Commit 16054407 authored Jun 01, 2015 by Herbert Xu

crypto: scatterwalk - Hide PageSlab call to optimise away flush_dcache_page



On architectures where flush_dcache_page is not needed, we will
end up generating all the code up to the PageSlab call.  This is
because PageSlab operates on a volatile pointer and thus cannot
be optimised away.

This patch works around this by checking whether flush_dcache_page
is needed before we call PageSlab which then allows PageSlab to be
compiled awy.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

parent b7c89d9e

crypto/scatterwalk.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -54,7 +54,11 @@ static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
		struct page *page;

		page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
		if (!PageSlab(page))
		/* Test ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE first as
		* PageSlab cannot be optimised away per se due to
		* use of volatile pointer.
		*/
		if (ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE && !PageSlab(page))
		flush_dcache_page(page);
		}