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tty: relock epca

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Bring epca into line with the port locking.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alan Cox 2009-01-02 13:47:58 +00:00 committed by Linus Torvalds
parent 542f548236
commit d1c815e549
1 changed files with 108 additions and 95 deletions
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203
drivers/char/epca.c
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@ -69,7 +69,9 @@ static int invalid_lilo_config;
/*
* The ISA boards do window flipping into the same spaces so its only sane with
* a single lock. It's still pretty efficient.
* a single lock. It's still pretty efficient. This lock guards the hardware
* and the tty_port lock guards the kernel side stuff like use counts. Take
* this lock inside the port lock if you must take both.
*/
static DEFINE_SPINLOCK(epca_lock);
@ -156,7 +158,7 @@ static struct channel *verifyChannel(struct tty_struct *);
static void pc_sched_event(struct channel *, int);
static void epca_error(int, char *);
static void pc_close(struct tty_struct *, struct file *);
static void shutdown(struct channel *);
static void shutdown(struct channel *, struct tty_struct *tty);
static void pc_hangup(struct tty_struct *);
static int pc_write_room(struct tty_struct *);
static int pc_chars_in_buffer(struct tty_struct *);
@ -419,76 +421,78 @@ static void epca_error(int line, char *msg)
static void pc_close(struct tty_struct *tty, struct file *filp)
{
struct channel *ch;
struct tty_port *port;
unsigned long flags;
/*
* verifyChannel returns the channel from the tty struct if it is
* valid. This serves as a sanity check.
*/
ch = verifyChannel(tty);
if (ch != NULL) {
spin_lock_irqsave(&epca_lock, flags);
if (tty_hung_up_p(filp)) {
spin_unlock_irqrestore(&epca_lock, flags);
return;
}
if (ch->port.count-- > 1) {
/* Begin channel is open more than once */
/*
* Return without doing anything. Someone might still
* be using the channel.
*/
spin_unlock_irqrestore(&epca_lock, flags);
return;
}
/* Port open only once go ahead with shutdown & reset */
BUG_ON(ch->port.count < 0);
if (ch == NULL)
return;
port = &ch->port;
/*
* Let the rest of the driver know the channel is being closed.
* This becomes important if an open is attempted before close
* is finished.
*/
ch->port.flags |= ASYNC_CLOSING;
tty->closing = 1;
spin_unlock_irqrestore(&epca_lock, flags);
if (ch->port.flags & ASYNC_INITIALIZED) {
/* Setup an event to indicate when the
transmit buffer empties */
setup_empty_event(tty, ch);
/* 30 seconds timeout */
tty_wait_until_sent(tty, 3000);
}
pc_flush_buffer(tty);
tty_ldisc_flush(tty);
shutdown(ch);
spin_lock_irqsave(&epca_lock, flags);
tty->closing = 0;
ch->event = 0;
ch->port.tty = NULL;
spin_unlock_irqrestore(&epca_lock, flags);
if (ch->port.blocked_open) {
if (ch->close_delay)
msleep_interruptible(jiffies_to_msecs(ch->close_delay));
wake_up_interruptible(&ch->port.open_wait);
}
ch->port.flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_INITIALIZED |
ASYNC_CLOSING);
wake_up_interruptible(&ch->port.close_wait);
spin_lock_irqsave(&port->lock, flags);
if (tty_hung_up_p(filp)) {
spin_unlock_irqrestore(&port->lock, flags);
return;
}
if (port->count-- > 1) {
/* Begin channel is open more than once */
/*
* Return without doing anything. Someone might still
* be using the channel.
*/
spin_unlock_irqrestore(&port->lock, flags);
return;
}
/* Port open only once go ahead with shutdown & reset */
WARN_ON(port->count < 0);
/*
* Let the rest of the driver know the channel is being closed.
* This becomes important if an open is attempted before close
* is finished.
