USB: serial: fix assumption that throttle/unthrottle cannot sleep

many serial subdrivers are clearly written as if throttle/unthrottle
cannot sleep. This leads to unneeded atomic submissions. This
patch converts affected drivers in a way to makes very clear that
throttle/unthrottle can sleep. Thus future misdesigns can be avoided
and efficiency and reliability improved.

This removes any such assumption using GFP_KERNEL and spin_lock_irq()

Signed-off-by: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

10 files changed, 37 insertions, 51 deletions

diff --git a/drivers/usb/serial/aircable.c b/drivers/usb/serial/aircable.c
index 2cbfab3716e5..b10ac8409411 100644
--- a/drivers/usb/serial/aircable.c
+++ b/drivers/usb/serial/aircable.c
@@ -554,13 +554,12 @@ static void aircable_throttle(struct tty_struct *tty)
 {
         struct usb_serial_port *port = tty->driver_data;
         struct aircable_private *priv = usb_get_serial_port_data(port);
-        unsigned long flags;
 
         dbg("%s - port %d", __func__, port->number);
 
-        spin_lock_irqsave(&priv->rx_lock, flags);
+        spin_lock_irq(&priv->rx_lock);
         priv->rx_flags |= THROTTLED;
-        spin_unlock_irqrestore(&priv->rx_lock, flags);
+        spin_unlock_irq(&priv->rx_lock);
 }
 
 /* Based on ftdi_sio.c unthrottle */
@@ -569,14 +568,13 @@ static void aircable_unthrottle(struct tty_struct *tty)
         struct usb_serial_port *port = tty->driver_data;
         struct aircable_private *priv = usb_get_serial_port_data(port);
         int actually_throttled;
-        unsigned long flags;
 
         dbg("%s - port %d", __func__, port->number);
 
-        spin_lock_irqsave(&priv->rx_lock, flags);
+        spin_lock_irq(&priv->rx_lock);
         actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
         priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED);
-        spin_unlock_irqrestore(&priv->rx_lock, flags);
+        spin_unlock_irq(&priv->rx_lock);
 
         if (actually_throttled)
                 schedule_work(&priv->rx_work);
diff --git a/drivers/usb/serial/cypress_m8.c b/drivers/usb/serial/cypress_m8.c
index e0a8b715f2f2..a591ebec0f89 100644
--- a/drivers/usb/serial/cypress_m8.c
+++ b/drivers/usb/serial/cypress_m8.c
@@ -1155,13 +1155,12 @@ static void cypress_throttle(struct tty_struct *tty)
 {
         struct usb_serial_port *port = tty->driver_data;
         struct cypress_private *priv = usb_get_serial_port_data(port);
-        unsigned long flags;
 
         dbg("%s - port %d", __func__, port->number);
 
-        spin_lock_irqsave(&priv->lock, flags);
+        spin_lock_irq(&priv->lock);
         priv->rx_flags = THROTTLED;
-        spin_unlock_irqrestore(&priv->lock, flags);
+        spin_unlock_irq(&priv->lock);
 }
 
 
@@ -1170,14 +1169,13 @@ static void cypress_unthrottle(struct tty_struct *tty)
         struct usb_serial_port *port = tty->driver_data;
         struct cypress_private *priv = usb_get_serial_port_data(port);
         int actually_throttled, result;
-        unsigned long flags;
 
         dbg("%s - port %d", __func__, port->number);
 
-        spin_lock_irqsave(&priv->lock, flags);
+        spin_lock_irq(&priv->lock);
         actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
         priv->rx_flags = 0;
-        spin_unlock_irqrestore(&priv->lock, flags);
+        spin_unlock_irq(&priv->lock);
 
         if (!priv->comm_is_ok)
                 return;
@@ -1185,7 +1183,7 @@ static void cypress_unthrottle(struct tty_struct *tty)
         if (actually_throttled) {
                 port->interrupt_in_urb->dev = port->serial->dev;
 
