[PATCH 0/2] i2c: i801: Replace waitqueue with completion API

[PATCH 0/2] i2c: i801: Replace waitqueue with completion API

[Heiner Kallweit]

Using the completion API is more intuitive and it allows to simplify
the code.

Heiner Kallweit (2):
  i2c: i801: Remove unneeded warning after wait_event_timeout timeout
  i2c: i801: Replace waitqueue with completion API

 drivers/i2c/busses/i2c-i801.c | 52 +++++++++++++----------------------
 1 file changed, 19 insertions(+), 33 deletions(-)

-- 
2.31.1

[PATCH 1/2] i2c: i801: Remove unneeded warning after wait_event_timeout timeout

[Heiner Kallweit]

When passing -ETIMEDOUT to i801_check_post() it will emit a timeout
error message. I don't see much benefit in an additional warning
stating more or less the same.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/i2c/busses/i2c-i801.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index 99d446763..bfea94d02 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -509,11 +509,9 @@ static int i801_transaction(struct i801_priv *priv, int xact)
 		result = wait_event_timeout(priv->waitq,
 					    (status = priv->status),
 					    adap->timeout);
-		if (!result) {
+		if (!result)
 			status = -ETIMEDOUT;
-			dev_warn(&priv->pci_dev->dev,
-				 "Timeout waiting for interrupt!\n");
-		}
+
 		priv->status = 0;
 		return i801_check_post(priv, status);
 	}
@@ -732,11 +730,9 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
 		result = wait_event_timeout(priv->waitq,
 					    (status = priv->status),
 					    adap->timeout);
-		if (!result) {
+		if (!result)
 			status = -ETIMEDOUT;
-			dev_warn(&priv->pci_dev->dev,
-				 "Timeout waiting for interrupt!\n");
-		}
+
 		priv->status = 0;
 		return i801_check_post(priv, status);
 	}
-- 
2.31.1

[PATCH 2/2] i2c: i801: Replace waitqueue with completion API

[Heiner Kallweit]

Using the completion API is more intuitive and it allows to simplify
the code. Note that we don't have to set priv->status = 0 any longer
with the completion API.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 drivers/i2c/busses/i2c-i801.c | 48 ++++++++++++++---------------------
 1 file changed, 19 insertions(+), 29 deletions(-)

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index bfea94d02..738204d77 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -103,7 +103,7 @@
 #include <linux/dmi.h>
 #include <linux/slab.h>
 #include <linux/string.h>
-#include <linux/wait.h>
+#include <linux/completion.h>
 #include <linux/err.h>
 #include <linux/platform_device.h>
 #include <linux/platform_data/itco_wdt.h>
@@ -270,7 +270,7 @@ struct i801_priv {
 	unsigned int features;
 
 	/* isr processing */
-	wait_queue_head_t waitq;
+	struct completion done;
 	u8 status;
 
 	/* Command state used by isr for byte-by-byte block transactions */
@@ -496,24 +496,19 @@ static int i801_wait_byte_done(struct i801_priv *priv)
 static int i801_transaction(struct i801_priv *priv, int xact)
 {
 	int status;
-	int result;
+	unsigned long result;
 	const struct i2c_adapter *adap = &priv->adapter;
 
-	result = i801_check_pre(priv);
-	if (result < 0)
-		return result;
+	status = i801_check_pre(priv);
+	if (status < 0)
+		return status;
 
 	if (priv->features & FEATURE_IRQ) {
+		reinit_completion(&priv->done);
 		outb_p(xact | SMBHSTCNT_INTREN | SMBHSTCNT_START,
 		       SMBHSTCNT(priv));
-		result = wait_event_timeout(priv->waitq,
-					    (status = priv->status),
-					    adap->timeout);
-		if (!result)
-			status = -ETIMEDOUT;
-
-		priv->status = 0;
-		return i801_check_post(priv, status);
+		result = wait_for_completion_timeout(&priv->done, adap->timeout);
+		return i801_check_post(priv, result ? priv->status : -ETIMEDOUT);
 	}
 
