tty: Remove ASYNC_CLOSING checks in open()/hangup() methods

Since at least before 2.6.30, tty drivers that do not drop the tty lock
while closing cannot observe ASYNC_CLOSING set while holding the
tty lock; this includes the tty driver's open() and hangup() methods,
since the tty core calls these methods holding the tty lock.

For these drivers, waiting for ASYNC_CLOSING to clear while opening
is not required, since this condition cannot occur. Similarly, even
when the open() method drops and reacquires the tty lock after
blocking, ASYNC_CLOSING cannot be set (again, for drivers that
do not drop the tty lock while closing).

Now that tty port drivers no longer drop the tty lock while closing
(since 'tty: Remove tty_wait_until_sent_from_close()'), the same
conditions apply: waiting for ASYNC_CLOSING to clear while opening
is not required, nor is re-checking ASYNC_CLOSING after dropping and
reacquiring the tty lock while blocking (eg., in *_block_til_ready()).

Note: The ASYNC_CLOSING flag state is still maintained since several
bitrotting drivers use it for (dubious) other purposes.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/char/pcmcia/synclink_cs.c b/drivers/char/pcmcia/synclink_cs.c
index 7680d5213ff840a095e94b1ce666b41a266617c1..45df4bf914f89fc6ec1fb2398c272f1b6f0444b9 100644 (file)
--- a/drivers/char/pcmcia/synclink_cs.c
+++ b/drivers/char/pcmcia/synclink_cs.c
@@ -2507,15 +2507,6 @@ static int mgslpc_open(struct tty_struct *tty, struct file * filp)
                printk("%s(%d):mgslpc_open(%s), old ref count = %d\n",
                         __FILE__, __LINE__, tty->driver->name, port->count);
 
-       /* If port is closing, signal caller to try again */
-       if (port->flags & ASYNC_CLOSING){
-               wait_event_interruptible_tty(tty, port->close_wait,
-                                            !(port->flags & ASYNC_CLOSING));
-               retval = ((port->flags & ASYNC_HUP_NOTIFY) ?
-                       -EAGAIN : -ERESTARTSYS);
-               goto cleanup;
-       }
-
        port->low_latency = (port->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
 
        spin_lock_irqsave(&info->netlock, flags);

diff --git a/drivers/tty/cyclades.c b/drivers/tty/cyclades.c
index 87f6578c6f4a389fbad842aebe9077d1577bab3a..d4a1331675ed5d69a3be971f91ceb59f27e0dbee 100644 (file)
--- a/drivers/tty/cyclades.c
+++ b/drivers/tty/cyclades.c
@@ -1576,15 +1576,6 @@ static int cy_open(struct tty_struct *tty, struct file *filp)
                current->pid, info->port.count);
 #endif
 
-       /*
-        * If the port is the middle of closing, bail out now
-        */
-       if (info->port.flags & ASYNC_CLOSING) {
-               wait_event_interruptible_tty(tty, info->port.close_wait,
-                               !(info->port.flags & ASYNC_CLOSING));
-               return (info->port.flags & ASYNC_HUP_NOTIFY) ? -EAGAIN: -ERESTARTSYS;
-       }
-
        /*
         * Start up serial port
         */

diff --git a/drivers/tty/rocket.c b/drivers/tty/rocket.c
index c8dd8dc31086ee5d373427dc5a7f04bee7cce1bb..69c72d1aa62753d80a61714ebe1e91c8385abb97 100644 (file)
--- a/drivers/tty/rocket.c
+++ b/drivers/tty/rocket.c
@@ -895,14 +895,6 @@ static int rp_open(struct tty_struct *tty, struct file *filp)
        if (!page)
                return -ENOMEM;
 
