[PATCH 3/8] tty: Replace ASYNC_NORMAL_ACTIVE bit and update atomically

From: Peter Hurley
Date: Sat Apr 09 2016 - 20:55:25 EST

Replace ASYNC_NORMAL_ACTIVE bit in the tty_port::flags field with
TTY_PORT_ACTIVE bit in the tty_port::iflags field. Introduce helpers
tty_port_set_active() and tty_port_active() to abstract atomic bit ops.

Extract state changes from port lock sections, as this usage is
broken and confused; the state transitions are protected by the
tty lock (which mutually excludes parallel open/close/hangup),
and no user tests the active state while holding the port lock.

Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
---
drivers/isdn/i4l/isdn_tty.c | 20 +++++++++-----------
drivers/tty/amiserial.c | 2 +-
drivers/tty/rocket.c | 5 +++--
drivers/tty/serial/crisv10.c | 8 ++++----
drivers/tty/serial/serial_core.c | 8 ++++----
drivers/tty/synclink.c | 6 +++---
drivers/tty/synclink_gt.c | 6 +++---
drivers/tty/synclinkmp.c | 6 +++---
drivers/tty/tty_port.c | 12 ++++++------
include/linux/tty.h | 12 ++++++++++++
net/irda/ircomm/ircomm_tty.c | 10 +++++-----
11 files changed, 53 insertions(+), 42 deletions(-)

diff --git a/drivers/isdn/i4l/isdn_tty.c b/drivers/isdn/i4l/isdn_tty.c
index f1edc08..d8468f3 100644
--- a/drivers/isdn/i4l/isdn_tty.c
+++ b/drivers/isdn/i4l/isdn_tty.c
@@ -1622,7 +1622,7 @@ isdn_tty_hangup(struct tty_struct *tty)
return;
isdn_tty_shutdown(info);
port->count = 0;
- port->flags &= ~ASYNC_NORMAL_ACTIVE;
+ tty_port_set_active(port, 0);
port->tty = NULL;
wake_up_interruptible(&port->open_wait);
}
@@ -1979,7 +1979,7 @@ isdn_tty_find_icall(int di, int ch, setup_parm *setup)
#endif
if (
#ifndef FIX_FILE_TRANSFER
- (info->port.flags & ASYNC_NORMAL_ACTIVE) &&
+ tty_port_active(&info->port) &&
#endif
(info->isdn_driver == -1) &&
(info->isdn_channel == -1) &&
@@ -2018,8 +2018,6 @@ isdn_tty_find_icall(int di, int ch, setup_parm *setup)
return (wret == 2) ? 3 : 0;
}

