diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index f290fbe21d633ef2181989f7fe011e2f2e82b128..673aeda713883ee884fcda84dcb54abb5b0f632c 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -329,6 +329,7 @@ struct sc16is7xx_one {
 	struct kthread_work		reg_work;
 	struct kthread_delayed_work	ms_work;
 	struct sc16is7xx_one_config	config;
+	unsigned char           buf[SC16IS7XX_FIFO_SIZE]; /* Rx buffer. */
 	bool				irda_mode;
 	unsigned int			old_mctrl;
 };
@@ -341,7 +342,6 @@ struct sc16is7xx_port {
 	unsigned long			gpio_valid_mask;
 #endif
 	u8				mctrl_mask;
-	unsigned char			buf[SC16IS7XX_FIFO_SIZE];
 	struct kthread_worker		kworker;
 	struct task_struct		*kworker_task;
 	struct sc16is7xx_one		p[];
@@ -378,17 +378,15 @@ static void sc16is7xx_port_write(struct uart_port *port, u8 reg, u8 val)
 	regmap_write(one->regmap, reg, val);
 }
 
-static void sc16is7xx_fifo_read(struct uart_port *port, unsigned int rxlen)
+static void sc16is7xx_fifo_read(struct uart_port *port, u8 *rxbuf, unsigned int rxlen)
 {
-	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
 
-	regmap_noinc_read(one->regmap, SC16IS7XX_RHR_REG, s->buf, rxlen);
+	regmap_noinc_read(one->regmap, SC16IS7XX_RHR_REG, rxbuf, rxlen);
 }
 
-static void sc16is7xx_fifo_write(struct uart_port *port, u8 to_send)
+static void sc16is7xx_fifo_write(struct uart_port *port, u8 *txbuf, u8 to_send)
 {
-	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
 
 	/*
@@ -398,7 +396,7 @@ static void sc16is7xx_fifo_write(struct uart_port *port, u8 to_send)
 	if (unlikely(!to_send))
 		return;
 
-	regmap_noinc_write(one->regmap, SC16IS7XX_THR_REG, s->buf, to_send);
+	regmap_noinc_write(one->regmap, SC16IS7XX_THR_REG, txbuf, to_send);
 }
 
 static void sc16is7xx_port_update(struct uart_port *port, u8 reg,
@@ -568,18 +566,18 @@ static int sc16is7xx_set_baud(struct uart_port *port, int baud)
 static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen,
 				unsigned int iir)
 {
-	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
+	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
 	unsigned int lsr = 0, bytes_read, i;
 	bool read_lsr = (iir == SC16IS7XX_IIR_RLSE_SRC) ? true : false;
 	u8 ch, flag;
 
-	if (unlikely(rxlen >= sizeof(s->buf))) {
+	if (unlikely(rxlen >= sizeof(one->buf))) {
 		dev_warn_ratelimited(port->dev,
 				     "ttySC%i: Possible RX FIFO overrun: %d\n",
 				     port->line, rxlen);
 		port->icount.buf_overrun++;
 		/* Ensure sanity of RX level */
-		rxlen = sizeof(s->buf);
+		rxlen = sizeof(one->buf);
 	}
 
 	while (rxlen) {
@@ -592,10 +590,10 @@ static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen,
 			lsr = 0;
 
 		if (read_lsr) {
-			s->buf[0] = sc16is7xx_port_read(port, SC16IS7XX_RHR_REG);
+			one->buf[0] = sc16is7xx_port_read(port, SC16IS7XX_RHR_REG);
 			bytes_read = 1;
 		} else {
-			sc16is7xx_fifo_read(port, rxlen);
+			sc16is7xx_fifo_read(port, one->buf, rxlen);
 			bytes_read = rxlen;
 		}
 
@@ -628,7 +626,7 @@ static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen,
 		}
 
 		for (i = 0; i < bytes_read; ++i) {
-			ch = s->buf[i];
+			ch = one->buf[i];
 			if (uart_handle_sysrq_char(port, ch))
 				continue;
 
