serial: sc16is7xx: dynamically allocate tx/rx buffer

This fixes the warnings:

   drivers/tty/serial/sc16is7xx.c: In function 'sc16is7xx_handle_rx':
>> drivers/tty/serial/sc16is7xx.c:548:1: warning: 'sc16is7xx_handle_rx' uses dynamic stack allocation [enabled by default]
   drivers/tty/serial/sc16is7xx.c: In function 'sc16is7xx_handle_tx':
>> drivers/tty/serial/sc16is7xx.c:589:1: warning: 'sc16is7xx_handle_tx' uses dynamic stack allocation [enabled by default]

Signed-off-by: Jon Ringle <jringle@gridpoint.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 8 insertions, 9 deletions

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 80b0ca68f6e2..1b6a77c4b2cb 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -317,6 +317,7 @@ struct sc16is7xx_port {
 #ifdef CONFIG_GPIOLIB
         struct gpio_chip                gpio;
 #endif
+        unsigned char                   buf[SC16IS7XX_FIFO_SIZE];
         struct sc16is7xx_one            p[0];
 };
 
@@ -471,16 +472,15 @@ static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen,
 {
         struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
         unsigned int lsr = 0, ch, flag, bytes_read, i;
-        u8 buf[port->fifosize];
         bool read_lsr = (iir == SC16IS7XX_IIR_RLSE_SRC) ? true : false;
 
-        if (unlikely(rxlen >= port->fifosize)) {
+        if (unlikely(rxlen >= sizeof(s->buf))) {
                 dev_warn_ratelimited(port->dev,
                                      "Port %i: Possible RX FIFO overrun: %d\n",
                                      port->line, rxlen);
                 port->icount.buf_overrun++;
                 /* Ensure sanity of RX level */
-                rxlen = port->fifosize;
+                rxlen = sizeof(s->buf);
         }
 
         while (rxlen) {
@@ -493,12 +493,12 @@ static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen,
                         lsr = 0;
 
                 if (read_lsr) {
-                        buf[0] = sc16is7xx_port_read(port, SC16IS7XX_RHR_REG);
+                        s->buf[0] = sc16is7xx_port_read(port, SC16IS7XX_RHR_REG);
                         bytes_read = 1;
                 } else {
                         regcache_cache_bypass(s->regmap, true);
                         regmap_raw_read(s->regmap, SC16IS7XX_RHR_REG,
-                                        buf, rxlen);
+                                        s->buf, rxlen);
                         regcache_cache_bypass(s->regmap, false);
                         bytes_read = rxlen;
                 }
@@ -532,7 +532,7 @@ static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen,
                 }
 
                 for (i = 0; i < bytes_read; ++i) {
-                        ch = buf[i];
+                        ch = s->buf[i];
                         if (uart_handle_sysrq_char(port, ch))
                                 continue;
 
@@ -553,7 +553,6 @@ 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;
-        u8 buf[port->fifosize];
 
         if (unlikely(port->x_char)) {
                 sc16is7xx_port_write(port, SC16IS7XX_THR_REG, port->x_char);
@@ -577,11 +576,11 @@ static void sc16is7xx_handle_tx(struct uart_port *port)
 
                 /* Convert to linear buffer */
                 for (i = 0; i < to_send; ++i) {
-                        buf[i] = xmit->buf[xmit->tail];
+                        s->buf[i] = xmit->buf[xmit->tail];
                         xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
                 }
                 regcache_cache_bypass(s->regmap, true);
-                regmap_raw_write(s->regmap, SC16IS7XX_THR_REG, buf, to_send);
+                regmap_raw_write(s->regmap, SC16IS7XX_THR_REG, s->buf, to_send);
                 regcache_cache_bypass(s->regmap, false);
         }