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path: root/drivers/tty/n_tty.c
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Diffstat (limited to 'drivers/tty/n_tty.c')
-rw-r--r--drivers/tty/n_tty.c22
1 files changed, 18 insertions, 4 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index cf6e0f2e1331..cc57a3a6b02b 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -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))) {