HID: allocate hid_parser in a proper way

hid_parser is non-trivially large structure, so it should be allocated
using vmalloc() to avoid unsuccessful allocations when memory fragmentation
is too high.
This structue has a very short life, it's destroyed as soon as the report
descriptor has been completely parsed.

This should be considered a temporary solution, until the hid_parser is
rewritten to consume less memory during report descriptor parsing.

Acked-by: Mariusz Kozlowski <[e-mail]>
Signed-off-by: Jiri Kosina <[e-mail]>

drivers/hid/hid-core.c

···
 #include <asm/byteorder.h>
 #include <linux/input.h>
 #include <linux/wait.h>
+#include <linux/vmalloc.h>
 
 #include <linux/hid.h>
 #include <linux/hiddev.h>
···
 	memcpy(device->rdesc, start, size);
 	device->rsize = size;
 
-	if (!(parser = kzalloc(sizeof(struct hid_parser), GFP_KERNEL))) {
+	if (!(parser = vmalloc(sizeof(struct hid_parser)))) {
 		kfree(device->rdesc);
 		kfree(device->collection);
 		kfree(device);
 		return NULL;
 	}
+	memset(parser, 0, sizeof(struct hid_parser));
 	parser->device = device;
 
 	end = start + size;
···
 		if (item.format != HID_ITEM_FORMAT_SHORT) {
 			dbg("unexpected long global item");
 			hid_free_device(device);
-			kfree(parser);
+			vfree(parser);
 			return NULL;
 		}
 
···
 			dbg("item %u %u %u %u parsing failed\n",
 				item.format, (unsigned)item.size, (unsigned)item.type, (unsigned)item.tag);
 			hid_free_device(device);
-			kfree(parser);
+			vfree(parser);
 			return NULL;
 		}
 
···
 			if (parser->collection_stack_ptr) {
 				dbg("unbalanced collection at end of report description");
 				hid_free_device(device);
-				kfree(parser);
+				vfree(parser);
 				return NULL;
 			}
 			if (parser->local.delimiter_depth) {
 				dbg("unbalanced delimiter at end of report description");
 				hid_free_device(device);
-				kfree(parser);
+				vfree(parser);
 				return NULL;
 			}
-			kfree(parser);
+			vfree(parser);
 			return device;
 		}
 	}
 
 	dbg("item fetching failed at offset %d\n", (int)(end - start));
 	hid_free_device(device);
-	kfree(parser);
+	vfree(parser);
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(hid_parse_report);