Re: Any idea why gcc "discards qualifiers from pointer target type"?

[Matthew Wilcox <matthew@wil.cx>]

On Tue, Jan 15, 2008 at 11:29:37AM +0100, rubisher wrote:
> Hello Dave,
> 
> Compiling p-l with gcc-4.2 I see new warning "discards qualifiers from pointer
> target type":

Joel, this is a standard C question ... this list really isn't for
teaching people how to program.

> /SRCTREE/drivers/net/lib82596.c:388: warning: passing argument 2 of
> 'dma_cache_sync' discards qualifiers from pointer target type

You're passing a volatile pointer to a function which is expecting a
non-volatile pointer.  That's potentially dangerous, so gcc warns about
it.

The normal way to fix this would be to add a volatile attribute to the
argument in question:

dma_cache_sync(struct device *dev, volatile void *vaddr, size_t size,
               enum dma_data_direction direction)

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