[PATCH 1/2] crypto: iaa - Remove potential infinite loop in check_completion()

["Zanussi, Tom" <tom.zanussi@linux.intel.com>]

For iaa_crypto operations, it's assumed that if an operation doesn't
make progress, the IAA watchdog timer will kick in and set the
completion status bit to failure and the reason to completion timeout.

Some systems may have broken hardware that doesn't even do that, which
can result in an infinite status-checking loop. Add a check for that
in the loop, and disable the driver if it occurs.

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
---
 drivers/crypto/intel/iaa/iaa_crypto_main.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/crypto/intel/iaa/iaa_crypto_main.c b/drivers/crypto/intel/iaa/iaa_crypto_main.c
index 237f87000070..8fced88d3d06 100644
--- a/drivers/crypto/intel/iaa/iaa_crypto_main.c
+++ b/drivers/crypto/intel/iaa/iaa_crypto_main.c
@@ -945,12 +945,22 @@ static inline int check_completion(struct device *dev,
 				   bool only_once)
 {
 	char *op_str = compress ? "compress" : "decompress";
+	int status_checks = 0;
 	int ret = 0;
 
 	while (!comp->status) {
 		if (only_once)
 			return -EAGAIN;
 		cpu_relax();
+		if (status_checks++ >= IAA_COMPLETION_TIMEOUT) {
+			/* Something is wrong with the hw, disable it. */
+			dev_err(dev, "%s completion timed out - "
+				"assuming broken hw, iaa_crypto now DISABLED\n",
+				op_str);
+			iaa_crypto_enabled = false;
+			ret = -ETIMEDOUT;
+			goto out;
+		}
 	}
 
 	if (comp->status != IAX_COMP_SUCCESS) {
-- 
2.38.1