tty/serial: lay the foundations for the next set of reworks

- Stop drivers calling their own flush method indirectly, it obfuscates code
  and it will change soon anyway

- A few more lock_kernel paths temporarily needed in some driver internal
  waiting code

- Remove private put_char method that does a write call for one char - we
  have that anyway

- Most but not yet all of the termios copy under lock fixing (some has other
  dependencies to follow)

- Note a few locking bugs in drivers found in the process

- Kill remaining [ab]users of TIOCG/SSOFTCAR in the driver, these must go to
  fix the termios locking

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

5 files changed, 20 insertions, 57 deletions

diff --git a/drivers/serial/68328serial.c b/drivers/serial/68328serial.c
index 2b8a410e0959..5ce3e57bff0b 100644
--- a/drivers/serial/68328serial.c
+++ b/drivers/serial/68328serial.c
@@ -1017,18 +1017,6 @@ static int rs_ioctl(struct tty_struct *tty, struct file * file,
                         tty_wait_until_sent(tty, 0);
                         send_break(info, arg ? arg*(100) : 250);
                         return 0;
-                case TIOCGSOFTCAR:
-                        error = put_user(C_CLOCAL(tty) ? 1 : 0,
-                                    (unsigned long *) arg);
-                        if (error)
-                                return error;
-                        return 0;
-                case TIOCSSOFTCAR:
-                        get_user(arg, (unsigned long *) arg);
-                        tty->termios->c_cflag =
-                                ((tty->termios->c_cflag & ~CLOCAL) |
-                                 (arg ? CLOCAL : 0));
-                        return 0;
                 case TIOCGSERIAL:
                         if (access_ok(VERIFY_WRITE, (void *) arg,
                                                 sizeof(struct serial_struct)))
@@ -1061,9 +1049,6 @@ static void rs_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
 {
         struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
 
-        if (tty->termios->c_cflag == old_termios->c_cflag)
-                return;
-
         change_speed(info);
 
         if ((old_termios->c_cflag & CRTSCTS) &&
@@ -1140,8 +1125,7 @@ static void rs_close(struct tty_struct *tty, struct file * filp)
         uart->ustcnt &= ~(USTCNT_RXEN | USTCNT_RX_INTR_MASK);
 
         shutdown(info);
-        if (tty->driver->flush_buffer)
-                tty->driver->flush_buffer(tty);
+        rs_flush_buffer(tty);
                 
         tty_ldisc_flush(tty);
         tty->closing = 0;
diff --git a/drivers/serial/68360serial.c b/drivers/serial/68360serial.c
index 6f540107d0bb..f4f737bfa0a7 100644
--- a/drivers/serial/68360serial.c
+++ b/drivers/serial/68360serial.c
@@ -1436,18 +1436,6 @@ static int rs_360_ioctl(struct tty_struct *tty, struct file * file,
                                 return retval;
                         end_break(info);
                         return 0;
-                case TIOCGSOFTCAR:
-                        /* return put_user(C_CLOCAL(tty) ? 1 : 0, (int *) arg); */
-                        put_user(C_CLOCAL(tty) ? 1 : 0, (int *) arg);
-                        return 0;
-                case TIOCSSOFTCAR:
-                        error = get_user(arg, (unsigned int *) arg); 
-                        if (error)
-                                return error;
-                        tty->termios->c_cflag =
-                                ((tty->termios->c_cflag & ~CLOCAL) |
-                                 (arg ? CLOCAL : 0));
-                        return 0;
 #ifdef maybe
                 case TIOCSERGETLSR: /* Get line status register */
                         return get_lsr_info(info, (unsigned int *) arg);
@@ -1665,8 +1653,7 @@ static void rs_360_close(struct tty_struct *tty, struct file * filp)
                 rs_360_wait_until_sent(tty, info->timeout);
         }
         shutdown(info);
-        if (tty->driver->flush_buffer)
-                tty->driver->flush_buffer(tty);
+        rs_360_flush_buffer(tty);
         tty_ldisc_flush(tty);           
         tty->closing = 0;
         info->event = 0;
@@ -1717,6 +1704,7 @@ static void rs_360_wait_until_sent(struct tty_struct *tty, int timeout)
         printk("jiff=%lu...", jiffies);
 #endif
 
+        lock_kernel();
         /* We go through the loop at least once because we can't tell
          * exactly when the last character exits the shifter.  There can
          * be at least two characters waiting to be sent after the buffers
@@ -1745,6 +1733,7 @@ static void rs_360_wait_until_sent(struct tty_struct *tty, int timeout)
                         bdp--;
         } while (bdp->status & BD_SC_READY);
         current->state = TASK_RUNNING;
+        unlock_kernel();
 #ifdef SERIAL_DEBUG_RS_WAIT_UNTIL_SENT
         printk("lsr = %d (jiff=%lu)...done\n", lsr, jiffies);
 #endif
diff --git a/drivers/serial/crisv10.c b/drivers/serial/crisv10.c
index 88e7c1d5b919..8b9af73c1d59 100644
--- a/drivers/serial/crisv10.c
+++ b/drivers/serial/crisv10.c
@@ -3581,8 +3581,9 @@ rs_tiocmset(struct tty_struct *tty, struct file *file,
                 unsigned int set, unsigned int clear)
 {
         struct e100_serial *info = (struct e100_serial *)tty->driver_data;
+        unsigned long flags;
 
-        lock_kernel();
+        local_irq_save(flags);
 
         if (clear & TIOCM_RTS)
                 e100_rts(info, 0);
@@ -3604,7 +3605,7 @@ rs_tiocmset(struct tty_struct *tty, struct file *file,
         if (set & TIOCM_CD)
                 e100_cd_out(info, 1);
 
