[PATCH 0/2] fpga: use 'time_left' instead of 'timeout' with wait_for_*() functions

[PATCH 0/2] fpga: use 'time_left' instead of 'timeout' with wait_for_*() functions

[Wolfram Sang]

There is a confusing pattern in the kernel to use a variable named 'timeout' to
store the result of wait_for_*() functions causing patterns like:

        timeout = wait_for_completion_timeout(...)
        if (!timeout) return -ETIMEDOUT;

with all kinds of permutations. Use 'time_left' as a variable to make the code
obvious and self explaining.

This is part of a tree-wide series. The rest of the patches can be found here
(some parts may still be WIP):

git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git i2c/time_left

Because these patches are generated, I audit them before sending. This is why I
will send series step by step. Build bot is happy with these patches, though.
No functional changes intended.

Wolfram Sang (2):
  fpga: socfpga: use 'time_left' variable with
    wait_for_completion_interruptible_timeout()
  fpga: zynq-fpga: use 'time_left' variable with
    wait_for_completion_timeout()

 drivers/fpga/socfpga.c   | 7 ++++---
 drivers/fpga/zynq-fpga.c | 8 ++++----
 2 files changed, 8 insertions(+), 7 deletions(-)

-- 
2.43.0

[PATCH 1/2] fpga: socfpga: use 'time_left' variable with wait_for_completion_interruptible_timeout()

[Wolfram Sang]

There is a confusing pattern in the kernel to use a variable named 'timeout' to
store the result of wait_for_completion_interruptible_timeout() causing patterns like:

	timeout = wait_for_completion_interruptible_timeout(...)
	if (!timeout) return -ETIMEDOUT;

with all kinds of permutations. Use 'time_left' as a variable to make the code
self explaining.

Fix to the proper variable type 'long' while here.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 drivers/fpga/socfpga.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/fpga/socfpga.c b/drivers/fpga/socfpga.c
index 723ea0ad3f09..b08b4bb8f650 100644
--- a/drivers/fpga/socfpga.c
+++ b/drivers/fpga/socfpga.c
@@ -301,16 +301,17 @@ static irqreturn_t socfpga_fpga_isr(int irq, void *dev_id)
 
 static int socfpga_fpga_wait_for_config_done(struct socfpga_fpga_priv *priv)
 {
-	int timeout, ret = 0;
+	int ret = 0;
+	long time_left;
 
 	socfpga_fpga_disable_irqs(priv);
 	init_completion(&priv->status_complete);
 	socfpga_fpga_enable_irqs(priv, SOCFPGA_FPGMGR_MON_CONF_DONE);
 
-	timeout = wait_for_completion_interruptible_timeout(
+	time_left = wait_for_completion_interruptible_timeout(
 						&priv->status_complete,
 						msecs_to_jiffies(10));
-	if (timeout == 0)
+	if (time_left == 0)
 		ret = -ETIMEDOUT;
 
 	socfpga_fpga_disable_irqs(priv);
-- 
2.43.0

Re: [PATCH 1/2] fpga: socfpga: use 'time_left' variable with wait_for_completion_interruptible_timeout()

[Xu Yilun]

On Thu, May 02, 2024 at 11:00:36PM +0200, Wolfram Sang wrote:
Sorry for late reply.

First of all, please limit your subject/shortlog/summary within 70
chars.

> There is a confusing pattern in the kernel to use a variable named 'timeout' to

Please make the changelog line wrapped at less than 75 chars.

