TTY/Serial fixes for 3.15-rc4
Here are some tty and serial driver fixes for things reported recently. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iEYEABECAAYFAlNn/10ACgkQMUfUDdst+ynKXgCg1BE7sLm2Nmxkm+nfYceWmRG2 pQAAnRnY2wBwtpVa4mVy1ZR3ykiKPvmY =42O2 -----END PGP SIGNATURE----- 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.
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commit
df862f625d
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@ -190,7 +190,7 @@ static struct tty_driver *hvc_console_device(struct console *c, int *index)
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return hvc_driver;
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}
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static int __init hvc_console_setup(struct console *co, char *options)
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static int hvc_console_setup(struct console *co, char *options)
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{
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if (co->index < 0 || co->index >= MAX_NR_HVC_CONSOLES)
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return -ENODEV;
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@ -2353,8 +2353,12 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
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if (tty->ops->flush_chars)
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tty->ops->flush_chars(tty);
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} else {
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struct n_tty_data *ldata = tty->disc_data;
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while (nr > 0) {
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mutex_lock(&ldata->output_lock);
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c = tty->ops->write(tty, b, nr);
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mutex_unlock(&ldata->output_lock);
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if (c < 0) {
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retval = c;
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goto break_out;
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@ -555,7 +555,7 @@ static void serial8250_set_sleep(struct uart_8250_port *p, int sleep)
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*/
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if ((p->port.type == PORT_XR17V35X) ||
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(p->port.type == PORT_XR17D15X)) {
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serial_out(p, UART_EXAR_SLEEP, 0xff);
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serial_out(p, UART_EXAR_SLEEP, sleep ? 0xff : 0);
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return;
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}
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@ -255,16 +255,15 @@ static int __tty_buffer_request_room(struct tty_port *port, size_t size,
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if (change || left < size) {
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/* This is the slow path - looking for new buffers to use */
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if ((n = tty_buffer_alloc(port, size)) != NULL) {
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unsigned long iflags;
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n->flags = flags;
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buf->tail = n;
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spin_lock_irqsave(&buf->flush_lock, iflags);
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b->commit = b->used;
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/* paired w/ barrier in flush_to_ldisc(); ensures the
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* latest commit value can be read before the head is
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* advanced to the next buffer
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*/
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smp_wmb();
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b->next = n;
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spin_unlock_irqrestore(&buf->flush_lock, iflags);
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} else if (change)
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size = 0;
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else
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@ -448,27 +447,28 @@ static void flush_to_ldisc(struct work_struct *work)
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mutex_lock(&buf->lock);
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while (1) {
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unsigned long flags;
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struct tty_buffer *head = buf->head;
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struct tty_buffer *next;
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int count;
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/* Ldisc or user is trying to gain exclusive access */
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if (atomic_read(&buf->priority))
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break;
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spin_lock_irqsave(&buf->flush_lock, flags);
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next = head->next;
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/* paired w/ barrier in __tty_buffer_request_room();
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* ensures commit value read is not stale if the head
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* is advancing to the next buffer
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*/
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smp_rmb();
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count = head->commit - head->read;
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if (!count) {
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if (head->next == NULL) {
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spin_unlock_irqrestore(&buf->flush_lock, flags);
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if (next == NULL)
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break;
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}
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buf->head = head->next;
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spin_unlock_irqrestore(&buf->flush_lock, flags);
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buf->head = next;
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tty_buffer_free(port, head);
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continue;
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}
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spin_unlock_irqrestore(&buf->flush_lock, flags);
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count = receive_buf(tty, head, count);
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if (!count)
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@ -523,7 +523,6 @@ void tty_buffer_init(struct tty_port *port)
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struct tty_bufhead *buf = &port->buf;
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mutex_init(&buf->lock);
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spin_lock_init(&buf->flush_lock);
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tty_buffer_reset(&buf->sentinel, 0);
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buf->head = &buf->sentinel;
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buf->tail = &buf->sentinel;
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@ -61,7 +61,6 @@ struct tty_bufhead {
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struct tty_buffer *head; /* Queue head */
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struct work_struct work;
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struct mutex lock;
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spinlock_t flush_lock;
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atomic_t priority;
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struct tty_buffer sentinel;
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struct llist_head free; /* Free queue head */
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