Hi Ondrej,

On Mon, Sep 10, 2018 at 01:28:41PM +0200, Ondrej Mosnacek wrote:

 
-static int init_crypt(struct skcipher_request *req, crypto_completion_t done)
+static int xor_tweak_pre(struct skcipher_request *req)
 {
-	struct priv *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
-	struct rctx *rctx = skcipher_request_ctx(req);
-	struct skcipher_request *subreq;
-	gfp_t gfp;
-
-	subreq = &rctx->subreq;
-	skcipher_request_set_tfm(subreq, ctx->child);
-	skcipher_request_set_callback(subreq, req->base.flags, done, req);
-
-	gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL :
-							   GFP_ATOMIC;
-	rctx->ext = NULL;
-
-	subreq->cryptlen = XTS_BUFFER_SIZE;
-	if (req->cryptlen > XTS_BUFFER_SIZE) {
-		unsigned int n = min(req->cryptlen, (unsigned int)PAGE_SIZE);
-
-		rctx->ext = kmalloc(n, gfp);
-		if (rctx->ext)
-			subreq->cryptlen = n;
-	}
-
-	rctx->src = req->src;
-	rctx->dst = req->dst;
-	rctx->left = req->cryptlen;
-
-	/* calculate first value of T */
-	crypto_cipher_encrypt_one(ctx->tweak, (u8 *)&rctx->t, req->iv);
-
-	return 0;
+	return xor_tweak(req, false);
 }
 
-static void exit_crypt(struct skcipher_request *req)
+static int xor_tweak_post(struct skcipher_request *req)
 {
-	struct rctx *rctx = skcipher_request_ctx(req);
-
-	rctx->left = 0;
-
-	if (rctx->ext)
-		kzfree(rctx->ext);
+	return xor_tweak(req, false);
 }

I think you meant 'xor_tweak(req, true);' here?

+static void crypt_done(struct crypto_async_request *areq, int err)
 {
 	struct skcipher_request *req = areq->data;
-	struct skcipher_request *subreq;
-	struct rctx *rctx;
-
-	rctx = skcipher_request_ctx(req);
-
-	if (err == -EINPROGRESS) {
-		if (rctx->left != req->cryptlen)
-			return;
-		goto out;
-	}
-
-	subreq = &rctx->subreq;
-	subreq->base.flags &= CRYPTO_TFM_REQ_MAY_BACKLOG;
 
-	err = do_encrypt(req, err ?: post_crypt(req));
-	if (rctx->left)
-		return;
+	if (!err)
+		err = xor_tweak(req, true);

Use xor_tweak_post()?

Note that you could also change the bool to

enum {
	FIRST_PASS,
	SECOND_PASS,
}

if you find the bool to be unclear.

Thanks,

- Eric