* [PATCH] spi: atmel: Fix test unsigned var < 0
@ 2014-03-22 14:33 Axel Lin
2014-03-26 16:51 ` Mark Brown
0 siblings, 1 reply; 5+ messages in thread
From: Axel Lin @ 2014-03-22 14:33 UTC (permalink / raw)
To: Mark Brown; +Cc: Wenyou Yang, linux-spi-u79uwXL29TY76Z2rM5mHXA
current_remaining_bytes is an unsigned long and cannot be below 0.
Signed-off-by: Axel Lin <axel.lin-8E1dMatC8ynQT0dZR+AlfA@public.gmane.org>
---
drivers/spi/spi-atmel.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index bda961e..3e8c4cc 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -873,13 +873,11 @@ atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer)
} else {
spi_readl(as, RDR);
}
- if (xfer->bits_per_word > 8) {
+
+ if (xfer->bits_per_word > 8)
as->current_remaining_bytes -= 2;
- if (as->current_remaining_bytes < 0)
- as->current_remaining_bytes = 0;
- } else {
+ else
as->current_remaining_bytes--;
- }
}
/* Interrupt
--
1.8.3.2
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^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] spi: atmel: Fix test unsigned var < 0
2014-03-22 14:33 [PATCH] spi: atmel: Fix test unsigned var < 0 Axel Lin
@ 2014-03-26 16:51 ` Mark Brown
[not found] ` <20140326165145.GD14287-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
0 siblings, 1 reply; 5+ messages in thread
From: Mark Brown @ 2014-03-26 16:51 UTC (permalink / raw)
To: Axel Lin; +Cc: Wenyou Yang, linux-spi-u79uwXL29TY76Z2rM5mHXA
[-- Attachment #1: Type: text/plain, Size: 712 bytes --]
On Sat, Mar 22, 2014 at 10:33:29PM +0800, Axel Lin wrote:
> current_remaining_bytes is an unsigned long and cannot be below 0.
> - if (xfer->bits_per_word > 8) {
> +
> + if (xfer->bits_per_word > 8)
> as->current_remaining_bytes -= 2;
> - if (as->current_remaining_bytes < 0)
> - as->current_remaining_bytes = 0;
> - } else {
> + else
> as->current_remaining_bytes--;
> - }
This removes an error check in the case that we set the remaining bytes
to -1. The length validation the core does should ensure that never
happens but it seems wrong to just ignore that - we should at least note
in the changelog that the analysis has been done.
Are you sure that the best fix isn't to just use an int here?
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] spi: atmel: Fix test unsigned var < 0
[not found] ` <20140326165145.GD14287-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
@ 2014-03-27 0:46 ` Axel Lin
[not found] ` <CAFRkauBh+4-NmneTh=io7grG4MpSZ98riybAOOpEff+KiPZUjg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
0 siblings, 1 reply; 5+ messages in thread
From: Axel Lin @ 2014-03-27 0:46 UTC (permalink / raw)
To: Mark Brown; +Cc: Wenyou Yang, linux-spi
2014-03-27 0:51 GMT+08:00 Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>:
> On Sat, Mar 22, 2014 at 10:33:29PM +0800, Axel Lin wrote:
>> current_remaining_bytes is an unsigned long and cannot be below 0.
>
>> - if (xfer->bits_per_word > 8) {
>> +
>> + if (xfer->bits_per_word > 8)
>> as->current_remaining_bytes -= 2;
>> - if (as->current_remaining_bytes < 0)
>> - as->current_remaining_bytes = 0;
>> - } else {
>> + else
>> as->current_remaining_bytes--;
>> - }
>
> This removes an error check in the case that we set the remaining bytes
> to -1. The length validation the core does should ensure that never
> happens but it seems wrong to just ignore that - we should at least note
> in the changelog that the analysis has been done.
I thought it never happen and there is no bug report for this so it's
safe with this patch.
>
> Are you sure that the best fix isn't to just use an int here?
Wenyou,
Any comments for this?
Regards,
Axel
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^ permalink raw reply [flat|nested] 5+ messages in thread
* RE: [PATCH] spi: atmel: Fix test unsigned var < 0
[not found] ` <CAFRkauBh+4-NmneTh=io7grG4MpSZ98riybAOOpEff+KiPZUjg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
@ 2014-03-27 1:13 ` Yang, Wenyou
2014-03-27 1:23 ` Axel Lin
0 siblings, 1 reply; 5+ messages in thread
From: Yang, Wenyou @ 2014-03-27 1:13 UTC (permalink / raw)
To: Axel Lin, Mark Brown; +Cc: linux-spi
> -----Original Message-----
> From: Axel Lin [mailto:axel.lin-8E1dMatC8ynQT0dZR+AlfA@public.gmane.org]
> Sent: Thursday, March 27, 2014 8:46 AM
> To: Mark Brown
> Cc: Yang, Wenyou; linux-spi
> Subject: Re: [PATCH] spi: atmel: Fix test unsigned var < 0
>
> 2014-03-27 0:51 GMT+08:00 Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>:
> > On Sat, Mar 22, 2014 at 10:33:29PM +0800, Axel Lin wrote:
> >> current_remaining_bytes is an unsigned long and cannot be below 0.
