linux-kernel - [PATCH] [v2] i2c: stm32f7: Fix runtime PM imbalance on error

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Message-Id: <20200527013853.30252-1-dinghao.liu@zju.edu.cn>
Date:   Wed, 27 May 2020 09:38:53 +0800
From:   Dinghao Liu <dinghao.liu@....edu.cn>
To:     dinghao.liu@....edu.cn, kjlu@....edu
Cc:     Pierre-Yves MORDRET <pierre-yves.mordret@...com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        linux-i2c@...r.kernel.org,
        linux-stm32@...md-mailman.stormreply.com,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH] [v2] i2c: stm32f7: Fix runtime PM imbalance on error

pm_runtime_get_sync() increments the runtime PM usage counter even
the call returns an error code. Thus a pairing decrement is needed
on the error handling path to keep the counter balanced.

Signed-off-by: Dinghao Liu <dinghao.liu@....edu.cn>
---

Changelog:

v2: - Use pm_runtime_put_noidle() instead of
      pm_runtime_put_autosuspend(). Fix 5 more
      similar cases within this dirver.
---
 drivers/i2c/busses/i2c-stm32f7.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
index 330ffed011e0..822fd1f5b5ae 100644
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c
@@ -1620,8 +1620,10 @@ static int stm32f7_i2c_xfer(struct i2c_adapter *i2c_adap,
 	f7_msg->smbus = false;
 
 	ret = pm_runtime_get_sync(i2c_dev->dev);
-	if (ret < 0)
+	if (ret < 0) {
+		pm_runtime_put_noidle(i2c_dev->dev);
 		return ret;
+	}
 
 	ret = stm32f7_i2c_wait_free_bus(i2c_dev);
 	if (ret)
@@ -1666,8 +1668,10 @@ static int stm32f7_i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
 	f7_msg->smbus = true;
 
 	ret = pm_runtime_get_sync(dev);
-	if (ret < 0)
+	if (ret < 0) {
+		pm_runtime_put_noidle(dev);
 		return ret;
+	}
 
 	ret = stm32f7_i2c_wait_free_bus(i2c_dev);
 	if (ret)
@@ -1767,8 +1771,10 @@ static int stm32f7_i2c_reg_slave(struct i2c_client *slave)
 		return ret;
 
 	ret = pm_runtime_get_sync(dev);
-	if (ret < 0)
+	if (ret < 0) {
+		pm_runtime_put_noidle(dev);
 		return ret;
+	}
 
 	if (!stm32f7_i2c_is_slave_registered(i2c_dev))
 		stm32f7_i2c_enable_wakeup(i2c_dev, true);
@@ -1837,8 +1843,10 @@ static int stm32f7_i2c_unreg_slave(struct i2c_client *slave)
 	WARN_ON(!i2c_dev->slave[id]);
 
 	ret = pm_runtime_get_sync(i2c_dev->dev);
-	if (ret < 0)
+	if (ret < 0) {
+		pm_runtime_put_noidle(i2c_dev->dev);
 		return ret;
+	}
 
 	if (id == 0) {
 		mask = STM32F7_I2C_OAR1_OA1EN;
@@ -2182,8 +2190,10 @@ static int stm32f7_i2c_regs_backup(struct stm32f7_i2c_dev *i2c_dev)
 	struct stm32f7_i2c_regs *backup_regs = &i2c_dev->backup_regs;
 
 	ret = pm_runtime_get_sync(i2c_dev->dev);
-	if (ret < 0)
+	if (ret < 0) {
+		pm_runtime_put_noidle(i2c_dev->dev);
 		return ret;
+	}
 
 	backup_regs->cr1 = readl_relaxed(i2c_dev->base + STM32F7_I2C_CR1);
 	backup_regs->cr2 = readl_relaxed(i2c_dev->base + STM32F7_I2C_CR2);
@@ -2204,8 +2214,10 @@ static int stm32f7_i2c_regs_restore(struct stm32f7_i2c_dev *i2c_dev)
 	struct stm32f7_i2c_regs *backup_regs = &i2c_dev->backup_regs;
 
 	ret = pm_runtime_get_sync(i2c_dev->dev);
-	if (ret < 0)
+	if (ret < 0) {
+		pm_runtime_put_noidle(i2c_dev->dev);
 		return ret;
+	}
 
 	cr1 = readl_relaxed(i2c_dev->base + STM32F7_I2C_CR1);
 	if (cr1 & STM32F7_I2C_CR1_PE)
-- 
2.17.1