Invoking a possibly async. crypto op and waiting for completion
while correctly handling backlog processing is a common task
in the crypto API implementation and outside users of it.

This patch re-factors one of the in crypto API implementation in
preparation for using it across the board instead of hand
rolled versions.

Signed-off-by: Gilad Ben-Yossef <gi...@benyossef.com>
---
 crypto/af_alg.c         | 27 ---------------------------
 crypto/algif_aead.c     | 14 +++++++-------
 crypto/algif_hash.c     | 30 +++++++++++++++---------------
 crypto/algif_skcipher.c | 10 +++++-----
 crypto/api.c            | 28 ++++++++++++++++++++++++++++
 include/crypto/if_alg.h | 14 --------------
 include/linux/crypto.h  | 28 ++++++++++++++++++++++++++++
 7 files changed, 83 insertions(+), 68 deletions(-)

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 3556d8e..bf4acaf 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -480,33 +480,6 @@ int af_alg_cmsg_send(struct msghdr *msg, struct 
af_alg_control *con)
 }
 EXPORT_SYMBOL_GPL(af_alg_cmsg_send);
 
-int af_alg_wait_for_completion(int err, struct af_alg_completion *completion)
-{
-       switch (err) {
-       case -EINPROGRESS:
-       case -EBUSY:
-               wait_for_completion(&completion->completion);
-               reinit_completion(&completion->completion);
-               err = completion->err;
-               break;
-       };
-
-       return err;
-}
-EXPORT_SYMBOL_GPL(af_alg_wait_for_completion);
-
-void af_alg_complete(struct crypto_async_request *req, int err)
-{
-       struct af_alg_completion *completion = req->data;
-
-       if (err == -EINPROGRESS)
-               return;
-
-       completion->err = err;
-       complete(&completion->completion);
-}
-EXPORT_SYMBOL_GPL(af_alg_complete);
-
 static int __init af_alg_init(void)
 {
        int err = proto_register(&alg_proto, 0);
diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index 8af664f..9543589 100644
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -57,7 +57,7 @@ struct aead_ctx {
 
        void *iv;
 
-       struct af_alg_completion completion;
+       struct crypto_wait wait;
 
        unsigned long used;
 
@@ -648,10 +648,10 @@ static int aead_recvmsg_sync(struct socket *sock, struct 
msghdr *msg, int flags)
                               used, ctx->iv);
        aead_request_set_ad(&ctx->aead_req, ctx->aead_assoclen);
 
-       err = af_alg_wait_for_completion(ctx->enc ?
-                                        crypto_aead_encrypt(&ctx->aead_req) :
-                                        crypto_aead_decrypt(&ctx->aead_req),
-                                        &ctx->completion);
+       err = crypto_wait_req(ctx->enc ?
+                                crypto_aead_encrypt(&ctx->aead_req) :
+                                crypto_aead_decrypt(&ctx->aead_req),
+                                &ctx->wait);
 
        if (err) {
                /* EBADMSG implies a valid cipher operation took place */
@@ -912,7 +912,7 @@ static int aead_accept_parent_nokey(void *private, struct 
sock *sk)
        ctx->enc = 0;
        ctx->tsgl.cur = 0;
        ctx->aead_assoclen = 0;
-       af_alg_init_completion(&ctx->completion);
+       crypto_init_wait(&ctx->wait);
        sg_init_table(ctx->tsgl.sg, ALG_MAX_PAGES);
        INIT_LIST_HEAD(&ctx->list);
 
@@ -920,7 +920,7 @@ static int aead_accept_parent_nokey(void *private, struct 
sock *sk)
 
        aead_request_set_tfm(&ctx->aead_req, aead);
        aead_request_set_callback(&ctx->aead_req, CRYPTO_TFM_REQ_MAY_BACKLOG,
-                                 af_alg_complete, &ctx->completion);
+                                 crypto_req_done, &ctx->wait);
 
        sk->sk_destruct = aead_sock_destruct;
 
diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index 5e92bd2..fd7a6010 100644
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c
@@ -26,7 +26,7 @@ struct hash_ctx {
 
        u8 *result;
 
-       struct af_alg_completion completion;
+       struct crypto_wait wait;
 
        unsigned int len;
        bool more;
@@ -88,8 +88,8 @@ static int hash_sendmsg(struct socket *sock, struct msghdr 
*msg,
                if ((msg->msg_flags & MSG_MORE))
                        hash_free_result(sk, ctx);
 
