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From:   Ricardo Ribalda <ribalda@chromium.org>
Date:   Wed, 14 Dec 2022 12:23:41 +0100
Subject: [PATCH] media: uvcvideo: Do not alloc dev->status
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Message-Id: <20221214-uvc-status-alloc-v1-0-a0098ddc7c93@chromium.org>
To:     Yunke Cao <yunkec@chromium.org>, Max Staudt <mstaudt@google.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc:     Ricardo Ribalda <ribalda@chromium.org>,
        linux-kernel@vger.kernel.org, linux-media@vger.kernel.org
Precedence: bulk

UVC_MAX_STATUS_SIZE is 16, simplify the code by inlining dev->status.

Now that we are at it, remove all the castings.

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
---
To: Yunke Cao <yunkec@chromium.org>
To: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Max Staudt <mstaudt@google.com>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-media@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
---
 drivers/media/usb/uvc/uvc_status.c | 69 ++++++++++++--------------------------
 drivers/media/usb/uvc/uvcvideo.h   | 22 +++++++++++-
 2 files changed, 42 insertions(+), 49 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_status.c b/drivers/media/usb/uvc/uvc_status.c
index 7518ffce22ed..adf63e7616c9 100644
--- a/drivers/media/usb/uvc/uvc_status.c
+++ b/drivers/media/usb/uvc/uvc_status.c
@@ -73,38 +73,24 @@ static void uvc_input_report_key(struct uvc_device *dev, unsigned int code,
 /* --------------------------------------------------------------------------
  * Status interrupt endpoint
  */
-struct uvc_streaming_status {
-	u8	bStatusType;
-	u8	bOriginator;
-	u8	bEvent;
-	u8	bValue[];
-} __packed;
-
-struct uvc_control_status {
-	u8	bStatusType;
-	u8	bOriginator;
-	u8	bEvent;
-	u8	bSelector;
-	u8	bAttribute;
-	u8	bValue[];
-} __packed;
-
 static void uvc_event_streaming(struct uvc_device *dev,
-				struct uvc_streaming_status *status, int len)
+				struct uvc_status *status, int len)
 {
-	if (len < 3) {
+	if (len <= offsetof(struct uvc_status, bEvent)) {
 		uvc_dbg(dev, STATUS,
 			"Invalid streaming status event received\n");
 		return;
 	}
 
 	if (status->bEvent == 0) {
-		if (len < 4)
+		if (len <= offsetof(struct uvc_status, streaming))
 			return;
+
 		uvc_dbg(dev, STATUS, "Button (intf %u) %s len %d\n",
 			status->bOriginator,
-			status->bValue[0] ? "pressed" : "released", len);
-		uvc_input_report_key(dev, KEY_CAMERA, status->bValue[0]);
+			status->streaming.button ? "pressed" : "released", len);
+		uvc_input_report_key(dev, KEY_CAMERA,
+				     status->streaming.button);
 	} else {
 		uvc_dbg(dev, STATUS, "Stream %u error event %02x len %d\n",
 			status->bOriginator, status->bEvent, len);
@@ -131,7 +117,7 @@ static struct uvc_control *uvc_event_entity_find_ctrl(struct uvc_entity *entity,
 }
 
 static struct uvc_control *uvc_event_find_ctrl(struct uvc_device *dev,
-					const struct uvc_control_status *status,
+					const struct uvc_status *status,
 					struct uvc_video_chain **chain)
 {
 	list_for_each_entry((*chain), &dev->chains, list) {
@@ -143,7 +129,7 @@ static struct uvc_control *uvc_event_find_ctrl(struct uvc_device *dev,
 				continue;
 
 			ctrl = uvc_event_entity_find_ctrl(entity,
-							  status->bSelector);
+						     status->control.bSelector);
 			if (ctrl)
 				return ctrl;
 		}
@@ -153,7 +139,7 @@ static struct uvc_control *uvc_event_find_ctrl(struct uvc_device *dev,
 }
 
 static bool uvc_event_control(struct urb *urb,
-			      const struct uvc_control_status *status, int len)
+			      const struct uvc_status *status, int len)
 {
 	static const char *attrs[] = { "value", "info", "failure", "min", "max" };
 	struct uvc_device *dev = urb->context;
@@ -161,24 +147,24 @@ static bool uvc_event_control(struct urb *urb,
 	struct uvc_control *ctrl;
 
 	if (len < 6 || status->bEvent != 0 ||
-	    status->bAttribute >= ARRAY_SIZE(attrs)) {
+	    status->control.bAttribute >= ARRAY_SIZE(attrs)) {
 		uvc_dbg(dev, STATUS, "Invalid control status event received\n");
 		return false;
 	}
 
 	uvc_dbg(dev, STATUS, "Control %u/%u %s change len %d\n",
-		status->bOriginator, status->bSelector,
-		attrs[status->bAttribute], len);
+		status->bOriginator, status->control.bSelector,
+		attrs[status->control.bAttribute], len);
 
