[PATCH V2] i2c-imx: do not allow interruptions when waiting for I2C to complete (resend)

[PATCH V2] i2c-imx: do not allow interruptions when waiting for I2C to complete (resend)

[Marc Kleine-Budde]

[-- Attachment #1: Type: text/plain, Size: 1969 bytes --]

The i2c_imx_trx_complete() function is using
wait_event_interruptible_timeout() to wait for the I2C controller to
signal that it has completed an I2C bus operation. If the process that
causes the I2C operation receives a signal, the wait will be
interrupted, returning an error. It is better to let the I2C operation
finished before handling the signal (i.e. returning into userspace).

It is safe to use wait_event_timeout() instead, because the timeout
will allow the process to exit if the I2C bus hangs. It's also better
to allow the I2C operation to finish, because unacknowledged I2C
operations can cause the I2C bus to hang.

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>
---

V2: Remove check for "result < 0" as commented by Wolfram Sang.

 drivers/i2c/busses/i2c-imx.c |    9 +++------
 1 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index d1ff940..58df809 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -161,13 +161,10 @@ static int i2c_imx_trx_complete(struct
imx_i2c_struct *i2c_imx)
 {
 	int result;

-	result = wait_event_interruptible_timeout(i2c_imx->queue,
+	result = wait_event_timeout(i2c_imx->queue,
 		i2c_imx->i2csr & I2SR_IIF, HZ / 10);

-	if (unlikely(result < 0)) {
-		dev_dbg(&i2c_imx->adapter.dev, "<%s> result < 0\n", __func__);
-		return result;
-	} else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
+	if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
 		dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
 		return -ETIMEDOUT;
 	}
@@ -295,7 +292,7 @@ static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
 		i2c_imx->i2csr = temp;
 		temp &= ~I2SR_IIF;
 		writeb(temp, i2c_imx->base + IMX_I2C_I2SR);
-		wake_up_interruptible(&i2c_imx->queue);
+		wake_up(&i2c_imx->queue);
 		return IRQ_HANDLED;
 	}

-- 
1.7.1


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[PATCH V2] i2c-imx: do not allow interruptions when waiting for I2C to complete (resend)

[Marc Kleine-Budde]

[-- Attachment #1: Type: text/plain, Size: 2019 bytes --]

The i2c_imx_trx_complete() function is using
wait_event_interruptible_timeout() to wait for the I2C controller to
signal that it has completed an I2C bus operation. If the process that
causes the I2C operation receives a signal, the wait will be
interrupted, returning an error. It is better to let the I2C operation
finished before handling the signal (i.e. returning into userspace).

It is safe to use wait_event_timeout() instead, because the timeout
will allow the process to exit if the I2C bus hangs. It's also better
to allow the I2C operation to finish, because unacknowledged I2C
operations can cause the I2C bus to hang.

Signed-off-by: Marc Kleine-Budde <mkl-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Reviewed-by: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---

V2: Remove check for "result < 0" as commented by Wolfram Sang.

 drivers/i2c/busses/i2c-imx.c |    9 +++------
 1 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index d1ff940..58df809 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -161,13 +161,10 @@ static int i2c_imx_trx_complete(struct
imx_i2c_struct *i2c_imx)
 {
 	int result;

-	result = wait_event_interruptible_timeout(i2c_imx->queue,
+	result = wait_event_timeout(i2c_imx->queue,
 		i2c_imx->i2csr & I2SR_IIF, HZ / 10);

-	if (unlikely(result < 0)) {
-		dev_dbg(&i2c_imx->adapter.dev, "<%s> result < 0\n", __func__);
-		return result;
-	} else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
+	if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
 		dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
 		return -ETIMEDOUT;
 	}
@@ -295,7 +292,7 @@ static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
 		i2c_imx->i2csr = temp;
 		temp &= ~I2SR_IIF;
 		writeb(temp, i2c_imx->base + IMX_I2C_I2SR);
-		wake_up_interruptible(&i2c_imx->queue);
+		wake_up(&i2c_imx->queue);
 		return IRQ_HANDLED;
 	}

-- 
1.7.1


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Re: [PATCH V2] i2c-imx: do not allow interruptions when waiting for I2C to complete (resend)

[Ben Dooks]