-#define TTY_IS_ACTIVE(info) (info->port.flags & ASYNC_NORMAL_ACTIVE)
-
int
isdn_tty_stat_callback(int i, isdn_ctrl *c)
{
@@ -2077,7 +2075,7 @@ isdn_tty_stat_callback(int i, isdn_ctrl *c)
#ifdef ISDN_TTY_STAT_DEBUG
printk(KERN_DEBUG "tty_STAT_DCONN ttyI%d\n", info->line);
#endif
- if (TTY_IS_ACTIVE(info)) {
+ if (tty_port_active(&info->port)) {
if (info->dialing == 1) {
info->dialing = 2;
return 1;
@@ -2088,7 +2086,7 @@ isdn_tty_stat_callback(int i, isdn_ctrl *c)
#ifdef ISDN_TTY_STAT_DEBUG
printk(KERN_DEBUG "tty_STAT_DHUP ttyI%d\n", info->line);
#endif
- if (TTY_IS_ACTIVE(info)) {
+ if (tty_port_active(&info->port)) {
if (info->dialing == 1)
isdn_tty_modem_result(RESULT_BUSY, info);
if (info->dialing > 1)
@@ -2118,7 +2116,7 @@ isdn_tty_stat_callback(int i, isdn_ctrl *c)
* waiting for it and
* set DCD-bit of its modem-status.
*/
- if (TTY_IS_ACTIVE(info) ||
+ if (tty_port_active(&info->port) ||
(info->port.blocked_open &&
(info->emu.mdmreg[REG_DCD] & BIT_DCD))) {
info->msr |= UART_MSR_DCD;
@@ -2145,7 +2143,7 @@ isdn_tty_stat_callback(int i, isdn_ctrl *c)
#ifdef ISDN_TTY_STAT_DEBUG
printk(KERN_DEBUG "tty_STAT_BHUP ttyI%d\n", info->line);
#endif
- if (TTY_IS_ACTIVE(info)) {
+ if (tty_port_active(&info->port)) {
#ifdef ISDN_DEBUG_MODEM_HUP
printk(KERN_DEBUG "Mhup in ISDN_STAT_BHUP\n");
#endif
@@ -2157,7 +2155,7 @@ isdn_tty_stat_callback(int i, isdn_ctrl *c)
#ifdef ISDN_TTY_STAT_DEBUG
printk(KERN_DEBUG "tty_STAT_NODCH ttyI%d\n", info->line);
#endif
- if (TTY_IS_ACTIVE(info)) {
+ if (tty_port_active(&info->port)) {
if (info->dialing) {
info->dialing = 0;
info->last_l2 = -1;
@@ -2183,14 +2181,14 @@ isdn_tty_stat_callback(int i, isdn_ctrl *c)
return 1;
#ifdef CONFIG_ISDN_TTY_FAX
case ISDN_STAT_FAXIND:
- if (TTY_IS_ACTIVE(info)) {
+ if (tty_port_active(&info->port)) {
isdn_tty_fax_command(info, c);
}
break;
#endif
#ifdef CONFIG_ISDN_AUDIO
case ISDN_STAT_AUDIO:
- if (TTY_IS_ACTIVE(info)) {
+ if (tty_port_active(&info->port)) {
switch (c->parm.num[0]) {
case ISDN_AUDIO_DTMF:
if (info->vonline) {
diff --git a/drivers/tty/amiserial.c b/drivers/tty/amiserial.c
index 92717b0..80d6165 100644
--- a/drivers/tty/amiserial.c
+++ b/drivers/tty/amiserial.c
@@ -1493,7 +1493,7 @@ static void rs_hangup(struct tty_struct *tty)
rs_flush_buffer(tty);
shutdown(tty, info);
info->tport.count = 0;
- info->tport.flags &= ~ASYNC_NORMAL_ACTIVE;
+ tty_port_set_active(&info->tport, 0);
info->tport.tty = NULL;
wake_up_interruptible(&info->tport.open_wait);
}
diff --git a/drivers/tty/rocket.c b/drivers/tty/rocket.c
index 0b802cd..eb8311b 100644
--- a/drivers/tty/rocket.c
+++ b/drivers/tty/rocket.c
@@ -1042,9 +1042,10 @@ static void rp_close(struct tty_struct *tty, struct file *filp)
}
}
spin_lock_irq(&port->lock);
- info->port.flags &= ~(ASYNC_INITIALIZED | ASYNC_NORMAL_ACTIVE);
+ port->flags &= ~ASYNC_INITIALIZED;
tty->closing = 0;
spin_unlock_irq(&port->lock);
+ tty_port_set_active(port, 0);
mutex_unlock(&port->mutex);
tty_port_tty_set(port, NULL);

@@ -1624,7 +1625,7 @@ static int rp_write(struct tty_struct *tty,
/* Write remaining data into the port's xmit_buf */
while (1) {
/* Hung up ? */
- if (!test_bit(ASYNCB_NORMAL_ACTIVE, &info->port.flags))
+ if (!tty_port_active(&info->port))
goto end;
c = min(count, XMIT_BUF_SIZE - info->xmit_cnt - 1);
c = min(c, XMIT_BUF_SIZE - info->xmit_head);
diff --git a/drivers/tty/serial/crisv10.c b/drivers/tty/serial/crisv10.c
index 5469903..92c8c62 100644
--- a/drivers/tty/serial/crisv10.c
+++ b/drivers/tty/serial/crisv10.c
@@ -3648,8 +3648,8 @@ rs_close(struct tty_struct *tty, struct file * filp)
schedule_timeout_interruptible(info->port.close_delay);
wake_up_interruptible(&info->port.open_wait);
}
- info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
local_irq_restore(flags);
+ tty_port_set_active(&info->port, 0);

