4 files changed, 20 insertions, 18 deletions

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 6b6abce6b..d2daf0a72 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -2969,6 +2969,9 @@ static int gsmld_open(struct tty_struct *tty)
 {
 	struct gsm_mux *gsm;
 
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
 	if (tty->ops->write == NULL)
 		return -EINVAL;
 
diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index d21a4f3ef..8b31017e7 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -1094,11 +1094,13 @@ static void mxs_auart_set_ldisc(struct uart_port *port,
 
 static irqreturn_t mxs_auart_irq_handle(int irq, void *context)
 {
-	u32 istat;
+	u32 istat, stat;
 	struct mxs_auart_port *s = context;
 	u32 mctrl_temp = s->mctrl_prev;
-	u32 stat = mxs_read(s, REG_STAT);
 
+	uart_port_lock(&s->port);
+
+	stat = mxs_read(s, REG_STAT);
 	istat = mxs_read(s, REG_INTR);
 
 	/* ack irq */
@@ -1134,6 +1136,8 @@ static irqreturn_t mxs_auart_irq_handle(int irq, void *context)
 		istat &= ~AUART_INTR_TXIS;
 	}
 
+	uart_port_unlock(&s->port);
+
 	return IRQ_HANDLED;
 }
 
diff --git a/drivers/tty/serial/pmac_zilog.c b/drivers/tty/serial/pmac_zilog.c
index fe2e4ec42..daf15d23b 100644
--- a/drivers/tty/serial/pmac_zilog.c
+++ b/drivers/tty/serial/pmac_zilog.c
@@ -210,7 +210,6 @@ static bool pmz_receive_chars(struct uart_pmac_port *uap)
 {
 	struct tty_port *port;
 	unsigned char ch, r1, drop, flag;
-	int loops = 0;
 
 	/* Sanity check, make sure the old bug is no longer happening */
 	if (uap->port.state == NULL) {
@@ -291,25 +290,12 @@ static bool pmz_receive_chars(struct uart_pmac_port *uap)
 		if (r1 & Rx_OVR)
 			tty_insert_flip_char(port, 0, TTY_OVERRUN);
 	next_char:
-		/* We can get stuck in an infinite loop getting char 0 when the
-		 * line is in a wrong HW state, we break that here.
-		 * When that happens, I disable the receive side of the driver.
-		 * Note that what I've been experiencing is a real irq loop where
-		 * I'm getting flooded regardless of the actual port speed.
-		 * Something strange is going on with the HW
-		 */
-		if ((++loops) > 1000)
-			goto flood;
 		ch = read_zsreg(uap, R0);
 		if (!(ch & Rx_CH_AV))
 			break;
 	}
 
 	return true;
- flood:
-	pmz_interrupt_control(uap, 0);
-	pmz_error("pmz: rx irq flood !\n");
-	return true;
 }
 
 static void pmz_status_handle(struct uart_pmac_port *uap)
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 2a9c40588..7d11511c8 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -755,6 +755,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
 	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 	u32 sr;
 	unsigned int size;
+	irqreturn_t ret = IRQ_NONE;
 
 	sr = readl_relaxed(port->membase + ofs->isr);
 
@@ -763,11 +764,14 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
 	    (sr & USART_SR_TC)) {
 		stm32_usart_tc_interrupt_disable(port);
 		stm32_usart_rs485_rts_disable(port);
+		ret = IRQ_HANDLED;
 	}
 
-	if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG)
+	if ((sr & USART_SR_RTOF) && ofs->icr != UNDEF_REG) {
 		writel_relaxed(USART_ICR_RTOCF,
 			       port->membase + ofs->icr);
+		ret = IRQ_HANDLED;
+	}
 
 	if ((sr & USART_SR_WUF) && ofs->icr != UNDEF_REG) {
 		/* Clear wake up flag and disable wake up interrupt */
@@ -776,6 +780,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
 		stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE);
 		if (irqd_is_wakeup_set(irq_get_irq_data(port->irq)))
 			pm_wakeup_event(tport->tty->dev, 0);
+		ret = IRQ_HANDLED;
 	}
 
 	/*
@@ -790,6 +795,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
 			uart_unlock_and_check_sysrq(port);
 			if (size)
 				tty_flip_buffer_push(tport);
+			ret = IRQ_HANDLED;
 		}
 	}
 
@@ -797,6 +803,7 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
 		spin_lock(&port->lock);
 		stm32_usart_transmit_chars(port);
 		spin_unlock(&port->lock);
+		ret = IRQ_HANDLED;
 	}
 
 	/* Receiver timeout irq for DMA RX */
@@ -806,9 +813,10 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
 		uart_unlock_and_check_sysrq(port);
 		if (size)
 			tty_flip_buffer_push(tport);
+		ret = IRQ_HANDLED;
 	}
 
-	return IRQ_HANDLED;
+	return ret;
 }
 
 static void stm32_usart_set_mctrl(struct uart_port *port, unsigned int mctrl)
@@ -1013,6 +1021,7 @@ static int stm32_usart_startup(struct uart_port *port)
 		val |= USART_CR2_SWAP;
 		writel_relaxed(val, port->membase + ofs->cr2);
 	}
+	stm32_port->throttled = false;
 
 	/* RX FIFO Flush */
 	if (ofs->rqr != UNDEF_REG)