I had to go twice through the history to get a grasp at this code.
De-duplicate the various tests in one common helper to make it
more explicit.
Note that the `HID_UP_KEYBOARD + 1` condition is tested through
https://gitlab.freedesktop.org/libevdev/hid-tools/-/merge_requests/121
Signed-off-by: Benjamin Tissoires <[email protected]>
---
drivers/hid/hid-core.c | 54 ++++++++++++++++++++++++++++++------------
1 file changed, 39 insertions(+), 15 deletions(-)
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 75e7b8447bf7..fad4dbdf6391 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1525,6 +1525,24 @@ static void hid_process_event(struct hid_device *hid, struct hid_field *field,
hid->hiddev_hid_event(hid, field, usage, value);
}
+/*
+ * Checks if the given value is valid within this field
+ */
+static inline int hid_array_value_is_valid(struct hid_field *field,
+ __s32 value)
+{
+ __s32 min = field->logical_minimum;
+
+ /*
+ * Value needs to be between logical min and max, and
+ * (value - min) is used as an index in the usage array.
+ * This array is of size field->maxusage
+ */
+ return value >= min &&
+ value <= field->logical_maximum &&
+ value - min < field->maxusage;
+}
+
/*
* Analyse a received field, and fetch the data from it. The field
* content is stored for next report processing (we do differential
@@ -1539,7 +1557,6 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field,
unsigned offset = field->report_offset;
unsigned size = field->report_size;
__s32 min = field->logical_minimum;
- __s32 max = field->logical_maximum;
__s32 *value;
value = field->new_value;
@@ -1554,8 +1571,7 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field,
/* Ignore report if ErrorRollOver */
if (!(field->flags & HID_MAIN_ITEM_VARIABLE) &&
- value[n] >= min && value[n] <= max &&
- value[n] - min < field->maxusage &&
+ hid_array_value_is_valid(field, value[n]) &&
field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1)
return;
}
@@ -1563,21 +1579,29 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field,
for (n = 0; n < count; n++) {
if (HID_MAIN_ITEM_VARIABLE & field->flags) {
- hid_process_event(hid, field, &field->usage[n], value[n], interrupt);
+ hid_process_event(hid,
+ field,
+ &field->usage[n],
+ value[n],
+ interrupt);
continue;
}
- if (field->value[n] >= min && field->value[n] <= max
- && field->value[n] - min < field->maxusage
- && field->usage[field->value[n] - min].hid
- && search(value, field->value[n], count))
- hid_process_event(hid, field, &field->usage[field->value[n] - min], 0, interrupt);
-
- if (value[n] >= min && value[n] <= max
- && value[n] - min < field->maxusage
- && field->usage[value[n] - min].hid
- && search(field->value, value[n], count))
- hid_process_event(hid, field, &field->usage[value[n] - min], 1, interrupt);
+ if (hid_array_value_is_valid(field, field->value[n]) &&
+ search(value, field->value[n], count))
+ hid_process_event(hid,
+ field,
+ &field->usage[field->value[n] - min],
+ 0,
+ interrupt);
+
+ if (hid_array_value_is_valid(field, value[n]) &&
+ search(field->value, value[n], count))
+ hid_process_event(hid,
+ field,
+ &field->usage[value[n] - min],
+ 1,
+ interrupt);
}
memcpy(field->value, value, count * sizeof(__s32));
--
2.33.1