serial: 8250_ni: Fix build warning

Allocate memory on heap instead of stack to fix following warning that
clang version 20.1.2 produces on W=1 build.

drivers/tty/serial/8250/8250_ni.c:277:12: warning: stack frame size (1072) exceeds limit (1024) in 'ni16550_probe' [-Wframe-larger-than]
  277 | static int ni16550_probe(struct platform_device *pdev)
      |            ^
  1 warning generated.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202507030557.vIewJJQO-lkp@intel.com/
Cc: Jason Smith <jason.smith@emerson.com>
Cc: Gratian Crisan <gratian.crisan@emerson.com>
Signed-off-by: Chaitanya Vadrevu <chaitanya.vadrevu@emerson.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250711200418.1858682-2-chaitanya.vadrevu@emerson.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_ni.c b/drivers/tty/serial/8250/8250_ni.c
index b0e44fb00b3a4df68ca1010d6f00429c4922705f..81f2255012153836db50cb9ebac00e01d743d6a5 100644 (file)
--- a/drivers/tty/serial/8250/8250_ni.c
+++ b/drivers/tty/serial/8250/8250_ni.c
@@ -277,7 +277,7 @@ static int ni16550_probe(struct platform_device *pdev)
 {
        const struct ni16550_device_info *info;
        struct device *dev = &pdev->dev;
-       struct uart_8250_port uart = {};
+       struct uart_8250_port *uart __free(kfree) = NULL;
        unsigned int txfifosz, rxfifosz;
        unsigned int prescaler;
        struct ni16550_data *data;
@@ -285,66 +285,70 @@ static int ni16550_probe(struct platform_device *pdev)
        bool rs232_property;
        int ret;
 
+       uart = kzalloc(sizeof(*uart), GFP_KERNEL);
+       if (!uart)
+               return -ENOMEM;
+
        data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;
 
-       spin_lock_init(&uart.port.lock);
+       spin_lock_init(&uart->port.lock);
 
-       ret = ni16550_get_regs(pdev, &uart.port);
+       ret = ni16550_get_regs(pdev, &uart->port);
        if (ret < 0)
                return ret;
 
        /* early setup so that serial_in()/serial_out() work */
-       serial8250_set_defaults(&uart);
+       serial8250_set_defaults(uart);
 
        info = device_get_match_data(dev);
 
-       uart.port.dev           = dev;
-       uart.port.flags         = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT | UPF_FIXED_TYPE;
-       uart.port.startup       = ni16550_port_startup;
-       uart.port.shutdown      = ni16550_port_shutdown;
+       uart->port.dev          = dev;
+       uart->port.flags        = UPF_BOOT_AUTOCONF | UPF_FIXED_PORT | UPF_FIXED_TYPE;
+       uart->port.startup      = ni16550_port_startup;
+       uart->port.shutdown     = ni16550_port_shutdown;
 
        /*
         * Hardware instantiation of FIFO sizes are held in registers.
         */
-       txfifosz = ni16550_read_fifo_size(&uart, NI16550_TFS_OFFSET);
-       rxfifosz = ni16550_read_fifo_size(&uart, NI16550_RFS_OFFSET);
+       txfifosz = ni16550_read_fifo_size(uart, NI16550_TFS_OFFSET);
+       rxfifosz = ni16550_read_fifo_size(uart, NI16550_RFS_OFFSET);
 
        dev_dbg(dev, "NI 16550 has TX FIFO size %u, RX FIFO size %u\n",
                txfifosz, rxfifosz);
 
-       uart.port.type          = PORT_16550A;
-       uart.port.fifosize      = txfifosz;
-       uart.tx_loadsz          = txfifosz;
-       uart.fcr                = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10;
-       uart.capabilities       = UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR;
+       uart->port.type         = PORT_16550A;
+       uart->port.fifosize     = txfifosz;
+       uart->tx_loadsz         = txfifosz;
+       uart->fcr               = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10;
+       uart->capabilities      = UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR;
 
        /*
         * Declaration of the base clock frequency can come from one of:
         * - static declaration in this driver (for older ACPI IDs)
         * - a "clock-frequency" ACPI
         */
-       uart.port.uartclk = info->uartclk;
+       uart->port.uartclk = info->uartclk;
 
-       ret = uart_read_port_properties(&uart.port);
+       ret = uart_read_port_properties(&uart->port);
        if (ret)
                return ret;
 
-       if (!uart.port.uartclk) {
+       if (!uart->port.uartclk) {
                data->clk = devm_clk_get_enabled(dev, NULL);
                if (!IS_ERR(data->clk))
-                       uart.port.uartclk = clk_get_rate(data->clk);
+                       uart->port.uartclk = clk_get_rate(data->clk);
        }
 
-       if (!uart.port.uartclk)
+       if (!uart->port.uartclk)
                return dev_err_probe(dev, -ENODEV, "unable to determine clock frequency!\n");
 
        prescaler = info->prescaler;
        device_property_read_u32(dev, "clock-prescaler", &prescaler);
        if (prescaler) {
-               uart.port.set_mctrl = ni16550_set_mctrl;
-               ni16550_config_prescaler(&uart, (u8)prescaler);
+               uart->port.set_mctrl = ni16550_set_mctrl;
+               ni16550_config_prescaler(uart, (u8)prescaler);
        }
 
        /*
@@ -362,7 +366,7 @@ static int ni16550_probe(struct platform_device *pdev)
                dev_dbg(dev, "port is in %s mode (via device property)\n",
                        rs232_property ? "RS-232" : "RS-485");
        } else if (info->flags & NI_HAS_PMR) {
-               rs232_property = is_pmr_rs232_mode(&uart);
+               rs232_property = is_pmr_rs232_mode(uart);
 
                dev_dbg(dev, "port is in %s mode (via PMR)\n",
                        rs232_property ? "RS-232" : "RS-485");
@@ -377,10 +381,10 @@ static int ni16550_probe(struct platform_device *pdev)
                 * Neither the 'transceiver' property nor the PMR indicate
                 * that this is an RS-232 port, so it must be an RS-485 one.
                 */
-               ni16550_rs485_setup(&uart.port);
+               ni16550_rs485_setup(&uart->port);
        }
 
-       ret = serial8250_register_8250_port(&uart);
+       ret = serial8250_register_8250_port(uart);
        if (ret < 0)
                return ret;
        data->line = ret;