-               err = af_alg_wait_for_completion(crypto_ahash_init(&ctx->req),
-                                               &ctx->completion);
+               err = crypto_wait_req(crypto_ahash_init(&ctx->req),
+                                               &ctx->wait);
                if (err)
                        goto unlock;
        }
@@ -110,8 +110,8 @@ static int hash_sendmsg(struct socket *sock, struct msghdr 
*msg,
 
                ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, NULL, len);
 
-               err = af_alg_wait_for_completion(crypto_ahash_update(&ctx->req),
-                                                &ctx->completion);
+               err = crypto_wait_req(crypto_ahash_update(&ctx->req),
+                                                &ctx->wait);
                af_alg_free_sg(&ctx->sgl);
                if (err)
                        goto unlock;
@@ -129,8 +129,8 @@ static int hash_sendmsg(struct socket *sock, struct msghdr 
*msg,
                        goto unlock;
 
                ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
-               err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req),
-                                                &ctx->completion);
+               err = crypto_wait_req(crypto_ahash_final(&ctx->req),
+                                                &ctx->wait);
        }
 
 unlock:
@@ -171,7 +171,7 @@ static ssize_t hash_sendpage(struct socket *sock, struct 
page *page,
        } else {
                if (!ctx->more) {
                        err = crypto_ahash_init(&ctx->req);
-                       err = af_alg_wait_for_completion(err, &ctx->completion);
+                       err = crypto_wait_req(err, &ctx->wait);
                        if (err)
                                goto unlock;
                }
@@ -179,7 +179,7 @@ static ssize_t hash_sendpage(struct socket *sock, struct 
page *page,
                err = crypto_ahash_update(&ctx->req);
        }
 
-       err = af_alg_wait_for_completion(err, &ctx->completion);
+       err = crypto_wait_req(err, &ctx->wait);
        if (err)
                goto unlock;
 
@@ -215,17 +215,17 @@ static int hash_recvmsg(struct socket *sock, struct 
msghdr *msg, size_t len,
        ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
 
        if (!result && !ctx->more) {
-               err = af_alg_wait_for_completion(
+               err = crypto_wait_req(
                                crypto_ahash_init(&ctx->req),
-                               &ctx->completion);
+                               &ctx->wait);
                if (err)
                        goto unlock;
        }
 
        if (!result || ctx->more) {
                ctx->more = 0;
-               err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req),
-                                                &ctx->completion);
+               err = crypto_wait_req(crypto_ahash_final(&ctx->req),
+                                                &ctx->wait);
                if (err)
                        goto unlock;
        }
@@ -476,13 +476,13 @@ static int hash_accept_parent_nokey(void *private, struct 
sock *sk)
        ctx->result = NULL;
        ctx->len = len;
        ctx->more = 0;
-       af_alg_init_completion(&ctx->completion);
+       crypto_init_wait(&ctx->wait);
 
        ask->private = ctx;
 
        ahash_request_set_tfm(&ctx->req, hash);
        ahash_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
-                                  af_alg_complete, &ctx->completion);
+                                  crypto_req_done, &ctx->wait);
 
        sk->sk_destruct = hash_sock_destruct;
 
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 43839b0..ec7b40f 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -43,7 +43,7 @@ struct skcipher_ctx {
 
        void *iv;
 
-       struct af_alg_completion completion;
+       struct crypto_wait wait;
 
        atomic_t inflight;
        size_t used;
@@ -684,11 +684,11 @@ static int skcipher_recvmsg_sync(struct socket *sock, 
struct msghdr *msg,
                skcipher_request_set_crypt(&ctx->req, sg, ctx->rsgl.sg, used,
                                           ctx->iv);
 
-               err = af_alg_wait_for_completion(
+               err = crypto_wait_req(
                                ctx->enc ?
                                        crypto_skcipher_encrypt(&ctx->req) :
                                        crypto_skcipher_decrypt(&ctx->req),
-                               &ctx->completion);
+                               &ctx->wait);
 
 free:
                af_alg_free_sg(&ctx->rsgl);
@@ -948,14 +948,14 @@ static int skcipher_accept_parent_nokey(void *private, 
struct sock *sk)
        ctx->merge = 0;
        ctx->enc = 0;
        atomic_set(&ctx->inflight, 0);
-       af_alg_init_completion(&ctx->completion);
+       crypto_init_wait(&ctx->wait);
 
        ask->private = ctx;
 
        skcipher_request_set_tfm(&ctx->req, skcipher);
        skcipher_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_SLEEP |
                                                 CRYPTO_TFM_REQ_MAY_BACKLOG,
-                                     af_alg_complete, &ctx->completion);
+                                     crypto_req_done, &ctx->wait);
 
        sk->sk_destruct = skcipher_sock_destruct;
 
diff --git a/crypto/api.c b/crypto/api.c
index 941cd4c..1c6e9cd 100644
--- a/crypto/api.c
+++ b/crypto/api.c
@@ -24,6 +24,7 @@
 #include <linux/sched/signal.h>
 #include <linux/slab.h>
 #include <linux/string.h>
+#include <linux/completion.h>
 #include "internal.h"
 