 	/* Find the control. */
 	ctrl = uvc_event_find_ctrl(dev, status, &chain);
 	if (!ctrl)
 		return false;
 
-	switch (status->bAttribute) {
+	switch (status->control.bAttribute) {
 	case UVC_CTRL_VALUE_CHANGE:
 		return uvc_ctrl_status_event_async(urb, chain, ctrl,
-						   status->bValue);
+						   status->control.bValue);
 
 	case UVC_CTRL_INFO_CHANGE:
 	case UVC_CTRL_FAILURE_CHANGE:
@@ -214,28 +200,22 @@ static void uvc_status_complete(struct urb *urb)
 
 	len = urb->actual_length;
 	if (len > 0) {
-		switch (dev->status[0] & 0x0f) {
+		switch (dev->status.bStatusType & 0x0f) {
 		case UVC_STATUS_TYPE_CONTROL: {
-			struct uvc_control_status *status =
-				(struct uvc_control_status *)dev->status;
-
-			if (uvc_event_control(urb, status, len))
+			if (uvc_event_control(urb, &dev->status, len))
 				/* The URB will be resubmitted in work context. */
 				return;
 			break;
 		}
 
 		case UVC_STATUS_TYPE_STREAMING: {
-			struct uvc_streaming_status *status =
-				(struct uvc_streaming_status *)dev->status;
-
-			uvc_event_streaming(dev, status, len);
+			uvc_event_streaming(dev, &dev->status, len);
 			break;
 		}
 
 		default:
 			uvc_dbg(dev, STATUS, "Unknown status event type %u\n",
-				dev->status[0]);
+				dev->status.bStatusType);
 			break;
 		}
 	}
@@ -259,15 +239,9 @@ int uvc_status_init(struct uvc_device *dev)
 
 	uvc_input_init(dev);
 
-	dev->status = kzalloc(UVC_MAX_STATUS_SIZE, GFP_KERNEL);
-	if (dev->status == NULL)
-		return -ENOMEM;
-
 	dev->int_urb = usb_alloc_urb(0, GFP_KERNEL);
-	if (dev->int_urb == NULL) {
-		kfree(dev->status);
+	if (!dev->int_urb)
 		return -ENOMEM;
-	}
 
 	pipe = usb_rcvintpipe(dev->udev, ep->desc.bEndpointAddress);
 
@@ -281,7 +255,7 @@ int uvc_status_init(struct uvc_device *dev)
 		interval = fls(interval) - 1;
 
 	usb_fill_int_urb(dev->int_urb, dev->udev, pipe,
-		dev->status, UVC_MAX_STATUS_SIZE, uvc_status_complete,
+		&dev->status, sizeof(dev->status), uvc_status_complete,
 		dev, interval);
 
 	return 0;
@@ -296,7 +270,6 @@ void uvc_status_unregister(struct uvc_device *dev)
 void uvc_status_cleanup(struct uvc_device *dev)
 {
 	usb_free_urb(dev->int_urb);
-	kfree(dev->status);
 }
 
 int uvc_status_start(struct uvc_device *dev, gfp_t flags)
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index df93db259312..cdd2e328acc2 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -527,6 +527,26 @@ struct uvc_device_info {
 	const struct uvc_control_mapping **mappings;
 };
 
+struct uvc_status_streaming {
+	u8	button;
+} __packed;
+
+struct uvc_status_control {
+	u8	bSelector;
+	u8	bAttribute;
+	u8	bValue[11];
+} __packed;
+
+struct uvc_status {
+	u8	bStatusType;
+	u8	bOriginator;
+	u8	bEvent;
+	union {
+		struct uvc_status_control control;
+		struct uvc_status_streaming streaming;
+	};
+} __packed;
+
 struct uvc_device {
 	struct usb_device *udev;
 	struct usb_interface *intf;
@@ -559,7 +579,7 @@ struct uvc_device {
 	/* Status Interrupt Endpoint */
 	struct usb_host_endpoint *int_ep;
 	struct urb *int_urb;
-	u8 *status;
+	struct uvc_status status;
 	struct input_dev *input;
 	char input_phys[64];
 

---
base-commit: 0ec5a38bf8499f403f81cb81a0e3a60887d1993c
change-id: 20221214-uvc-status-alloc-93becb783898

Best regards,
-- 
Ricardo Ribalda <ribalda@chromium.org>