Improve the code responsible for waking up the crypto_proc thread.

Checking if the queues are empty is not enough for the crypto_proc thread
(it is enough for the crypto_ret_thread), because drivers can be marked
as blocked. In a situation where we have operations related to different
crypto drivers in the queue, it is possible that one driver is marked as
blocked. In this case, the queue will not be empty and we won't wakeup
the crypto_proc thread to execute operations for the others drivers.

Simply setting a global variable to 1 when we goes to sleep and setting
it back to 0 when we wake up is sufficient. The variable is protected
with the queue lock.

1 files changed, 11 insertions, 14 deletions

diff --git a/sys/opencrypto/crypto.c b/sys/opencrypto/crypto.c
index bd3e578..249a45b 100644
--- a/sys/opencrypto/crypto.c
+++ b/sys/opencrypto/crypto.c
@@ -59,12 +59,12 @@ static	int crypto_drivers_num = 0;
  * have one per-queue but having one simplifies handling of block/unblock
  * operations.
  */
+static	int crp_sleep = 0;
 static	TAILQ_HEAD(,cryptop) crp_q;		/* request queues */
 static	TAILQ_HEAD(,cryptkop) crp_kq;
 static	struct mtx crypto_q_mtx;
 #define	CRYPTO_Q_LOCK()		mtx_lock(&crypto_q_mtx)
 #define	CRYPTO_Q_UNLOCK()	mtx_unlock(&crypto_q_mtx)
-#define	CRYPTO_Q_EMPTY()	(TAILQ_EMPTY(&crp_q) && TAILQ_EMPTY(&crp_kq))
 
 /*
  * There are two queues for processing completed crypto requests; one
@@ -639,21 +639,16 @@ int
 crypto_unblock(u_int32_t driverid, int what)
 {
 	struct cryptocap *cap;
-	int needwakeup, err;
+	int err;
 
 	CRYPTO_Q_LOCK();
 	cap = crypto_checkdriver(driverid);
 	if (cap != NULL) {
-		needwakeup = 0;
-		if (what & CRYPTO_SYMQ) {
-			needwakeup |= cap->cc_qblocked;
+		if (what & CRYPTO_SYMQ)
 			cap->cc_qblocked = 0;
-		}
-		if (what & CRYPTO_ASYMQ) {
-			needwakeup |= cap->cc_kqblocked;
+		if (what & CRYPTO_ASYMQ)
 			cap->cc_kqblocked = 0;
-		}
-		if (needwakeup)
+		if (crp_sleep)
 			wakeup_one(&crp_q);
 		err = 0;
 	} else
@@ -702,9 +697,9 @@ crypto_dispatch(struct cryptop *crp)
 		}
 	}
 	CRYPTO_Q_LOCK();
-	if (CRYPTO_Q_EMPTY())
-		wakeup_one(&crp_q);
 	TAILQ_INSERT_TAIL(&crp_q, crp, crp_next);
+	if (crp_sleep)
+		wakeup_one(&crp_q);
 	CRYPTO_Q_UNLOCK();
 	return 0;
 }
@@ -724,9 +719,9 @@ crypto_kdispatch(struct cryptkop *krp)
 	if (result != ERESTART)
 		return (result);
 	CRYPTO_Q_LOCK();
-	if (CRYPTO_Q_EMPTY())
-		wakeup_one(&crp_q);
 	TAILQ_INSERT_TAIL(&crp_kq, krp, krp_next);
+	if (crp_sleep)
+		wakeup_one(&crp_q);
 	CRYPTO_Q_UNLOCK();
 
 	return 0;
@@ -1157,7 +1152,9 @@ crypto_proc(void)
 			 * out of order if dispatched to different devices
 			 * and some become blocked while others do not.
 			 */
+			crp_sleep = 1;
 			msleep(&crp_q, &crypto_q_mtx, PWAIT, "crypto_wait", 0);
+			crp_sleep = 0;
 			if (cryptoproc == NULL)
 				break;
 			cryptostats.cs_intrs++;