/* port closed */

@@ -3732,7 +3732,7 @@ rs_hangup(struct tty_struct *tty)
shutdown(info);
info->event = 0;
info->port.count = 0;
- info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
+ tty_port_set_active(&info->port, 0);
info->port.tty = NULL;
wake_up_interruptible(&info->port.open_wait);
}
@@ -3756,7 +3756,7 @@ block_til_ready(struct tty_struct *tty, struct file * filp,
* then make the check up front and then exit.
*/
if ((filp->f_flags & O_NONBLOCK) || tty_io_error(tty)) {
- info->port.flags |= ASYNC_NORMAL_ACTIVE;
+ tty_port_set_active(&info->port, 1);
return 0;
}

@@ -3825,7 +3825,7 @@ block_til_ready(struct tty_struct *tty, struct file * filp,
#endif
if (retval)
return retval;
- info->port.flags |= ASYNC_NORMAL_ACTIVE;
+ tty_port_set_active(&info->port, 1);
return 0;
}

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 64a5c00..2471380 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1418,12 +1418,12 @@ static void uart_close(struct tty_struct *tty, struct file *filp)
uart_change_pm(state, UART_PM_STATE_OFF);
spin_lock_irq(&port->lock);
}
+ spin_unlock_irq(&port->lock);
+ tty_port_set_active(port, 0);

/*
* Wake up anyone trying to open this port.
*/
- clear_bit(ASYNCB_NORMAL_ACTIVE, &port->flags);
- spin_unlock_irq(&port->lock);
wake_up_interruptible(&port->open_wait);

mutex_unlock(&port->mutex);
@@ -1501,13 +1501,13 @@ static void uart_hangup(struct tty_struct *tty)
pr_debug("uart_hangup(%d)\n", tty->index);

mutex_lock(&port->mutex);
- if (port->flags & ASYNC_NORMAL_ACTIVE) {
+ if (tty_port_active(port)) {
uart_flush_buffer(tty);
uart_shutdown(tty, state);
spin_lock_irqsave(&port->lock, flags);
port->count = 0;
- clear_bit(ASYNCB_NORMAL_ACTIVE, &port->flags);
spin_unlock_irqrestore(&port->lock, flags);
+ tty_port_set_active(port, 0);
tty_port_tty_set(port, NULL);
if (!uart_console(state->uart_port))
uart_change_pm(state, UART_PM_STATE_OFF);
diff --git a/drivers/tty/synclink.c b/drivers/tty/synclink.c
index 0e42901..b55f846 100644
--- a/drivers/tty/synclink.c
+++ b/drivers/tty/synclink.c
@@ -3201,7 +3201,7 @@ static void mgsl_hangup(struct tty_struct *tty)
shutdown(info);

info->port.count = 0;
- info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
+ tty_port_set_active(&info->port, 0);
info->port.tty = NULL;

wake_up_interruptible(&info->port.open_wait);
@@ -3269,7 +3269,7 @@ static int block_til_ready(struct tty_struct *tty, struct file * filp,

if (filp->f_flags & O_NONBLOCK || tty_io_error(tty)) {
/* nonblock mode is set or port is not enabled */
- port->flags |= ASYNC_NORMAL_ACTIVE;
+ tty_port_set_active(port, 1);
return 0;
}