 LIST_HEAD(crypto_alg_list);
@@ -595,5 +596,32 @@ int crypto_has_alg(const char *name, u32 type, u32 mask)
 }
 EXPORT_SYMBOL_GPL(crypto_has_alg);
 
+int crypto_wait_req(int err, struct crypto_wait *wait)
+{
+       switch (err) {
+       case -EINPROGRESS:
+       case -EBUSY:
+               wait_for_completion(&wait->completion);
+               reinit_completion(&wait->completion);
+               err = wait->err;
+               break;
+       };
+
+       return err;
+}
+EXPORT_SYMBOL_GPL(crypto_wait_req);
+
+void crypto_req_done(struct crypto_async_request *req, int err)
+{
+       struct crypto_wait *wait = req->data;
+
+       if (err == -EINPROGRESS)
+               return;
+
+       wait->err = err;
+       complete(&wait->completion);
+}
+EXPORT_SYMBOL_GPL(crypto_req_done);
+
 MODULE_DESCRIPTION("Cryptographic core API");
 MODULE_LICENSE("GPL");
diff --git a/include/crypto/if_alg.h b/include/crypto/if_alg.h
index e2b9c6f..86764fb 100644
--- a/include/crypto/if_alg.h
+++ b/include/crypto/if_alg.h
@@ -14,7 +14,6 @@
 #define _CRYPTO_IF_ALG_H
 
 #include <linux/compiler.h>
-#include <linux/completion.h>
 #include <linux/if_alg.h>
 #include <linux/scatterlist.h>
 #include <linux/types.h>
@@ -37,11 +36,6 @@ struct alg_sock {
        void *private;
 };
 
-struct af_alg_completion {
-       struct completion completion;
-       int err;
-};
-
 struct af_alg_control {
        struct af_alg_iv *iv;
        int op;
@@ -81,17 +75,9 @@ void af_alg_link_sg(struct af_alg_sgl *sgl_prev, struct 
af_alg_sgl *sgl_new);
 
 int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con);
 
-int af_alg_wait_for_completion(int err, struct af_alg_completion *completion);
-void af_alg_complete(struct crypto_async_request *req, int err);
-
 static inline struct alg_sock *alg_sk(struct sock *sk)
 {
        return (struct alg_sock *)sk;
 }
 
-static inline void af_alg_init_completion(struct af_alg_completion *completion)
-{
-       init_completion(&completion->completion);
-}
-
 #endif /* _CRYPTO_IF_ALG_H */
diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index 84da997..df2f72f 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -24,6 +24,7 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/uaccess.h>
+#include <linux/completion.h>
 
 /*
  * Autoloaded crypto modules should only use a prefixed name to avoid allowing
@@ -137,6 +138,13 @@
 
 #define CRYPTO_MINALIGN_ATTR __attribute__ ((__aligned__(CRYPTO_MINALIGN)))
 
+/*
+ * Macro for declaring a crypto op async wait object on stack
+ */
+#define DECLARE_CRYPTO_WAIT(_wait) \
+       struct crypto_wait _wait = { \
+               COMPLETION_INITIALIZER_ONSTACK((_wait).completion), 0 }
+
 struct scatterlist;
 struct crypto_ablkcipher;
 struct crypto_async_request;
@@ -467,6 +475,25 @@ struct crypto_alg {
        struct module *cra_module;
 } CRYPTO_MINALIGN_ATTR;
 
+/**
+ * A helper struct for waiting for completion of async crypto ops
+ */
+struct crypto_wait {
+       struct completion completion;
+       int err;
+};
+
+/*
+ * Async ops completion helper functioons
+ */
+int crypto_wait_req(int err, struct crypto_wait *wait);
+void crypto_req_done(struct crypto_async_request *req, int err);
+
+static inline void crypto_init_wait(struct crypto_wait *wait)
+{
+       init_completion(&wait->completion);
+}
+
 /*
  * Algorithm registration interface.
  */
@@ -1604,5 +1631,6 @@ static inline int crypto_comp_decompress(struct 
crypto_comp *tfm,
                                                    src, slen, dst, dlen);
 }
 
+
 #endif /* _LINUX_CRYPTO_H */
 
-- 
2.1.4

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