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author | Herbert Xu <herbert@gondor.apana.org.au> | 2015-06-01 16:22:03 +0800 |
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committer | Herbert Xu <herbert@gondor.apana.org.au> | 2015-06-03 10:51:25 +0800 |
commit | 0cf71a16fe0e984647c56ce9177522dfc4ebaff7 (patch) | |
tree | 3266a3e487deca6bea340bce0dfe1b946b0c6bf4 /crypto/scatterwalk.c | |
parent | 329ed874da6960a17a8defd0944646277052e7e0 (diff) | |
download | linux-crypto-0cf71a16fe0e984647c56ce9177522dfc4ebaff7.tar.gz linux-crypto-0cf71a16fe0e984647c56ce9177522dfc4ebaff7.zip |
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>
Diffstat (limited to 'crypto/scatterwalk.c')
-rw-r--r-- | crypto/scatterwalk.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c index 2ef9cbbc..ea5815c5 100644 --- a/crypto/scatterwalk.c +++ b/crypto/scatterwalk.c @@ -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); } |