Commit efb704ab authored by Uwe Kleine-König's avatar Uwe Kleine-König Committed by Thierry Reding
Browse files

pwm: Reduce number of pointer dereferences in pwm_device_request() 



pwm->chip and pwm->chip->ops are used several times in this function.
Introduce local variables for these.

There is no semantical change, but with ARCH=arm, allmodconfig and
gcc-13 bloat-o-meter reports a slight improvement:

	add/remove: 1/1 grow/shrink: 1/1 up/down: 8/-36 (-28)
	Function                                     old     new   delta
	pwm_apply_state                              476     480      +4
	__initcall__kmod_core__307_1092_pwm_debugfs_init4       -       4      +4
	__initcall__kmod_core__307_1090_pwm_debugfs_init4       4       -      -4
	pwm_request_from_chip                        628     596     -32
	Total: Before=15091, After=15063, chg -0.19%

Signed-off-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
parent d243221d

drivers/pwm/core.c

+8 −6
Original line number Diff line number Diff line
@@ -59,22 +59,24 @@ static struct pwm_chip *pwmchip_find_by_name(const char *name) 
static int pwm_device_request(struct pwm_device *pwm, const char *label)

{

	int err;

	struct pwm_chip *chip = pwm->chip;

	const struct pwm_ops *ops = chip->ops;



	if (test_bit(PWMF_REQUESTED, &pwm->flags))

		return -EBUSY;



	if (!try_module_get(pwm->chip->owner))

	if (!try_module_get(chip->owner))

		return -ENODEV;



	if (pwm->chip->ops->request) {

		err = pwm->chip->ops->request(pwm->chip, pwm);

	if (ops->request) {

		err = ops->request(chip, pwm);

		if (err) {

			module_put(pwm->chip->owner);

			module_put(chip->owner);

			return err;

		}

	}



	if (pwm->chip->ops->get_state) {

	if (ops->get_state) {

		/*

		 * Zero-initialize state because most drivers are unaware of

		 * .usage_power. The other members of state are supposed to be
@@ -84,7 +86,7 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label) 
		 */

		struct pwm_state state = { 0, };



		err = pwm->chip->ops->get_state(pwm->chip, pwm, &state);

		err = ops->get_state(chip, pwm, &state);

		trace_pwm_get(pwm, &state, err);



		if (!err)