crypto: skcipher - Add ablkcipher_walk interfaces

These are akin to the blkcipher_walk helpers.

The main differences in the async variant are:

1) Only physical walking is supported.  We can't hold on to
   kmap mappings across the async operation to support virtual
   ablkcipher_walk operations anyways.

2) Bounce buffers used for async more need to be persistent and
   freed at a later point in time when the async op completes.
   Therefore we maintain a list of writeback buffers and require
   that the ablkcipher_walk user call the 'complete' operation
   so we can copy the bounce buffers out to the real buffers and
   free up the bounce buffer chunks.

These interfaces will be used by the new Niagara2 crypto driver.

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

1 files changed, 40 insertions, 0 deletions

diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h
index fc0d575c71e0..59c3e5bd2c06 100644
--- a/include/crypto/algapi.h
+++ b/include/crypto/algapi.h
@@ -103,6 +103,23 @@ struct blkcipher_walk {
         unsigned int blocksize;
 };
 
+struct ablkcipher_walk {
+        struct {
+                struct page *page;
+                unsigned int offset;
+        } src, dst;
+
+        struct scatter_walk     in;
+        unsigned int            nbytes;
+        struct scatter_walk     out;
+        unsigned int            total;
+        struct list_head        buffers;
+        u8                      *iv_buffer;
+        u8                      *iv;
+        int                     flags;
+        unsigned int            blocksize;
+};
+
 extern const struct crypto_type crypto_ablkcipher_type;
 extern const struct crypto_type crypto_aead_type;
 extern const struct crypto_type crypto_blkcipher_type;
@@ -173,6 +190,12 @@ int blkcipher_walk_virt_block(struct blkcipher_desc *desc,
                               struct blkcipher_walk *walk,
                               unsigned int blocksize);
 
+int ablkcipher_walk_done(struct ablkcipher_request *req,
+                         struct ablkcipher_walk *walk, int err);
+int ablkcipher_walk_phys(struct ablkcipher_request *req,
+                         struct ablkcipher_walk *walk);
+void __ablkcipher_walk_complete(struct ablkcipher_walk *walk);
+
 static inline void *crypto_tfm_ctx_aligned(struct crypto_tfm *tfm)
 {
         return PTR_ALIGN(crypto_tfm_ctx(tfm),
@@ -283,6 +306,23 @@ static inline void blkcipher_walk_init(struct blkcipher_walk *walk,
         walk->total = nbytes;
 }
 
+static inline void ablkcipher_walk_init(struct ablkcipher_walk *walk,
+                                        struct scatterlist *dst,
+                                        struct scatterlist *src,
+                                        unsigned int nbytes)
+{
+        walk->in.sg = src;
+        walk->out.sg = dst;
+        walk->total = nbytes;
+        INIT_LIST_HEAD(&walk->buffers);
+}
+
+static inline void ablkcipher_walk_complete(struct ablkcipher_walk *walk)
+{
+        if (unlikely(!list_empty(&walk->buffers)))
+                __ablkcipher_walk_complete(walk);
+}
+
 static inline struct crypto_async_request *crypto_get_backlog(
         struct crypto_queue *queue)
 {