Ilpo Järvinen wrote:

On Thu, 16 Aug 2007, Herbert Xu wrote:

quoted

We've been through that already.  If it's a busy-wait it
should use cpu_relax. 

I looked around a bit by using some command lines and ended up wondering 
if these are equal to busy-wait case (and should be fixed) or not:

./drivers/telephony/ixj.c
6674:   while (atomic_read(&j->DSPWrite) > 0)
6675-           atomic_dec(&j->DSPWrite);

...besides that, there are couple of more similar cases in the same file 
(with braces)...

atomic_dec() already has volatile behavior everywhere, so this is 
semantically okay, but this code (and any like it) should be calling 
cpu_relax() each iteration through the loop, unless there's a compelling 
reason not to.  I'll allow that for some hardware drivers (possibly this 
one) such a compelling reason may exist, but hardware-independent core 
subsystems probably have no excuse.

If the maintainer of this code doesn't see a compelling reason not to 
add cpu_relax() in this loop, then it should be patched.

	-- Chris