Commit 19998acb authored by Cyrille Pitchen's avatar Cyrille Pitchen Committed by Herbert Xu
Browse files

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



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: default avatarCyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent dd3f9f40

drivers/crypto/atmel-sha.c

+22 −5
Original line number Diff line number Diff line
@@ -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);

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