@@ -646,10 +644,10 @@ static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen,
 
 static void sc16is7xx_handle_tx(struct uart_port *port)
 {
-	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
-	struct circ_buf *xmit = &port->state->xmit;
-	unsigned int txlen, to_send, i;
+	struct tty_port *tport = &port->state->port;
 	unsigned long flags;
+	unsigned int txlen;
+	unsigned char *tail;
 
 	if (unlikely(port->x_char)) {
 		sc16is7xx_port_write(port, SC16IS7XX_THR_REG, port->x_char);
@@ -658,40 +656,31 @@ static void sc16is7xx_handle_tx(struct uart_port *port)
 		return;
 	}
 
-	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
+	if (kfifo_is_empty(&tport->xmit_fifo) || uart_tx_stopped(port)) {
 		uart_port_lock_irqsave(port, &flags);
 		sc16is7xx_stop_tx(port);
 		uart_port_unlock_irqrestore(port, flags);
 		return;
 	}
 
-	/* Get length of data pending in circular buffer */
-	to_send = uart_circ_chars_pending(xmit);
-	if (likely(to_send)) {
-		/* Limit to size of TX FIFO */
-		txlen = sc16is7xx_port_read(port, SC16IS7XX_TXLVL_REG);
-		if (txlen > SC16IS7XX_FIFO_SIZE) {
-			dev_err_ratelimited(port->dev,
-				"chip reports %d free bytes in TX fifo, but it only has %d",
-				txlen, SC16IS7XX_FIFO_SIZE);
-			txlen = 0;
-		}
-		to_send = (to_send > txlen) ? txlen : to_send;
-
-		/* Convert to linear buffer */
-		for (i = 0; i < to_send; ++i) {
-			s->buf[i] = xmit->buf[xmit->tail];
-			uart_xmit_advance(port, 1);
-		}
-
-		sc16is7xx_fifo_write(port, to_send);
+	/* Limit to space available in TX FIFO */
+	txlen = sc16is7xx_port_read(port, SC16IS7XX_TXLVL_REG);
+	if (txlen > SC16IS7XX_FIFO_SIZE) {
+		dev_err_ratelimited(port->dev,
+			"chip reports %d free bytes in TX fifo, but it only has %d",
+			txlen, SC16IS7XX_FIFO_SIZE);
+		txlen = 0;
 	}
 
+	txlen = kfifo_out_linear_ptr(&tport->xmit_fifo, &tail, txlen);
+	sc16is7xx_fifo_write(port, tail, txlen);
+	uart_xmit_advance(port, txlen);
+
 	uart_port_lock_irqsave(port, &flags);
-	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+	if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS)
 		uart_write_wakeup(port);
 
-	if (uart_circ_empty(xmit))
+	if (kfifo_is_empty(&tport->xmit_fifo))
 		sc16is7xx_stop_tx(port);
 	else
 		sc16is7xx_ier_set(port, SC16IS7XX_IER_THRI_BIT);
diff --git a/include/linux/kfifo.h b/include/linux/kfifo.h
index 0b35a41440ff13751277c3356b743eadb341d007..0f2e7effe17c644c65cc0c2c29ce8b5e7b5aaaf0 100644
--- a/include/linux/kfifo.h
+++ b/include/linux/kfifo.h
@@ -828,6 +828,63 @@ __kfifo_uint_must_check_helper( \
 }) \
 )
 
