crypto: scatterwalk - Avoid flush_dcache_page on slab pages

It's illegal to call flush_dcache_page on slab pages on a number
of architectures.  So this patch avoids doing so if PageSlab is
true.

In future we can move the flush_dcache_page call to those page
cache users that actually need it.

Reported-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 2 insertions, 1 deletions

diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c
index 9aeeb52004a5..3de89a424401 100644
--- a/crypto/scatterwalk.c
+++ b/crypto/scatterwalk.c
@@ -54,7 +54,8 @@ static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
                 struct page *page;
 
                 page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
-                flush_dcache_page(page);
+                if (!PageSlab(page))
+                        flush_dcache_page(page);
         }
 
         if (more) {