-       if (port->flags & ASYNC_CLOSING) {
-               retval = wait_for_completion_interruptible(&info->close_wait);
-               free_page(page);
-               if (retval)
-                       return retval;
-               return ((port->flags & ASYNC_HUP_NOTIFY) ? -EAGAIN : -ERESTARTSYS);
-       }
-
        /*
         * We must not sleep from here until the port is marked fully in use.
         */
@@ -1511,10 +1503,6 @@ static void rp_hangup(struct tty_struct *tty)
 #endif
        rp_flush_buffer(tty);
        spin_lock_irqsave(&info->port.lock, flags);
-       if (info->port.flags & ASYNC_CLOSING) {
-               spin_unlock_irqrestore(&info->port.lock, flags);
-               return;
-       }
        if (info->port.count)
                atomic_dec(&rp_num_ports_open);
        clear_bit((info->aiop * 8) + info->chan, (void *) &xmit_flags[info->board]);

diff --git a/drivers/tty/serial/crisv10.c b/drivers/tty/serial/crisv10.c
index 3e4470af5c50d56f8484273af1c61f864d8d2d03..06f4fe928dcd9b28567151ce281da027e6f8f241 100644 (file)
--- a/drivers/tty/serial/crisv10.c
+++ b/drivers/tty/serial/crisv10.c
@@ -3758,23 +3758,6 @@ block_til_ready(struct tty_struct *tty, struct file * filp,
        int             retval;
        int             do_clocal = 0;
 
-       /*
-        * If the device is in the middle of being closed, then block
-        * until it's done, and then try again.
-        */
-       if (info->port.flags & ASYNC_CLOSING) {
-               wait_event_interruptible_tty(tty, info->port.close_wait,
-                       !(info->port.flags & ASYNC_CLOSING));
-#ifdef SERIAL_DO_RESTART
-               if (info->port.flags & ASYNC_HUP_NOTIFY)
-                       return -EAGAIN;
-               else
-                       return -ERESTARTSYS;
-#else
-               return -EAGAIN;
-#endif
-       }
-
        /*
         * If non-blocking mode is set, or the port is not enabled,
         * then make the check up front and then exit.
@@ -3825,7 +3808,7 @@ block_til_ready(struct tty_struct *tty, struct file * filp,
 #endif
                        break;
                }
-               if (!(info->port.flags & ASYNC_CLOSING) && do_clocal)
+               if (do_clocal)
                        /* && (do_clocal || DCD_IS_ASSERTED) */
                        break;
                if (signal_pending(current)) {
@@ -3894,20 +3877,6 @@ rs_open(struct tty_struct *tty, struct file * filp)
 
        info->port.low_latency = !!(info->port.flags & ASYNC_LOW_LATENCY);
 
-       /*
-        * If the port is in the middle of closing, bail out now
-        */
-       if (info->port.flags & ASYNC_CLOSING) {
-               wait_event_interruptible_tty(tty, info->port.close_wait,
-                       !(info->port.flags & ASYNC_CLOSING));
-#ifdef SERIAL_DO_RESTART
-               return ((info->port.flags & ASYNC_HUP_NOTIFY) ?
-                       -EAGAIN : -ERESTARTSYS);
-#else
-               return -EAGAIN;
-#endif
-       }
-
        /*
         * If DMA is enabled try to allocate the irq's.
         */

diff --git a/drivers/tty/synclink.c b/drivers/tty/synclink.c
index 2fac7123b27419c16a53c7e01b6d08743b959cee..11d322b351dd584b4b2cf9429bb4e57431e63cb6 100644 (file)
--- a/drivers/tty/synclink.c
+++ b/drivers/tty/synclink.c
@@ -3314,12 +3314,11 @@ static int block_til_ready(struct tty_struct *tty, struct file * filp,
                                        -EAGAIN : -ERESTARTSYS;
                        break;
                }
-               
+
                dcd = tty_port_carrier_raised(&info->port);
-               
-               if (!(port->flags & ASYNC_CLOSING) && (do_clocal || dcd))
-                       break;
-                       
+               if (do_clocal || dcd)
+                       break;
+
                if (signal_pending(current)) {
                        retval = -ERESTARTSYS;
                        break;
@@ -3398,15 +3397,6 @@ static int mgsl_open(struct tty_struct *tty, struct file * filp)
                printk("%s(%d):mgsl_open(%s), old ref count = %d\n",
                         __FILE__,__LINE__,tty->driver->name, info->port.count);
 
