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Subject: Re: [PATCH] net/8021q/vlan_dev.c - Use print_mac
From: Joe Perches <joe@perches.com>
To: David Miller <davem@davemloft.net>
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Date: Mon, 18 Feb 2008 17:03:32 -0800
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On Mon, 2008-02-18 at 16:50 -0800, David Miller wrote:
> Actually it seems the 'pure' attribute is more important
> here.  Although it's not semantically a perfect match,
> what we need to tell the compiler is basically that:
> 
> 1) the return value depends upon the inputs
> 2) if the input is not used, it's safe to avoid the call
> 
> and 'pure' accomplishes that without any unwanted side-effects.
> 
> I think this will not result in any unwanted over-optimization.
> Because if the inputs change in any way GCC has to emit the
> call.
> 
> Any objections?

Does this need to be done for all function calls
declared with __attribute__((format(printf, x, y)))
{
return 0;
}

ie: pr_debug, dev_dbg, dev_vdbg?

Perhaps it's more sensible to go back to

#ifdef DEBUG
#define pr_debug(fmt, arg...) do {} while (0)
#endif

and give up the printf argument verification