-        unlock_kernel();
+        local_irq_restore(flags);
         return 0;
 }
 
@@ -3613,8 +3614,10 @@ rs_tiocmget(struct tty_struct *tty, struct file *file)
 {
         struct e100_serial *info = (struct e100_serial *)tty->driver_data;
         unsigned int result;
+        unsigned long flags;
+
+        local_irq_save(flags);
 
-        lock_kernel();
         result =
                 (!E100_RTS_GET(info) ? TIOCM_RTS : 0)
                 | (!E100_DTR_GET(info) ? TIOCM_DTR : 0)
@@ -3623,7 +3626,7 @@ rs_tiocmget(struct tty_struct *tty, struct file *file)
                 | (!E100_CD_GET(info) ? TIOCM_CAR : 0)
                 | (!E100_CTS_GET(info) ? TIOCM_CTS : 0);
 
-        unlock_kernel();
+        local_irq_restore(flags);
 
 #ifdef SERIAL_DEBUG_IO
         printk(KERN_DEBUG "ser%i: modem state: %i 0x%08X\n",
@@ -3702,10 +3705,6 @@ rs_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
 {
         struct e100_serial *info = (struct e100_serial *)tty->driver_data;
 
-        if (tty->termios->c_cflag == old_termios->c_cflag &&
-            tty->termios->c_iflag == old_termios->c_iflag)
-                return;
-
         change_speed(info);
 
         /* Handle turning off CRTSCTS */
@@ -3808,10 +3807,8 @@ rs_close(struct tty_struct *tty, struct file * filp)
 #endif
 
         shutdown(info);
-        if (tty->driver->flush_buffer)
-                tty->driver->flush_buffer(tty);
-        if (tty->ldisc.flush_buffer)
-                tty->ldisc.flush_buffer(tty);
+        rs_flush_buffer(tty);
+        tty_ldisc_flush_buffer(tty);
         tty->closing = 0;
         info->event = 0;
         info->tty = 0;
@@ -3885,6 +3882,7 @@ static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
          * Check R_DMA_CHx_STATUS bit 0-6=number of available bytes in FIFO
          * R_DMA_CHx_HWSW bit 31-16=nbr of bytes left in DMA buffer (0=64k)
          */
+        lock_kernel();
         orig_jiffies = jiffies;
         while (info->xmit.head != info->xmit.tail || /* More in send queue */
                (*info->ostatusadr & 0x007f) ||  /* more in FIFO */
@@ -3901,6 +3899,7 @@ static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
                         curr_time_usec - info->last_tx_active_usec;
         }
         set_current_state(TASK_RUNNING);
+        unlock_kernel();
 }
 
 /*
diff --git a/drivers/serial/mcfserial.c b/drivers/serial/mcfserial.c
index ddd3aa50d4ad..aafa1704e1ab 100644
--- a/drivers/serial/mcfserial.c
+++ b/drivers/serial/mcfserial.c
@@ -1072,18 +1072,6 @@ static int mcfrs_ioctl(struct tty_struct *tty, struct file * file,
                         tty_wait_until_sent(tty, 0);
                         send_break(info, arg ? arg*(HZ/10) : HZ/4);
                         return 0;
-                case TIOCGSOFTCAR:
-                        error = put_user(C_CLOCAL(tty) ? 1 : 0,
-                                    (unsigned long *) arg);
-                        if (error)
-                                return error;
-                        return 0;
-                case TIOCSSOFTCAR:
-                        get_user(arg, (unsigned long *) arg);
-                        tty->termios->c_cflag =
-                                ((tty->termios->c_cflag & ~CLOCAL) |
-                                 (arg ? CLOCAL : 0));
-                        return 0;
                 case TIOCGSERIAL:
                         if (access_ok(VERIFY_WRITE, (void *) arg,
                                                 sizeof(struct serial_struct)))
@@ -1222,8 +1210,7 @@ static void mcfrs_close(struct tty_struct *tty, struct file * filp)
         } else
 #endif
         shutdown(info);
-        if (tty->driver->flush_buffer)
-                tty->driver->flush_buffer(tty);
+        mcfrs_flush_buffer(tty);
         tty_ldisc_flush(tty);
         
         tty->closing = 0;
@@ -1276,6 +1263,8 @@ mcfrs_wait_until_sent(struct tty_struct *tty, int timeout)
          * Note: we have to use pretty tight timings here to satisfy
          * the NIST-PCTS.
          */
+        lock_kernel();
+
         fifo_time = (MCF5272_FIFO_SIZE * HZ * 10) / info->baud;
         char_time = fifo_time / 5;
         if (char_time == 0)
@@ -1312,6 +1301,7 @@ mcfrs_wait_until_sent(struct tty_struct *tty, int timeout)
                 if (timeout && time_after(jiffies, orig_jiffies + timeout))
                         break;
         }
+        unlock_kernel();
 #else
         /*
          * For the other coldfire models, assume all data has been sent
diff --git a/drivers/serial/netx-serial.c b/drivers/serial/netx-serial.c
index 3123ffeac8ad..81ac9bb4f39b 100644
--- a/drivers/serial/netx-serial.c
+++ b/drivers/serial/netx-serial.c
@@ -287,6 +287,7 @@ static void netx_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
         unsigned int val;
 
+        /* FIXME: Locking needed ? */
         if (mctrl & TIOCM_RTS) {
                 val = readl(port->membase + UART_RTS_CR);
                 writel(val | RTS_CR_RTS, port->membase + UART_RTS_CR);