-by: ye xingchen <ye.xingchen@zte.com.cn>
Link: https://lore.kernel.org/r/202212021133398847947@zte.com.cn
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>