-       /* If port is closing, signal caller to try again */
-       if (info->port.flags & ASYNC_CLOSING){
-               wait_event_interruptible_tty(tty, info->port.close_wait,
-                                    !(info->port.flags & ASYNC_CLOSING));
-               retval = ((info->port.flags & ASYNC_HUP_NOTIFY) ?
-                       -EAGAIN : -ERESTARTSYS);
-               goto cleanup;
-       }
-       
        info->port.low_latency = (info->port.flags & ASYNC_LOW_LATENCY) ? 1 : 0;
 
        spin_lock_irqsave(&info->netlock, flags);

diff --git a/drivers/tty/synclink_gt.c b/drivers/tty/synclink_gt.c
index 0ea8eee0017865af58c528c551b137711ea22ec2..6fc39fbfc27556088e0aa1e6744996497bcb06ea 100644 (file)
--- a/drivers/tty/synclink_gt.c
+++ b/drivers/tty/synclink_gt.c
@@ -672,15 +672,6 @@ static int open(struct tty_struct *tty, struct file *filp)
 
        DBGINFO(("%s open, old ref count = %d\n", info->device_name, info->port.count));
 
-       /* If port is closing, signal caller to try again */
-       if (info->port.flags & ASYNC_CLOSING){
-               wait_event_interruptible_tty(tty, info->port.close_wait,
-                                            !(info->port.flags & ASYNC_CLOSING));
-               retval = ((info->port.flags & ASYNC_HUP_NOTIFY) ?
-                       -EAGAIN : -ERESTARTSYS);
-               goto cleanup;
-       }
-
        mutex_lock(&info->port.mutex);
        info->port.low_latency = (info->port.flags & ASYNC_LOW_LATENCY) ? 1 : 0;
 
@@ -3320,9 +3311,8 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
                }
 
                cd = tty_port_carrier_raised(port);
-
-               if (!(port->flags & ASYNC_CLOSING) && (do_clocal || cd ))
-                       break;
+               if (do_clocal || cd)
+                       break;
 
                if (signal_pending(current)) {
                        retval = -ERESTARTSYS;

diff --git a/drivers/tty/synclinkmp.c b/drivers/tty/synclinkmp.c
index 08633a8139ffa072cc600d71ebc9ff023ff4b671..fb00a06dfa4bba12e41f4dd42bd38e2c95d16ee4 100644 (file)
--- a/drivers/tty/synclinkmp.c
+++ b/drivers/tty/synclinkmp.c
@@ -752,15 +752,6 @@ static int open(struct tty_struct *tty, struct file *filp)
                printk("%s(%d):%s open(), old ref count = %d\n",
                         __FILE__,__LINE__,tty->driver->name, info->port.count);
 
-       /* If port is closing, signal caller to try again */
-       if (info->port.flags & ASYNC_CLOSING){
-               wait_event_interruptible_tty(tty, info->port.close_wait,
-                                            !(info->port.flags & ASYNC_CLOSING));
-               retval = ((info->port.flags & ASYNC_HUP_NOTIFY) ?
-                       -EAGAIN : -ERESTARTSYS);
-               goto cleanup;
-       }
-
        info->port.low_latency = (info->port.flags & ASYNC_LOW_LATENCY) ? 1 : 0;
 
        spin_lock_irqsave(&info->netlock, flags);
@@ -3341,9 +3332,8 @@ static int block_til_ready(struct tty_struct *tty, struct file *filp,
                }
 
                cd = tty_port_carrier_raised(port);
-
-               if (!(port->flags & ASYNC_CLOSING) && (do_clocal || cd))
-                       break;
+               if (do_clocal || cd)
+                       break;
 
                if (signal_pending(current)) {
                        retval = -ERESTARTSYS;

diff --git a/drivers/tty/tty_port.c b/drivers/tty/tty_port.c
index d7d9f9cde964f8b3bcc18f2fe3949c669836df27..0e1cf0495fb9e0eb9d2f694f43aca80c8ee630d2 100644 (file)
--- a/drivers/tty/tty_port.c
+++ b/drivers/tty/tty_port.c
@@ -363,16 +363,6 @@ int tty_port_block_til_ready(struct tty_port *port,
        unsigned long flags;
        DEFINE_WAIT(wait);
 