*/
port->flags |= ASYNC_CLOSING;
tty->closing = 1;
spin_unlock_irqrestore(&port->lock, flags);
if (port->flags & ASYNC_INITIALIZED) {
/* Setup an event to indicate when the
transmit buffer empties */
setup_empty_event(tty, ch);
/* 30 seconds timeout */
tty_wait_until_sent(tty, 3000);
}
pc_flush_buffer(tty);
tty_ldisc_flush(tty);
shutdown(ch, tty);
spin_lock_irqsave(&port->lock, flags);
tty->closing = 0;
ch->event = 0;
port->tty = NULL;
spin_unlock_irqrestore(&port->lock, flags);
if (port->blocked_open) {
if (ch->close_delay)
msleep_interruptible(jiffies_to_msecs(ch->close_delay));
wake_up_interruptible(&port->open_wait);
}
port->flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_INITIALIZED |
ASYNC_CLOSING);
wake_up_interruptible(&port->close_wait);
}
static void shutdown(struct channel *ch)
static void shutdown(struct channel *ch, struct tty_struct *tty)
{
unsigned long flags;
struct tty_struct *tty;
struct board_chan __iomem *bc;
struct tty_port *port = &ch->port;
if (!(ch->port.flags & ASYNC_INITIALIZED))
if (!(port->flags & ASYNC_INITIALIZED))
return;
spin_lock_irqsave(&epca_lock, flags);
@ -503,7 +507,6 @@ static void shutdown(struct channel *ch)
*/
if (bc)
writeb(0, &bc->idata);
tty = ch->port.tty;
/* If we're a modem control device and HUPCL is on, drop RTS & DTR. */
if (tty->termios->c_cflag & HUPCL) {
@ -517,13 +520,15 @@ static void shutdown(struct channel *ch)
* will have to reinitialized. Set a flag to indicate this.
*/
/* Prevent future Digi programmed interrupts from coming active */
ch->port.flags &= ~ASYNC_INITIALIZED;
port->flags &= ~ASYNC_INITIALIZED;
spin_unlock_irqrestore(&epca_lock, flags);
}
static void pc_hangup(struct tty_struct *tty)
{
struct channel *ch;
struct tty_port *port;
/*
* verifyChannel returns the channel from the tty struct if it is
* valid. This serves as a sanity check.
@ -531,18 +536,19 @@ static void pc_hangup(struct tty_struct *tty)
ch = verifyChannel(tty);
if (ch != NULL) {
unsigned long flags;
port = &ch->port;
pc_flush_buffer(tty);
tty_ldisc_flush(tty);
shutdown(ch);
shutdown(ch, tty);
spin_lock_irqsave(&epca_lock, flags);
ch->port.tty = NULL;
ch->event = 0;
ch->port.count = 0;
ch->port.flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_INITIALIZED);
spin_unlock_irqrestore(&epca_lock, flags);
wake_up_interruptible(&ch->port.open_wait);
spin_lock_irqsave(&port->lock, flags);
port->tty = NULL;
ch->event = 0; /* FIXME: review locking of ch->event */
port->count = 0;
port->flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_INITIALIZED);
spin_unlock_irqrestore(&port->lock, flags);
wake_up_interruptible(&port->open_wait);
}
}
@ -792,9 +798,10 @@ static int block_til_ready(struct tty_struct *tty,
DECLARE_WAITQUEUE(wait, current);
int retval, do_clocal = 0;
unsigned long flags;
struct tty_port *port = &ch->port;
if (tty_hung_up_p(filp)) {
if (ch->port.flags & ASYNC_HUP_NOTIFY)
if (port->flags & ASYNC_HUP_NOTIFY)
retval = -EAGAIN;
else
retval = -ERESTARTSYS;
@ -805,10 +812,10 @@ static int block_til_ready(struct tty_struct *tty,
* If the device is in the middle of being closed, then block until
* it's done, and then try again.
*/
if (ch->port.flags & ASYNC_CLOSING) {
interruptible_sleep_on(&ch->port.close_wait);
if (port->flags & ASYNC_CLOSING) {
interruptible_sleep_on(&port->close_wait);
if (ch->port.flags & ASYNC_HUP_NOTIFY)
if (port->flags & ASYNC_HUP_NOTIFY)
return -EAGAIN;
else
return -ERESTARTSYS;
@ -819,7 +826,7 @@ static int block_til_ready(struct tty_struct *tty,
* If non-blocking mode is set, then make the check up front
* and then exit.