-                result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
+                result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
                 if (result) {
                         dev_err(&port->dev, "%s - failed submitting read urb, "
                                         "error %d\n", __func__, result);
diff --git a/drivers/usb/serial/empeg.c b/drivers/usb/serial/empeg.c
index 33c9e9cf9eb2..7dd0e3eadbe6 100644
--- a/drivers/usb/serial/empeg.c
+++ b/drivers/usb/serial/empeg.c
@@ -391,7 +391,7 @@ static void empeg_unthrottle(struct tty_struct *tty)
         dbg("%s - port %d", __func__, port->number);
 
         port->read_urb->dev = port->serial->dev;
-        result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
+        result = usb_submit_urb(port->read_urb, GFP_KERNEL);
         if (result)
                 dev_err(&port->dev,
                         "%s - failed submitting read urb, error %d\n",
diff --git a/drivers/usb/serial/garmin_gps.c b/drivers/usb/serial/garmin_gps.c
index 20432d345529..5ac900e5a50e 100644
--- a/drivers/usb/serial/garmin_gps.c
+++ b/drivers/usb/serial/garmin_gps.c
@@ -1390,14 +1390,13 @@ static void garmin_throttle(struct tty_struct *tty)
 {
         struct usb_serial_port *port = tty->driver_data;
         struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
-        unsigned long flags;
 
         dbg("%s - port %d", __func__, port->number);
         /* set flag, data received will be put into a queue
            for later processing */
-        spin_lock_irqsave(&garmin_data_p->lock, flags);
+        spin_lock_irq(&garmin_data_p->lock);
         garmin_data_p->flags |= FLAGS_QUEUING|FLAGS_THROTTLED;
-        spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+        spin_unlock_irq(&garmin_data_p->lock);
 }
 
 
@@ -1405,13 +1404,12 @@ static void garmin_unthrottle(struct tty_struct *tty)
 {
         struct usb_serial_port *port = tty->driver_data;
         struct garmin_data *garmin_data_p = usb_get_serial_port_data(port);
-        unsigned long flags;
         int status;
 
         dbg("%s - port %d", __func__, port->number);
-        spin_lock_irqsave(&garmin_data_p->lock, flags);
+        spin_lock_irq(&garmin_data_p->lock);
         garmin_data_p->flags &= ~FLAGS_THROTTLED;
-        spin_unlock_irqrestore(&garmin_data_p->lock, flags);
+        spin_unlock_irq(&garmin_data_p->lock);
 
         /* in native mode send queued data to tty, in
            serial mode nothing needs to be done here */
@@ -1419,7 +1417,7 @@ static void garmin_unthrottle(struct tty_struct *tty)
                 garmin_flush_queue(garmin_data_p);
 
         if (0 != (garmin_data_p->flags & FLAGS_BULK_IN_ACTIVE)) {
-                status = usb_submit_urb(port->read_urb, GFP_ATOMIC);
+                status = usb_submit_urb(port->read_urb, GFP_KERNEL);
                 if (status)
                         dev_err(&port->dev,
                                 "%s - failed resubmitting read urb, error %d\n",
diff --git a/drivers/usb/serial/keyspan_pda.c b/drivers/usb/serial/keyspan_pda.c
index 257c16cc6b2a..1296a097f5c3 100644
--- a/drivers/usb/serial/keyspan_pda.c
+++ b/drivers/usb/serial/keyspan_pda.c
@@ -290,7 +290,7 @@ static void keyspan_pda_rx_unthrottle(struct tty_struct *tty)
         /* just restart the receive interrupt URB */
         dbg("keyspan_pda_rx_unthrottle port %d", port->number);
         port->interrupt_in_urb->dev = port->serial->dev;
-        if (usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC))
+        if (usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL))
                 dbg(" usb_submit_urb(read urb) failed");
         return;
 }
diff --git a/drivers/usb/serial/kl5kusb105.c b/drivers/usb/serial/kl5kusb105.c
index f7373371b137..3a7873806f46 100644
--- a/drivers/usb/serial/kl5kusb105.c
+++ b/drivers/usb/serial/kl5kusb105.c
@@ -951,7 +951,7 @@ static void klsi_105_unthrottle(struct tty_struct *tty)
         dbg("%s - port %d", __func__, port->number);
 
