Re: [PATCH] n_tty: Fix poll() when TIME_CHAR and MIN_CHAR == 0

From: David Ahern
Date: Tue Feb 11 2014 - 13:31:14 EST


On 2/11/14, 9:49 AM, Peter Hurley wrote:
From: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
Date: Tue, 11 Feb 2014 10:10:07 -0500
Subject: [PATCH] n_tty: Fix poll() when TIME_CHAR and MIN_CHAR == 0

Commit eafbe67f84761d787802e5113d895a316b6292fe,
n_tty: Refactor input_available_p() by call site
broke poll() when TIME_CHAR(tty) and MIN_CHAR(tty) are both 0.

When TIME_CHAR and MIN_CHAR are both 0, input is available if the
read_cnt is 1 (not 0).

Reported-by: Stephane Eranian <eranian@xxxxxxxxxx>
Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
---
drivers/tty/n_tty.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index cb8017a..2747a3b 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -1896,7 +1896,7 @@ err:
static inline int input_available_p(struct tty_struct *tty, int poll)
{
struct n_tty_data *ldata = tty->disc_data;
- int amt = poll && !TIME_CHAR(tty) ? MIN_CHAR(tty) : 1;
+ int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1;

if (ldata->icanon && !L_EXTPROC(tty)) {
if (ldata->canon_head != ldata->read_tail)


Worked for me.

Tested-by: David Ahern <dsahern@xxxxxxxxx>
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