Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 656 insertions, 0 deletions

diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
new file mode 100644
index 000000000..6eaf74930
--- /dev/null
+++ b/drivers/usb/serial/generic.c
@@ -0,0 +1,656 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * USB Serial Converter Generic functions
+ *
+ * Copyright (C) 2010 - 2013 Johan Hovold (jhovold@gmail.com)
+ * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched/signal.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/sysrq.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+#include <linux/kfifo.h>
+#include <linux/serial.h>
+
+#ifdef CONFIG_USB_SERIAL_GENERIC
+
+static __u16 vendor  = 0x05f9;
+static __u16 product = 0xffff;
+
+module_param(vendor, ushort, 0);
+MODULE_PARM_DESC(vendor, "User specified USB idVendor");
+
+module_param(product, ushort, 0);
+MODULE_PARM_DESC(product, "User specified USB idProduct");
+
+static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */
+
+static int usb_serial_generic_probe(struct usb_serial *serial,
+					const struct usb_device_id *id)
+{
+	struct device *dev = &serial->interface->dev;
+
+	dev_info(dev, "The \"generic\" usb-serial driver is only for testing and one-off prototypes.\n");
+	dev_info(dev, "Tell linux-usb@vger.kernel.org to add your device to a proper driver.\n");
+
+	return 0;
+}
+
+static int usb_serial_generic_calc_num_ports(struct usb_serial *serial,
+					struct usb_serial_endpoints *epds)
+{
+	struct device *dev = &serial->interface->dev;
+	int num_ports;
+
+	num_ports = max(epds->num_bulk_in, epds->num_bulk_out);
+
+	if (num_ports == 0) {
+		dev_err(dev, "device has no bulk endpoints\n");
+		return -ENODEV;
+	}
+
+	return num_ports;
+}
+
+static struct usb_serial_driver usb_serial_generic_device = {
+	.driver = {
+		.name =		"generic",
+	},
+	.id_table =		generic_device_ids,
+	.probe =		usb_serial_generic_probe,
+	.calc_num_ports =	usb_serial_generic_calc_num_ports,
+	.throttle =		usb_serial_generic_throttle,
+	.unthrottle =		usb_serial_generic_unthrottle,
+	.resume =		usb_serial_generic_resume,
+};
+
+static struct usb_serial_driver * const serial_drivers[] = {
+	&usb_serial_generic_device, NULL
+};
+
+#endif
+
+int usb_serial_generic_register(void)
+{
+	int retval = 0;
+
+#ifdef CONFIG_USB_SERIAL_GENERIC
+	generic_device_ids[0].idVendor = vendor;
+	generic_device_ids[0].idProduct = product;
+	generic_device_ids[0].match_flags =
+		USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
+
+	retval = usb_serial_register_drivers(serial_drivers,
+			"usbserial_generic", generic_device_ids);
+#endif
+	return retval;
+}
+
+void usb_serial_generic_deregister(void)
+{
+#ifdef CONFIG_USB_SERIAL_GENERIC
+	usb_serial_deregister_drivers(serial_drivers);
+#endif
+}
+
+int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
+{
+	int result = 0;
+
+	clear_bit(USB_SERIAL_THROTTLED, &port->flags);
+
+	if (port->bulk_in_size)
+		result = usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
+
+	return result;
+}
+EXPORT_SYMBOL_GPL(usb_serial_generic_open);
+
+void usb_serial_generic_close(struct usb_serial_port *port)
+{
+	unsigned long flags;
+	int i;
+
+	if (port->bulk_out_size) {
+		for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
+			usb_kill_urb(port->write_urbs[i]);
+
+		spin_lock_irqsave(&port->lock, flags);
+		kfifo_reset_out(&port->write_fifo);
+		spin_unlock_irqrestore(&port->lock, flags);
+	}
+	if (port->bulk_in_size) {
+		for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
+			usb_kill_urb(port->read_urbs[i]);
+	}
+}
+EXPORT_SYMBOL_GPL(usb_serial_generic_close);
+
+int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port,
+						void *dest, size_t size)
+{
+	return kfifo_out_locked(&port->write_fifo, dest, size, &port->lock);
+}
+
+/**
+ * usb_serial_generic_write_start - start writing buffered data
+ * @port: usb-serial port
+ * @mem_flags: flags to use for memory allocations
+ *
+ * Serialised using USB_SERIAL_WRITE_BUSY flag.
+ *
+ * Return: Zero on success or if busy, otherwise a negative errno value.