> store the result of wait_for_completion_interruptible_timeout() causing patterns like:
> 
> 	timeout = wait_for_completion_interruptible_timeout(...)
> 	if (!timeout) return -ETIMEDOUT;
> 
> with all kinds of permutations. Use 'time_left' as a variable to make the code
> self explaining.
> 
> Fix to the proper variable type 'long' while here.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>  drivers/fpga/socfpga.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/fpga/socfpga.c b/drivers/fpga/socfpga.c
> index 723ea0ad3f09..b08b4bb8f650 100644
> --- a/drivers/fpga/socfpga.c
> +++ b/drivers/fpga/socfpga.c
> @@ -301,16 +301,17 @@ static irqreturn_t socfpga_fpga_isr(int irq, void *dev_id)
>  
>  static int socfpga_fpga_wait_for_config_done(struct socfpga_fpga_priv *priv)
>  {
> -	int timeout, ret = 0;
> +	int ret = 0;
> +	long time_left;

Please use reverse xmas tree when it is easy to follow.

The code change is good to me.

Thanks,
Yilun

>  
>  	socfpga_fpga_disable_irqs(priv);
>  	init_completion(&priv->status_complete);
>  	socfpga_fpga_enable_irqs(priv, SOCFPGA_FPGMGR_MON_CONF_DONE);
>  
> -	timeout = wait_for_completion_interruptible_timeout(
> +	time_left = wait_for_completion_interruptible_timeout(
>  						&priv->status_complete,
>  						msecs_to_jiffies(10));
> -	if (timeout == 0)
> +	if (time_left == 0)
>  		ret = -ETIMEDOUT;
>  
>  	socfpga_fpga_disable_irqs(priv);
> -- 
> 2.43.0
> 
> 

Re: [PATCH 1/2] fpga: socfpga: use 'time_left' variable with wait_for_completion_interruptible_timeout()

[Wolfram Sang]

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Hi Yilun,

> Sorry for late reply.

No worries, thank you for the review.

> First of all, please limit your subject/shortlog/summary within 70
> chars.

I'll try but it will be hard when it contains such a long function name.

> > There is a confusing pattern in the kernel to use a variable named 'timeout' to
> 
> Please make the changelog line wrapped at less than 75 chars.

Good point. My scripts reformat generated paragraphs now accordingly.

> > +	int ret = 0;
> > +	long time_left;
> 
> Please use reverse xmas tree when it is easy to follow.

Will fix.

All the best,

   Wolfram


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Re: [PATCH 1/2] fpga: socfpga: use 'time_left' variable with wait_for_completion_interruptible_timeout()

[Xu Yilun]

On Thu, Jun 20, 2024 at 12:21:10PM +0200, Wolfram Sang wrote:
> Hi Yilun,
> 
> > Sorry for late reply.
> 
> No worries, thank you for the review.
> 
> > First of all, please limit your subject/shortlog/summary within 70
> > chars.
> 
> I'll try but it will be hard when it contains such a long function name.

You don't have to include the funtion name. The code change itself
explains.

Thanks,
Yilun

> 
> > > There is a confusing pattern in the kernel to use a variable named 'timeout' to
> > 
> > Please make the changelog line wrapped at less than 75 chars.
> 
> Good point. My scripts reformat generated paragraphs now accordingly.
> 
> > > +	int ret = 0;
> > > +	long time_left;
> > 
> > Please use reverse xmas tree when it is easy to follow.
> 
> Will fix.
> 
> All the best,
> 
>    Wolfram
> 

[PATCH 2/2] fpga: zynq-fpga: use 'time_left' variable with wait_for_completion_timeout()

[Wolfram Sang]

There is a confusing pattern in the kernel to use a variable named 'timeout' to
store the result of wait_for_completion_timeout() causing patterns like:

	timeout = wait_for_completion_timeout(...)
	if (!timeout) return -ETIMEDOUT;

with all kinds of permutations. Use 'time_left' as a variable to make the code
self explaining.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 drivers/fpga/zynq-fpga.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/fpga/zynq-fpga.c b/drivers/fpga/zynq-fpga.c
index 0ac93183d201..4db3d80e10b0 100644
--- a/drivers/fpga/zynq-fpga.c
+++ b/drivers/fpga/zynq-fpga.c
@@ -387,7 +387,7 @@ static int zynq_fpga_ops_write(struct fpga_manager *mgr, struct sg_table *sgt)
 	const char *why;
 	int err;
 	u32 intr_status;
-	unsigned long timeout;
+	unsigned long time_left;
 	unsigned long flags;
 	struct scatterlist *sg;
 	int i;
@@ -427,8 +427,8 @@ static int zynq_fpga_ops_write(struct fpga_manager *mgr, struct sg_table *sgt)
 	zynq_step_dma(priv);
 	spin_unlock_irqrestore(&priv->dma_lock, flags);
 
