[alsa-devel] [PATCH 4/4] ASoC: clean up cache accesser

Dimitris Papastamos dp at opensource.wolfsonmicro.com
Mon Dec 20 18:09:00 CET 2010

On Mon, 2010-12-20 at 16:54 +0000, Mark Brown wrote:
> On Mon, Dec 20, 2010 at 05:47:13PM +0100, Takashi Iwai wrote:
> > Yes, this would be safer.  I didn't put it since I wasn't sure whether
> > BUG() content is also expanded at each caller.  If yes, it would
> > bloat.   (Alternatively we may use snd_BUG_ON() -- it's built in only
> > when CONFIG_SND_DEBUG is set.)
> That's entirely up to the compiler - inline is purely advice and may
> well be completely ignored by the compile (and of course functions that 
> aren't marked inline may be inlined if it decides that's useful).

One way to enforce the expansion of inline functions on gcc is to use
__attribute__ ((always_inline)).  Generally it is best left up to the
compiler to perform the inling if it so deems necessary.

> One reason for making it a BUG() is that if we get far enough for the
> check to go off when doing actual register lookups we've hit a definite
> bug in the code.

By performing the check at *_init, it will be impossible for the code to
ever reach any of the read()/write() functions if an unsupported word
size has been passed in.  The downside is that we depend on the
implementers of the *_init functions to perform this check.


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