crypto: hash - Add request chaining API

This adds request chaining to the ahash interface.  Request chaining
allows multiple requests to be submitted in one shot.  An algorithm
can elect to receive chained requests by setting the flag
CRYPTO_ALG_REQ_CHAIN.  If this bit is not set, the API will break
up chained requests and submit them one-by-one.

A new err field is added to struct crypto_async_request to record
the return value for each individual request.

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

1 files changed, 24 insertions, 0 deletions

diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index b164da5e129e..1d2a6c515d58 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -13,6 +13,8 @@
 #define _LINUX_CRYPTO_H
 
 #include <linux/completion.h>
+#include <linux/errno.h>
+#include <linux/list.h>
 #include <linux/refcount.h>
 #include <linux/slab.h>
 #include <linux/types.h>
@@ -124,6 +126,9 @@
  */
 #define CRYPTO_ALG_FIPS_INTERNAL	0x00020000
 
+/* Set if the algorithm supports request chains. */
+#define CRYPTO_ALG_REQ_CHAIN		0x00040000
+
 /*
  * Transform masks and values (for crt_flags).
  */
@@ -174,6 +179,7 @@ struct crypto_async_request {
 	struct crypto_tfm *tfm;
 
 	u32 flags;
+	int err;
 };
 
 /**
@@ -540,5 +546,23 @@ int crypto_comp_decompress(struct crypto_comp *tfm,
 			   const u8 *src, unsigned int slen,
 			   u8 *dst, unsigned int *dlen);
 
+static inline void crypto_reqchain_init(struct crypto_async_request *req)
+{
+	req->err = -EINPROGRESS;
+	INIT_LIST_HEAD(&req->list);
+}
+
+static inline void crypto_request_chain(struct crypto_async_request *req,
+					struct crypto_async_request *head)
+{
+	req->err = -EINPROGRESS;
+	list_add_tail(&req->list, &head->list);
+}
+
+static inline bool crypto_tfm_is_async(struct crypto_tfm *tfm)
+{
+	return tfm->__crt_alg->cra_flags & CRYPTO_ALG_ASYNC;
+}
+
 #endif	/* _LINUX_CRYPTO_H */