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TTY/Serial fixes for 4.1-rc4

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Here's some TTY and serial driver fixes for reported issues.  All of
 these have been in linux-next successfully.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-4.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial fixes from Greg KH:
 "Here's some TTY and serial driver fixes for reported issues.

  All of these have been in linux-next successfully"

* tag 'tty-4.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  pty: Fix input race when closing
  tty/n_gsm.c: fix a memory leak when gsmtty is removed
  Revert "serial/amba-pl011: Leave the TX IRQ alone when the UART is not open"
  serial: omap: Fix error handling in probe
  earlycon: Revert log warnings
This commit is contained in:
Linus Torvalds 2015-05-16 21:10:05 -07:00
commit dd8edd7e97
10 changed files with 64 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
Documentation/serial/tty.txt
View File

@ -198,6 +198,9 @@ TTY_IO_ERROR If set, causes all subsequent userspace read/write
TTY_OTHER_CLOSED Device is a pty and the other side has closed.
TTY_OTHER_DONE Device is a pty and the other side has closed and
all pending input processing has been completed.
TTY_NO_WRITE_SPLIT Prevent driver from splitting up writes into
smaller chunks.

5
drivers/tty/n_gsm.c
View File

@ -3170,7 +3170,7 @@ static int gsmtty_break_ctl(struct tty_struct *tty, int state)
return gsmtty_modem_update(dlci, encode);
}
static void gsmtty_remove(struct tty_driver *driver, struct tty_struct *tty)
static void gsmtty_cleanup(struct tty_struct *tty)
{
struct gsm_dlci *dlci = tty->driver_data;
struct gsm_mux *gsm = dlci->gsm;
@ -3178,7 +3178,6 @@ static void gsmtty_remove(struct tty_driver *driver, struct tty_struct *tty)
dlci_put(dlci);
dlci_put(gsm->dlci[0]);
mux_put(gsm);
driver->ttys[tty->index] = NULL;
}
/* Virtual ttys for the demux */
@ -3199,7 +3198,7 @@ static const struct tty_operations gsmtty_ops = {
.tiocmget = gsmtty_tiocmget,
.tiocmset = gsmtty_tiocmset,
.break_ctl = gsmtty_break_ctl,
.remove = gsmtty_remove,
.cleanup = gsmtty_cleanup,
};

4
drivers/tty/n_hdlc.c
View File

@ -600,7 +600,7 @@ static ssize_t n_hdlc_tty_read(struct tty_struct *tty, struct file *file,
add_wait_queue(&tty->read_wait, &wait);
for (;;) {
if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
if (test_bit(TTY_OTHER_DONE, &tty->flags)) {
ret = -EIO;
break;
}
@ -828,7 +828,7 @@ static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp,
/* set bits for operations that won't block */
if (n_hdlc->rx_buf_list.head)
mask |= POLLIN | POLLRDNORM; /* readable */
if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
if (test_bit(TTY_OTHER_DONE, &tty->flags))
mask |= POLLHUP;
if (tty_hung_up_p(filp))
mask |= POLLHUP;

22
drivers/tty/n_tty.c
View File

@ -1949,6 +1949,18 @@ static inline int input_available_p(struct tty_struct *tty, int poll)
return ldata->commit_head - ldata->read_tail >= amt;
}
static inline int check_other_done(struct tty_struct *tty)
{
int done = test_bit(TTY_OTHER_DONE, &tty->flags);
if (done) {
/* paired with cmpxchg() in check_other_closed(); ensures
* read buffer head index is not stale
*/
smp_mb__after_atomic();
}
return done;
}
/**
* copy_from_read_buf - copy read data directly
* @tty: terminal device
@ -2167,7 +2179,7 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
struct n_tty_data *ldata = tty->disc_data;
unsigned char __user *b = buf;
DEFINE_WAIT_FUNC(wait, woken_wake_function);
int c;
int c, done;
int minimum, time;
ssize_t retval = 0;
long timeout;
@ -2235,8 +2247,10 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
((minimum - (b - buf)) >= 1))
ldata->minimum_to_wake = (minimum - (b - buf));
done = check_other_done(tty);
if (!input_available_p(tty, 0)) {
if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
if (done) {
retval = -EIO;
break;
}
@ -2443,12 +2457,12 @@ static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
poll_wait(file, &tty->read_wait, wait);
poll_wait(file, &tty->write_wait, wait);
if (check_other_done(tty))
mask |= POLLHUP;
if (input_available_p(tty, 1))
mask |= POLLIN | POLLRDNORM;
if (tty->packet && tty->link->ctrl_status)
mask |= POLLPRI | POLLIN | POLLRDNORM;
if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
mask |= POLLHUP;
if (tty_hung_up_p(file))
mask |= POLLHUP;
if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) {

5
drivers/tty/pty.c
View File

@ -53,9 +53,8 @@ static void pty_close(struct tty_struct *tty, struct file *filp)
/* Review - krefs on tty_link ?? */
if (!tty->link)
return;
tty_flush_to_ldisc(tty->link);
set_bit(TTY_OTHER_CLOSED, &tty->link->flags);
wake_up_interruptible(&tty->link->read_wait);
tty_flip_buffer_push(tty->link->port);
wake_up_interruptible(&tty->link->write_wait);
if (tty->driver->subtype == PTY_TYPE_MASTER) {
set_bit(TTY_OTHER_CLOSED, &tty->flags);
@ -243,7 +242,9 @@ static int pty_open(struct tty_struct *tty, struct file *filp)
goto out;
clear_bit(TTY_IO_ERROR, &tty->flags);
/* TTY_OTHER_CLOSED must be cleared before TTY_OTHER_DONE */
clear_bit(TTY_OTHER_CLOSED, &tty->link->flags);
clear_bit(TTY_OTHER_DONE, &tty->link->flags);
set_bit(TTY_THROTTLED, &tty->flags);
return 0;

