[PATCH v3 3/4] HID: multitouch: use __free(kfree) to clean up temporary buffers

[Benjamin Tissoires <bentiss@kernel.org>]

This simplifies error handling and protects against memory leaks.

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
---
 drivers/hid/hid-multitouch.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index eeab0b6e32cc..b19463e545d6 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -507,7 +507,6 @@ static void mt_get_feature(struct hid_device *hdev, struct hid_report *report)
 {
 	int ret;
 	u32 size = hid_report_len(report);
-	u8 *buf;
 
 	/*
 	 * Do not fetch the feature report if the device has been explicitly
@@ -516,7 +515,7 @@ static void mt_get_feature(struct hid_device *hdev, struct hid_report *report)
 	if (hdev->quirks & HID_QUIRK_NO_INIT_REPORTS)
 		return;
 
-	buf = hid_alloc_report_buf(report, GFP_KERNEL);
+	u8 *buf __free(kfree) = hid_alloc_report_buf(report, GFP_KERNEL);
 	if (!buf)
 		return;
 
@@ -529,7 +528,7 @@ static void mt_get_feature(struct hid_device *hdev, struct hid_report *report)
 		/* The report ID in the request and the response should match */
 		if (report->id != buf[0]) {
 			hid_err(hdev, "Returned feature report did not match the request\n");
-			goto free;
+			return;
 		}
 
 		ret = hid_report_raw_event(hdev, HID_FEATURE_REPORT, buf,
@@ -537,9 +536,6 @@ static void mt_get_feature(struct hid_device *hdev, struct hid_report *report)
 		if (ret)
 			dev_warn(&hdev->dev, "failed to report feature\n");
 	}
-
-free:
-	kfree(buf);
 }
 
 static void mt_feature_mapping(struct hid_device *hdev,
@@ -1658,7 +1654,6 @@ static bool mt_need_to_apply_feature(struct hid_device *hdev,
 	struct mt_class *cls = &td->mtclass;
 	struct hid_report *report = field->report;
 	unsigned int index = usage->usage_index;
-	char *buf;
 	u32 report_len;
 	int max;
 
@@ -1673,17 +1668,18 @@ static bool mt_need_to_apply_feature(struct hid_device *hdev,
 			return false;
 
 		if (cls->quirks & MT_QUIRK_FORCE_GET_FEATURE) {
-			report_len = hid_report_len(report);
-			buf = hid_alloc_report_buf(report, GFP_KERNEL);
+			char *buf __free(kfree) = hid_alloc_report_buf(report, GFP_KERNEL);
+
 			if (!buf) {
 				hid_err(hdev,
 					"failed to allocate buffer for report\n");
 				return false;
 			}
+
+			report_len = hid_report_len(report);
 			hid_hw_raw_request(hdev, report->id, buf, report_len,
 					   HID_FEATURE_REPORT,
 					   HID_REQ_GET_REPORT);
-			kfree(buf);
 		}
 
 		field->value[index] = td->inputmode_value;

-- 
2.54.0