On Mon, Nov 26, 2012 at 05:46:48PM +0000, Chris Wilson wrote: > On Mon, 26 Nov 2012 19:40:16 +0200, Ville Syrj?l? <ville.syrjala at linux.intel.com> wrote: > > On Mon, Nov 26, 2012 at 04:25:47PM +0000, Chris Wilson wrote: > > > On Mon, 26 Nov 2012 14:48:19 +0200, ville.syrjala at linux.intel.com wrote: > > > > From: Ville Syrj?l? <ville.syrjala at linux.intel.com> > > > > > > > > Ringbuffer tail pointer must be qword aligned. Warn if someone > > > > makes a mistake and forgets to pad the ring when the commands > > > > inserted into the ring don't align to qword naturally. > > > > > > The assertion should be that we wrote precisely the number of dwords we > > > declared in intel_ring_begin(). Which is one of the important factors to > > > check whenever reviewing such code. This assertion (which should be a > > > BUG_ON) is no substitute for such review. > > > > Yeah. I was considering adding some reserved_space field to the ring, > > populate it in ring_begin(), and and make sure it was correctly > > consumed at ring_advance(). If you think that sounds good, I can cook > > up a patch for it. > > To be honest, I was thinking of a firing squad for the author and > reviewers of any such patch that gets intel_ring_begin()..end() wrong. I was mainly thinking it might helpful during development, to catch obvious bugs. A compile time check would be even better though. -- Ville Syrj?l? Intel OTC
