[PATCH] media: uvcvideo: Do not alloc dev->status

From: Ricardo Ribalda
Date: Wed Dec 14 2022 - 06:24:23 EST


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@xxxxxxxxxxxx>
---
To: Yunke Cao <yunkec@xxxxxxxxxxxx>
To: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
To: Max Staudt <mstaudt@xxxxxxxxxx>
To: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
To: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Cc: linux-media@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
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@xxxxxxxxxxxx>