         port->read_urb->dev = port->serial->dev;
-        result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
+        result = usb_submit_urb(port->read_urb, GFP_KERNEL);
         if (result)
                 dev_err(&port->dev,
                         "%s - failed submitting read urb, error %d\n",
diff --git a/drivers/usb/serial/mct_u232.c b/drivers/usb/serial/mct_u232.c
index ad4998bbf16f..cd009cb280a5 100644
--- a/drivers/usb/serial/mct_u232.c
+++ b/drivers/usb/serial/mct_u232.c
@@ -777,20 +777,19 @@ static void mct_u232_throttle(struct tty_struct *tty)
 {
         struct usb_serial_port *port = tty->driver_data;
         struct mct_u232_private *priv = usb_get_serial_port_data(port);
-        unsigned long flags;
         unsigned int control_state;
 
         dbg("%s - port %d", __func__, port->number);
 
-        spin_lock_irqsave(&priv->lock, flags);
+        spin_lock_irq(&priv->lock);
         priv->rx_flags |= THROTTLED;
         if (C_CRTSCTS(tty)) {
                 priv->control_state &= ~TIOCM_RTS;
                 control_state = priv->control_state;
-                spin_unlock_irqrestore(&priv->lock, flags);
+                spin_unlock_irq(&priv->lock);
                 (void) mct_u232_set_modem_ctrl(port->serial, control_state);
         } else {
-                spin_unlock_irqrestore(&priv->lock, flags);
+                spin_unlock_irq(&priv->lock);
         }
 }
 
@@ -799,20 +798,19 @@ static void mct_u232_unthrottle(struct tty_struct *tty)
 {
         struct usb_serial_port *port = tty->driver_data;
         struct mct_u232_private *priv = usb_get_serial_port_data(port);
-        unsigned long flags;
         unsigned int control_state;
 
         dbg("%s - port %d", __func__, port->number);
 
-        spin_lock_irqsave(&priv->lock, flags);
+        spin_lock_irq(&priv->lock);
         if ((priv->rx_flags & THROTTLED) && C_CRTSCTS(tty)) {
                 priv->rx_flags &= ~THROTTLED;
                 priv->control_state |= TIOCM_RTS;
                 control_state = priv->control_state;
-                spin_unlock_irqrestore(&priv->lock, flags);
+                spin_unlock_irq(&priv->lock);
                 (void) mct_u232_set_modem_ctrl(port->serial, control_state);
         } else {
-                spin_unlock_irqrestore(&priv->lock, flags);
+                spin_unlock_irq(&priv->lock);
         }
 }
 
diff --git a/drivers/usb/serial/symbolserial.c b/drivers/usb/serial/symbolserial.c
index f25e54526843..b282c0f2d8e5 100644
--- a/drivers/usb/serial/symbolserial.c
+++ b/drivers/usb/serial/symbolserial.c
@@ -165,33 +165,31 @@ static void symbol_throttle(struct tty_struct *tty)
 {
         struct usb_serial_port *port = tty->driver_data;
         struct symbol_private *priv = usb_get_serial_data(port->serial);
-        unsigned long flags;
 
         dbg("%s - port %d", __func__, port->number);
-        spin_lock_irqsave(&priv->lock, flags);
+        spin_lock_irq(&priv->lock);
         priv->throttled = true;
-        spin_unlock_irqrestore(&priv->lock, flags);
+        spin_unlock_irq(&priv->lock);
 }
 
 static void symbol_unthrottle(struct tty_struct *tty)
 {
         struct usb_serial_port *port = tty->driver_data;
         struct symbol_private *priv = usb_get_serial_data(port->serial);
-        unsigned long flags;
         int result;
         bool was_throttled;
 
         dbg("%s - port %d", __func__, port->number);
 
