* [PATCH] Fix missing 'cnt' in ?: in dmatest
@ 2011-08-21 0:50 Dr. David Alan Gilbert
2011-08-21 1:12 ` Al Viro
0 siblings, 1 reply; 3+ messages in thread
From: Dr. David Alan Gilbert @ 2011-08-21 0:50 UTC (permalink / raw)
To: linux-kernel; +Cc: nicolas.ferre, dan.j.williams, akpm
Hi,
On the latest tree my compiler has started giving the warning:
drivers/dma/dmatest.c:575:28: warning: the omitted middle operand in ?: will always be ?true?, suggest explicit middle operand [-Wparentheses]
The following patch fixes the missing middle clause with the same
fix that Nicolas Ferre used in the similar clauses.
(There seems to have been a race between him fixing that and
the extra clause going in a little later).
I don't actually know the dmatest code/structures, nor do I own
any hardware to test it on (assuming it needs a DMA engine);
but this patch builds, the existing code is almost certainly
wrong and the fix is the same as the corresponding lines above it.
(WTH is x=y?:z legal C anyway?)
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
---
diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c
index 765f5ff..1b0ec9d 100644
--- a/drivers/dma/dmatest.c
+++ b/drivers/dma/dmatest.c
@@ -572,7 +572,7 @@ static int dmatest_add_channel(struct dma_chan *chan)
}
if (dma_has_cap(DMA_PQ, dma_dev->cap_mask)) {
cnt = dmatest_add_threads(dtc, DMA_PQ);
- thread_count += cnt > 0 ?: 0;
+ thread_count += cnt > 0 ? cnt : 0;
}
pr_info("dmatest: Started %u threads using %s\n",
--
-----Open up your eyes, open up your mind, open up your code -------
/ Dr. David Alan Gilbert | Running GNU/Linux | Happy \
\ gro.gilbert @ treblig.org | | In Hex /
\ _________________________|_____ http://www.treblig.org |_______/
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] Fix missing 'cnt' in ?: in dmatest
2011-08-21 0:50 [PATCH] Fix missing 'cnt' in ?: in dmatest Dr. David Alan Gilbert
@ 2011-08-21 1:12 ` Al Viro
2011-08-25 22:55 ` Dan Williams
0 siblings, 1 reply; 3+ messages in thread
From: Al Viro @ 2011-08-21 1:12 UTC (permalink / raw)
To: Dr. David Alan Gilbert; +Cc: linux-kernel, nicolas.ferre, dan.j.williams, akpm
On Sun, Aug 21, 2011 at 01:50:31AM +0100, Dr. David Alan Gilbert wrote:
> (WTH is x=y?:z legal C anyway?)
gccism. It's not legal C; it's a gcc extension, and not a pretty one at
that. It's almost definitely a bug in this case - what used to be in the
tree is equivalent to cnt > 0 ? cnt > 0 : 0, i.e. cnt > 0 ? 1 : 0, i.e.
cnt > 0. AFAICS, after your patch it does make sense.
> Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
>
> ---
> diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c
> index 765f5ff..1b0ec9d 100644
> --- a/drivers/dma/dmatest.c
> +++ b/drivers/dma/dmatest.c
> @@ -572,7 +572,7 @@ static int dmatest_add_channel(struct dma_chan *chan)
> }
> if (dma_has_cap(DMA_PQ, dma_dev->cap_mask)) {
> cnt = dmatest_add_threads(dtc, DMA_PQ);
> - thread_count += cnt > 0 ?: 0;
> + thread_count += cnt > 0 ? cnt : 0;
> }
>
> pr_info("dmatest: Started %u threads using %s\n",
>
> --
> -----Open up your eyes, open up your mind, open up your code -------
> / Dr. David Alan Gilbert | Running GNU/Linux | Happy \
> \ gro.gilbert @ treblig.org | | In Hex /
> \ _________________________|_____ http://www.treblig.org |_______/
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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> Please read the FAQ at http://www.tux.org/lkml/
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Fix missing 'cnt' in ?: in dmatest
2011-08-21 1:12 ` Al Viro
@ 2011-08-25 22:55 ` Dan Williams
0 siblings, 0 replies; 3+ messages in thread
From: Dan Williams @ 2011-08-25 22:55 UTC (permalink / raw)
To: Al Viro; +Cc: Dr. David Alan Gilbert, linux-kernel, nicolas.ferre, akpm
On Sat, Aug 20, 2011 at 6:12 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
> On Sun, Aug 21, 2011 at 01:50:31AM +0100, Dr. David Alan Gilbert wrote:
>
>> (WTH is x=y?:z legal C anyway?)
>
> gccism. It's not legal C; it's a gcc extension, and not a pretty one at
> that. It's almost definitely a bug in this case - what used to be in the
> tree is equivalent to cnt > 0 ? cnt > 0 : 0, i.e. cnt > 0 ? 1 : 0, i.e.
> cnt > 0. AFAICS, after your patch it does make sense.
>
>> Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Thanks, I'll take this through the async_tx.git tree.
--
Dan
^ permalink raw reply [flat|nested] 3+ messages in thread
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2011-08-21 0:50 [PATCH] Fix missing 'cnt' in ?: in dmatest Dr. David Alan Gilbert
2011-08-21 1:12 ` Al Viro
2011-08-25 22:55 ` Dan Williams
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