On Tue, Jun 15, 2010 at 12:20:38PM +0200, Marc Kleine-Budde wrote:
> The i2c_imx_trx_complete() function is using
> wait_event_interruptible_timeout() to wait for the I2C controller to
> signal that it has completed an I2C bus operation. If the process that
> causes the I2C operation receives a signal, the wait will be
> interrupted, returning an error. It is better to let the I2C operation
> finished before handling the signal (i.e. returning into userspace).
> 
> It is safe to use wait_event_timeout() instead, because the timeout
> will allow the process to exit if the I2C bus hangs. It's also better
> to allow the I2C operation to finish, because unacknowledged I2C
> operations can cause the I2C bus to hang.

Hmm, if it times out, do you need to at-least try sending a stop
on the bus? or does the caller do that for you?
 
> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
> Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>
> ---
> 
> V2: Remove check for "result < 0" as commented by Wolfram Sang.
> 
>  drivers/i2c/busses/i2c-imx.c |    9 +++------
>  1 files changed, 3 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index d1ff940..58df809 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -161,13 +161,10 @@ static int i2c_imx_trx_complete(struct
> imx_i2c_struct *i2c_imx)
>  {
>  	int result;
> 
> -	result = wait_event_interruptible_timeout(i2c_imx->queue,
> +	result = wait_event_timeout(i2c_imx->queue,
>  		i2c_imx->i2csr & I2SR_IIF, HZ / 10);
> 
> -	if (unlikely(result < 0)) {
> -		dev_dbg(&i2c_imx->adapter.dev, "<%s> result < 0\n", __func__);
> -		return result;
> -	} else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
> +	if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
>  		dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
>  		return -ETIMEDOUT;
>  	}
> @@ -295,7 +292,7 @@ static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
>  		i2c_imx->i2csr = temp;
>  		temp &= ~I2SR_IIF;
>  		writeb(temp, i2c_imx->base + IMX_I2C_I2SR);
> -		wake_up_interruptible(&i2c_imx->queue);
> +		wake_up(&i2c_imx->queue);
>  		return IRQ_HANDLED;
>  	}
> 
> -- 
> 1.7.1
> 



-- 
Ben (ben@fluff.org, http://www.fluff.org/)

  'a smiley only costs 4 bytes'

Re: [PATCH V2] i2c-imx: do not allow interruptions when waiting for I2C to complete (resend)

[Marc Kleine-Budde]

[-- Attachment #1: Type: text/plain, Size: 1432 bytes --]

Ben Dooks wrote:
> On Tue, Jun 15, 2010 at 12:20:38PM +0200, Marc Kleine-Budde wrote:
>> The i2c_imx_trx_complete() function is using
>> wait_event_interruptible_timeout() to wait for the I2C controller to
>> signal that it has completed an I2C bus operation. If the process that
>> causes the I2C operation receives a signal, the wait will be
>> interrupted, returning an error. It is better to let the I2C operation
>> finished before handling the signal (i.e. returning into userspace).
>>
>> It is safe to use wait_event_timeout() instead, because the timeout
>> will allow the process to exit if the I2C bus hangs. It's also better
>> to allow the I2C operation to finish, because unacknowledged I2C
>> operations can cause the I2C bus to hang.
> 
> Hmm, if it times out, do you need to at-least try sending a stop
> on the bus? or does the caller do that for you?

The caller of the caller does this. "i2c_imx_xfer" will call
"i2c_imx_stop", and this function will generate the stop condition if
not already done so.

I'm sending a V3 version of the patch, which removes the only written to
variable "result".

cheers, Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |


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Re: [PATCH V2] i2c-imx: do not allow interruptions when waiting for I2C to complete (resend)

[Marc Kleine-Budde]

[-- Attachment #1: Type: text/plain, Size: 1432 bytes --]

Ben Dooks wrote:
> On Tue, Jun 15, 2010 at 12:20:38PM +0200, Marc Kleine-Budde wrote:
>> The i2c_imx_trx_complete() function is using
>> wait_event_interruptible_timeout() to wait for the I2C controller to
>> signal that it has completed an I2C bus operation. If the process that
>> causes the I2C operation receives a signal, the wait will be
>> interrupted, returning an error. It is better to let the I2C operation
>> finished before handling the signal (i.e. returning into userspace).
>>
>> It is safe to use wait_event_timeout() instead, because the timeout
>> will allow the process to exit if the I2C bus hangs. It's also better
>> to allow the I2C operation to finish, because unacknowledged I2C
>> operations can cause the I2C bus to hang.
> 
> Hmm, if it times out, do you need to at-least try sending a stop
> on the bus? or does the caller do that for you?

