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Message-Id: <20190820134253.11562-9-sashal@kernel.org>
Date: Tue, 20 Aug 2019 09:42:50 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Wolfram Sang <wsa+renesas@...g-engineering.com>,
Krzysztof Adamski <krzysztof.adamski@...ia.com>,
Wolfram Sang <wsa@...-dreams.de>,
Sasha Levin <sashal@...nel.org>, linux-i2c@...r.kernel.org
Subject: [PATCH AUTOSEL 4.14 09/12] i2c: emev2: avoid race when unregistering slave client
From: Wolfram Sang <wsa+renesas@...g-engineering.com>
[ Upstream commit d7437fc0d8291181debe032671a289b6bd93f46f ]
After we disabled interrupts, there might still be an active one
running. Sync before clearing the pointer to the slave device.
Fixes: c31d0a00021d ("i2c: emev2: add slave support")
Reported-by: Krzysztof Adamski <krzysztof.adamski@...ia.com>
Signed-off-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
Reviewed-by: Krzysztof Adamski <krzysztof.adamski@...ia.com>
Signed-off-by: Wolfram Sang <wsa@...-dreams.de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
drivers/i2c/busses/i2c-emev2.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/drivers/i2c/busses/i2c-emev2.c b/drivers/i2c/busses/i2c-emev2.c
index d2e84480fbe96..dd97e5d9f49a2 100644
--- a/drivers/i2c/busses/i2c-emev2.c
+++ b/drivers/i2c/busses/i2c-emev2.c
@@ -72,6 +72,7 @@ struct em_i2c_device {
struct completion msg_done;
struct clk *sclk;
struct i2c_client *slave;
+ int irq;
};
static inline void em_clear_set_bit(struct em_i2c_device *priv, u8 clear, u8 set, u8 reg)
@@ -342,6 +343,12 @@ static int em_i2c_unreg_slave(struct i2c_client *slave)
writeb(0, priv->base + I2C_OFS_SVA0);
+ /*
+ * Wait for interrupt to finish. New slave irqs cannot happen because we
+ * cleared the slave address and, thus, only extension codes will be
+ * detected which do not use the slave ptr.
+ */
+ synchronize_irq(priv->irq);
priv->slave = NULL;
return 0;
@@ -358,7 +365,7 @@ static int em_i2c_probe(struct platform_device *pdev)
{
struct em_i2c_device *priv;
struct resource *r;
- int irq, ret;
+ int ret;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
@@ -393,8 +400,8 @@ static int em_i2c_probe(struct platform_device *pdev)
em_i2c_reset(&priv->adap);
- irq = platform_get_irq(pdev, 0);
- ret = devm_request_irq(&pdev->dev, irq, em_i2c_irq_handler, 0,
+ priv->irq = platform_get_irq(pdev, 0);
+ ret = devm_request_irq(&pdev->dev, priv->irq, em_i2c_irq_handler, 0,
"em_i2c", priv);
if (ret)
goto err_clk;
@@ -404,7 +411,8 @@ static int em_i2c_probe(struct platform_device *pdev)
if (ret)
goto err_clk;
- dev_info(&pdev->dev, "Added i2c controller %d, irq %d\n", priv->adap.nr, irq);
+ dev_info(&pdev->dev, "Added i2c controller %d, irq %d\n", priv->adap.nr,
+ priv->irq);
return 0;
--
2.20.1
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