 	/* the current contents of SMBHSTCNT can be overwritten, since PEC,
@@ -638,7 +633,7 @@ static irqreturn_t i801_host_notify_isr(struct i801_priv *priv)
  *      DEV_ERR - Invalid command, NAK or communication timeout
  *      BUS_ERR - SMI# transaction collision
  *      FAILED - transaction was canceled due to a KILL request
- *    When any of these occur, update ->status and wake up the waitq.
+ *    When any of these occur, update ->status and signal completion.
  *    ->status must be cleared before kicking off the next transaction.
  *
  * 2) For byte-by-byte (I2C read/write) transactions, one BYTE_DONE interrupt
@@ -675,7 +670,7 @@ static irqreturn_t i801_isr(int irq, void *dev_id)
 	if (status) {
 		outb_p(status, SMBHSTSTS(priv));
 		priv->status = status;
-		wake_up(&priv->waitq);
+		complete(&priv->done);
 	}
 
 	return IRQ_HANDLED;
@@ -694,15 +689,15 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
 	int i, len;
 	int smbcmd;
 	int status;
-	int result;
+	unsigned long result;
 	const struct i2c_adapter *adap = &priv->adapter;
 
 	if (command == I2C_SMBUS_BLOCK_PROC_CALL)
 		return -EOPNOTSUPP;
 
-	result = i801_check_pre(priv);
-	if (result < 0)
-		return result;
+	status = i801_check_pre(priv);
+	if (status < 0)
+		return status;
 
 	len = data->block[0];
 
@@ -726,15 +721,10 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
 		priv->count = 0;
 		priv->data = &data->block[1];
 
+		reinit_completion(&priv->done);
 		outb_p(priv->cmd | SMBHSTCNT_START, SMBHSTCNT(priv));
-		result = wait_event_timeout(priv->waitq,
-					    (status = priv->status),
-					    adap->timeout);
-		if (!result)
-			status = -ETIMEDOUT;
-
-		priv->status = 0;
-		return i801_check_post(priv, status);
+		result = wait_for_completion_timeout(&priv->done, adap->timeout);
+		return i801_check_post(priv, result ? priv->status : -ETIMEDOUT);
 	}
 
 	for (i = 1; i <= len; i++) {
@@ -1889,7 +1879,7 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	}
 
 	if (priv->features & FEATURE_IRQ) {
-		init_waitqueue_head(&priv->waitq);
+		init_completion(&priv->done);
 
 		err = devm_request_irq(&dev->dev, dev->irq, i801_isr,
 				       IRQF_SHARED,
-- 
2.31.1

Re: [PATCH 1/2] i2c: i801: Remove unneeded warning after wait_event_timeout timeout

[Jean Delvare]

On Sat, 22 May 2021 00:00:28 +0200, Heiner Kallweit wrote:
> When passing -ETIMEDOUT to i801_check_post() it will emit a timeout
> error message. I don't see much benefit in an additional warning
> stating more or less the same.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
>  drivers/i2c/busses/i2c-i801.c | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
> index 99d446763..bfea94d02 100644
> --- a/drivers/i2c/busses/i2c-i801.c
> +++ b/drivers/i2c/busses/i2c-i801.c
> @@ -509,11 +509,9 @@ static int i801_transaction(struct i801_priv *priv, int xact)
>  		result = wait_event_timeout(priv->waitq,
>  					    (status = priv->status),
>  					    adap->timeout);
> -		if (!result) {
> +		if (!result)
>  			status = -ETIMEDOUT;
> -			dev_warn(&priv->pci_dev->dev,
> -				 "Timeout waiting for interrupt!\n");
> -		}
> +
>  		priv->status = 0;
>  		return i801_check_post(priv, status);
>  	}
> @@ -732,11 +730,9 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
>  		result = wait_event_timeout(priv->waitq,
>  					    (status = priv->status),
>  					    adap->timeout);
> -		if (!result) {
> +		if (!result)
>  			status = -ETIMEDOUT;
> -			dev_warn(&priv->pci_dev->dev,
> -				 "Timeout waiting for interrupt!\n");
> -		}
> +
>  		priv->status = 0;
>  		return i801_check_post(priv, status);
>  	}

I have to agree.

