[ofa-general] Re: [ewg] [PATCH] mlx4: remove limitation on LSO header size

[Roland Dreier]

 > +	*blh = unlikely(halign > 64) ? 1 : 0;

This idiom of "(boolean condition) ? 1 : 0" looks odd to me... doesn't
(halign > 64) already evaluate to 1 or 0 anyway?  Does the unlikely()
actually affect code generation here?

With that said, see below...

 > +	int blh = 0;

I assume this initialization is to avoid a compiler warning.  But the
code is actually correct without initializing blh -- so I think that we
save a tiny bit of code by doing uninitialized_var() instead?

 > +			(blh ? cpu_to_be32(1 << 6) : 0);

...given that the only use of blh is as a flag to decide what constant
to use here, does it generate better code to make blh be __be32 and set
the value directly in build_lso_seg, ie do:

	*blh = unlikely(halign > 64) ? cpu_to_be32(1 << 6) : 0;

and then use blh without ?: in mlx4_ib_post_send...

 - R.