5
drivers/tty/serial/amba-pl011.c
View File

@ -1639,6 +1639,9 @@ static int pl011_startup(struct uart_port *port)
writew(uap->vendor->ifls, uap->port.membase + UART011_IFLS);
/* Assume that TX IRQ doesn't work until we see one: */
uap->tx_irq_seen = 0;
spin_lock_irq(&uap->port.lock);
/* restore RTS and DTR */
@ -1702,7 +1705,7 @@ static void pl011_shutdown(struct uart_port *port)
spin_lock_irq(&uap->port.lock);
uap->im = 0;
writew(uap->im, uap->port.membase + UART011_IMSC);
writew(0xffff & ~UART011_TXIS, uap->port.membase + UART011_ICR);
writew(0xffff, uap->port.membase + UART011_ICR);
spin_unlock_irq(&uap->port.lock);
pl011_dma_shutdown(uap);

9
drivers/tty/serial/earlycon.c
View File

@ -187,13 +187,8 @@ static int __init param_setup_earlycon(char *buf)
return 0;
err = setup_earlycon(buf);
if (err == -ENOENT) {
pr_warn("no match for %s\n", buf);
err = 0;
} else if (err == -EALREADY) {
pr_warn("already registered\n");
err = 0;
}
if (err == -ENOENT || err == -EALREADY)
return 0;
return err;
}
early_param("earlycon", param_setup_earlycon);

2
drivers/tty/serial/omap-serial.c
View File

@ -1735,6 +1735,8 @@ static int serial_omap_probe(struct platform_device *pdev)
err_add_port:
pm_runtime_put(&pdev->dev);
pm_runtime_disable(&pdev->dev);
pm_qos_remove_request(&up->pm_qos_request);
device_init_wakeup(up->dev, false);
err_rs485:
err_port_line:
return ret;

41
drivers/tty/tty_buffer.c
View File

@ -37,6 +37,28 @@
#define TTY_BUFFER_PAGE (((PAGE_SIZE - sizeof(struct tty_buffer)) / 2) & ~0xFF)
/*
* If all tty flip buffers have been processed by flush_to_ldisc() or
* dropped by tty_buffer_flush(), check if the linked pty has been closed.
* If so, wake the reader/poll to process
*/
static inline void check_other_closed(struct tty_struct *tty)
{
unsigned long flags, old;
/* transition from TTY_OTHER_CLOSED => TTY_OTHER_DONE must be atomic */
for (flags = ACCESS_ONCE(tty->flags);
test_bit(TTY_OTHER_CLOSED, &flags);
) {
old = flags;
__set_bit(TTY_OTHER_DONE, &flags);
flags = cmpxchg(&tty->flags, old, flags);
if (old == flags) {
wake_up_interruptible(&tty->read_wait);
break;
}
}
}
/**
* tty_buffer_lock_exclusive - gain exclusive access to buffer
@ -229,6 +251,8 @@ void tty_buffer_flush(struct tty_struct *tty, struct tty_ldisc *ld)
if (ld && ld->ops->flush_buffer)
ld->ops->flush_buffer(tty);
check_other_closed(tty);
atomic_dec(&buf->priority);
mutex_unlock(&buf->lock);
}
@ -471,8 +495,10 @@ static void flush_to_ldisc(struct work_struct *work)
smp_rmb();
count = head->commit - head->read;
if (!count) {
if (next == NULL)
if (next == NULL) {
check_other_closed(tty);
break;
}
buf->head = next;
tty_buffer_free(port, head);
continue;
@ -488,19 +514,6 @@ static void flush_to_ldisc(struct work_struct *work)
tty_ldisc_deref(disc);
}
/**
* tty_flush_to_ldisc
* @tty: tty to push
*
* Push the terminal flip buffers to the line discipline.
*
* Must not be called from IRQ context.
*/
void tty_flush_to_ldisc(struct tty_struct *tty)
{
flush_work(&tty->port->buf.work);
}
/**
* tty_flip_buffer_push - terminal
* @port: tty port to push

2
include/linux/tty.h
View File

@ -339,6 +339,7 @@ struct tty_file_private {
#define TTY_EXCLUSIVE 3 /* Exclusive open mode */
#define TTY_DEBUG 4 /* Debugging */
#define TTY_DO_WRITE_WAKEUP 5 /* Call write_wakeup after queuing new */
#define TTY_OTHER_DONE 6 /* Closed pty has completed input processing */
#define TTY_LDISC_OPEN 11 /* Line discipline is open */
#define TTY_PTY_LOCK 16 /* pty private */
#define TTY_NO_WRITE_SPLIT 17 /* Preserve write boundaries to driver */
@ -462,7 +463,6 @@ extern int tty_hung_up_p(struct file *filp);
extern void do_SAK(struct tty_struct *tty);
extern void __do_SAK(struct tty_struct *tty);
extern void no_tty(void);
extern void tty_flush_to_ldisc(struct tty_struct *tty);
extern void tty_buffer_free_all(struct tty_port *port);
extern void tty_buffer_flush(struct tty_struct *tty, struct tty_ldisc *ld);
extern void tty_buffer_init(struct tty_port *port);