Reviewed-by: Jean Delvare <jdelvare@suse.de>
Tested-by: Jean Delvare <jdelvare@suse.de>

-- 
Jean Delvare
SUSE L3 Support

Re: [PATCH 2/2] i2c: i801: Replace waitqueue with completion API

[Jean Delvare]

Hi Heiner,

Adding Daniel Kurtz, who wrote the original wait queue-based code, to
Cc. I'm not sure if Daniel is still into kernel code though.

On Sat, 22 May 2021 00:02:43 +0200, Heiner Kallweit wrote:
> Using the completion API is more intuitive and it allows to simplify
> the code. Note that we don't have to set priv->status = 0 any longer
> with the completion API.

OK, but you need to call reinit_completion() instead, which has the
same cost. So that's not a good argument ;-)

> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
>  drivers/i2c/busses/i2c-i801.c | 48 ++++++++++++++---------------------
>  1 file changed, 19 insertions(+), 29 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
> index bfea94d02..738204d77 100644
> --- a/drivers/i2c/busses/i2c-i801.c
> +++ b/drivers/i2c/busses/i2c-i801.c
> @@ -103,7 +103,7 @@
>  #include <linux/dmi.h>
>  #include <linux/slab.h>
>  #include <linux/string.h>
> -#include <linux/wait.h>
> +#include <linux/completion.h>
>  #include <linux/err.h>
>  #include <linux/platform_device.h>
>  #include <linux/platform_data/itco_wdt.h>
> @@ -270,7 +270,7 @@ struct i801_priv {
>  	unsigned int features;
>  
>  	/* isr processing */
> -	wait_queue_head_t waitq;
> +	struct completion done;
>  	u8 status;
>  
>  	/* Command state used by isr for byte-by-byte block transactions */
> @@ -496,24 +496,19 @@ static int i801_wait_byte_done(struct i801_priv *priv)
>  static int i801_transaction(struct i801_priv *priv, int xact)
>  {
>  	int status;
> -	int result;
> +	unsigned long result;
>  	const struct i2c_adapter *adap = &priv->adapter;
>  
> -	result = i801_check_pre(priv);
> -	if (result < 0)
> -		return result;
> +	status = i801_check_pre(priv);
> +	if (status < 0)
> +		return status;
>  
>  	if (priv->features & FEATURE_IRQ) {
> +		reinit_completion(&priv->done);
>  		outb_p(xact | SMBHSTCNT_INTREN | SMBHSTCNT_START,
>  		       SMBHSTCNT(priv));
> -		result = wait_event_timeout(priv->waitq,
> -					    (status = priv->status),
> -					    adap->timeout);
> -		if (!result)
> -			status = -ETIMEDOUT;
> -
> -		priv->status = 0;
> -		return i801_check_post(priv, status);
> +		result = wait_for_completion_timeout(&priv->done, adap->timeout);
> +		return i801_check_post(priv, result ? priv->status : -ETIMEDOUT);
>  	}
>  
>  	/* the current contents of SMBHSTCNT can be overwritten, since PEC,
> @@ -638,7 +633,7 @@ static irqreturn_t i801_host_notify_isr(struct i801_priv *priv)
>   *      DEV_ERR - Invalid command, NAK or communication timeout
>   *      BUS_ERR - SMI# transaction collision
>   *      FAILED - transaction was canceled due to a KILL request
> - *    When any of these occur, update ->status and wake up the waitq.
> + *    When any of these occur, update ->status and signal completion.
>   *    ->status must be cleared before kicking off the next transaction.
>   *
>   * 2) For byte-by-byte (I2C read/write) transactions, one BYTE_DONE interrupt
> @@ -675,7 +670,7 @@ static irqreturn_t i801_isr(int irq, void *dev_id)
>  	if (status) {
>  		outb_p(status, SMBHSTSTS(priv));
>  		priv->status = status;
> -		wake_up(&priv->waitq);
> +		complete(&priv->done);
>  	}
>  
>  	return IRQ_HANDLED;
> @@ -694,15 +689,15 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
>  	int i, len;
>  	int smbcmd;
>  	int status;
> -	int result;
> +	unsigned long result;
>  	const struct i2c_adapter *adap = &priv->adapter;
>  
>  	if (command == I2C_SMBUS_BLOCK_PROC_CALL)
>  		return -EOPNOTSUPP;
>  
> -	result = i801_check_pre(priv);
> -	if (result < 0)
> -		return result;
> +	status = i801_check_pre(priv);
> +	if (status < 0)
> +		return status;
>  
>  	len = data->block[0];
>  
> @@ -726,15 +721,10 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
>  		priv->count = 0;
>  		priv->data = &data->block[1];
>  
> +		reinit_completion(&priv->done);
>  		outb_p(priv->cmd | SMBHSTCNT_START, SMBHSTCNT(priv));
> -		result = wait_event_timeout(priv->waitq,
> -					    (status = priv->status),
> -					    adap->timeout);
> -		if (!result)
> -			status = -ETIMEDOUT;
> -
> -		priv->status = 0;
> -		return i801_check_post(priv, status);
> +		result = wait_for_completion_timeout(&priv->done, adap->timeout);
> +		return i801_check_post(priv, result ? priv->status : -ETIMEDOUT);
>  	}
>  
>  	for (i = 1; i <= len; i++) {
> @@ -1889,7 +1879,7 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
>  	}
>  
>  	if (priv->features & FEATURE_IRQ) {
> -		init_waitqueue_head(&priv->waitq);
> +		init_completion(&priv->done);
>  
>  		err = devm_request_irq(&dev->dev, dev->irq, i801_isr,
>  				       IRQF_SHARED,

