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    Subject[PATCH v9 20/20] crypto: adapt api sample to use async. op wait
    Date
    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>
    ---
    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 2531948..006827e 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);
    --
    2.7.4
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