Re: [PATCH v3 8/8] media: uvcvideo: Use standard names for menus

From: Laurent Pinchart
Date: Tue Jan 03 2023 - 15:47:08 EST

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In reply to: Ricardo Ribalda: "[PATCH v3 8/8] media: uvcvideo: Use standard names for menus"
Next in thread: kernel test robot: "Re: [PATCH v3 8/8] media: uvcvideo: Use standard names for menus"
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Hi Ricardo,

Thank you for the patch.

On Tue, Jan 03, 2023 at 03:36:26PM +0100, Ricardo Ribalda wrote:
> Instead of duplicating the menu info, use the one from the core.
> Also, do not use extra memory for 1:1 mappings.
>
> Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
> Suggested-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> ---
> drivers/media/usb/uvc/uvc_ctrl.c | 126 +++++++++++++++++++++++++------------
> drivers/media/usb/uvc/uvc_driver.c | 9 +--
> drivers/media/usb/uvc/uvc_v4l2.c | 104 ++++++++++++++++++++++--------
> drivers/media/usb/uvc/uvcvideo.h | 3 +-
> include/uapi/linux/uvcvideo.h | 4 +-
> 5 files changed, 170 insertions(+), 76 deletions(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> index 4830120e6506..86d74c9740b0 100644
> --- a/drivers/media/usb/uvc/uvc_ctrl.c
> +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> @@ -364,19 +364,31 @@ static const u32 uvc_control_classes[] = {
> V4L2_CID_USER_CLASS,
> };
>
> -static const struct uvc_menu_info power_line_frequency_controls[] = {
> - { 0, "Disabled" },
> - { 1, "50 Hz" },
> - { 2, "60 Hz" },
> - { 3, "Auto" },
> -};
> +static const int exposure_auto_mapping[] = { 2, 1, 4, 8 };
>
> -static const struct uvc_menu_info exposure_auto_controls[] = {
> - { 2, "Auto Mode" },
> - { 1, "Manual Mode" },
> - { 4, "Shutter Priority Mode" },
> - { 8, "Aperture Priority Mode" },
> -};
> +static int uvc_mapping_get_menu_value(const struct uvc_control_mapping *mapping,
> + u32 idx)
> +{
> + if (!test_bit(idx, &mapping->menu_mask))
> + return -EINVAL;
> +
> + if (mapping->menu_mapping)
> + return mapping->menu_mapping[idx];
> +
> + return idx;
> +}
> +
> +static const char *
> +uvc_mapping_get_menu_name(const struct uvc_control_mapping *mapping, u32 idx)
> +{
> + if (!test_bit(idx, &mapping->menu_mask))
> + return NULL;
> +
> + if (mapping->menu_names)
> + return mapping->menu_names[idx];
> +
> + return v4l2_ctrl_get_menu(mapping->id)[idx];
> +}
>
> static s32 uvc_ctrl_get_zoom(struct uvc_control_mapping *mapping,
> u8 query, const u8 *data)
> @@ -525,8 +537,8 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_MENU,
> .data_type = UVC_CTRL_DATA_TYPE_BITMASK,
> - .menu_info = exposure_auto_controls,
> - .menu_mask = BIT_MASK(ARRAY_SIZE(exposure_auto_controls)),
> + .menu_mapping = exposure_auto_mapping,
> + .menu_mask = GENMASK(ARRAY_SIZE(exposure_auto_mapping) - 1, 0),
> .slave_ids = { V4L2_CID_EXPOSURE_ABSOLUTE, },
> },
> {
> @@ -731,8 +743,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings_uvc11[] = {
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_MENU,
> .data_type = UVC_CTRL_DATA_TYPE_ENUM,