The caller of the caller does this. "i2c_imx_xfer" will call
"i2c_imx_stop", and this function will generate the stop condition if
not already done so.

I'm sending a V3 version of the patch, which removes the only written to
variable "result".

cheers, Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |


[-- Attachment #2: OpenPGP digital signature --]
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[PATCH V3] i2c-imx: do not allow interruptions when waiting for I2C to complete

[Marc Kleine-Budde]

The i2c_imx_trx_complete() function is using
wait_event_interruptible_timeout() to wait for the I2C controller to
signal that it has completed an I2C bus operation. If the process that
causes the I2C operation receives a signal, the wait will be
interrupted, returning an error. It is better to let the I2C operation
finished before handling the signal (i.e. returning into userspace).

It is safe to use wait_event_timeout() instead, because the timeout
will allow the process to exit if the I2C bus hangs. It's also better
to allow the I2C operation to finish, because unacknowledged I2C
operations can cause the I2C bus to hang.

Signed-off-by: Marc Kleine-Budde <mkl-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Reviewed-by: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---

V2: Remove check for "result < 0" as commented by Wolfram Sang.
V3: Remove "result" entirely.

 drivers/i2c/busses/i2c-imx.c |   12 +++---------
 1 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index d1ff940..4c2a62b 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -159,15 +159,9 @@ static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy)
 
 static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx)
 {
-	int result;
-
-	result = wait_event_interruptible_timeout(i2c_imx->queue,
-		i2c_imx->i2csr & I2SR_IIF, HZ / 10);
+	wait_event_timeout(i2c_imx->queue, i2c_imx->i2csr & I2SR_IIF, HZ / 10);
 
-	if (unlikely(result < 0)) {
-		dev_dbg(&i2c_imx->adapter.dev, "<%s> result < 0\n", __func__);
-		return result;
-	} else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
+	if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
 		dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
 		return -ETIMEDOUT;
 	}
@@ -295,7 +289,7 @@ static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
 		i2c_imx->i2csr = temp;
 		temp &= ~I2SR_IIF;
 		writeb(temp, i2c_imx->base + IMX_I2C_I2SR);
-		wake_up_interruptible(&i2c_imx->queue);
+		wake_up(&i2c_imx->queue);
 		return IRQ_HANDLED;
 	}
 
-- 
1.7.1

[PATCH V3 RESEND] i2c-imx: do not allow interruptions when waiting for I2C to complete

[Marc Kleine-Budde]

[-- Attachment #1: Type: text/plain, Size: 2382 bytes --]

The i2c_imx_trx_complete() function is using
wait_event_interruptible_timeout() to wait for the I2C controller to
signal that it has completed an I2C bus operation. If the process that
causes the I2C operation receives a signal, the wait will be
interrupted, returning an error. It is better to let the I2C operation
finished before handling the signal (i.e. returning into userspace).

It is safe to use wait_event_timeout() instead, because the timeout
will allow the process to exit if the I2C bus hangs. It's also better
to allow the I2C operation to finish, because unacknowledged I2C
operations can cause the I2C bus to hang.

Signed-off-by: Marc Kleine-Budde <mkl-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Reviewed-by: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---

V2: Remove check for "result < 0" as commented by Wolfram Sang.
V3: Remove "result" entirely.

 drivers/i2c/busses/i2c-imx.c |   12 +++---------
 1 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index d1ff940..4c2a62b 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -159,15 +159,9 @@ static int i2c_imx_bus_busy(struct imx_i2c_struct
*i2c_imx, int for_busy)

 static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx)
 {
-	int result;
-
-	result = wait_event_interruptible_timeout(i2c_imx->queue,
-		i2c_imx->i2csr & I2SR_IIF, HZ / 10);
+	wait_event_timeout(i2c_imx->queue, i2c_imx->i2csr & I2SR_IIF, HZ / 10);