*/
ch->port.flags |= ASYNC_NORMAL_ACTIVE;
port->flags |= ASYNC_NORMAL_ACTIVE;
return 0;
}
if (tty->termios->c_cflag & CLOCAL)
@ -827,31 +834,31 @@ static int block_til_ready(struct tty_struct *tty,
/* Block waiting for the carrier detect and the line to become free */
retval = 0;
add_wait_queue(&ch->port.open_wait, &wait);
add_wait_queue(&port->open_wait, &wait);
spin_lock_irqsave(&epca_lock, flags);
spin_lock_irqsave(&port->lock, flags);
/* We dec count so that pc_close will know when to free things */
if (!tty_hung_up_p(filp))
ch->port.count--;
ch->port.blocked_open++;
port->count--;
port->blocked_open++;
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
if (tty_hung_up_p(filp) ||
!(ch->port.flags & ASYNC_INITIALIZED)) {
if (ch->port.flags & ASYNC_HUP_NOTIFY)
!(port->flags & ASYNC_INITIALIZED)) {
if (port->flags & ASYNC_HUP_NOTIFY)
retval = -EAGAIN;
else
retval = -ERESTARTSYS;
break;
}
if (!(ch->port.flags & ASYNC_CLOSING) &&
if (!(port->flags & ASYNC_CLOSING) &&
(do_clocal || (ch->imodem & ch->dcd)))
break;
if (signal_pending(current)) {
retval = -ERESTARTSYS;
break;
}
spin_unlock_irqrestore(&epca_lock, flags);
spin_unlock_irqrestore(&port->lock, flags);
/*
* Allow someone else to be scheduled. We will occasionally go
* through this loop until one of the above conditions change.
@ -859,27 +866,28 @@ static int block_til_ready(struct tty_struct *tty,
* and prevent this loop from hogging the cpu.
*/
schedule();
spin_lock_irqsave(&epca_lock, flags);
spin_lock_irqsave(&port->lock, flags);
}
__set_current_state(TASK_RUNNING);
remove_wait_queue(&ch->port.open_wait, &wait);
remove_wait_queue(&port->open_wait, &wait);
if (!tty_hung_up_p(filp))
ch->port.count++;
ch->port.blocked_open--;
port->count++;
port->blocked_open--;
spin_unlock_irqrestore(&epca_lock, flags);
spin_unlock_irqrestore(&port->lock, flags);
if (retval)
return retval;
ch->port.flags |= ASYNC_NORMAL_ACTIVE;
port->flags |= ASYNC_NORMAL_ACTIVE;
return 0;
}
static int pc_open(struct tty_struct *tty, struct file *filp)
{
struct channel *ch;
struct tty_port *port;
unsigned long flags;
int line, retval, boardnum;
struct board_chan __iomem *bc;
@ -890,6 +898,7 @@ static int pc_open(struct tty_struct *tty, struct file *filp)
return -ENODEV;
ch = &digi_channels[line];
port = &ch->port;
boardnum = ch->boardnum;
/* Check status of board configured in system. */
@ -926,22 +935,24 @@ static int pc_open(struct tty_struct *tty, struct file *filp)
return -ENODEV;
}
spin_lock_irqsave(&epca_lock, flags);
spin_lock_irqsave(&port->lock, flags);
/*
* Every time a channel is opened, increment a counter. This is
* necessary because we do not wish to flush and shutdown the channel
* until the last app holding the channel open, closes it.
*/
ch->port.count++;
port->count++;
/*
* Set a kernel structures pointer to our local channel structure. This
* way we can get to it when passed only a tty struct.
*/
tty->driver_data = ch;
port->tty = tty;
/*
* If this is the first time the channel has been opened, initialize
* the tty->termios struct otherwise let pc_close handle it.
*/
spin_lock(&epca_lock);
globalwinon(ch);
ch->statusflags = 0;
@ -956,16 +967,16 @@ static int pc_open(struct tty_struct *tty, struct file *filp)
writew(head, &bc->rout);
/* Set the channels associated tty structure */
ch->port.tty = tty;
/*
* The below routine generally sets up parity, baud, flow control
* issues, etc.... It effect both control flags and input flags.
*/
epcaparam(tty, ch);
ch->port.flags |= ASYNC_INITIALIZED;
memoff(ch);
spin_unlock_irqrestore(&epca_lock, flags);
spin_unlock(&epca_lock);
port->flags |= ASYNC_INITIALIZED;
spin_unlock_irqrestore(&port->lock, flags);
retval = block_til_ready(tty, filp, ch);
if (retval)
@ -974,13 +985,15 @@ static int pc_open(struct tty_struct *tty, struct file *filp)
* Set this again in case a hangup set it to zero while this open() was
* waiting for the line...
*/
spin_lock_irqsave(&epca_lock, flags);
ch->port.tty = tty;
spin_lock_irqsave(&port->lock, flags);
port->tty = tty;
spin_lock(&epca_lock);
globalwinon(ch);
/* Enable Digi Data events */
writeb(1, &bc->idata);
memoff(ch);
spin_unlock_irqrestore(&epca_lock, flags);
spin_unlock(&epca_lock);
spin_unlock_irqrestore(&port->lock, flags);
return 0;
}