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crypto: doc - adapt api sample to use async. op wait

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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@benyossef.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Gilad Ben-Yossef 2017-10-18 08:00:52 +01:00 committed by Herbert Xu
parent 591b95af3d
commit aba973c69e
1 changed files with 9 additions and 41 deletions
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50
Documentation/crypto/api-samples.rst
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@ -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);
rc = crypto_wait_req(crypto_skcipher_decrypt(sk->req), &sk->wait);
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);
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);