@@ -3338,7 +3338,7 @@ static int block_til_ready(struct tty_struct *tty, struct file * filp,
__FILE__,__LINE__, tty->driver->name, port->count );

if (!retval)
- port->flags |= ASYNC_NORMAL_ACTIVE;
+ tty_port_set_active(port, 1);

return retval;

diff --git a/drivers/tty/synclink_gt.c b/drivers/tty/synclink_gt.c
index 5da69d3..c76f546 100644
--- a/drivers/tty/synclink_gt.c
+++ b/drivers/tty/synclink_gt.c
@@ -756,9 +756,9 @@ static void hangup(struct tty_struct *tty)

spin_lock_irqsave(&info->port.lock, flags);
info->port.count = 0;
- info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
info->port.tty = NULL;
spin_unlock_irqrestore(&info->port.lock, flags);
+ tty_port_set_active(&info->port, 0);
mutex_unlock(&info->port.mutex);

wake_up_interruptible(&info->port.open_wait);
@@ -3268,7 +3268,7 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,

if (filp->f_flags & O_NONBLOCK || tty_io_error(tty)) {
/* nonblock mode is set or port is not enabled */
- port->flags |= ASYNC_NORMAL_ACTIVE;
+ tty_port_set_active(port, 1);
return 0;
}

@@ -3325,7 +3325,7 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
port->blocked_open--;

if (!retval)
- port->flags |= ASYNC_NORMAL_ACTIVE;
+ tty_port_set_active(port, 1);

DBGINFO(("%s block_til_ready ready, rc=%d\n", tty->driver->name, retval));
return retval;
diff --git a/drivers/tty/synclinkmp.c b/drivers/tty/synclinkmp.c
index 7a21491..95eddc4 100644
--- a/drivers/tty/synclinkmp.c
+++ b/drivers/tty/synclinkmp.c
@@ -849,9 +849,9 @@ static void hangup(struct tty_struct *tty)

spin_lock_irqsave(&info->port.lock, flags);
info->port.count = 0;
- info->port.flags &= ~ASYNC_NORMAL_ACTIVE;
info->port.tty = NULL;
spin_unlock_irqrestore(&info->port.lock, flags);
+ tty_port_set_active(&info->port, 1);
mutex_unlock(&info->port.mutex);

wake_up_interruptible(&info->port.open_wait);
@@ -3285,7 +3285,7 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
if (filp->f_flags & O_NONBLOCK || tty_io_error(tty)) {
/* nonblock mode is set or port is not enabled */
/* just verify that callout device is not active */
- port->flags |= ASYNC_NORMAL_ACTIVE;
+ tty_port_set_active(port, 1);
return 0;
}

@@ -3352,7 +3352,7 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
__FILE__,__LINE__, tty->driver->name, port->count );

if (!retval)
- port->flags |= ASYNC_NORMAL_ACTIVE;
+ tty_port_set_active(port, 1);

return retval;
}
diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index 9127c54..130c8cf 100644
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -236,12 +236,12 @@ void tty_port_hangup(struct tty_port *port)

spin_lock_irqsave(&port->lock, flags);
port->count = 0;
- port->flags &= ~ASYNC_NORMAL_ACTIVE;
tty = port->tty;
if (tty)
set_bit(TTY_IO_ERROR, &tty->flags);
port->tty = NULL;
spin_unlock_irqrestore(&port->lock, flags);
+ tty_port_set_active(port, 0);
tty_port_shutdown(port, tty);
tty_kref_put(tty);
wake_up_interruptible(&port->open_wait);
@@ -365,14 +365,14 @@ int tty_port_block_til_ready(struct tty_port *port,
/* if non-blocking mode is set we can pass directly to open unless
the port has just hung up or is in another error state */
if (tty_io_error(tty)) {
- port->flags |= ASYNC_NORMAL_ACTIVE;
+ tty_port_set_active(port, 1);
return 0;
}
if (filp->f_flags & O_NONBLOCK) {
/* Indicate we are open */
if (C_BAUD(tty))
tty_port_raise_dtr_rts(port);
- port->flags |= ASYNC_NORMAL_ACTIVE;
+ tty_port_set_active(port, 1);
return 0;
}

