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Commit df862f62 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'tty-3.15-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty 

Pull tty/serial fixes from Greg KH:
 "Here are some tty and serial driver fixes for things reported
  recently"

* tag 'tty-3.15-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  tty: Fix lockless tty buffer race
  Revert "tty: Fix race condition between __tty_buffer_request_room and flush_to_ldisc"
  drivers/tty/hvc: don't free hvc_console_setup after init
  n_tty: Fix n_tty_write crash when echoing in raw mode
  tty: serial: 8250_core.c Bug fix for Exar chips.
parents a1e74464 62a0d8d7

drivers/tty/hvc/hvc_console.c

+1 −1
Original line number Diff line number Diff line
@@ -190,7 +190,7 @@ static struct tty_driver *hvc_console_device(struct console *c, int *index) 
	return hvc_driver;

}



static int __init hvc_console_setup(struct console *co, char *options)

static int hvc_console_setup(struct console *co, char *options)

{	

	if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES)

		return -ENODEV;

drivers/tty/n_tty.c

+4 −0
Original line number Diff line number Diff line
@@ -2353,8 +2353,12 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file, 
			if (tty->ops->flush_chars)

				tty->ops->flush_chars(tty);

		} else {

			struct n_tty_data *ldata = tty->disc_data;



			while (nr > 0) {

				mutex_lock(&ldata->output_lock);

				c = tty->ops->write(tty, b, nr);

				mutex_unlock(&ldata->output_lock);

				if (c < 0) {

					retval = c;

					goto break_out;

drivers/tty/serial/8250/8250_core.c

+1 −1
Original line number Diff line number Diff line
@@ -555,7 +555,7 @@ static void serial8250_set_sleep(struct uart_8250_port *p, int sleep) 
	 */

	if ((p->port.type == PORT_XR17V35X) ||

	   (p->port.type == PORT_XR17D15X)) {

		serial_out(p, UART_EXAR_SLEEP, 0xff);

		serial_out(p, UART_EXAR_SLEEP, sleep ? 0xff : 0);

		return;

	}

drivers/tty/tty_buffer.c

+14 −15
Original line number Diff line number Diff line
@@ -255,16 +255,15 @@ static int __tty_buffer_request_room(struct tty_port *port, size_t size, 
	if (change || left < size) {

		/* This is the slow path - looking for new buffers to use */

		if ((n = tty_buffer_alloc(port, size)) != NULL) {

			unsigned long iflags;



			n->flags = flags;

			buf->tail = n;



			spin_lock_irqsave(&buf->flush_lock, iflags);

			b->commit = b->used;

			/* paired w/ barrier in flush_to_ldisc(); ensures the

			 * latest commit value can be read before the head is

			 * advanced to the next buffer

			 */

			smp_wmb();

			b->next = n;

			spin_unlock_irqrestore(&buf->flush_lock, iflags);



		} else if (change)

			size = 0;

		else
@@ -448,27 +447,28 @@ static void flush_to_ldisc(struct work_struct *work) 
	mutex_lock(&buf->lock);



	while (1) {

		unsigned long flags;

		struct tty_buffer *head = buf->head;

		struct tty_buffer *next;

		int count;



		/* Ldisc or user is trying to gain exclusive access */

		if (atomic_read(&buf->priority))

			break;



		spin_lock_irqsave(&buf->flush_lock, flags);

		next = head->next;

		/* paired w/ barrier in __tty_buffer_request_room();

		 * ensures commit value read is not stale if the head

		 * is advancing to the next buffer

		 */

		smp_rmb();

		count = head->commit - head->read;

		if (!count) {

			if (head->next == NULL) {

				spin_unlock_irqrestore(&buf->flush_lock, flags);

			if (next == NULL)

				break;

			}

			buf->head = head->next;

			spin_unlock_irqrestore(&buf->flush_lock, flags);

			buf->head = next;

			tty_buffer_free(port, head);

			continue;

		}

		spin_unlock_irqrestore(&buf->flush_lock, flags);



		count = receive_buf(tty, head, count);

		if (!count)
@@ -523,7 +523,6 @@ void tty_buffer_init(struct tty_port *port) 
	struct tty_bufhead *buf = &port->buf;



	mutex_init(&buf->lock);

	spin_lock_init(&buf->flush_lock);

	tty_buffer_reset(&buf->sentinel, 0);

	buf->head = &buf->sentinel;

	buf->tail = &buf->sentinel;

include/linux/tty.h

+0 −1
Original line number Diff line number Diff line
@@ -61,7 +61,6 @@ struct tty_bufhead { 
	struct tty_buffer *head;	/* Queue head */

	struct work_struct work;

	struct mutex	   lock;

	spinlock_t	   flush_lock;

	atomic_t	   priority;

	struct tty_buffer sentinel;

	struct llist_head free;		/* Free queue head */