The clean-up isn't massive but I agree the code is a bit more pleasant
to read after the change, and I also see the binary size shrink a bit,
so I vote for it.

Reviewed-by: Jean Delvare <jdelvare@suse.de>
Tested-by: Jean Delvare <jdelvare@suse.de>

-- 
Jean Delvare
SUSE L3 Support

Re: [PATCH 2/2] i2c: i801: Replace waitqueue with completion API

[Heiner Kallweit]

On 25.05.2021 14:12, Jean Delvare wrote:
> Hi Heiner,
> 
> Adding Daniel Kurtz, who wrote the original wait queue-based code, to
> Cc. I'm not sure if Daniel is still into kernel code though.
> 
> On Sat, 22 May 2021 00:02:43 +0200, Heiner Kallweit wrote:
>> Using the completion API is more intuitive and it allows to simplify
>> the code. Note that we don't have to set priv->status = 0 any longer
>> with the completion API.
> 
> OK, but you need to call reinit_completion() instead, which has the
> same cost. So that's not a good argument ;-)
> 
Maybe my comment wasn't clear enough. I didn't want to say that we
save something but that it's safe from a functional point of view
to remove clearing priv->status.

>> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
>> ---
>>  drivers/i2c/busses/i2c-i801.c | 48 ++++++++++++++---------------------
>>  1 file changed, 19 insertions(+), 29 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
>> index bfea94d02..738204d77 100644
>> --- a/drivers/i2c/busses/i2c-i801.c
>> +++ b/drivers/i2c/busses/i2c-i801.c
>> @@ -103,7 +103,7 @@
>>  #include <linux/dmi.h>
>>  #include <linux/slab.h>
>>  #include <linux/string.h>
>> -#include <linux/wait.h>
>> +#include <linux/completion.h>
>>  #include <linux/err.h>
>>  #include <linux/platform_device.h>
>>  #include <linux/platform_data/itco_wdt.h>
>> @@ -270,7 +270,7 @@ struct i801_priv {
>>  	unsigned int features;
>>  
>>  	/* isr processing */
>> -	wait_queue_head_t waitq;
>> +	struct completion done;
>>  	u8 status;
>>  
>>  	/* Command state used by isr for byte-by-byte block transactions */
>> @@ -496,24 +496,19 @@ static int i801_wait_byte_done(struct i801_priv *priv)
>>  static int i801_transaction(struct i801_priv *priv, int xact)
>>  {
>>  	int status;
>> -	int result;
>> +	unsigned long result;
>>  	const struct i2c_adapter *adap = &priv->adapter;
>>  
>> -	result = i801_check_pre(priv);
>> -	if (result < 0)
>> -		return result;
>> +	status = i801_check_pre(priv);
>> +	if (status < 0)
>> +		return status;
>>  
>>  	if (priv->features & FEATURE_IRQ) {
>> +		reinit_completion(&priv->done);
>>  		outb_p(xact | SMBHSTCNT_INTREN | SMBHSTCNT_START,
>>  		       SMBHSTCNT(priv));
>> -		result = wait_event_timeout(priv->waitq,
>> -					    (status = priv->status),
>> -					    adap->timeout);
>> -		if (!result)
>> -			status = -ETIMEDOUT;
>> -
>> -		priv->status = 0;
>> -		return i801_check_post(priv, status);
