tty: The big operations rework
- Operations are now a shared const function block as with most other Linux
objects
- Introduce wrappers for some optional functions to get consistent behaviour
- Wrap put_char which used to be patched by the tty layer
- Document which functions are needed/optional
- Make put_char report success/fail
- Cache the driver->ops pointer in the tty as tty->ops
- Remove various surplus lock calls we no longer need
- Remove proc_write method as noted by Alexey Dobriyan
- Introduce some missing sanity checks where certain driver/ldisc
combinations would oops as they didn't check needed methods were present
[akpm@linux-foundation.org: fix fs/compat_ioctl.c build]
[akpm@linux-foundation.org: fix isicom]
[akpm@linux-foundation.org: fix arch/ia64/hp/sim/simserial.c build]
[akpm@linux-foundation.org: fix kgdb]
Signed-off-by: Alan Cox <alan@redhat.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 6c7a5cf..1e2b9d8 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -532,15 +532,25 @@
static int uart_write_room(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
+ unsigned long flags;
+ int ret;
- return uart_circ_chars_free(&state->info->xmit);
+ spin_lock_irqsave(&state->port->lock, flags);
+ ret = uart_circ_chars_free(&state->info->xmit);
+ spin_unlock_irqrestore(&state->port->lock, flags);
+ return ret;
}
static int uart_chars_in_buffer(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
+ unsigned long flags;
+ int ret;
- return uart_circ_chars_pending(&state->info->xmit);
+ spin_lock_irqsave(&state->port->lock, flags);
+ ret = uart_circ_chars_pending(&state->info->xmit);
+ spin_unlock_irqrestore(&state->port->lock, flags);
+ return ret;
}
static void uart_flush_buffer(struct tty_struct *tty)
@@ -622,6 +632,11 @@
struct serial_struct tmp;
memset(&tmp, 0, sizeof(tmp));
+
+ /* Ensure the state we copy is consistent and no hardware changes
+ occur as we go */
+ mutex_lock(&state->mutex);
+
tmp.type = port->type;
tmp.line = port->line;
tmp.port = port->iobase;
@@ -641,6 +656,8 @@
tmp.iomem_reg_shift = port->regshift;
tmp.iomem_base = (void *)(unsigned long)port->mapbase;
+ mutex_unlock(&state->mutex);
+
if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
return -EFAULT;
return 0;
@@ -918,14 +935,12 @@
struct uart_state *state = tty->driver_data;
struct uart_port *port = state->port;
- lock_kernel();
mutex_lock(&state->mutex);
if (port->type != PORT_UNKNOWN)
port->ops->break_ctl(port, break_state);
mutex_unlock(&state->mutex);
- unlock_kernel();
}
static int uart_do_autoconfig(struct uart_state *state)
@@ -1074,7 +1089,6 @@
int ret = -ENOIOCTLCMD;
- lock_kernel();
/*
* These ioctls don't rely on the hardware to be present.
*/
@@ -1144,10 +1158,9 @@
break;
}
}
- out_up:
+out_up:
mutex_unlock(&state->mutex);
- out:
- unlock_kernel();
+out:
return ret;
}
@@ -1173,7 +1186,6 @@
return;
}
- lock_kernel();
uart_change_speed(state, old_termios);
/* Handle transition to B0 status */
@@ -1206,7 +1218,6 @@
}
spin_unlock_irqrestore(&state->port->lock, flags);
}
- unlock_kernel();
#if 0
/*
* No need to wake up processes in open wait, since they
@@ -1322,11 +1333,11 @@
struct uart_port *port = state->port;
unsigned long char_time, expire;
- BUG_ON(!kernel_locked());
-
if (port->type == PORT_UNKNOWN || port->fifosize == 0)
return;
+ lock_kernel();
+
/*
* Set the check interval to be 1/5 of the estimated time to
* send a single character, and make it at least 1. The check
@@ -1372,6 +1383,7 @@
break;
}
set_current_state(TASK_RUNNING); /* might not be needed */
+ unlock_kernel();
}
/*
@@ -2085,7 +2097,9 @@
int ret;
uart_change_pm(state, 0);
+ spin_lock_irq(&port->lock);
ops->set_mctrl(port, 0);
+ spin_unlock_irq(&port->lock);
ret = ops->startup(port);
if (ret == 0) {
uart_change_speed(state, NULL);