> - .menu_info = power_line_frequency_controls,
> - .menu_mask = BIT_MASK(ARRAY_SIZE(power_line_frequency_controls) - 1),
> + .menu_mask = GENMASK(V4L2_CID_POWER_LINE_FREQUENCY_60HZ, 0),
> },
> };
>
> @@ -745,8 +756,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings_uvc15[] = {
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_MENU,
> .data_type = UVC_CTRL_DATA_TYPE_ENUM,
> - .menu_info = power_line_frequency_controls,
> - .menu_mask = BIT_MASK(ARRAY_SIZE(power_line_frequency_controls)),
> + .menu_mask = GENMASK(V4L2_CID_POWER_LINE_FREQUENCY_AUTO, 0),
> },
> };
>
> @@ -973,13 +983,17 @@ static s32 __uvc_ctrl_get_value(struct uvc_control_mapping *mapping,
> s32 value = mapping->get(mapping, UVC_GET_CUR, data);
>
> if (mapping->v4l2_type == V4L2_CTRL_TYPE_MENU) {
> - const struct uvc_menu_info *menu = mapping->menu_info;
> unsigned int i;
>
> - for (i = 0; BIT(i) <= mapping->menu_mask; ++i, ++menu) {
> + for (i = 0; BIT(i) <= mapping->menu_mask; ++i) {
> + u32 menu_value;
> +
> if (!test_bit(i, &mapping->menu_mask))
> continue;
> - if (menu->value == value) {
> +
> + menu_value = uvc_mapping_get_menu_value(mapping, i);
> +
> + if (menu_value == value) {
> value = i;
> break;
> }
> @@ -1190,7 +1204,6 @@ static int __uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
> {
> struct uvc_control_mapping *master_map = NULL;
> struct uvc_control *master_ctrl = NULL;
> - const struct uvc_menu_info *menu;
> unsigned int i;
>
> memset(v4l2_ctrl, 0, sizeof(*v4l2_ctrl));
> @@ -1235,11 +1248,15 @@ static int __uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
> v4l2_ctrl->maximum = fls(mapping->menu_mask) - 1;
> v4l2_ctrl->step = 1;
>
> - menu = mapping->menu_info;
> - for (i = 0; BIT(i) <= mapping->menu_mask; ++i, ++menu) {
> + for (i = 0; BIT(i) <= mapping->menu_mask; ++i) {
> + u32 menu_value;
> +
> if (!test_bit(i, &mapping->menu_mask))
> continue;
> - if (menu->value == v4l2_ctrl->default_value) {
> +
> + menu_value = uvc_mapping_get_menu_value(mapping, i);
> +
> + if (menu_value == v4l2_ctrl->default_value) {
> v4l2_ctrl->default_value = i;
> break;
> }
> @@ -1338,11 +1355,11 @@ int uvc_query_v4l2_ctrl(struct uvc_video_chain *chain,
> int uvc_query_v4l2_menu(struct uvc_video_chain *chain,
> struct v4l2_querymenu *query_menu)
> {
> - const struct uvc_menu_info *menu_info;
> struct uvc_control_mapping *mapping;
> struct uvc_control *ctrl;
> u32 index = query_menu->index;
> u32 id = query_menu->id;
> + const char *name;
> int ret;
>
> memset(query_menu, 0, sizeof(*query_menu));
> @@ -1364,22 +1381,34 @@ int uvc_query_v4l2_menu(struct uvc_video_chain *chain,
> goto done;
> }
>
> - menu_info = &mapping->menu_info[query_menu->index];
> -
> if (mapping->data_type == UVC_CTRL_DATA_TYPE_BITMASK) {
> + u32 menu_value;
> +
> if (!ctrl->cached) {
> ret = uvc_ctrl_populate_cache(chain, ctrl);
> if (ret < 0)
> goto done;
> }
>
> - if (!(uvc_get_ctrl_bitmap(ctrl, mapping) & menu_info->value)) {
> + menu_value = uvc_mapping_get_menu_value(mapping,
> + query_menu->index);
> + if (menu_value < 0) {
> + ret = menu_value;
> + goto done;
> + }