-	if (unlikely(result < 0)) {
-		dev_dbg(&i2c_imx->adapter.dev, "<%s> result < 0\n", __func__);
-		return result;
-	} else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
+	if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
 		dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
 		return -ETIMEDOUT;
 	}
@@ -295,7 +289,7 @@ static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
 		i2c_imx->i2csr = temp;
 		temp &= ~I2SR_IIF;
 		writeb(temp, i2c_imx->base + IMX_I2C_I2SR);
-		wake_up_interruptible(&i2c_imx->queue);
+		wake_up(&i2c_imx->queue);
 		return IRQ_HANDLED;
 	}

-- 
1.7.1

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[PATCH V3 RESEND2] i2c-imx: do not allow interruptions when waiting for I2C to complete

[Marc Kleine-Budde]

[-- Attachment #1: Type: text/plain, Size: 2514 bytes --]

Hello Ben,

what about this patch?

cheers, Marc

--------8<--------8<--------8<--------8<--------8<--------8<--------

The i2c_imx_trx_complete() function is using
wait_event_interruptible_timeout() to wait for the I2C controller to
signal that it has completed an I2C bus operation. If the process that
causes the I2C operation receives a signal, the wait will be
interrupted, returning an error. It is better to let the I2C operation
finished before handling the signal (i.e. returning into userspace).

It is safe to use wait_event_timeout() instead, because the timeout
will allow the process to exit if the I2C bus hangs. It's also better
to allow the I2C operation to finish, because unacknowledged I2C
operations can cause the I2C bus to hang.

Signed-off-by: Marc Kleine-Budde <mkl-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Reviewed-by: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---

V2: Remove check for "result < 0" as commented by Wolfram Sang.
V3: Remove "result" entirely.

 drivers/i2c/busses/i2c-imx.c |   12 +++---------
 1 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index d1ff940..4c2a62b 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -159,15 +159,9 @@ static int i2c_imx_bus_busy(struct imx_i2c_struct
*i2c_imx, int for_busy)

 static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx)
 {
-	int result;
-
-	result = wait_event_interruptible_timeout(i2c_imx->queue,
-		i2c_imx->i2csr & I2SR_IIF, HZ / 10);
+	wait_event_timeout(i2c_imx->queue, i2c_imx->i2csr & I2SR_IIF, HZ / 10);

-	if (unlikely(result < 0)) {
-		dev_dbg(&i2c_imx->adapter.dev, "<%s> result < 0\n", __func__);
-		return result;
-	} else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
+	if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
 		dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
 		return -ETIMEDOUT;
 	}
@@ -295,7 +289,7 @@ static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
 		i2c_imx->i2csr = temp;
 		temp &= ~I2SR_IIF;
 		writeb(temp, i2c_imx->base + IMX_I2C_I2SR);
-		wake_up_interruptible(&i2c_imx->queue);
+		wake_up(&i2c_imx->queue);
 		return IRQ_HANDLED;
 	}

-- 
1.7.1

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[PATCH V3 RESEND3] i2c-imx: do not allow interruptions when waiting for I2C to complete

[Marc Kleine-Budde]

[-- Attachment #1: Type: text/plain, Size: 2518 bytes --]

Hello Ben,

what about this patch?

cheers, Marc

--------8<--------8<--------8<--------8<--------8<--------8<--------

The i2c_imx_trx_complete() function is using
wait_event_interruptible_timeout() to wait for the I2C controller to
signal that it has completed an I2C bus operation. If the process that
causes the I2C operation receives a signal, the wait will be
interrupted, returning an error. It is better to let the I2C operation
finished before handling the signal (i.e. returning into userspace).

It is safe to use wait_event_timeout() instead, because the timeout
will allow the process to exit if the I2C bus hangs. It's also better
to allow the I2C operation to finish, because unacknowledged I2C
operations can cause the I2C bus to hang.

