From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: linux-pwm@vger.kernel.org, kernel@pengutronix.de
Subject: [PATCH] pwm: Reduce number of pointer dereferences in pwm_device_request()
Date: Thu, 30 Nov 2023 08:21:06 +0100 [thread overview]
Message-ID: <20231130072105.966848-1-u.kleine-koenig@pengutronix.de> (raw)
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: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
drivers/pwm/core.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index f60b715abe62..eea93ed8a49b 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -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)
base-commit: 53a2eaaf19c4e652ac53b5b2441582a555768516
--
2.42.0.586.gbc5204569f7d.dirty
reply other threads:[~2023-11-30 7:21 UTC|newest]
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