>> +		result = wait_for_completion_timeout(&priv->done, adap->timeout);
>> +		return i801_check_post(priv, result ? priv->status : -ETIMEDOUT);
>>  	}
>>  
>>  	/* the current contents of SMBHSTCNT can be overwritten, since PEC,
>> @@ -638,7 +633,7 @@ static irqreturn_t i801_host_notify_isr(struct i801_priv *priv)
>>   *      DEV_ERR - Invalid command, NAK or communication timeout
>>   *      BUS_ERR - SMI# transaction collision
>>   *      FAILED - transaction was canceled due to a KILL request
>> - *    When any of these occur, update ->status and wake up the waitq.
>> + *    When any of these occur, update ->status and signal completion.
>>   *    ->status must be cleared before kicking off the next transaction.
>>   *
>>   * 2) For byte-by-byte (I2C read/write) transactions, one BYTE_DONE interrupt
>> @@ -675,7 +670,7 @@ static irqreturn_t i801_isr(int irq, void *dev_id)
>>  	if (status) {
>>  		outb_p(status, SMBHSTSTS(priv));
>>  		priv->status = status;
>> -		wake_up(&priv->waitq);
>> +		complete(&priv->done);
>>  	}
>>  
>>  	return IRQ_HANDLED;
>> @@ -694,15 +689,15 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
>>  	int i, len;
>>  	int smbcmd;
>>  	int status;
>> -	int result;
>> +	unsigned long result;
>>  	const struct i2c_adapter *adap = &priv->adapter;
>>  
>>  	if (command == I2C_SMBUS_BLOCK_PROC_CALL)
>>  		return -EOPNOTSUPP;
>>  
>> -	result = i801_check_pre(priv);
>> -	if (result < 0)
>> -		return result;
>> +	status = i801_check_pre(priv);
>> +	if (status < 0)
>> +		return status;
>>  
>>  	len = data->block[0];
>>  
>> @@ -726,15 +721,10 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
>>  		priv->count = 0;
>>  		priv->data = &data->block[1];
>>  
>> +		reinit_completion(&priv->done);
>>  		outb_p(priv->cmd | SMBHSTCNT_START, SMBHSTCNT(priv));
>> -		result = wait_event_timeout(priv->waitq,
>> -					    (status = priv->status),
>> -					    adap->timeout);
>> -		if (!result)
>> -			status = -ETIMEDOUT;
>> -
>> -		priv->status = 0;
>> -		return i801_check_post(priv, status);
>> +		result = wait_for_completion_timeout(&priv->done, adap->timeout);
>> +		return i801_check_post(priv, result ? priv->status : -ETIMEDOUT);
>>  	}
>>  
>>  	for (i = 1; i <= len; i++) {
>> @@ -1889,7 +1879,7 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
>>  	}
>>  
>>  	if (priv->features & FEATURE_IRQ) {
>> -		init_waitqueue_head(&priv->waitq);
>> +		init_completion(&priv->done);
>>  
>>  		err = devm_request_irq(&dev->dev, dev->irq, i801_isr,
>>  				       IRQF_SHARED,
> 
> The clean-up isn't massive but I agree the code is a bit more pleasant
> to read after the change, and I also see the binary size shrink a bit,
> so I vote for it.
> 
> Reviewed-by: Jean Delvare <jdelvare@suse.de>
> Tested-by: Jean Delvare <jdelvare@suse.de>
> 