Signed-off-by: Marc Kleine-Budde <mkl-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Reviewed-by: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---

V2: Remove check for "result < 0" as commented by Wolfram Sang.
V3: Remove "result" entirely.

 drivers/i2c/busses/i2c-imx.c |   12 +++---------
 1 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index d1ff940..4c2a62b 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -159,15 +159,9 @@ static int i2c_imx_bus_busy(struct imx_i2c_struct
*i2c_imx, int for_busy)

 static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx)
 {
-	int result;
-
-	result = wait_event_interruptible_timeout(i2c_imx->queue,
-		i2c_imx->i2csr & I2SR_IIF, HZ / 10);
+	wait_event_timeout(i2c_imx->queue, i2c_imx->i2csr & I2SR_IIF, HZ / 10);

-	if (unlikely(result < 0)) {
-		dev_dbg(&i2c_imx->adapter.dev, "<%s> result < 0\n", __func__);
-		return result;
-	} else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
+	if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
 		dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
 		return -ETIMEDOUT;
 	}
@@ -295,7 +289,7 @@ static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
 		i2c_imx->i2csr = temp;
 		temp &= ~I2SR_IIF;
 		writeb(temp, i2c_imx->base + IMX_I2C_I2SR);
-		wake_up_interruptible(&i2c_imx->queue);
+		wake_up(&i2c_imx->queue);
 		return IRQ_HANDLED;
 	}

-- 
1.7.1

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[PATCH V3 RESEND4] i2c-imx: do not allow interruptions when waiting for I2C to complete

[Marc Kleine-Budde]

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Hello Ben,

what about this patch?

cheers, Marc

--------8<--------8<--------8<--------8<--------8<--------8<--------

The i2c_imx_trx_complete() function is using
wait_event_interruptible_timeout() to wait for the I2C controller to
signal that it has completed an I2C bus operation. If the process that
causes the I2C operation receives a signal, the wait will be
interrupted, returning an error. It is better to let the I2C operation
finished before handling the signal (i.e. returning into userspace).

It is safe to use wait_event_timeout() instead, because the timeout
will allow the process to exit if the I2C bus hangs. It's also better
to allow the I2C operation to finish, because unacknowledged I2C
operations can cause the I2C bus to hang.

Signed-off-by: Marc Kleine-Budde <mkl-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Reviewed-by: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---

V2: Remove check for "result < 0" as commented by Wolfram Sang.
V3: Remove "result" entirely.

 drivers/i2c/busses/i2c-imx.c |   12 +++---------
 1 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index d1ff940..4c2a62b 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -159,15 +159,9 @@ static int i2c_imx_bus_busy(struct imx_i2c_struct
*i2c_imx, int for_busy)

 static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx)
 {
-	int result;
-
-	result = wait_event_interruptible_timeout(i2c_imx->queue,
-		i2c_imx->i2csr & I2SR_IIF, HZ / 10);
+	wait_event_timeout(i2c_imx->queue, i2c_imx->i2csr & I2SR_IIF, HZ / 10);

-	if (unlikely(result < 0)) {
-		dev_dbg(&i2c_imx->adapter.dev, "<%s> result < 0\n", __func__);
-		return result;
-	} else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
+	if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
 		dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
 		return -ETIMEDOUT;
 	}
@@ -295,7 +289,7 @@ static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
 		i2c_imx->i2csr = temp;
 		temp &= ~I2SR_IIF;
 		writeb(temp, i2c_imx->base + IMX_I2C_I2SR);
-		wake_up_interruptible(&i2c_imx->queue);
+		wake_up(&i2c_imx->queue);
 		return IRQ_HANDLED;
 	}

-- 
1.7.1

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Re: [PATCH V3 RESEND4] i2c-imx: do not allow interruptions when waiting for I2C to complete

[Wolfram Sang]

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On Fri, Sep 24, 2010 at 04:50:09PM +0200, Marc Kleine-Budde wrote:
> Hello Ben,
> 
> what about this patch?

Ben, any reason you did not pick up this one while you were picking up
other patches?

