From: Cyrille Pitchen Subject: [PATCH next 2/2] crypto: atmel-sha: fix error management in atmel_sha_start() Date: Thu, 9 Feb 2017 17:51:21 +0100 Message-ID: <3852cb16370171988f6669b3bac98b06477bacb6.1486655562.git.cyrille.pitchen@atmel.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Cyrille Pitchen , dan.carpenter@oracle.com, linux-crypto@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org To: , , Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org List-Id: linux-crypto.vger.kernel.org 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 --- drivers/crypto/atmel-sha.c | 27 ++++++++++++++++++++++----- 1 file changed, 22 insertions(+), 5 deletions(-) diff --git a/drivers/crypto/atmel-sha.c b/drivers/crypto/atmel-sha.c index d6c3d9529d36..0d207dac9aa2 100644 --- a/drivers/crypto/atmel-sha.c +++ b/drivers/crypto/atmel-sha.c @@ -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); -- 2.7.4