[PATCH][next] platform/chrome: cros_kbd_led_backlight: Avoid -Wflex-array-member-not-at-end warnings

[PATCH][next] platform/chrome: cros_kbd_led_backlight: Avoid -Wflex-array-member-not-at-end warnings

[Gustavo A. R. Silva]

-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.

Use the `DEFINE_RAW_FLEX()` helper for an on-stack definition of
a flexible structure where the size of the flexible-array member
is known at compile-time, and refactor the rest of the code,
accordingly.

So, with these changes, fix the following warnings:

drivers/platform/chrome/cros_kbd_led_backlight.c:141:40: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
drivers/platform/chrome/cros_kbd_led_backlight.c:162:40: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 .../platform/chrome/cros_kbd_led_backlight.c  | 24 +++++++------------
 1 file changed, 8 insertions(+), 16 deletions(-)

diff --git a/drivers/platform/chrome/cros_kbd_led_backlight.c b/drivers/platform/chrome/cros_kbd_led_backlight.c
index fc27bd7fc4b9..f4c2282129f5 100644
--- a/drivers/platform/chrome/cros_kbd_led_backlight.c
+++ b/drivers/platform/chrome/cros_kbd_led_backlight.c
@@ -137,16 +137,12 @@ static int
 keyboard_led_set_brightness_ec_pwm(struct led_classdev *cdev,
 				   enum led_brightness brightness)
 {
-	struct {
-		struct cros_ec_command msg;
-		struct ec_params_pwm_set_keyboard_backlight params;
-	} __packed buf;
-	struct ec_params_pwm_set_keyboard_backlight *params = &buf.params;
-	struct cros_ec_command *msg = &buf.msg;
+	DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
+			sizeof(struct ec_params_pwm_set_keyboard_backlight));
+	struct ec_params_pwm_set_keyboard_backlight *params =
+			(struct ec_params_pwm_set_keyboard_backlight *)msg->data;
 	struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev);
 
-	memset(&buf, 0, sizeof(buf));
-
 	msg->command = EC_CMD_PWM_SET_KEYBOARD_BACKLIGHT;
 	msg->outsize = sizeof(*params);
 
@@ -158,17 +154,13 @@ keyboard_led_set_brightness_ec_pwm(struct led_classdev *cdev,
 static enum led_brightness
 keyboard_led_get_brightness_ec_pwm(struct led_classdev *cdev)
 {
-	struct {
-		struct cros_ec_command msg;
-		struct ec_response_pwm_get_keyboard_backlight resp;
-	} __packed buf;
-	struct ec_response_pwm_get_keyboard_backlight *resp = &buf.resp;
-	struct cros_ec_command *msg = &buf.msg;
+	DEFINE_RAW_FLEX(struct cros_ec_command, msg, data,
+			sizeof(struct ec_response_pwm_get_keyboard_backlight));
+	struct ec_response_pwm_get_keyboard_backlight *resp =
+			(struct ec_response_pwm_get_keyboard_backlight *)msg->data;
 	struct keyboard_led *keyboard_led = container_of(cdev, struct keyboard_led, cdev);
 	int ret;
 
-	memset(&buf, 0, sizeof(buf));
-
 	msg->command = EC_CMD_PWM_GET_KEYBOARD_BACKLIGHT;
 	msg->insize = sizeof(*resp);
 
-- 
2.43.0

Re: [PATCH][next] platform/chrome: cros_kbd_led_backlight: Avoid -Wflex-array-member-not-at-end warnings

[Tzung-Bi Shih]

On Fri, Mar 28, 2025 at 07:07:38AM -0600, Gustavo A. R. Silva wrote:
> -Wflex-array-member-not-at-end was introduced in GCC-14, and we are
> getting ready to enable it, globally.
> 
> Use the `DEFINE_RAW_FLEX()` helper for an on-stack definition of
> a flexible structure where the size of the flexible-array member
> is known at compile-time, and refactor the rest of the code,
> accordingly.
> 
> So, with these changes, fix the following warnings:
> 
> drivers/platform/chrome/cros_kbd_led_backlight.c:141:40: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
> drivers/platform/chrome/cros_kbd_led_backlight.c:162:40: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
> 
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

For my reference:
Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>

Re: [PATCH][next] platform/chrome: cros_kbd_led_backlight: Avoid -Wflex-array-member-not-at-end warnings

[Tzung-Bi Shih]

On Fri, Mar 28, 2025 at 07:07:38AM -0600, Gustavo A. R. Silva wrote:
> -Wflex-array-member-not-at-end was introduced in GCC-14, and we are
> getting ready to enable it, globally.
> 
> Use the `DEFINE_RAW_FLEX()` helper for an on-stack definition of
> a flexible structure where the size of the flexible-array member
> is known at compile-time, and refactor the rest of the code,
> accordingly.
> 
> [...]

Applied to

    https://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux.git for-next

[1/1] platform/chrome: cros_kbd_led_backlight: Avoid -Wflex-array-member-not-at-end warnings
      commit: 04251bc86653a839ccb1f5ec248ad5e8afd9a627

Thanks!