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HID: core: statically allocate read buffers

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This is a preparation patch for rethinking the generic processing
of HID reports.

We can actually pre-allocate all of our memory instead of dynamically
allocating/freeing it whenever we parse a report.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: Ping Cheng <ping.cheng@wacom.com>
Acked-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Benjamin Tissoires 2022-02-03 15:32:15 +01:00 committed by Jiri Kosina
parent a254a9da45
commit 1c1813a743
2 changed files with 6 additions and 7 deletions
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12
drivers/hid/hid-core.c
View file

@ -101,7 +101,7 @@ static struct hid_field *hid_register_field(struct hid_report *report, unsigned
field = kzalloc((sizeof(struct hid_field) +
usages * sizeof(struct hid_usage) +
usages * sizeof(unsigned)), GFP_KERNEL);
2 * usages * sizeof(unsigned int)), GFP_KERNEL);
if (!field)
return NULL;
@ -109,6 +109,7 @@ static struct hid_field *hid_register_field(struct hid_report *report, unsigned
report->field[field->index] = field;
field->usage = (struct hid_usage *)(field + 1);
field->value = (s32 *)(field->usage + usages);
field->new_value = (s32 *)(field->value + usages);
field->report = report;
return field;
@ -1541,9 +1542,8 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field,
__s32 max = field->logical_maximum;
__s32 *value;
value = kmalloc_array(count, sizeof(__s32), GFP_ATOMIC);
if (!value)
return;
value = field->new_value;
memset(value, 0, count * sizeof(__s32));
for (n = 0; n < count; n++) {
@ -1557,7 +1557,7 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field,
value[n] >= min && value[n] <= max &&
value[n] - min < field->maxusage &&
field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1)
goto exit;
return;
}
for (n = 0; n < count; n++) {
@ -1581,8 +1581,6 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field,
}
memcpy(field->value, value, count * sizeof(__s32));
exit:
kfree(value);
}
/*

1
include/linux/hid.h
View file

@ -476,6 +476,7 @@ struct hid_field {
unsigned report_count; /* number of this field in the report */
unsigned report_type; /* (input,output,feature) */
__s32 *value; /* last known value(s) */
__s32 *new_value; /* newly read value(s) */
__s32 logical_minimum;
__s32 logical_maximum;
__s32 physical_minimum;