[PATCH 2/3] dmaengine: pxa_dma: add function declaration

[PATCH 2/3] dmaengine: pxa_dma: add function declaration

[Baoyou Xie]

We get 1 warning when building kernel with W=1:
drivers/dma/pxa_dma.c:1525:5: warning: no previous prototype for 'pxad_toggle_reserved_channel' [-Wmissing-prototypes]

In fact, this function is undeclared in any header files.

So this patch adds function declaration in include/linux/dma/pxa-dma.h.

Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
---
 include/linux/dma/pxa-dma.h | 1 ++++++
 1 file changed, 1 insertions(+)

diff --git a/include/linux/dma/pxa-dma.h b/include/linux/dma/pxa-dma.h
index 3edc992..1823257 100644
--- a/include/linux/dma/pxa-dma.h
+++ b/include/linux/dma/pxa-dma.h
@@ -17,6 +17,7 @@ struct dma_chan;
 
 #ifdef CONFIG_PXA_DMA
 bool pxad_filter_fn(struct dma_chan *chan, void *param);
+int pxad_toggle_reserved_channel(int legacy_channel);
 #else
 static inline bool pxad_filter_fn(struct dma_chan *chan, void *param)
 {
-- 
2.7.4

Re: [PATCH 2/3] dmaengine: pxa_dma: add function declaration

[Arnd Bergmann]

On Saturday, September 24, 2016 12:58:39 PM CEST Baoyou Xie wrote:
> We get 1 warning when building kernel with W=1:
> drivers/dma/pxa_dma.c:1525:5: warning: no previous prototype for 'pxad_toggle_reserved_channel' [-Wmissing-prototypes]
> 
> In fact, this function is undeclared in any header files.
> 
> So this patch adds function declaration in include/linux/dma/pxa-dma.h.
> 
> Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
> 

No, this is wrong: the function was originally introduced as the
interface between  drivers/dma/pxa_dma.c and arch/arm/plat-pxa/dma.c,
but the latter file has been removed recently, along with the
declaration.

Please remove the function as well now.

In the future, when you find an exported function without a
declaration, don't assume that it should be declared, but instead
look up the git history of that identifier to see if the users
were all removed, or if it was perhaps never used.

	Arnd