[PATCH 5.10 189/199] tty: fix up hung_up_tty_write() conversion

Greg Kroah-Hartman
2021-01-25T19:36:20Z

From: Linus Torvalds <torvalds@linux-foundation.org>

commit 17749851eb9ca2298e7c3b81aae4228961b36f28 upstream.

In commit "tty: implement write_iter", I left the write_iter conversion
of the hung up tty case alone, because I incorrectly thought it didn't
matter.

Jiri showed me the errors of my ways, and pointed out the problems with
that incomplete conversion. Fix it all up.

Reported-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/CAHk-=wh+-rGsa=xruEWdg_fJViFG8rN9bpLrfLz=_yBYh2tBhA@mail.gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/tty/tty_io.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -437,8 +437,7 @@ static ssize_t hung_up_tty_read(struct f
return 0;
}

-static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
- size_t count, loff_t *ppos)
+static ssize_t hung_up_tty_write(struct kiocb *iocb, struct iov_iter *from)
{
return -EIO;
}
@@ -504,7 +503,7 @@ static const struct file_operations cons
static const struct file_operations hung_up_tty_fops = {
.llseek = no_llseek,
.read = hung_up_tty_read,
- .write = hung_up_tty_write,
+ .write_iter = hung_up_tty_write,
.poll = hung_up_tty_poll,
.unlocked_ioctl = hung_up_tty_ioctl,
.compat_ioctl = hung_up_tty_compat_ioctl,
@@ -1045,7 +1044,9 @@ static ssize_t tty_write(struct kiocb *i
if (tty->ops->write_room == NULL)
tty_err(tty, "missing write_room method\n");
ld = tty_ldisc_ref_wait(tty);
- if (!ld || !ld->ops->write)
+ if (!ld)
+ return hung_up_tty_write(iocb, from);
+ if (!ld->ops->write)
ret = -EIO;
else
ret = do_tty_write(ld->ops->write, tty, file, from);