Please add a blank line.

> + if (!(uvc_get_ctrl_bitmap(ctrl, mapping) & menu_value)) {

If mapping->menu_mapping is not specified, uvc_mapping_get_menu_value()
return an index, and here you interpret it as a bitmask. I assume this
works because the UVC_CTRL_DATA_TYPE_BITMASK control supported by the
driver (there's only one) has a menu_mapping that translates to a
bitmask.

> ret = -EINVAL;
> goto done;
> }
> }
>
> - strscpy(query_menu->name, menu_info->name, sizeof(query_menu->name));
> + name = uvc_mapping_get_menu_name(mapping, query_menu->index);
> + if (!name) {
> + ret = -EINVAL;
> + goto done;
> + }
> +
> + strscpy(query_menu->name, name, sizeof(query_menu->name));
>
> done:
> mutex_unlock(&chain->ctrl_mutex);
> @@ -1880,7 +1909,7 @@ int uvc_ctrl_set(struct uvc_fh *handle,
> if (!test_bit(xctrl->value, &mapping->menu_mask))
> return -EINVAL;
>
> - value = mapping->menu_info[xctrl->value].value;
> + value = uvc_mapping_get_menu_value(mapping, xctrl->value);
>
> /*
> * Valid menu indices are reported by the GET_RES request for
> @@ -2305,21 +2334,36 @@ static int __uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
> return -ENOMEM;
>
> map->name = NULL;
> - map->menu_info = NULL;
> + map->menu_names = NULL;
> + map->menu_mapping = NULL;
>
> /* For UVCIOC_CTRL_MAP custom control */
> if (mapping->name) {
> map->name = kstrdup(mapping->name, GFP_KERNEL);
> - if (!map->name)
> - goto nomem;
> + if (!map->name) {
> + kfree(map);
> + return -ENOMEM;

Anything wrong with the goto nomem here ?

> + }
> }
>
> INIT_LIST_HEAD(&map->ev_subs);
>
> - size = sizeof(*mapping->menu_info) * fls(mapping->menu_mask);
> - map->menu_info = kmemdup(mapping->menu_info, size, GFP_KERNEL);
> - if (!map->menu_info)
> - goto nomem;
> + if (mapping->menu_mapping && mapping->menu_mask) {
> + size = sizeof(mapping->menu_mapping[0])
> + * fls(mapping->menu_mask);
> + map->menu_mapping = kmemdup(mapping->menu_mapping, size,
> + GFP_KERNEL);
> + if (!map->menu_mapping)
> + goto nomem;
> + }
> + if (mapping->menu_names && mapping->menu_mask) {
> + size = sizeof(mapping->menu_names[0])
> + * fls(mapping->menu_mask);
> + map->menu_names = kmemdup(mapping->menu_names, size,
> + GFP_KERNEL);
> + if (!map->menu_names)
> + goto nomem;
> + }
>
> if (map->get == NULL)
> map->get = uvc_get_le_value;
> @@ -2342,7 +2386,8 @@ static int __uvc_ctrl_add_mapping(struct uvc_video_chain *chain,
> return 0;
>
> nomem:
> - kfree(map->menu_info);
> + kfree(map->menu_names);
> + kfree(map->menu_mapping);
> kfree(map->name);
> kfree(map);
> return -ENOMEM;
> @@ -2673,7 +2718,8 @@ static void uvc_ctrl_cleanup_mappings(struct uvc_device *dev,
>
> list_for_each_entry_safe(mapping, nm, &ctrl->info.mappings, list) {
> list_del(&mapping->list);
> - kfree(mapping->menu_info);
> + kfree(mapping->menu_names);
> + kfree(mapping->menu_mapping);
