linux-kernel - [PATCH 5.15 231/779] pwm: lpc18xx-sct: Reduce number of devm memory allocations

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Message-Id: <20220815180347.162000913@linuxfoundation.org>
Date:   Mon, 15 Aug 2022 19:57:55 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>,
        Thierry Reding <thierry.reding@...il.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.15 231/779] pwm: lpc18xx-sct: Reduce number of devm memory allocations

From: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>

[ Upstream commit 20d9de9c4d6642bb40c935233697723b56573cbc ]

Each devm allocations has an overhead of 24 bytes to store the related
struct devres_node additionally to the fragmentation of the allocator.
So allocating 16 struct lpc18xx_pwm_data (which only hold a single int)
adds quite some overhead. Instead put the per-channel data into the
driver data struct and allocate it in one go.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@...il.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/pwm/pwm-lpc18xx-sct.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/pwm/pwm-lpc18xx-sct.c b/drivers/pwm/pwm-lpc18xx-sct.c
index 8cc8ae16553c..6cf02554066c 100644
--- a/drivers/pwm/pwm-lpc18xx-sct.c
+++ b/drivers/pwm/pwm-lpc18xx-sct.c
@@ -76,6 +76,8 @@
 #define LPC18XX_PWM_EVENT_PERIOD	0
 #define LPC18XX_PWM_EVENT_MAX		16
 
+#define LPC18XX_NUM_PWMS		16
+
 /* SCT conflict resolution */
 enum lpc18xx_pwm_res_action {
 	LPC18XX_PWM_RES_NONE,
@@ -101,6 +103,7 @@ struct lpc18xx_pwm_chip {
 	unsigned long event_map;
 	struct mutex res_lock;
 	struct mutex period_lock;
+	struct lpc18xx_pwm_data channeldata[LPC18XX_NUM_PWMS];
 };
 
 static inline struct lpc18xx_pwm_chip *
@@ -370,7 +373,7 @@ static int lpc18xx_pwm_probe(struct platform_device *pdev)
 
 	lpc18xx_pwm->chip.dev = &pdev->dev;
 	lpc18xx_pwm->chip.ops = &lpc18xx_pwm_ops;
-	lpc18xx_pwm->chip.npwm = 16;
+	lpc18xx_pwm->chip.npwm = LPC18XX_NUM_PWMS;
 
 	/* SCT counter must be in unify (32 bit) mode */
 	lpc18xx_pwm_writel(lpc18xx_pwm, LPC18XX_PWM_CONFIG,
@@ -400,12 +403,7 @@ static int lpc18xx_pwm_probe(struct platform_device *pdev)
 
 		pwm = &lpc18xx_pwm->chip.pwms[i];
 
-		data = devm_kzalloc(lpc18xx_pwm->dev, sizeof(*data),
-				    GFP_KERNEL);
-		if (!data) {
-			ret = -ENOMEM;
-			goto disable_pwmclk;
-		}
+		data = &lpc18xx_pwm->channeldata[i];
 
 		pwm_set_chip_data(pwm, data);
 	}
-- 
2.35.1