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crypto: atmel-sha - fix error management in atmel_sha_start()

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This patch clarifies and fixes how errors should be handled by
atmel_sha_start().

For update operations, the previous code wrongly assumed that
(err != -EINPROGRESS) implies (err == 0). It's wrong because that doesn't
take the error cases (err < 0) into account.

This patch also adds many comments to detail all the possible returned
values and what should be done in each case.

Especially, when an error occurs, since atmel_sha_complete() has already
been called, hence releasing the hardware, atmel_sha_start() must not call
atmel_sha_finish_req() later otherwise atmel_sha_complete() would be
called a second time.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Cyrille Pitchen 2017-02-09 17:51:21 +01:00 committed by Herbert Xu
parent dd3f9f40b5
commit 19998acb0f
1 changed files with 22 additions and 5 deletions
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27
drivers/crypto/atmel-sha.c
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@ -1106,22 +1106,39 @@ static int atmel_sha_start(struct atmel_sha_dev *dd)
ctx->op, req->nbytes);
err = atmel_sha_hw_init(dd);
if (err)
goto err1;
return atmel_sha_complete(dd, err);
/*
* atmel_sha_update_req() and atmel_sha_final_req() can return either:
* -EINPROGRESS: the hardware is busy and the SHA driver will resume
* its job later in the done_task.
* This is the main path.
*
* 0: the SHA driver can continue its job then release the hardware
* later, if needed, with atmel_sha_finish_req().
* This is the alternate path.
*
* < 0: an error has occurred so atmel_sha_complete(dd, err) has already
* been called, hence the hardware has been released.
* The SHA driver must stop its job without calling
* atmel_sha_finish_req(), otherwise atmel_sha_complete() would be
* called a second time.
*
* Please note that currently, atmel_sha_final_req() never returns 0.
*/
dd->resume = atmel_sha_done;
if (ctx->op == SHA_OP_UPDATE) {
err = atmel_sha_update_req(dd);
if (err != -EINPROGRESS && (ctx->flags & SHA_FLAGS_FINUP))
if (!err && (ctx->flags & SHA_FLAGS_FINUP))
/* no final() after finup() */
err = atmel_sha_final_req(dd);
} else if (ctx->op == SHA_OP_FINAL) {
err = atmel_sha_final_req(dd);
}
err1:
if (err != -EINPROGRESS)
if (!err)
/* done_task will not finish it, so do it here */
atmel_sha_finish_req(req, err);