-        spin_lock_irqsave(&priv->lock, flags);
+        spin_lock_irq(&priv->lock);
         priv->throttled = false;
         was_throttled = priv->actually_throttled;
         priv->actually_throttled = false;
-        spin_unlock_irqrestore(&priv->lock, flags);
+        spin_unlock_irq(&priv->lock);
 
         priv->int_urb->dev = port->serial->dev;
         if (was_throttled) {
-                result = usb_submit_urb(priv->int_urb, GFP_ATOMIC);
+                result = usb_submit_urb(priv->int_urb, GFP_KERNEL);
                 if (result)
                         dev_err(&port->dev,
                                 "%s - failed submitting read urb, error %d\n",
diff --git a/drivers/usb/serial/visor.c b/drivers/usb/serial/visor.c
index 8e2d6dd9add0..b9341f0e452b 100644
--- a/drivers/usb/serial/visor.c
+++ b/drivers/usb/serial/visor.c
@@ -583,12 +583,11 @@ static void visor_throttle(struct tty_struct *tty)
 {
         struct usb_serial_port *port = tty->driver_data;
         struct visor_private *priv = usb_get_serial_port_data(port);
-        unsigned long flags;
 
         dbg("%s - port %d", __func__, port->number);
-        spin_lock_irqsave(&priv->lock, flags);
+        spin_lock_irq(&priv->lock);
         priv->throttled = 1;
-        spin_unlock_irqrestore(&priv->lock, flags);
+        spin_unlock_irq(&priv->lock);
 }
 
 
@@ -596,17 +595,16 @@ static void visor_unthrottle(struct tty_struct *tty)
 {
         struct usb_serial_port *port = tty->driver_data;
         struct visor_private *priv = usb_get_serial_port_data(port);
-        unsigned long flags;
         int result;
 
         dbg("%s - port %d", __func__, port->number);
-        spin_lock_irqsave(&priv->lock, flags);
+        spin_lock_irq(&priv->lock);
         priv->throttled = 0;
         priv->actually_throttled = 0;
-        spin_unlock_irqrestore(&priv->lock, flags);
+        spin_unlock_irq(&priv->lock);
 
         port->read_urb->dev = port->serial->dev;
-        result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
+        result = usb_submit_urb(port->read_urb, GFP_KERNEL);
         if (result)
                 dev_err(&port->dev,
                         "%s - failed submitting read urb, error %d\n",
diff --git a/drivers/usb/serial/whiteheat.c b/drivers/usb/serial/whiteheat.c
index 62424eec33ec..1093d2eb046a 100644
--- a/drivers/usb/serial/whiteheat.c
+++ b/drivers/usb/serial/whiteheat.c
@@ -949,13 +949,12 @@ static void whiteheat_throttle(struct tty_struct *tty)
 {
         struct usb_serial_port *port = tty->driver_data;
         struct whiteheat_private *info = usb_get_serial_port_data(port);
-        unsigned long flags;
 
         dbg("%s - port %d", __func__, port->number);
 
-        spin_lock_irqsave(&info->lock, flags);
+        spin_lock_irq(&info->lock);
         info->flags |= THROTTLED;
-        spin_unlock_irqrestore(&info->lock, flags);
+        spin_unlock_irq(&info->lock);
 
         return;
 }
@@ -966,14 +965,13 @@ static void whiteheat_unthrottle(struct tty_struct *tty)
         struct usb_serial_port *port = tty->driver_data;
         struct whiteheat_private *info = usb_get_serial_port_data(port);
         int actually_throttled;
-        unsigned long flags;
 
         dbg("%s - port %d", __func__, port->number);
 
-        spin_lock_irqsave(&info->lock, flags);
+        spin_lock_irq(&info->lock);
         actually_throttled = info->flags & ACTUALLY_THROTTLED;
         info->flags &= ~(THROTTLED | ACTUALLY_THROTTLED);
-        spin_unlock_irqrestore(&info->lock, flags);
+        spin_unlock_irq(&info->lock);
 
         if (actually_throttled)
                 rx_data_softint(&info->rx_work);