Commit ee46967f authored by Peter Hutterer's avatar Peter Hutterer Committed by Jiri Kosina
Browse files

HID: core: replace the collection tree pointers with indices 



Previously, the pointer to the parent collection was stored. If a device
exceeds 16 collections (HID_DEFAULT_NUM_COLLECTIONS), the array to store
the collections is reallocated, the pointer to the parent collection becomes
invalid.

Replace the pointers with an index-based lookup into the collections array.

Fixes: c53431eb ("HID: core: store the collections as a basic tree")
Reported-by: default avatarPandruvada, Srinivas <srinivas.pandruvada@intel.com>
Signed-off-by: default avatarPeter Hutterer <peter.hutterer@who-t.net>
Tested-by: default avatarKyle Pelton <kyle.d.pelton@linux.intel.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent cf26057a

drivers/hid/hid-core.c

+21 −11
Original line number Diff line number Diff line
@@ -125,6 +125,7 @@ static int open_collection(struct hid_parser *parser, unsigned type) 
{

	struct hid_collection *collection;

	unsigned usage;

	int collection_index;



	usage = parser->local.usage[0];
@@ -167,13 +168,13 @@ static int open_collection(struct hid_parser *parser, unsigned type) 
	parser->collection_stack[parser->collection_stack_ptr++] =

		parser->device->maxcollection;



	collection = parser->device->collection +

		parser->device->maxcollection++;

	collection_index = parser->device->maxcollection++;

	collection = parser->device->collection + collection_index;

	collection->type = type;

	collection->usage = usage;

	collection->level = parser->collection_stack_ptr - 1;

	collection->parent = parser->active_collection;

	parser->active_collection = collection;

	collection->parent_idx = parser->active_collection_idx;

	parser->active_collection_idx = collection_index;



	if (type == HID_COLLECTION_APPLICATION)

		parser->device->maxapplication++;
@@ -192,8 +193,13 @@ static int close_collection(struct hid_parser *parser) 
		return -EINVAL;

	}

	parser->collection_stack_ptr--;

	if (parser->active_collection)

		parser->active_collection = parser->active_collection->parent;

	if (parser->active_collection_idx != -1) {

		struct hid_device *device = parser->device;

		struct hid_collection *c;



		c = &device->collection[parser->active_collection_idx];

		parser->active_collection_idx = c->parent_idx;

	}

	return 0;

}
@@ -819,6 +825,7 @@ static int hid_scan_report(struct hid_device *hid) 
		return -ENOMEM;



	parser->device = hid;

	parser->active_collection_idx = -1;

	hid->group = HID_GROUP_GENERIC;



	/*
@@ -1006,10 +1013,12 @@ static void hid_apply_multiplier_to_field(struct hid_device *hid, 
		usage = &field->usage[i];



		collection = &hid->collection[usage->collection_index];

		while (collection && collection != multiplier_collection)

			collection = collection->parent;

		while (collection->parent_idx != -1 &&

		       collection != multiplier_collection)

			collection = &hid->collection[collection->parent_idx];



		if (collection || multiplier_collection == NULL)

		if (collection->parent_idx != -1 ||

		    multiplier_collection == NULL)

			usage->resolution_multiplier = effective_multiplier;



	}
@@ -1044,9 +1053,9 @@ static void hid_apply_multiplier(struct hid_device *hid, 
	 * applicable fields later.

	 */

	multiplier_collection = &hid->collection[multiplier->usage->collection_index];

	while (multiplier_collection &&

	while (multiplier_collection->parent_idx != -1 &&

	       multiplier_collection->type != HID_COLLECTION_LOGICAL)

		multiplier_collection = multiplier_collection->parent;

		multiplier_collection = &hid->collection[multiplier_collection->parent_idx];



	effective_multiplier = hid_calculate_multiplier(hid, multiplier);
@@ -1170,6 +1179,7 @@ int hid_open_report(struct hid_device *device) 
	}



	parser->device = device;

	parser->active_collection_idx = -1;



	end = start + size;

include/linux/hid.h

+2 −2
Original line number Diff line number Diff line
@@ -430,7 +430,7 @@ struct hid_local { 
 */



struct hid_collection {

	struct hid_collection *parent;

	int parent_idx; /* device->collection */

	unsigned type;

	unsigned usage;

	unsigned level;
@@ -658,7 +658,7 @@ struct hid_parser { 
	unsigned int         *collection_stack;

	unsigned int          collection_stack_ptr;

	unsigned int          collection_stack_size;

	struct hid_collection *active_collection;

	int                   active_collection_idx; /* device->collection */

	struct hid_device    *device;

	unsigned int          scan_flags;

};

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