[PATCH 2/2] HID: core: use __free(kfree) and __free(kvfree) to clean up temporary buffers

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

This simplifies error handling and protects against memory leaks.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/hid/hid-core.c | 34 ++++++++++++----------------------
 1 file changed, 12 insertions(+), 22 deletions(-)

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index bb13dcb116a9..b40953e0f52e 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -924,7 +924,6 @@ static int hid_scan_main(struct hid_parser *parser, struct hid_item *item)
  */
 static int hid_scan_report(struct hid_device *hid)
 {
-	struct hid_parser *parser;
 	struct hid_item item;
 	const __u8 *start = hid->dev_rdesc;
 	const __u8 *end = start + hid->dev_rsize;
@@ -936,7 +935,7 @@ static int hid_scan_report(struct hid_device *hid)
 		hid_parser_reserved
 	};
 
-	parser = vzalloc(sizeof(struct hid_parser));
+	struct hid_parser *parser __free(kvfree) = vzalloc(sizeof(*parser));
 	if (!parser)
 		return -ENOMEM;
 
@@ -987,7 +986,6 @@ static int hid_scan_report(struct hid_device *hid)
 	}
 
 	kfree(parser->collection_stack);
-	vfree(parser);
 	return 0;
 }
 
@@ -1246,7 +1244,6 @@ 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;
@@ -1259,7 +1256,7 @@ static int hid_parse_collections(struct hid_device *device)
 		hid_parser_reserved
 	};
 
-	parser = vzalloc(sizeof(*parser));
+	struct hid_parser *parser __free(kvfree) = vzalloc(sizeof(*parser));
 	if (!parser)
 		return -ENOMEM;
 
@@ -1267,10 +1264,9 @@ static int hid_parse_collections(struct hid_device *device)
 
 	device->collection = kzalloc_objs(*device->collection,
 					  HID_DEFAULT_NUM_COLLECTIONS);
-	if (!device->collection) {
-		ret = -ENOMEM;
-		goto out;
-	}
+	if (!device->collection)
+		return -ENOMEM;
+
 	device->collection_size = HID_DEFAULT_NUM_COLLECTIONS;
 	for (unsigned int i = 0; i < HID_DEFAULT_NUM_COLLECTIONS; i++)
 		device->collection[i].parent_idx = -1;
@@ -1322,7 +1318,6 @@ static int hid_parse_collections(struct hid_device *device)
 
 out:
 	kfree(parser->collection_stack);
-	vfree(parser);
 	return ret;
 }
 
@@ -1358,9 +1353,9 @@ int hid_open_report(struct hid_device *device)
 		 * on a copy of our report descriptor so it can
 		 * change it.
 		 */
-		__u8 *buf = kmemdup(start, size, GFP_KERNEL);
+		u8 *buf __free(kfree) = kmemdup(start, size, GFP_KERNEL);
 
-		if (buf == NULL)
+		if (!buf)
 			return -ENOMEM;
 
 		start = device->driver->report_fixup(device, buf, &size);
@@ -1371,8 +1366,7 @@ int hid_open_report(struct hid_device *device)
 		 * needs to be cleaned up or not at the end.
 		 */
 		start = kmemdup(start, size, GFP_KERNEL);
-		kfree(buf);
-		if (start == NULL)
+		if (!start)
 			return -ENOMEM;
 	}
 
@@ -1998,11 +1992,11 @@ static struct hid_report *hid_get_report(struct hid_report_enum *report_enum,
 int __hid_request(struct hid_device *hid, struct hid_report *report,
 		enum hid_class_request reqtype)
 {
-	char *buf, *data_buf;
+	u8 *data_buf;
 	int ret;
 	u32 len;
 
-	buf = hid_alloc_report_buf(report, GFP_KERNEL);
+	u8 *buf __free(kfree) = hid_alloc_report_buf(report, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
 
@@ -2021,17 +2015,13 @@ int __hid_request(struct hid_device *hid, struct hid_report *report,
 	ret = hid_hw_raw_request(hid, report->id, buf, len, report->type, reqtype);
 	if (ret < 0) {
 		dbg_hid("unable to complete request: %d\n", ret);
-		goto out;
+		return ret;
 	}
 
 	if (reqtype == HID_REQ_GET_REPORT)
 		hid_input_report(hid, report->type, buf, ret, 0);
 
-	ret = 0;
-
-out:
-	kfree(buf);
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(__hid_request);
 
-- 
2.53.0.1018.g2bb0e51243-goog