-       /* block if port is in the process of being closed */
-       if (port->flags & ASYNC_CLOSING) {
-               wait_event_interruptible_tty(tty, port->close_wait,
-                               !(port->flags & ASYNC_CLOSING));
-               if (port->flags & ASYNC_HUP_NOTIFY)
-                       return -EAGAIN;
-               else
-                       return -ERESTARTSYS;
-       }
-
        /* 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->flags & (1 << TTY_IO_ERROR)) {
@@ -423,8 +413,7 @@ int tty_port_block_til_ready(struct tty_port *port,
                 * Never ask drivers if CLOCAL is set, this causes troubles
                 * on some hardware.
                 */
-               if (!(port->flags & ASYNC_CLOSING) &&
-                               (do_clocal || tty_port_carrier_raised(port)))
+               if (do_clocal || tty_port_carrier_raised(port))
                        break;
                if (signal_pending(current)) {
                        retval = -ERESTARTSYS;

diff --git a/net/irda/ircomm/ircomm_tty.c b/net/irda/ircomm/ircomm_tty.c
index 683346d2d633b4b2ac839e975e2c21d687242075..a4237707f79d56097099c2fe8704d686670cc9fe 100644 (file)
--- a/net/irda/ircomm/ircomm_tty.c
+++ b/net/irda/ircomm/ircomm_tty.c
@@ -335,8 +335,7 @@ static int ircomm_tty_block_til_ready(struct ircomm_tty_cb *self,
                 * specified, we cannot return before the IrCOMM link is
                 * ready
                 */
-               if (!test_bit(ASYNCB_CLOSING, &port->flags) &&
-                   (do_clocal || tty_port_carrier_raised(port)) &&
+               if ((do_clocal || tty_port_carrier_raised(port)) &&
                    self->state == IRCOMM_TTY_READY)
                {
                        break;
@@ -443,34 +442,6 @@ static int ircomm_tty_open(struct tty_struct *tty, struct file *filp)
        /* Not really used by us, but lets do it anyway */
        self->port.low_latency = (self->port.flags & ASYNC_LOW_LATENCY) ? 1 : 0;
 
-       /*
-        * If the port is the middle of closing, bail out now
-        */
-       if (test_bit(ASYNCB_CLOSING, &self->port.flags)) {
-
-               /* Hm, why are we blocking on ASYNC_CLOSING if we
-                * do return -EAGAIN/-ERESTARTSYS below anyway?
-                * IMHO it's either not needed in the first place
-                * or for some reason we need to make sure the async
-                * closing has been finished - if so, wouldn't we
-                * probably better sleep uninterruptible?
-                */
-
-               if (wait_event_interruptible(self->port.close_wait,
-                               !test_bit(ASYNCB_CLOSING, &self->port.flags))) {
-                       net_warn_ratelimited("%s - got signal while blocking on ASYNC_CLOSING!\n",
-                                            __func__);
-                       return -ERESTARTSYS;
-               }
-
-#ifdef SERIAL_DO_RESTART
-               return (self->port.flags & ASYNC_HUP_NOTIFY) ?
-                       -EAGAIN : -ERESTARTSYS;
-#else
-               return -EAGAIN;
-#endif
-       }
-
        /* Check if this is a "normal" ircomm device, or an irlpt device */
        if (self->line < 0x10) {
                self->service_type = IRCOMM_3_WIRE | IRCOMM_9_WIRE;