mxser: cleanup LSR handling in mxser_receive_chars

mxser_interrupt is a bit confusing as it passes a pointer to LSR
variable ("status") to mxser_receive_chars. That function can indeed
update the LCR variable. Make this clear by not passing a variable by
reference, instead, return updated status. And change its type
accordingly -- to u8.

Note that the next patches will rework ISR so that even the definition
of status will be u8 soon too.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210618061516.662-13-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/mxser.c b/drivers/tty/mxser.c
index 6602b2741271217d061d526d627307821930ff58..9ba3af4626c6ddefd293b278d0b7ba62740d592a 100644 (file)
--- a/drivers/tty/mxser.c
+++ b/drivers/tty/mxser.c
@@ -2056,8 +2056,8 @@ static int mxser_rs_break(struct tty_struct *tty, int break_state)
        return 0;
 }
 
-static void mxser_receive_chars(struct tty_struct *tty,
-                               struct mxser_port *port, int *status)
+static u8 mxser_receive_chars(struct tty_struct *tty,
+               struct mxser_port *port, u8 status)
 {
        unsigned char ch, gdl;
        int ignored = 0;
@@ -2070,12 +2070,12 @@ static void mxser_receive_chars(struct tty_struct *tty,
                mxser_stoprx(tty);
        if (port->board->must_hwid != MOXA_OTHER_UART) {
 
-               if (*status & UART_LSR_SPECIAL)
+               if (status & UART_LSR_SPECIAL)
                        goto intr_old;
                if (port->board->must_hwid == MOXA_MUST_MU860_HWID &&
-                               (*status & MOXA_MUST_LSR_RERR))
+                               (status & MOXA_MUST_LSR_RERR))
                        goto intr_old;
-               if (*status & MOXA_MUST_LSR_RERR)
+               if (status & MOXA_MUST_LSR_RERR)
                        goto intr_old;
 
                gdl = inb(port->ioaddr + MOXA_MUST_GDL_REGISTER);
@@ -2100,28 +2100,28 @@ intr_old:
                        break;
 
                ch = inb(port->ioaddr + UART_RX);
-               if (port->board->must_hwid && (*status & UART_LSR_OE))
+               if (port->board->must_hwid && (status & UART_LSR_OE))
                        outb(0x23, port->ioaddr + UART_FCR);
-               *status &= port->read_status_mask;
-               if (*status & port->ignore_status_mask) {
+               status &= port->read_status_mask;
+               if (status & port->ignore_status_mask) {
                        if (++ignored > 100)
                                break;
                } else {
                        char flag = 0;
-                       if (*status & UART_LSR_SPECIAL) {
-                               if (*status & UART_LSR_BI) {
+                       if (status & UART_LSR_SPECIAL) {
+                               if (status & UART_LSR_BI) {
                                        flag = TTY_BREAK;
                                        port->icount.brk++;
 
                                        if (port->port.flags & ASYNC_SAK)
                                                do_SAK(tty);
-                               } else if (*status & UART_LSR_PE) {
+                               } else if (status & UART_LSR_PE) {
                                        flag = TTY_PARITY;
                                        port->icount.parity++;
-                               } else if (*status & UART_LSR_FE) {
+                               } else if (status & UART_LSR_FE) {
                                        flag = TTY_FRAME;
                                        port->icount.frame++;
-                               } else if (*status & UART_LSR_OE) {
+                               } else if (status & UART_LSR_OE) {
                                        flag = TTY_OVERRUN;
                                        port->icount.overrun++;
                                } else
@@ -2140,8 +2140,8 @@ intr_old:
                if (port->board->must_hwid)
                        break;
 
-               *status = inb(port->ioaddr + UART_LSR);
-       } while (*status & UART_LSR_DR);
+               status = inb(port->ioaddr + UART_LSR);
+       } while (status & UART_LSR_DR);
 
 end_intr:
        mxvar_log.rxcnt[tty->index] += cnt;
@@ -2149,6 +2149,8 @@ end_intr:
        port->mon_data.up_rxcnt += cnt;
 
        tty_flip_buffer_push(&port->port);
+
+       return status;
 }
 
 static void mxser_transmit_chars(struct tty_struct *tty, struct mxser_port *port)
@@ -2262,14 +2264,14 @@ static irqreturn_t mxser_interrupt(int irq, void *dev_id)
                                            iir == MOXA_MUST_IIR_RDA ||
                                            iir == MOXA_MUST_IIR_RTO ||
                                            iir == MOXA_MUST_IIR_LSR)
-                                               mxser_receive_chars(tty, port,
-                                                               &status);
+                                               status = mxser_receive_chars(tty,
+                                                               port, status);
 
                                } else {
                                        status &= port->read_status_mask;
                                        if (status & UART_LSR_DR)
-                                               mxser_receive_chars(tty, port,
-                                                               &status);
+                                               status = mxser_receive_chars(tty,
+                                                               port, status);
                                }
                                msr = inb(port->ioaddr + UART_MSR);
                                if (msr & UART_MSR_ANY_DELTA)