-	timeout = wait_for_completion_timeout(&priv->dma_done,
-					      msecs_to_jiffies(DMA_TIMEOUT_MS));
+	time_left = wait_for_completion_timeout(&priv->dma_done,
+						msecs_to_jiffies(DMA_TIMEOUT_MS));
 
 	spin_lock_irqsave(&priv->dma_lock, flags);
 	zynq_fpga_set_irq(priv, 0);
@@ -452,7 +452,7 @@ static int zynq_fpga_ops_write(struct fpga_manager *mgr, struct sg_table *sgt)
 
 	if (priv->cur_sg ||
 	    !((intr_status & IXR_D_P_DONE_MASK) == IXR_D_P_DONE_MASK)) {
-		if (timeout == 0)
+		if (time_left == 0)
 			why = "DMA timed out";
 		else
 			why = "DMA did not complete";
-- 
2.43.0

Re: [PATCH 2/2] fpga: zynq-fpga: use 'time_left' variable with wait_for_completion_timeout()

[Michal Simek]

On 5/2/24 23:00, Wolfram Sang wrote:
> There is a confusing pattern in the kernel to use a variable named 'timeout' to
> store the result of wait_for_completion_timeout() causing patterns like:
> 
> 	timeout = wait_for_completion_timeout(...)
> 	if (!timeout) return -ETIMEDOUT;
> 
> with all kinds of permutations. Use 'time_left' as a variable to make the code
> self explaining.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>   drivers/fpga/zynq-fpga.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/fpga/zynq-fpga.c b/drivers/fpga/zynq-fpga.c
> index 0ac93183d201..4db3d80e10b0 100644
> --- a/drivers/fpga/zynq-fpga.c
> +++ b/drivers/fpga/zynq-fpga.c
> @@ -387,7 +387,7 @@ static int zynq_fpga_ops_write(struct fpga_manager *mgr, struct sg_table *sgt)
>   	const char *why;
>   	int err;
>   	u32 intr_status;
> -	unsigned long timeout;
> +	unsigned long time_left;
>   	unsigned long flags;
>   	struct scatterlist *sg;
>   	int i;
> @@ -427,8 +427,8 @@ static int zynq_fpga_ops_write(struct fpga_manager *mgr, struct sg_table *sgt)
>   	zynq_step_dma(priv);
>   	spin_unlock_irqrestore(&priv->dma_lock, flags);
>   
> -	timeout = wait_for_completion_timeout(&priv->dma_done,
> -					      msecs_to_jiffies(DMA_TIMEOUT_MS));
> +	time_left = wait_for_completion_timeout(&priv->dma_done,
> +						msecs_to_jiffies(DMA_TIMEOUT_MS));
>   
>   	spin_lock_irqsave(&priv->dma_lock, flags);
>   	zynq_fpga_set_irq(priv, 0);
> @@ -452,7 +452,7 @@ static int zynq_fpga_ops_write(struct fpga_manager *mgr, struct sg_table *sgt)
>   
>   	if (priv->cur_sg ||
>   	    !((intr_status & IXR_D_P_DONE_MASK) == IXR_D_P_DONE_MASK)) {
> -		if (timeout == 0)
> +		if (time_left == 0)
>   			why = "DMA timed out";
>   		else
>   			why = "DMA did not complete";

Acked-by: Michal Simek <michal.simek@amd.com>

Thanks,
Michal