> 
> cheers, Marc
> 
> --------8<--------8<--------8<--------8<--------8<--------8<--------
> 
> The i2c_imx_trx_complete() function is using
> wait_event_interruptible_timeout() to wait for the I2C controller to
> signal that it has completed an I2C bus operation. If the process that
> causes the I2C operation receives a signal, the wait will be
> interrupted, returning an error. It is better to let the I2C operation
> finished before handling the signal (i.e. returning into userspace).
> 
> It is safe to use wait_event_timeout() instead, because the timeout
> will allow the process to exit if the I2C bus hangs. It's also better
> to allow the I2C operation to finish, because unacknowledged I2C
> operations can cause the I2C bus to hang.
> 
> Signed-off-by: Marc Kleine-Budde <mkl-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> Reviewed-by: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
> ---
> 
> V2: Remove check for "result < 0" as commented by Wolfram Sang.
> V3: Remove "result" entirely.
> 
>  drivers/i2c/busses/i2c-imx.c |   12 +++---------
>  1 files changed, 3 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index d1ff940..4c2a62b 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -159,15 +159,9 @@ static int i2c_imx_bus_busy(struct imx_i2c_struct
> *i2c_imx, int for_busy)
> 
>  static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx)
>  {
> -	int result;
> -
> -	result = wait_event_interruptible_timeout(i2c_imx->queue,
> -		i2c_imx->i2csr & I2SR_IIF, HZ / 10);
> +	wait_event_timeout(i2c_imx->queue, i2c_imx->i2csr & I2SR_IIF, HZ / 10);
> 
> -	if (unlikely(result < 0)) {
> -		dev_dbg(&i2c_imx->adapter.dev, "<%s> result < 0\n", __func__);
> -		return result;
> -	} else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
> +	if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
>  		dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
>  		return -ETIMEDOUT;
>  	}
> @@ -295,7 +289,7 @@ static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
>  		i2c_imx->i2csr = temp;
>  		temp &= ~I2SR_IIF;
>  		writeb(temp, i2c_imx->base + IMX_I2C_I2SR);
> -		wake_up_interruptible(&i2c_imx->queue);
> +		wake_up(&i2c_imx->queue);
>  		return IRQ_HANDLED;
>  	}
> 
> -- 
> 1.7.1
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> 
> 
> 
> 
> 
> 



-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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[PATCH V3 RESEND5] i2c-imx: do not allow interruptions when waiting for I2C to complete

[Marc Kleine-Budde]

Hello Ben,

I've send this patch several times, can you please comment it or apply
it to your git tree. Please send me a note if you do so, then I can
stop bugging you :)

cheers, Marc

--------8<--------8<--------8<--------8<--------8<--------8<--------

The i2c_imx_trx_complete() function is using
wait_event_interruptible_timeout() to wait for the I2C controller to
signal that it has completed an I2C bus operation. If the process that
causes the I2C operation receives a signal, the wait will be
interrupted, returning an error. It is better to let the I2C operation
finished before handling the signal (i.e. returning into userspace).

It is safe to use wait_event_timeout() instead, because the timeout
will allow the process to exit if the I2C bus hangs. It's also better
to allow the I2C operation to finish, because unacknowledged I2C
operations can cause the I2C bus to hang.

Signed-off-by: Marc Kleine-Budde <mkl-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
Reviewed-by: Wolfram Sang <w.sang-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
---

V2: Remove check for "result < 0" as commented by Wolfram Sang.
V3: Remove "result" entirely.

 drivers/i2c/busses/i2c-imx.c |   12 +++---------
 1 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index d1ff940..4c2a62b 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -159,15 +159,9 @@ static int i2c_imx_bus_busy(struct imx_i2c_struct
*i2c_imx, int for_busy)

 static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx)
 {
-	int result;
-
-	result = wait_event_interruptible_timeout(i2c_imx->queue,
-		i2c_imx->i2csr & I2SR_IIF, HZ / 10);
+	wait_event_timeout(i2c_imx->queue, i2c_imx->i2csr & I2SR_IIF, HZ / 10);

-	if (unlikely(result < 0)) {
-		dev_dbg(&i2c_imx->adapter.dev, "<%s> result < 0\n", __func__);
-		return result;
-	} else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
+	if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
 		dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
 		return -ETIMEDOUT;
 	}
@@ -295,7 +289,7 @@ static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
 		i2c_imx->i2csr = temp;
 		temp &= ~I2SR_IIF;
 		writeb(temp, i2c_imx->base + IMX_I2C_I2SR);
-		wake_up_interruptible(&i2c_imx->queue);
+		wake_up(&i2c_imx->queue);
 		return IRQ_HANDLED;
 	}

-- 
1.7.1

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