+ */
+int usb_serial_generic_write_start(struct usb_serial_port *port,
+							gfp_t mem_flags)
+{
+	struct urb *urb;
+	int count, result;
+	unsigned long flags;
+	int i;
+
+	if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags))
+		return 0;
+retry:
+	spin_lock_irqsave(&port->lock, flags);
+	if (!port->write_urbs_free || !kfifo_len(&port->write_fifo)) {
+		clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
+		spin_unlock_irqrestore(&port->lock, flags);
+		return 0;
+	}
+	i = (int)find_first_bit(&port->write_urbs_free,
+						ARRAY_SIZE(port->write_urbs));
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	urb = port->write_urbs[i];
+	count = port->serial->type->prepare_write_buffer(port,
+						urb->transfer_buffer,
+						port->bulk_out_size);
+	urb->transfer_buffer_length = count;
+	usb_serial_debug_data(&port->dev, __func__, count, urb->transfer_buffer);
+	spin_lock_irqsave(&port->lock, flags);
+	port->tx_bytes += count;
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	clear_bit(i, &port->write_urbs_free);
+	result = usb_submit_urb(urb, mem_flags);
+	if (result) {
+		dev_err_console(port, "%s - error submitting urb: %d\n",
+						__func__, result);
+		set_bit(i, &port->write_urbs_free);
+		spin_lock_irqsave(&port->lock, flags);
+		port->tx_bytes -= count;
+		spin_unlock_irqrestore(&port->lock, flags);
+
+		clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
+		return result;
+	}
+
+	goto retry;	/* try sending off another urb */
+}
+EXPORT_SYMBOL_GPL(usb_serial_generic_write_start);
+
+/**
+ * usb_serial_generic_write - generic write function
+ * @tty: tty for the port
+ * @port: usb-serial port
+ * @buf: data to write
+ * @count: number of bytes to write
+ *
+ * Return: The number of characters buffered, which may be anything from
+ * zero to @count, or a negative errno value.
+ */
+int usb_serial_generic_write(struct tty_struct *tty,
+	struct usb_serial_port *port, const unsigned char *buf, int count)
+{
+	int result;
+
+	if (!port->bulk_out_size)
+		return -ENODEV;
+
+	if (!count)
+		return 0;
+
+	count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
+	result = usb_serial_generic_write_start(port, GFP_ATOMIC);
+	if (result)
+		return result;
+
+	return count;
+}
+EXPORT_SYMBOL_GPL(usb_serial_generic_write);
+
+unsigned int usb_serial_generic_write_room(struct tty_struct *tty)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	unsigned long flags;
+	unsigned int room;
+
+	if (!port->bulk_out_size)
+		return 0;
+
+	spin_lock_irqsave(&port->lock, flags);
+	room = kfifo_avail(&port->write_fifo);
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	dev_dbg(&port->dev, "%s - returns %u\n", __func__, room);
+	return room;
+}
+
+unsigned int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	unsigned long flags;
+	unsigned int chars;
+
+	if (!port->bulk_out_size)
+		return 0;
+
+	spin_lock_irqsave(&port->lock, flags);
+	chars = kfifo_len(&port->write_fifo) + port->tx_bytes;
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	dev_dbg(&port->dev, "%s - returns %u\n", __func__, chars);
+	return chars;
+}
+EXPORT_SYMBOL_GPL(usb_serial_generic_chars_in_buffer);
+
+void usb_serial_generic_wait_until_sent(struct tty_struct *tty, long timeout)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	unsigned int bps;
+	unsigned long period;
+	unsigned long expire;
+
+	bps = tty_get_baud_rate(tty);
+	if (!bps)
+		bps = 9600;	/* B0 */
+	/*
+	 * Use a poll-period of roughly the time it takes to send one
+	 * character or at least one jiffy.
+	 */
+	period = max_t(unsigned long, (10 * HZ / bps), 1);
+	if (timeout)
+		period = min_t(unsigned long, period, timeout);
+
+	dev_dbg(&port->dev, "%s - timeout = %u ms, period = %u ms\n",
+					__func__, jiffies_to_msecs(timeout),
+					jiffies_to_msecs(period));
+	expire = jiffies + timeout;
+	while (!port->serial->type->tx_empty(port)) {
+		schedule_timeout_interruptible(period);
+		if (signal_pending(current))
+			break;
+		if (timeout && time_after(jiffies, expire))
+			break;
+	}
+}
+EXPORT_SYMBOL_GPL(usb_serial_generic_wait_until_sent);
+
+static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
+						int index, gfp_t mem_flags)
+{
+	int res;
+
+	if (!test_and_clear_bit(index, &port->read_urbs_free))
+		return 0;
+
+	dev_dbg(&port->dev, "%s - urb %d\n", __func__, index);
+
+	res = usb_submit_urb(port->read_urbs[index], mem_flags);
+	if (res) {
+		if (res != -EPERM && res != -ENODEV) {
+			dev_err(&port->dev,
+					"%s - usb_submit_urb failed: %d\n",
+					__func__, res);
+		}
+		set_bit(index, &port->read_urbs_free);
+		return res;
+	}
+
+	return 0;
+}
+
+int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port,
+					gfp_t mem_flags)
+{
+	int res;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
+		res = usb_serial_generic_submit_read_urb(port, i, mem_flags);
+		if (res)
+			goto err;
+	}
+
+	return 0;
+err:
+	for (; i >= 0; --i)
+		usb_kill_urb(port->read_urbs[i]);
+
+	return res;
+}
+EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs);
+
+void usb_serial_generic_process_read_urb(struct urb *urb)
+{
+	struct usb_serial_port *port = urb->context;
+	char *ch = urb->transfer_buffer;
+	int i;
+
+	if (!urb->actual_length)
+		return;
+	/*
+	 * The per character mucking around with sysrq path it too slow for
+	 * stuff like 3G modems, so shortcircuit it in the 99.9999999% of
+	 * cases where the USB serial is not a console anyway.
