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crypto: scatterwalk - Hide PageSlab call to optimise away flush_dcache_page

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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>
This commit is contained in:
Herbert Xu 2015-06-01 16:22:03 +08:00
parent b7c89d9e2f
commit 160544075f
1 changed files with 5 additions and 1 deletions
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6
crypto/scatterwalk.c
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@ -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);
}