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HID: core: factor out hid_parse_collections()

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In preparation to making use of __free(...) cleanup facilities to
clean up temporary buffers, factor out code parsing collections into
a separate function to make the code simpler.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>
This commit is contained in:
Dmitry Torokhov 2026-03-25 23:25:37 -07:00 committed by Jiri Kosina
parent 4a58ae85c3
commit d7db259bd6
1 changed files with 89 additions and 80 deletions
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169
drivers/hid/hid-core.c
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@ -1244,6 +1244,88 @@ void hid_setup_resolution_multiplier(struct hid_device *hid)
}
EXPORT_SYMBOL_GPL(hid_setup_resolution_multiplier);
static int hid_parse_collections(struct hid_device *device)
{
struct hid_parser *parser;
struct hid_item item;
const u8 *start = device->rdesc;
const u8 *end = start + device->rsize;
const u8 *next;
int ret;
static typeof(hid_parser_main) (* const dispatch_type[]) = {
hid_parser_main,
hid_parser_global,
hid_parser_local,
hid_parser_reserved
};
parser = vzalloc(sizeof(*parser));
if (!parser)
return -ENOMEM;
parser->device = device;
device->collection = kzalloc_objs(*device->collection,
HID_DEFAULT_NUM_COLLECTIONS);
if (!device->collection) {
ret = -ENOMEM;
goto out;
}
device->collection_size = HID_DEFAULT_NUM_COLLECTIONS;
for (unsigned int i = 0; i < HID_DEFAULT_NUM_COLLECTIONS; i++)
device->collection[i].parent_idx = -1;
ret = -EINVAL;
while ((next = fetch_item(start, end, &item)) != NULL) {
start = next;
if (item.format != HID_ITEM_FORMAT_SHORT) {
hid_err(device, "unexpected long global item\n");
goto out;
}
if (dispatch_type[item.type](parser, &item)) {
hid_err(device, "item %u %u %u %u parsing failed\n",
item.format,
(unsigned int)item.size,
(unsigned int)item.type,
(unsigned int)item.tag);
goto out;
}
}
if (start != end) {
hid_err(device, "item fetching failed at offset %u/%u\n",
device->rsize - (unsigned int)(end - start),
device->rsize);
goto out;
}
if (parser->collection_stack_ptr) {
hid_err(device, "unbalanced collection at end of report description\n");
goto out;
}
if (parser->local.delimiter_depth) {
hid_err(device, "unbalanced delimiter at end of report description\n");
goto out;
}
/*
* fetch initial values in case the device's
* default multiplier isn't the recommended 1
*/
hid_setup_resolution_multiplier(device);
device->status |= HID_STAT_PARSED;
ret = 0;
out:
kfree(parser->collection_stack);
vfree(parser);
return ret;
}
/**
* hid_open_report - open a driver-specific device report
*
@ -1258,21 +1340,9 @@ EXPORT_SYMBOL_GPL(hid_setup_resolution_multiplier);
*/
int hid_open_report(struct hid_device *device)
{
struct hid_parser *parser;
struct hid_item item;
unsigned int size;
const __u8 *start;
const __u8 *end;
const __u8 *next;
int ret;
int i;
static int (*dispatch_type[])(struct hid_parser *parser,
struct hid_item *item) = {
hid_parser_main,
hid_parser_global,
hid_parser_local,
hid_parser_reserved
};
const u8 *start;
int error;
if (WARN_ON(device->status & HID_STAT_PARSED))
return -EBUSY;
@ -1309,74 +1379,13 @@ int hid_open_report(struct hid_device *device)
device->rdesc = start;
device->rsize = size;
parser = vzalloc(sizeof(struct hid_parser));
if (!parser) {
ret = -ENOMEM;
goto alloc_err;
error = hid_parse_collections(device);
if (error) {
hid_close_report(device);
return error;
}
parser->device = device;
end = start + size;
device->collection = kzalloc_objs(struct hid_collection,
HID_DEFAULT_NUM_COLLECTIONS);
if (!device->collection) {
ret = -ENOMEM;
goto err;
}
device->collection_size = HID_DEFAULT_NUM_COLLECTIONS;
for (i = 0; i < HID_DEFAULT_NUM_COLLECTIONS; i++)
device->collection[i].parent_idx = -1;
ret = -EINVAL;
while ((next = fetch_item(start, end, &item)) != NULL) {
start = next;
if (item.format != HID_ITEM_FORMAT_SHORT) {
hid_err(device, "unexpected long global item\n");
goto err;
}
if (dispatch_type[item.type](parser, &item)) {
hid_err(device, "item %u %u %u %u parsing failed\n",
item.format, (unsigned)item.size,
(unsigned)item.type, (unsigned)item.tag);
goto err;
}
if (start == end) {
if (parser->collection_stack_ptr) {
hid_err(device, "unbalanced collection at end of report description\n");
goto err;
}
if (parser->local.delimiter_depth) {
hid_err(device, "unbalanced delimiter at end of report description\n");
goto err;
}
/*
* fetch initial values in case the device's
* default multiplier isn't the recommended 1
*/
hid_setup_resolution_multiplier(device);
kfree(parser->collection_stack);
vfree(parser);
device->status |= HID_STAT_PARSED;
return 0;
}
}
hid_err(device, "item fetching failed at offset %u/%u\n",
size - (unsigned int)(end - start), size);
err:
kfree(parser->collection_stack);
alloc_err:
vfree(parser);
hid_close_report(device);
return ret;
return 0;
}
EXPORT_SYMBOL_GPL(hid_open_report);