@@ -430,9 +430,9 @@ int tty_port_block_til_ready(struct tty_port *port,
if (!tty_hung_up_p(filp))
port->count++;
port->blocked_open--;
- if (retval == 0)
- port->flags |= ASYNC_NORMAL_ACTIVE;
spin_unlock_irqrestore(&port->lock, flags);
+ if (retval == 0)
+ tty_port_set_active(port, 1);
return retval;
}
EXPORT_SYMBOL(tty_port_block_til_ready);
@@ -514,8 +514,8 @@ void tty_port_close_end(struct tty_port *port, struct tty_struct *tty)
spin_lock_irqsave(&port->lock, flags);
wake_up_interruptible(&port->open_wait);
}
- port->flags &= ~ASYNC_NORMAL_ACTIVE;
spin_unlock_irqrestore(&port->lock, flags);
+ tty_port_set_active(port, 0);
}
EXPORT_SYMBOL(tty_port_close_end);

diff --git a/include/linux/tty.h b/include/linux/tty.h
index 989d755b..dbeeb86 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -571,6 +571,18 @@ static inline void tty_port_set_cts_flow(struct tty_port *port, bool val)
clear_bit(TTY_PORT_CTS_FLOW, &port->iflags);
}

+static inline bool tty_port_active(struct tty_port *port)
+{
+ return test_bit(TTY_PORT_ACTIVE, &port->iflags);
+}
+
+static inline void tty_port_set_active(struct tty_port *port, bool val)
+{
+ if (val)
+ set_bit(TTY_PORT_ACTIVE, &port->iflags);
+ else
+ clear_bit(TTY_PORT_ACTIVE, &port->iflags);
+}

extern struct tty_struct *tty_port_tty_get(struct tty_port *port);
extern void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty);
diff --git a/net/irda/ircomm/ircomm_tty.c b/net/irda/ircomm/ircomm_tty.c
index 840b82f..681fe0b 100644
--- a/net/irda/ircomm/ircomm_tty.c
+++ b/net/irda/ircomm/ircomm_tty.c
@@ -281,7 +281,7 @@ static int ircomm_tty_block_til_ready(struct ircomm_tty_cb *self,
* then make the check up front and then exit.
*/
if (tty_io_error(tty)) {
- port->flags |= ASYNC_NORMAL_ACTIVE;
+ tty_port_set_active(port, 1);
return 0;
}

@@ -289,7 +289,7 @@ static int ircomm_tty_block_til_ready(struct ircomm_tty_cb *self,
/* nonblock mode is set */
if (C_BAUD(tty))
tty_port_raise_dtr_rts(port);
- port->flags |= ASYNC_NORMAL_ACTIVE;
+ tty_port_set_active(port, 1);
pr_debug("%s(), O_NONBLOCK requested!\n", __func__);
return 0;
}
@@ -365,7 +365,7 @@ static int ircomm_tty_block_til_ready(struct ircomm_tty_cb *self,
__FILE__, __LINE__, tty->driver->name, port->count);

if (!retval)
- port->flags |= ASYNC_NORMAL_ACTIVE;
+ tty_port_set_active(port, 1);

return retval;
}
@@ -925,7 +925,6 @@ static void ircomm_tty_hangup(struct tty_struct *tty)
ircomm_tty_shutdown(self);

spin_lock_irqsave(&port->lock, flags);
- port->flags &= ~ASYNC_NORMAL_ACTIVE;
if (port->tty) {
set_bit(TTY_IO_ERROR, &port->tty->flags);
tty_kref_put(port->tty);
@@ -933,6 +932,7 @@ static void ircomm_tty_hangup(struct tty_struct *tty)
port->tty = NULL;
port->count = 0;
spin_unlock_irqrestore(&port->lock, flags);
+ tty_port_set_active(port, 0);

wake_up_interruptible(&port->open_wait);
}
@@ -1267,7 +1267,7 @@ static void ircomm_tty_line_info(struct ircomm_tty_cb *self, struct seq_file *m)
seq_printf(m, "%cASYNC_LOW_LATENCY", sep);
sep = '|';
}
- if (self->port.flags & ASYNC_NORMAL_ACTIVE) {
+ if (tty_port_active(&self->port)) {
seq_printf(m, "%cASYNC_NORMAL_ACTIVE", sep);
sep = '|';
}
--
2.8.1