+/**
+ * kfifo_out_linear - gets a tail of/offset to available data
+ * @fifo: address of the fifo to be used
+ * @tail: pointer to an unsigned int to store the value of tail
+ * @n: max. number of elements to point at
+ *
+ * This macro obtains the offset (tail) to the available data in the fifo
+ * buffer and returns the
+ * numbers of elements available. It returns the available count till the end
+ * of data or till the end of the buffer. So that it can be used for linear
+ * data processing (like memcpy() of (@fifo->data + @tail) with count
+ * returned).
+ *
+ * Note that with only one concurrent reader and one concurrent
+ * writer, you don't need extra locking to use these macro.
+ */
+#define kfifo_out_linear(fifo, tail, n) \
+__kfifo_uint_must_check_helper( \
+({ \
+	typeof((fifo) + 1) __tmp = (fifo); \
+	unsigned int *__tail = (tail); \
+	unsigned long __n = (n); \
+	const size_t __recsize = sizeof(*__tmp->rectype); \
+	struct __kfifo *__kfifo = &__tmp->kfifo; \
+	(__recsize) ? \
+	__kfifo_out_linear_r(__kfifo, __tail, __n, __recsize) : \
+	__kfifo_out_linear(__kfifo, __tail, __n); \
+}) \
+)
+
+/**
+ * kfifo_out_linear_ptr - gets a pointer to the available data
+ * @fifo: address of the fifo to be used
+ * @ptr: pointer to data to store the pointer to tail
+ * @n: max. number of elements to point at
+ *
+ * Similarly to kfifo_out_linear(), this macro obtains the pointer to the
+ * available data in the fifo buffer and returns the numbers of elements
+ * available. It returns the available count till the end of available data or
+ * till the end of the buffer. So that it can be used for linear data
+ * processing (like memcpy() of @ptr with count returned).
+ *
+ * Note that with only one concurrent reader and one concurrent
+ * writer, you don't need extra locking to use these macro.
+ */
+#define kfifo_out_linear_ptr(fifo, ptr, n) \
+__kfifo_uint_must_check_helper( \
+({ \
+	typeof((fifo) + 1) ___tmp = (fifo); \
+	unsigned int ___tail; \
+	unsigned int ___n = kfifo_out_linear(___tmp, &___tail, (n)); \
+	*(ptr) = ___tmp->kfifo.data + ___tail * kfifo_esize(___tmp); \
+	___n; \
+}) \
+)
+
+
 extern int __kfifo_alloc(struct __kfifo *fifo, unsigned int size,
 	size_t esize, gfp_t gfp_mask);
 
@@ -857,6 +914,9 @@ extern unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo,
 extern unsigned int __kfifo_out_peek(struct __kfifo *fifo,
 	void *buf, unsigned int len);
 
+extern unsigned int __kfifo_out_linear(struct __kfifo *fifo,
+	unsigned int *tail, unsigned int n);
+
 extern unsigned int __kfifo_in_r(struct __kfifo *fifo,
 	const void *buf, unsigned int len, size_t recsize);
 
@@ -888,6 +948,9 @@ extern void __kfifo_skip_r(struct __kfifo *fifo, size_t recsize);
 extern unsigned int __kfifo_out_peek_r(struct __kfifo *fifo,
 	void *buf, unsigned int len, size_t recsize);
 
+extern unsigned int __kfifo_out_linear_r(struct __kfifo *fifo,
+	unsigned int *tail, unsigned int n, size_t recsize);
+
 extern unsigned int __kfifo_max_r(unsigned int len, size_t recsize);
 
 #endif
diff --git a/lib/kfifo.c b/lib/kfifo.c
index 12f5a347aa137088a5364c3dcb0919a316fd7e88..abad82f6e135f76c1e9beee9edbb344498227e01 100644
--- a/lib/kfifo.c
+++ b/lib/kfifo.c
@@ -163,6 +163,19 @@ unsigned int __kfifo_out_peek(struct __kfifo *fifo,
 }
 EXPORT_SYMBOL(__kfifo_out_peek);
 
+unsigned int __kfifo_out_linear(struct __kfifo *fifo,
+		unsigned int *tail, unsigned int n)
+{
+	unsigned int size = fifo->mask + 1;
+	unsigned int off = fifo->out & fifo->mask;
+
+	if (tail)
+		*tail = off;
+
+	return min3(n, fifo->in - fifo->out, size - off);
+}
+EXPORT_SYMBOL(__kfifo_out_linear);
+
 unsigned int __kfifo_out(struct __kfifo *fifo,
 		void *buf, unsigned int len)
 {
@@ -473,6 +486,19 @@ unsigned int __kfifo_out_peek_r(struct __kfifo *fifo, void *buf,
 }
 EXPORT_SYMBOL(__kfifo_out_peek_r);
 
+unsigned int __kfifo_out_linear_r(struct __kfifo *fifo,
+		unsigned int *tail, unsigned int n, size_t recsize)
+{
+	if (fifo->in == fifo->out)
+		return 0;
+
+	if (tail)
+		*tail = fifo->out + recsize;
+
+	return min(n, __kfifo_peek_n(fifo, recsize));
+}
+EXPORT_SYMBOL(__kfifo_out_linear_r);
+
 unsigned int __kfifo_out_r(struct __kfifo *fifo, void *buf,
 		unsigned int len, size_t recsize)
 {