+	 */
+	if (port->sysrq) {
+		for (i = 0; i < urb->actual_length; i++, ch++) {
+			if (!usb_serial_handle_sysrq_char(port, *ch))
+				tty_insert_flip_char(&port->port, *ch, TTY_NORMAL);
+		}
+	} else {
+		tty_insert_flip_string(&port->port, ch, urb->actual_length);
+	}
+	tty_flip_buffer_push(&port->port);
+}
+EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb);
+
+void usb_serial_generic_read_bulk_callback(struct urb *urb)
+{
+	struct usb_serial_port *port = urb->context;
+	unsigned char *data = urb->transfer_buffer;
+	bool stopped = false;
+	int status = urb->status;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
+		if (urb == port->read_urbs[i])
+			break;
+	}
+
+	dev_dbg(&port->dev, "%s - urb %d, len %d\n", __func__, i,
+							urb->actual_length);
+	switch (status) {
+	case 0:
+		usb_serial_debug_data(&port->dev, __func__, urb->actual_length,
+							data);
+		port->serial->type->process_read_urb(urb);
+		break;
+	case -ENOENT:
+	case -ECONNRESET:
+	case -ESHUTDOWN:
+		dev_dbg(&port->dev, "%s - urb stopped: %d\n",
+							__func__, status);
+		stopped = true;
+		break;
+	case -EPIPE:
+		dev_err(&port->dev, "%s - urb stopped: %d\n",
+							__func__, status);
+		stopped = true;
+		break;
+	default:
+		dev_dbg(&port->dev, "%s - nonzero urb status: %d\n",
+							__func__, status);
+		break;
+	}
+
+	/*
+	 * Make sure URB processing is done before marking as free to avoid
+	 * racing with unthrottle() on another CPU. Matches the barriers
+	 * implied by the test_and_clear_bit() in
+	 * usb_serial_generic_submit_read_urb().
+	 */
+	smp_mb__before_atomic();
+	set_bit(i, &port->read_urbs_free);
+	/*
+	 * Make sure URB is marked as free before checking the throttled flag
+	 * to avoid racing with unthrottle() on another CPU. Matches the
+	 * smp_mb__after_atomic() in unthrottle().
+	 */
+	smp_mb__after_atomic();
+
+	if (stopped)
+		return;
+
+	if (test_bit(USB_SERIAL_THROTTLED, &port->flags))
+		return;
+
+	usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
+}
+EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
+
+void usb_serial_generic_write_bulk_callback(struct urb *urb)
+{
+	unsigned long flags;
+	struct usb_serial_port *port = urb->context;
+	int status = urb->status;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) {
+		if (port->write_urbs[i] == urb)
+			break;
+	}
+	spin_lock_irqsave(&port->lock, flags);
+	port->tx_bytes -= urb->transfer_buffer_length;
+	set_bit(i, &port->write_urbs_free);
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	switch (status) {
+	case 0:
+		break;
+	case -ENOENT:
+	case -ECONNRESET:
+	case -ESHUTDOWN:
+		dev_dbg(&port->dev, "%s - urb stopped: %d\n",
+							__func__, status);
+		return;
+	case -EPIPE:
+		dev_err_console(port, "%s - urb stopped: %d\n",
+							__func__, status);
+		return;
+	default:
+		dev_err_console(port, "%s - nonzero urb status: %d\n",
+							__func__, status);
+		break;
+	}
+
+	usb_serial_generic_write_start(port, GFP_ATOMIC);
+	usb_serial_port_softint(port);
+}
+EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
+
+void usb_serial_generic_throttle(struct tty_struct *tty)
+{
+	struct usb_serial_port *port = tty->driver_data;
+
+	set_bit(USB_SERIAL_THROTTLED, &port->flags);
+}
+EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
+
+void usb_serial_generic_unthrottle(struct tty_struct *tty)
+{
+	struct usb_serial_port *port = tty->driver_data;
+
+	clear_bit(USB_SERIAL_THROTTLED, &port->flags);
+
+	/*
+	 * Matches the smp_mb__after_atomic() in
+	 * usb_serial_generic_read_bulk_callback().
