crypto: scatterwalk - Add no-copy support to copychunks

The function ablkcipher_done_slow is pretty much identical to
scatterwalk_copychunks except that it doesn't actually copy as
the processing hasn't been completed yet.

This patch allows scatterwalk_copychunks to be used in this case
by specifying out == 2.

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

1 files changed, 6 insertions, 4 deletions

diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c
index 03ca4aef1b9d..e124ce26feed 100644
--- a/crypto/scatterwalk.c
+++ b/crypto/scatterwalk.c
@@ -87,9 +87,11 @@ void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
                 if (len_this_page > nbytes)
                         len_this_page = nbytes;
 
-                vaddr = scatterwalk_map(walk);
-                memcpy_dir(buf, vaddr, len_this_page, out);
-                scatterwalk_unmap(vaddr);
+                if (out != 2) {
+                        vaddr = scatterwalk_map(walk);
+                        memcpy_dir(buf, vaddr, len_this_page, out);
+                        scatterwalk_unmap(vaddr);
+                }
 
                 scatterwalk_advance(walk, len_this_page);
 
@@ -99,7 +101,7 @@ void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
                 buf += len_this_page;
                 nbytes -= len_this_page;
 
-                scatterwalk_pagedone(walk, out, 1);
+                scatterwalk_pagedone(walk, out & 1, 1);
         }
 }
 EXPORT_SYMBOL_GPL(scatterwalk_copychunks);