[PATCH v2 11/11] crypto: adapt api sample to use async. op wait

From: Gilad Ben-Yossef
Date: Mon May 29 2017 - 04:25:31 EST


The code sample is waiting for an async. crypto op completion.
Adapt sample to use the new generic infrastructure to do the same.

This also fixes a possible data coruption bug created by the
use of wait_for_completion_interruptible() without dealing
correctly with an interrupt aborting the wait prior to the
async op finishing.

Signed-off-by: Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx>
---
Documentation/crypto/api-samples.rst | 52 +++++++-----------------------------
1 file changed, 10 insertions(+), 42 deletions(-)

diff --git a/Documentation/crypto/api-samples.rst b/Documentation/crypto/api-samples.rst
index d021fd9..73b466b 100644
--- a/Documentation/crypto/api-samples.rst
+++ b/Documentation/crypto/api-samples.rst
@@ -7,59 +7,27 @@ Code Example For Symmetric Key Cipher Operation
::


- struct tcrypt_result {
- struct completion completion;
- int err;
- };
-
/* tie all data structures together */
struct skcipher_def {
struct scatterlist sg;
struct crypto_skcipher *tfm;
struct skcipher_request *req;
- struct tcrypt_result result;
+ struct crypto_wait wait;
};

- /* Callback function */
- static void test_skcipher_cb(struct crypto_async_request *req, int error)
- {
- struct tcrypt_result *result = req->data;
-
- if (error == -EINPROGRESS)
- return;
- result->err = error;
- complete(&result->completion);
- pr_info("Encryption finished successfully\n");
- }
-
/* Perform cipher operation */
static unsigned int test_skcipher_encdec(struct skcipher_def *sk,
int enc)
{
- int rc = 0;
+ int rc;

if (enc)
- rc = crypto_skcipher_encrypt(sk->req);
+ rc = crypto_wait_req(crypto_skcipher_encrypt(sk->req), &sk->wait);
else
- rc = crypto_skcipher_decrypt(sk->req);
-
- switch (rc) {
- case 0:
- break;
- case -EINPROGRESS:
- case -EBUSY:
- rc = wait_for_completion_interruptible(
- &sk->result.completion);
- if (!rc && !sk->result.err) {
- reinit_completion(&sk->result.completion);
- break;
- }
- default:
- pr_info("skcipher encrypt returned with %d result %d\n",
- rc, sk->result.err);
- break;
- }
- init_completion(&sk->result.completion);
+ rc = crypto_wait_req(crypto_skcipher_decrypt(sk->req), &sk->wait);
+
+ if (rc)
+ pr_info("skcipher encrypt returned with result %d\n", rc);

return rc;
}
@@ -89,8 +57,8 @@ Code Example For Symmetric Key Cipher Operation
}

skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
- test_skcipher_cb,
- &sk.result);
+ crypto_req_done,
+ &sk.wait);

/* AES 256 with random key */
get_random_bytes(&key, 32);
@@ -122,7 +90,7 @@ Code Example For Symmetric Key Cipher Operation
/* We encrypt one block */
sg_init_one(&sk.sg, scratchpad, 16);
skcipher_request_set_crypt(req, &sk.sg, &sk.sg, 16, ivdata);
- init_completion(&sk.result.completion);
+ crypto_init_wait(&sk.wait);

/* encrypt data */
ret = test_skcipher_encdec(&sk, 1);
--
2.1.4