Re: [PATCH 04/22] staging: lustre: osc: handle osc eviction correctly

[Dan Carpenter]

On Fri, Dec 02, 2016 at 07:53:11PM -0500, James Simmons wrote:
> @@ -3183,8 +3182,10 @@ static int discard_cb(const struct lu_env *env, struct cl_io *io,
>  	/* page is top page. */
>  	info->oti_next_index = osc_index(ops) + 1;
>  	if (cl_page_own(env, io, page) == 0) {
> -		KLASSERT(ergo(page->cp_type == CPT_CACHEABLE,
> -			      !PageDirty(cl_page_vmpage(page))));
> +		if (!ergo(page->cp_type == CPT_CACHEABLE,
> +			  !PageDirty(cl_page_vmpage(page))))
> +			CL_PAGE_DEBUG(D_ERROR, env, page,
> +				      "discard dirty page?\n");


I don't understand the point of the ergo macro.  There are way too many
double negatives (some of them hidden for my small brain).  How is that
simpler than just writing it out:

	if (page->cp_type == CPT_CACHEABLE &&
	    PageDirty(cl_page_vmpage(page))
		 CL_PAGE_DEBUG(D_ERROR, env, page, "discard dirty page?\n");

regards,
dan carpenter