HID: bpf: make hid_bpf_input_report() sleep until the device is ready

hid_bpf_input_report() is already marked to be used in sleepable context
only. So instead of hammering with timers the device to hopefully get
an available slot where the device is not sending events, we can make
that kfunc wait for the current event to be terminated before it goes in.

This allows to work with the following pseudo code:

in struct_ops/hid_device_event:
  - schedule a bpf_wq, which calls hid_bpf_input_report()
  - once this struct_ops function terminates, hid_bpf_input_report()
    immediately starts before the next event

Link: https://patch.msgid.link/[email protected]
Acked-by: Jiri Kosina <[email protected]>
Signed-off-by: Benjamin Tissoires <[email protected]>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/linux/hid_bpf.h b/include/linux/hid_bpf.h
index f35508a73067..7f04353d09e9 100644
--- a/include/linux/hid_bpf.h
+++ b/include/linux/hid_bpf.h
@@ -72,7 +72,8 @@ struct hid_ops {
 	int (*hid_hw_output_report)(struct hid_device *hdev, __u8 *buf, size_t len,
 				    __u64 source, bool from_bpf);
 	int (*hid_input_report)(struct hid_device *hid, enum hid_report_type type,
-				u8 *data, u32 size, int interrupt, u64 source);
+				u8 *data, u32 size, int interrupt, u64 source,
+				bool lock_already_taken);
 	struct module *owner;
 	const struct bus_type *bus_type;
 };