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@xxxxxxxxx>
---
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