> kfree(mapping->name);
> kfree(mapping);
> }
> diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> index f9e6208c4636..ee016b370058 100644
> --- a/drivers/media/usb/uvc/uvc_driver.c
> +++ b/drivers/media/usb/uvc/uvc_driver.c
> @@ -2371,11 +2371,6 @@ MODULE_PARM_DESC(timeout, "Streaming control requests timeout");
> * Driver initialization and cleanup
> */
>
> -static const struct uvc_menu_info power_line_frequency_controls_limited[] = {
> - { 1, "50 Hz" },
> - { 2, "60 Hz" },
> -};
> -
> static const struct uvc_control_mapping uvc_ctrl_power_line_mapping_limited = {
> .id = V4L2_CID_POWER_LINE_FREQUENCY,
> .entity = UVC_GUID_UVC_PROCESSING,
> @@ -2384,8 +2379,8 @@ static const struct uvc_control_mapping uvc_ctrl_power_line_mapping_limited = {
> .offset = 0,
> .v4l2_type = V4L2_CTRL_TYPE_MENU,
> .data_type = UVC_CTRL_DATA_TYPE_ENUM,
> - .menu_info = power_line_frequency_controls_limited,
> - .menu_mask = BIT_MASK(ARRAY_SIZE(power_line_frequency_controls_limited)),
> + .menu_mask = GENMASK(V4L2_CID_POWER_LINE_FREQUENCY_60HZ,
> + V4L2_CID_POWER_LINE_FREQUENCY_50HZ),
> };
>
> static const struct uvc_device_info uvc_ctrl_power_line_limited = {
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
> index ed2525e7e2a5..dfa26ed0c7f1 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -26,14 +26,83 @@
>
> #include "uvcvideo.h"
>
> +static int uvc_control_add_xu_mapping(struct uvc_video_chain *chain,
> + struct uvc_control_mapping *map,
> + const struct uvc_xu_control_mapping *xmap)
> +{
> + unsigned int i;
> + size_t size;
> + int ret;
> +
> + /*
> + * Prevent excessive memory consumption, as well as integer
> + * overflows.
> + */
> + if (xmap->menu_count == 0 ||
> + xmap->menu_count > UVC_MAX_CONTROL_MENU_ENTRIES)
> + return -EINVAL;
> +
> + map->menu_names = NULL;
> + map->menu_mapping = NULL;
> +
> + map->menu_mask = BIT_MASK(xmap->menu_count);
> +
> + size = xmap->menu_count * sizeof(*map->menu_mapping);
> + map->menu_mapping = kzalloc(size, GFP_KERNEL);
> + if (!map->menu_mapping) {
> + ret = -ENOMEM;
> + goto exit;
> + }
> +
> + for (i = 0; i < xmap->menu_count ; i++) {
> + if (copy_from_user((u32 *)&map->menu_mapping[i],
> + &xmap->menu_info[i].value,
> + sizeof(map->menu_mapping[i]))) {
> + ret = -EACCES;
> + goto exit;
> + }
> + }
> +
> + /* Always use the standard naming if available. */
> + if (v4l2_ctrl_get_menu(map->id))
> + goto done_mapping;
> +
> + size = xmap->menu_count * sizeof(map->menu_names[0]);
> + map->menu_names = kzalloc(size, GFP_KERNEL);
> + if (!map->menu_names) {
> + ret = -ENOMEM;
> + goto exit;
> + }
> +
> + for (i = 0; i < xmap->menu_count ; i++) {
> + /* sizeof(names[i]) - 1: to take care of \0 */
> + if (copy_from_user((char *)map->menu_names[i],
> + xmap->menu_info[i].name,
> + sizeof(map->menu_names[i]) - 1)) {
> + ret = -EACCES;
> + goto exit;
> + }
> + }