Re: [PATCH 2/2] i2c: i801: Replace waitqueue with completion API

[Daniel Kurtz]

Hi Jean, Heiner,

On Tue, May 25, 2021 at 11:01 PM Heiner Kallweit <hkallweit1@gmail.com> wrote:
>
> On 25.05.2021 14:12, Jean Delvare wrote:
> > Hi Heiner,
> >
> > Adding Daniel Kurtz, who wrote the original wait queue-based code, to
> > Cc. I'm not sure if Daniel is still into kernel code though.

Thanks for thinking of me!  I'm still into kernel code, but I do a lot
more reading than writing these days.

> >
> > On Sat, 22 May 2021 00:02:43 +0200, Heiner Kallweit wrote:
> >> Using the completion API is more intuitive and it allows to simplify
> >> the code. Note that we don't have to set priv->status = 0 any longer
> >> with the completion API.
> >
> > OK, but you need to call reinit_completion() instead, which has the
> > same cost. So that's not a good argument ;-)
> >
> Maybe my comment wasn't clear enough. I didn't want to say that we
> save something but that it's safe from a functional point of view
> to remove clearing priv->status.
>
> >> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> >> ---
> >>  drivers/i2c/busses/i2c-i801.c | 48 ++++++++++++++---------------------
> >>  1 file changed, 19 insertions(+), 29 deletions(-)
> >>
> >> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
> >> index bfea94d02..738204d77 100644
> >> --- a/drivers/i2c/busses/i2c-i801.c
> >> +++ b/drivers/i2c/busses/i2c-i801.c
> >> @@ -103,7 +103,7 @@
> >>  #include <linux/dmi.h>
> >>  #include <linux/slab.h>
> >>  #include <linux/string.h>
> >> -#include <linux/wait.h>
> >> +#include <linux/completion.h>
> >>  #include <linux/err.h>
> >>  #include <linux/platform_device.h>
> >>  #include <linux/platform_data/itco_wdt.h>
> >> @@ -270,7 +270,7 @@ struct i801_priv {
> >>      unsigned int features;
> >>
> >>      /* isr processing */
> >> -    wait_queue_head_t waitq;
> >> +    struct completion done;
> >>      u8 status;
> >>
> >>      /* Command state used by isr for byte-by-byte block transactions */
> >> @@ -496,24 +496,19 @@ static int i801_wait_byte_done(struct i801_priv *priv)
> >>  static int i801_transaction(struct i801_priv *priv, int xact)
> >>  {
> >>      int status;
> >> -    int result;
> >> +    unsigned long result;
> >>      const struct i2c_adapter *adap = &priv->adapter;
> >>
> >> -    result = i801_check_pre(priv);
> >> -    if (result < 0)
> >> -            return result;
> >> +    status = i801_check_pre(priv);
> >> +    if (status < 0)
> >> +            return status;
> >>
> >>      if (priv->features & FEATURE_IRQ) {
> >> +            reinit_completion(&priv->done);
> >>              outb_p(xact | SMBHSTCNT_INTREN | SMBHSTCNT_START,
> >>                     SMBHSTCNT(priv));
> >> -            result = wait_event_timeout(priv->waitq,
> >> -                                        (status = priv->status),
> >> -                                        adap->timeout);
> >> -            if (!result)
> >> -                    status = -ETIMEDOUT;
> >> -
> >> -            priv->status = 0;
> >> -            return i801_check_post(priv, status);
> >> +            result = wait_for_completion_timeout(&priv->done, adap->timeout);
> >> +            return i801_check_post(priv, result ? priv->status : -ETIMEDOUT);
> >>      }
> >>
> >>      /* the current contents of SMBHSTCNT can be overwritten, since PEC,
> >> @@ -638,7 +633,7 @@ static irqreturn_t i801_host_notify_isr(struct i801_priv *priv)
> >>   *      DEV_ERR - Invalid command, NAK or communication timeout
> >>   *      BUS_ERR - SMI# transaction collision
> >>   *      FAILED - transaction was canceled due to a KILL request
> >> - *    When any of these occur, update ->status and wake up the waitq.
> >> + *    When any of these occur, update ->status and signal completion.
