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>

1 files changed, 11 insertions, 12 deletions

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();
 }
 
 /*