While I'm a big proponent of goto's for error handling, I tend to frown
upon them in most other case as they hinder readability and can hide
design problems. Here you can simply write

/*
* Always use the standard naming if available, otherwise copy the names
* supplied by userspace.
*/
if (!v4l2_ctrl_get_menu(map->id)) {
size = xmap->menu_count * sizeof(map->menu_names[0]);
map->menu_names = kzalloc(size, GFP_KERNEL);
if (!map->menu_names) {
ret = -ENOMEM;
goto exit;
}

for (i = 0; i < xmap->menu_count ; i++) {
/* sizeof(names[i]) - 1: to take care of \0 */
if (copy_from_user((char *)map->menu_names[i],
xmap->menu_info[i].name,
sizeof(map->menu_names[i]) - 1)) {
ret = -EACCES;
goto exit;
}
}
}

> +
> +done_mapping:
> + ret = uvc_ctrl_add_mapping(chain, map);
> +
> +exit:

The driver uses several done: labels but no exit:. Let's stick with
'done' for consistency.

> + kfree(map->menu_names);
> + map->menu_names = NULL;
> + kfree(map->menu_mapping);
> + map->menu_mapping = NULL;
> +
> + return ret;
> +}
> +
> /* ------------------------------------------------------------------------
> * UVC ioctls
> */
> -static int uvc_ioctl_ctrl_map(struct uvc_video_chain *chain,
> - struct uvc_xu_control_mapping *xmap)
> +static int uvc_ioctl_xu_ctrl_map(struct uvc_video_chain *chain,
> + struct uvc_xu_control_mapping *xmap)
> {
> struct uvc_control_mapping *map;
> - unsigned int size;
> int ret;
>
> map = kzalloc(sizeof(*map), GFP_KERNEL);
> @@ -61,39 +130,20 @@ static int uvc_ioctl_ctrl_map(struct uvc_video_chain *chain,
> case V4L2_CTRL_TYPE_INTEGER:
> case V4L2_CTRL_TYPE_BOOLEAN:
> case V4L2_CTRL_TYPE_BUTTON:
> + ret = uvc_ctrl_add_mapping(chain, map);
> break;
>
> case V4L2_CTRL_TYPE_MENU:
> - /*
> - * Prevent excessive memory consumption, as well as integer
> - * overflows.
> - */
> - if (xmap->menu_count == 0 ||
> - xmap->menu_count > UVC_MAX_CONTROL_MENU_ENTRIES) {
> - ret = -EINVAL;
> - goto free_map;
> - }
> -
> - size = xmap->menu_count * sizeof(*map->menu_info);
> - map->menu_info = memdup_user(xmap->menu_info, size);
> - if (IS_ERR(map->menu_info)) {
> - ret = PTR_ERR(map->menu_info);
> - goto free_map;
> - }
> -
> - map->menu_mask = BIT_MASK(xmap->menu_count);
> + ret = uvc_control_add_xu_mapping(chain, map, xmap);
> break;
>
> default:
> uvc_dbg(chain->dev, CONTROL,
> "Unsupported V4L2 control type %u\n", xmap->v4l2_type);
> ret = -ENOTTY;
> - goto free_map;
> + break;
> }
>
> - ret = uvc_ctrl_add_mapping(chain, map);
> -
> - kfree(map->menu_info);
> free_map:
> kfree(map);
>
> @@ -1316,7 +1366,7 @@ static long uvc_ioctl_default(struct file *file, void *fh, bool valid_prio,
> switch (cmd) {
> /* Dynamic controls. */
> case UVCIOC_CTRL_MAP:
> - return uvc_ioctl_ctrl_map(chain, arg);
> + return uvc_ioctl_xu_ctrl_map(chain, arg);
>
> case UVCIOC_CTRL_QUERY:
> return uvc_xu_ctrl_query(chain, arg);
> @@ -1429,7 +1479,7 @@ static long uvc_v4l2_compat_ioctl32(struct file *file,
> ret = uvc_v4l2_get_xu_mapping(&karg.xmap, up);
> if (ret)
> return ret;
> - ret = uvc_ioctl_ctrl_map(handle->chain, &karg.xmap);
> + ret = uvc_ioctl_xu_ctrl_map(handle->chain, &karg.xmap);
> if (ret)
> return ret;
> ret = uvc_v4l2_put_xu_mapping(&karg.xmap, up);
> diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> index f75e5864bbf7..0e816be556f2 100644
> --- a/drivers/media/usb/uvc/uvcvideo.h
> +++ b/drivers/media/usb/uvc/uvcvideo.h
> @@ -116,7 +116,8 @@ struct uvc_control_mapping {
> enum v4l2_ctrl_type v4l2_type;
> u32 data_type;
>
> - const struct uvc_menu_info *menu_info;
> + const u32 *menu_mapping;
> + const char (*menu_names)[UVC_MENU_NAME_LEN];
> unsigned long menu_mask;
>
> u32 master_id;
> diff --git a/include/uapi/linux/uvcvideo.h b/include/uapi/linux/uvcvideo.h
> index 8288137387c0..d45d0c2ea252 100644
> --- a/include/uapi/linux/uvcvideo.h
> +++ b/include/uapi/linux/uvcvideo.h
> @@ -36,9 +36,11 @@
> UVC_CTRL_FLAG_GET_MAX | UVC_CTRL_FLAG_GET_RES | \
> UVC_CTRL_FLAG_GET_DEF)
>
> +#define UVC_MENU_NAME_LEN 32
> +
> struct uvc_menu_info {
> __u32 value;
> - __u8 name[32];
> + __u8 name[UVC_MENU_NAME_LEN];
> };
>
> struct uvc_xu_control_mapping {
>

--
Regards,

Laurent Pinchart

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In reply to: Ricardo Ribalda: "[PATCH v3 8/8] media: uvcvideo: Use standard names for menus"
Next in thread: kernel test robot: "Re: [PATCH v3 8/8] media: uvcvideo: Use standard names for menus"
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