> >>   *    ->status must be cleared before kicking off the next transaction.
> >>   *
> >>   * 2) For byte-by-byte (I2C read/write) transactions, one BYTE_DONE interrupt
> >> @@ -675,7 +670,7 @@ static irqreturn_t i801_isr(int irq, void *dev_id)
> >>      if (status) {
> >>              outb_p(status, SMBHSTSTS(priv));
> >>              priv->status = status;
> >> -            wake_up(&priv->waitq);
> >> +            complete(&priv->done);
> >>      }
> >>
> >>      return IRQ_HANDLED;
> >> @@ -694,15 +689,15 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
> >>      int i, len;
> >>      int smbcmd;
> >>      int status;
> >> -    int result;
> >> +    unsigned long result;
> >>      const struct i2c_adapter *adap = &priv->adapter;
> >>
> >>      if (command == I2C_SMBUS_BLOCK_PROC_CALL)
> >>              return -EOPNOTSUPP;
> >>
> >> -    result = i801_check_pre(priv);
> >> -    if (result < 0)
> >> -            return result;
> >> +    status = i801_check_pre(priv);
> >> +    if (status < 0)
> >> +            return status;
> >>
> >>      len = data->block[0];
> >>
> >> @@ -726,15 +721,10 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
> >>              priv->count = 0;
> >>              priv->data = &data->block[1];
> >>
> >> +            reinit_completion(&priv->done);
> >>              outb_p(priv->cmd | SMBHSTCNT_START, SMBHSTCNT(priv));
> >> -            result = wait_event_timeout(priv->waitq,
> >> -                                        (status = priv->status),
> >> -                                        adap->timeout);
> >> -            if (!result)
> >> -                    status = -ETIMEDOUT;
> >> -
> >> -            priv->status = 0;
> >> -            return i801_check_post(priv, status);
> >> +            result = wait_for_completion_timeout(&priv->done, adap->timeout);
> >> +            return i801_check_post(priv, result ? priv->status : -ETIMEDOUT);
> >>      }
> >>
> >>      for (i = 1; i <= len; i++) {
> >> @@ -1889,7 +1879,7 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
> >>      }
> >>
> >>      if (priv->features & FEATURE_IRQ) {
> >> -            init_waitqueue_head(&priv->waitq);
> >> +            init_completion(&priv->done);
> >>
> >>              err = devm_request_irq(&dev->dev, dev->irq, i801_isr,
> >>                                     IRQF_SHARED,
> >
> > The clean-up isn't massive but I agree the code is a bit more pleasant
> > to read after the change, and I also see the binary size shrink a bit,
> > so I vote for it.
> >
> > Reviewed-by: Jean Delvare <jdelvare@suse.de>
> > Tested-by: Jean Delvare <jdelvare@suse.de>
> >
>

I agree, shorter and sweeter. Thanks for cleaning this up!

Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>

Re: [PATCH 1/2] i2c: i801: Remove unneeded warning after wait_event_timeout timeout

[Wolfram Sang]

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On Tue, May 25, 2021 at 12:00:12PM +0200, Jean Delvare wrote:
> On Sat, 22 May 2021 00:00:28 +0200, Heiner Kallweit wrote:
> > When passing -ETIMEDOUT to i801_check_post() it will emit a timeout
> > error message. I don't see much benefit in an additional warning
> > stating more or less the same.
> > 
> > Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>

Applied to for-next, thanks!


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Re: [PATCH 2/2] i2c: i801: Replace waitqueue with completion API

[Wolfram Sang]

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On Sat, May 22, 2021 at 12:02:43AM +0200, Heiner Kallweit wrote:
> Using the completion API is more intuitive and it allows to simplify
> the code. Note that we don't have to set priv->status = 0 any longer
> with the completion API.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>

Applied to for-next, thanks!


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