* [PATCH] spi: limit reaches -1, tested 0
@ 2009-02-08 14:18 Roel Kluin
2009-02-08 15:55 ` David Brownell
0 siblings, 1 reply; 7+ messages in thread
From: Roel Kluin @ 2009-02-08 14:18 UTC (permalink / raw)
To: dbrownell; +Cc: spi-devel-general, lkml
With a postfix decrement limit will reach -1 rather than 0,
so the warning will not be issued.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
diff --git a/drivers/spi/spi_imx.c b/drivers/spi/spi_imx.c
index 269a55e..a4652f1 100644
--- a/drivers/spi/spi_imx.c
+++ b/drivers/spi/spi_imx.c
@@ -779,7 +779,7 @@ static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
/* Read trailing bytes */
limit = loops_per_jiffy << 1;
- while ((read(drv_data) == 0) && limit--);
+ while ((read(drv_data) == 0) && --limit);
if (limit == 0)
dev_err(&drv_data->pdev->dev,
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] spi: limit reaches -1, tested 0
2009-02-08 14:18 [PATCH] spi: limit reaches -1, tested 0 Roel Kluin
@ 2009-02-08 15:55 ` David Brownell
2009-02-08 16:28 ` David Brownell
0 siblings, 1 reply; 7+ messages in thread
From: David Brownell @ 2009-02-08 15:55 UTC (permalink / raw)
To: Roel Kluin; +Cc: spi-devel-general, lkml, Andrew Morton
On Sunday 08 February 2009, Roel Kluin wrote:
> With a postfix decrement limit will reach -1 rather than 0,
> so the warning will not be issued.
>
> Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
> ---
> diff --git a/drivers/spi/spi_imx.c b/drivers/spi/spi_imx.c
> index 269a55e..a4652f1 100644
> --- a/drivers/spi/spi_imx.c
> +++ b/drivers/spi/spi_imx.c
> @@ -779,7 +779,7 @@ static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
>
> /* Read trailing bytes */
> limit = loops_per_jiffy << 1;
> - while ((read(drv_data) == 0) && limit--);
> + while ((read(drv_data) == 0) && --limit);
>
> if (limit == 0)
> dev_err(&drv_data->pdev->dev,
>
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] spi: limit reaches -1, tested 0
2009-02-08 15:55 ` David Brownell
@ 2009-02-08 16:28 ` David Brownell
2009-02-08 16:50 ` Roel Kluin
0 siblings, 1 reply; 7+ messages in thread
From: David Brownell @ 2009-02-08 16:28 UTC (permalink / raw)
To: Roel Kluin; +Cc: spi-devel-general, lkml, Andrew Morton
On Sunday 08 February 2009, David Brownell wrote:
> On Sunday 08 February 2009, Roel Kluin wrote:
> > With a postfix decrement limit will reach -1 rather than 0,
> > so the warning will not be issued.
> >
> > Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
>
> Acked-by: David Brownell <dbrownell@users.sourceforge.net>
>
>
>
> > ---
> > diff --git a/drivers/spi/spi_imx.c b/drivers/spi/spi_imx.c
> > index 269a55e..a4652f1 100644
> > --- a/drivers/spi/spi_imx.c
> > +++ b/drivers/spi/spi_imx.c
> > @@ -779,7 +779,7 @@ static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
> >
> > /* Read trailing bytes */
> > limit = loops_per_jiffy << 1;
> > - while ((read(drv_data) == 0) && limit--);
> > + while ((read(drv_data) == 0) && --limit);
... although I wouldn't have resisted the urge to make the
loop body be "cpu_relax();" instead of an empty statement.
> >
> > if (limit == 0)
> > dev_err(&drv_data->pdev->dev,
> >
> >
>
>
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] spi: limit reaches -1, tested 0
2009-02-08 16:28 ` David Brownell
@ 2009-02-08 16:50 ` Roel Kluin
2009-02-08 17:26 ` David Brownell
2009-02-08 17:42 ` Mariusz Ceier
0 siblings, 2 replies; 7+ messages in thread
From: Roel Kluin @ 2009-02-08 16:50 UTC (permalink / raw)
To: David Brownell; +Cc: spi-devel-general, lkml, Andrew Morton
>>> - while ((read(drv_data) == 0) && limit--);
>>> + while ((read(drv_data) == 0) && --limit);
>
> ... although I wouldn't have resisted the urge to make the
> loop body be "cpu_relax();" instead of an empty statement.
