diff --git a/drivers/serial/sb1250-duart.c b/drivers/serial/sb1250-duart.c
index a4fb343a..319e8b8 100644
--- a/drivers/serial/sb1250-duart.c
+++ b/drivers/serial/sb1250-duart.c
@@ -204,7 +204,7 @@
 {
 	int loops = 10000;
 
-	while (sbd_receive_ready(sport) && loops--)
+	while (sbd_receive_ready(sport) && --loops)
 		read_sbdchn(sport, R_DUART_RX_HOLD);
 	return loops;
 }
@@ -218,7 +218,7 @@
 {
 	int loops = 10000;
 
-	while (!sbd_transmit_ready(sport) && loops--)
+	while (!sbd_transmit_ready(sport) && --loops)
 		udelay(2);
 	return loops;
 }
@@ -232,7 +232,7 @@
 {
 	int loops = 10000;
 
-	while (!sbd_transmit_empty(sport) && loops--)
+	while (!sbd_transmit_empty(sport) && --loops)
 		udelay(2);
 	return loops;
 }
diff --git a/drivers/serial/sunhv.c b/drivers/serial/sunhv.c
index a94a2ab..1df5325 100644
--- a/drivers/serial/sunhv.c
+++ b/drivers/serial/sunhv.c
@@ -461,7 +461,7 @@
 					break;
 				udelay(1);
 			}
-			if (limit <= 0)
+			if (limit < 0)
 				break;
 			page_bytes -= written;
 			ra += written;
diff --git a/drivers/serial/zs.c b/drivers/serial/zs.c
index 9e6a873..d8c2809 100644
--- a/drivers/serial/zs.c
+++ b/drivers/serial/zs.c
@@ -231,7 +231,7 @@
 {
 	int loops = 10000;
 
-	while ((read_zsreg(zport, R0) & Rx_CH_AV) && loops--)
+	while ((read_zsreg(zport, R0) & Rx_CH_AV) && --loops)
 		read_zsdata(zport);
 	return loops;
 }
@@ -241,7 +241,7 @@
 	struct zs_scc *scc = zport->scc;
 	int loops = 10000;
 
-	while (!(read_zsreg(zport, R0) & Tx_BUF_EMP) && loops--) {
+	while (!(read_zsreg(zport, R0) & Tx_BUF_EMP) && --loops) {
 		zs_spin_unlock_cond_irq(&scc->zlock, irq);
 		udelay(2);
 		zs_spin_lock_cond_irq(&scc->zlock, irq);
@@ -254,7 +254,7 @@
 	struct zs_scc *scc = zport->scc;
 	int loops = 10000;
 
-	while (!(read_zsreg(zport, R1) & ALL_SNT) && loops--) {
+	while (!(read_zsreg(zport, R1) & ALL_SNT) && --loops) {
 		zs_spin_unlock_cond_irq(&scc->zlock, irq);
 		udelay(2);
 		zs_spin_lock_cond_irq(&scc->zlock, irq);