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HID: core: replace the collection tree pointers with indices

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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: c53431eb69 ("HID: core: store the collections as a basic tree")
Reported-by: Pandruvada, Srinivas <srinivas.pandruvada@intel.com>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Tested-by: Kyle Pelton <kyle.d.pelton@linux.intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Peter Hutterer 2019-01-09 13:50:18 +10:00 committed by Jiri Kosina
parent cf26057a94
commit ee46967fc6
2 changed files with 23 additions and 13 deletions
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32
drivers/hid/hid-core.c
View File

@ -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;

4
include/linux/hid.h
View File

@ -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;
};