Ok,
---------------------------->8-------------------8<-----------------------------
With a postfix decrement limit will reach -1 rather than 0, so the warning will
not be issued.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
diff --git a/drivers/spi/spi_imx.c b/drivers/spi/spi_imx.c
index 269a55e..15abe61 100644
--- a/drivers/spi/spi_imx.c
+++ b/drivers/spi/spi_imx.c
@@ -779,7 +779,8 @@ static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
/* Read trailing bytes */
limit = loops_per_jiffy << 1;
- while ((read(drv_data) == 0) && limit--);
+ while ((read(drv_data) == 0) && limit--)
+ cpu_relax();
if (limit == 0)
dev_err(&drv_data->pdev->dev,
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] spi: limit reaches -1, tested 0
2009-02-08 16:50 ` Roel Kluin
@ 2009-02-08 17:26 ` David Brownell
2009-02-08 17:42 ` Mariusz Ceier
1 sibling, 0 replies; 7+ messages in thread
From: David Brownell @ 2009-02-08 17:26 UTC (permalink / raw)
To: Roel Kluin; +Cc: spi-devel-general, lkml, Andrew Morton
On Sunday 08 February 2009, Roel Kluin wrote:
> >>> - while ((read(drv_data) == 0) && limit--);
> >>> + while ((read(drv_data) == 0) && --limit);
> >
> > ... although I wouldn't have resisted the urge to make the
> > loop body be "cpu_relax();" instead of an empty statement.
>
> Ok,
> ---------------------------->8-------------------8<-----------------------------
> With a postfix decrement limit will reach -1 rather than 0, so the warning will
> not be issued.
>
> Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Still:
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
> ---
> diff --git a/drivers/spi/spi_imx.c b/drivers/spi/spi_imx.c
> index 269a55e..15abe61 100644
> --- a/drivers/spi/spi_imx.c
> +++ b/drivers/spi/spi_imx.c
> @@ -779,7 +779,8 @@ static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
>
> /* Read trailing bytes */
> limit = loops_per_jiffy << 1;
> - while ((read(drv_data) == 0) && limit--);
> + while ((read(drv_data) == 0) && limit--)
> + cpu_relax();
>
> if (limit == 0)
> dev_err(&drv_data->pdev->dev,
>
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] spi: limit reaches -1, tested 0
2009-02-08 16:50 ` Roel Kluin
2009-02-08 17:26 ` David Brownell
@ 2009-02-08 17:42 ` Mariusz Ceier
2009-02-08 17:46 ` Roel Kluin
1 sibling, 1 reply; 7+ messages in thread
From: Mariusz Ceier @ 2009-02-08 17:42 UTC (permalink / raw)
To: Roel Kluin; +Cc: David Brownell, spi-devel-general, lkml, Andrew Morton
Roel Kluin writes in first post:
> - while ((read(drv_data) == 0) && limit--);
> + while ((read(drv_data) == 0) && --limit);
Roel Kluin writes in last post:
> - while ((read(drv_data) == 0) && limit--);
> + while ((read(drv_data) == 0) && limit--)
> + cpu_relax();
so should there be postfix or prefix decrement ? :)
Mariusz Ceier
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] spi: limit reaches -1, tested 0
2009-02-08 17:42 ` Mariusz Ceier
@ 2009-02-08 17:46 ` Roel Kluin
0 siblings, 0 replies; 7+ messages in thread
From: Roel Kluin @ 2009-02-08 17:46 UTC (permalink / raw)
To: Mariusz Ceier; +Cc: David Brownell, spi-devel-general, lkml, Andrew Morton
Mariusz Ceier wrote:
> Roel Kluin writes in first post:
>> - while ((read(drv_data) == 0) && limit--);
>> + while ((read(drv_data) == 0) && --limit);
>
> Roel Kluin writes in last post:
>> - while ((read(drv_data) == 0) && limit--);
>> + while ((read(drv_data) == 0) && limit--)
>> + cpu_relax();
>
> so should there be postfix or prefix decrement ? :)
Thanks for spotting, I took the liberty to add David Brownell's Acked-by
in this case.
----------------------->8------------------8<---------------------------
With a postfix decrement limit will reach -1 rather than 0,
so the warning will not be issued.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
---
diff --git a/drivers/spi/spi_imx.c b/drivers/spi/spi_imx.c
index 269a55e..b143e8c 100644
--- a/drivers/spi/spi_imx.c
+++ b/drivers/spi/spi_imx.c
@@ -779,7 +779,8 @@ static irqreturn_t interrupt_transfer(struct driver_data *drv_data)
/* Read trailing bytes */
limit = loops_per_jiffy << 1;
- while ((read(drv_data) == 0) && limit--);
+ while ((read(drv_data) == 0) && --limit)
+ cpu_relax();
if (limit == 0)
dev_err(&drv_data->pdev->dev,
^ permalink raw reply related [flat|nested] 7+ messages in thread
end of thread, other threads:[~2009-02-08 17:46 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
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2009-02-08 14:18 [PATCH] spi: limit reaches -1, tested 0 Roel Kluin
2009-02-08 15:55 ` David Brownell
2009-02-08 16:28 ` David Brownell
2009-02-08 16:50 ` Roel Kluin
2009-02-08 17:26 ` David Brownell
2009-02-08 17:42 ` Mariusz Ceier
2009-02-08 17:46 ` Roel Kluin
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