+	 */
+	smp_mb__after_atomic();
+
+	usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
+}
+EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
+
+static bool usb_serial_generic_msr_changed(struct tty_struct *tty,
+				unsigned long arg, struct async_icount *cprev)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	struct async_icount cnow;
+	unsigned long flags;
+	bool ret;
+
+	/*
+	 * Use tty-port initialised flag to detect all hangups including the
+	 * one generated at USB-device disconnect.
+	 */
+	if (!tty_port_initialized(&port->port))
+		return true;
+
+	spin_lock_irqsave(&port->lock, flags);
+	cnow = port->icount;				/* atomic copy*/
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	ret =	((arg & TIOCM_RNG) && (cnow.rng != cprev->rng)) ||
+		((arg & TIOCM_DSR) && (cnow.dsr != cprev->dsr)) ||
+		((arg & TIOCM_CD)  && (cnow.dcd != cprev->dcd)) ||
+		((arg & TIOCM_CTS) && (cnow.cts != cprev->cts));
+
+	*cprev = cnow;
+
+	return ret;
+}
+
+int usb_serial_generic_tiocmiwait(struct tty_struct *tty, unsigned long arg)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	struct async_icount cnow;
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&port->lock, flags);
+	cnow = port->icount;				/* atomic copy */
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	ret = wait_event_interruptible(port->port.delta_msr_wait,
+			usb_serial_generic_msr_changed(tty, arg, &cnow));
+	if (!ret && !tty_port_initialized(&port->port))
+		ret = -EIO;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_serial_generic_tiocmiwait);
+
+int usb_serial_generic_get_icount(struct tty_struct *tty,
+					struct serial_icounter_struct *icount)
+{
+	struct usb_serial_port *port = tty->driver_data;
+	struct async_icount cnow;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+	cnow = port->icount;				/* atomic copy */
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	icount->cts = cnow.cts;
+	icount->dsr = cnow.dsr;
+	icount->rng = cnow.rng;
+	icount->dcd = cnow.dcd;
+	icount->tx = cnow.tx;
+	icount->rx = cnow.rx;
+	icount->frame = cnow.frame;
+	icount->parity = cnow.parity;
+	icount->overrun = cnow.overrun;
+	icount->brk = cnow.brk;
+	icount->buf_overrun = cnow.buf_overrun;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_serial_generic_get_icount);
+
+#if defined(CONFIG_USB_SERIAL_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
+{
+	if (port->sysrq) {
+		if (ch && time_before(jiffies, port->sysrq)) {
+			handle_sysrq(ch);
+			port->sysrq = 0;
+			return 1;
+		}
+		port->sysrq = 0;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
+
+int usb_serial_handle_break(struct usb_serial_port *port)
+{
+	if (!port->port.console)
+		return 0;
+
+	if (!port->sysrq) {
+		port->sysrq = jiffies + HZ*5;
+		return 1;
+	}
+	port->sysrq = 0;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(usb_serial_handle_break);
+#endif
+
+/**
+ * usb_serial_handle_dcd_change - handle a change of carrier detect state
+ * @port: usb-serial port
+ * @tty: tty for the port
+ * @status: new carrier detect status, nonzero if active
+ */
+void usb_serial_handle_dcd_change(struct usb_serial_port *port,
+				struct tty_struct *tty, unsigned int status)
+{
+	dev_dbg(&port->dev, "%s - status %d\n", __func__, status);
+
+	if (tty) {
+		struct tty_ldisc *ld = tty_ldisc_ref(tty);
+
+		if (ld) {
+			if (ld->ops->dcd_change)
+				ld->ops->dcd_change(tty, status);
+			tty_ldisc_deref(ld);
+		}
+	}
+
+	if (status)
+		wake_up_interruptible(&port->port.open_wait);
+	else if (tty && !C_CLOCAL(tty))
+		tty_hangup(tty);
+}
+EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);
+
+int usb_serial_generic_resume(struct usb_serial *serial)
+{
+	struct usb_serial_port *port;
+	int i, c = 0, r;
+
+	for (i = 0; i < serial->num_ports; i++) {
+		port = serial->port[i];
+		if (!tty_port_initialized(&port->port))
+			continue;
+
+		if (port->bulk_in_size) {
+			r = usb_serial_generic_submit_read_urbs(port,
+								GFP_NOIO);
+			if (r < 0)
+				c++;
+		}
+
+		if (port->bulk_out_size) {
+			r = usb_serial_generic_write_start(port, GFP_NOIO);
+			if (r < 0)
+				c++;
+		}
+	}
+
+	return c ? -EIO : 0;
+}
+EXPORT_SYMBOL_GPL(usb_serial_generic_resume);