> >
> >> - if (xfer->bits_per_word > 8) {
> >> +
> >> + if (xfer->bits_per_word > 8)
> >> as->current_remaining_bytes -= 2;
> >> - if (as->current_remaining_bytes < 0)
> >> - as->current_remaining_bytes = 0;
> >> - } else {
> >> + else
> >> as->current_remaining_bytes--;
> >> - }
> >
> > This removes an error check in the case that we set the remaining
> > bytes to -1. The length validation the core does should ensure that
> > never happens but it seems wrong to just ignore that - we should at
> > least note in the changelog that the analysis has been done.
> I thought it never happen and there is no bug report for this so it's
> safe with this patch.
>
> >
> > Are you sure that the best fix isn't to just use an int here?
> Wenyou,
> Any comments for this?
Like Mark said, It seems it is more reasonable using a signed int, instead of unsigned int.
-->8 ---
diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 8005f98..485e6cc 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -224,7 +224,7 @@ struct atmel_spi {
struct platform_device *pdev;
struct spi_transfer *current_transfer;
- unsigned long current_remaining_bytes;
+ int current_remaining_bytes;
int done_status;
struct completion xfer_completion;
@@ -1110,6 +1110,8 @@ static int atmel_spi_one_transfer(struct spi_master *master,
atmel_spi_next_xfer_pio(master, xfer);
} else {
as->current_remaining_bytes -= len;
+ if (as->current_remaining_bytes < 0)
+ as->current_remaining_bytes = 0;
}
} else {
atmel_spi_next_xfer_pio(master, xfer);
--<8 ---
Best Regards,
Wenyou Yang
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^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] spi: atmel: Fix test unsigned var < 0
2014-03-27 1:13 ` Yang, Wenyou
@ 2014-03-27 1:23 ` Axel Lin
0 siblings, 0 replies; 5+ messages in thread
From: Axel Lin @ 2014-03-27 1:23 UTC (permalink / raw)
To: Yang, Wenyou; +Cc: Mark Brown, linux-spi
2014-03-27 9:13 GMT+08:00 Yang, Wenyou <Wenyou.Yang-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org>:
>
>> -----Original Message-----
>> From: Axel Lin [mailto:axel.lin-8E1dMatC8ynQT0dZR+AlfA@public.gmane.org]
>> Sent: Thursday, March 27, 2014 8:46 AM
>> To: Mark Brown
>> Cc: Yang, Wenyou; linux-spi
>> Subject: Re: [PATCH] spi: atmel: Fix test unsigned var < 0
>>
>> 2014-03-27 0:51 GMT+08:00 Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>:
>> > On Sat, Mar 22, 2014 at 10:33:29PM +0800, Axel Lin wrote:
>> >> current_remaining_bytes is an unsigned long and cannot be below 0.
>> >
>> >> - if (xfer->bits_per_word > 8) {
>> >> +
>> >> + if (xfer->bits_per_word > 8)
>> >> as->current_remaining_bytes -= 2;
>> >> - if (as->current_remaining_bytes < 0)
>> >> - as->current_remaining_bytes = 0;
>> >> - } else {
>> >> + else
>> >> as->current_remaining_bytes--;
>> >> - }
>> >
>> > This removes an error check in the case that we set the remaining
>> > bytes to -1. The length validation the core does should ensure that
>> > never happens but it seems wrong to just ignore that - we should at
>> > least note in the changelog that the analysis has been done.
>> I thought it never happen and there is no bug report for this so it's
>> safe with this patch.
>>
>> >
>> > Are you sure that the best fix isn't to just use an int here?
>> Wenyou,
>> Any comments for this?
>
> Like Mark said, It seems it is more reasonable using a signed int, instead of unsigned int.
OK. I'm sending a formal patch with your Signed-off-by now.
Regards,
Axel
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^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2014-03-27 1:23 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2014-03-22 14:33 [PATCH] spi: atmel: Fix test unsigned var < 0 Axel Lin
2014-03-26 16:51 ` Mark Brown
[not found] ` <20140326165145.GD14287-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
2014-03-27 0:46 ` Axel Lin
[not found] ` <CAFRkauBh+4-NmneTh=io7grG4MpSZ98riybAOOpEff+KiPZUjg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-03-27 1:13 ` Yang, Wenyou
2014-03-27 1:23 ` Axel Lin
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