From cf79202e76dfd48425e7de5102b3da7346ab94ba Mon Sep 17 00:00:00 2001
From: Jiri Slaby <jslaby@suse.cz>
Date: Thu, 26 Apr 2012 20:13:00 +0200
Subject: [PATCH] --- yaml --- r: 304205 b: refs/heads/master c:
 3fa10cc83fb92750af11fab81e11ad96dc75d656 h: refs/heads/master i:   304203:
 76ba3f92159a33b08d331216bfba6d165e1f89fb v: v3

---
 [refs]                    | 2 +-
 trunk/drivers/tty/n_tty.c | 9 +++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/[refs] b/[refs]
index 43319d013767..2065095c1015 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 5d1a33fa5573702394a4d09a9872f3f930c06d58
+refs/heads/master: 3fa10cc83fb92750af11fab81e11ad96dc75d656
diff --git a/trunk/drivers/tty/n_tty.c b/trunk/drivers/tty/n_tty.c
index 94b6eda87afd..ee1c268f5f9d 100644
--- a/trunk/drivers/tty/n_tty.c
+++ b/trunk/drivers/tty/n_tty.c
@@ -1630,6 +1630,7 @@ static int copy_from_read_buf(struct tty_struct *tty,
 	int retval;
 	size_t n;
 	unsigned long flags;
+	bool is_eof;
 
 	retval = 0;
 	spin_lock_irqsave(&tty->read_lock, flags);
@@ -1639,15 +1640,15 @@ static int copy_from_read_buf(struct tty_struct *tty,
 	if (n) {
 		retval = copy_to_user(*b, &tty->read_buf[tty->read_tail], n);
 		n -= retval;
+		is_eof = n == 1 &&
+			tty->read_buf[tty->read_tail] == EOF_CHAR(tty);
 		tty_audit_add_data(tty, &tty->read_buf[tty->read_tail], n);
 		spin_lock_irqsave(&tty->read_lock, flags);
 		tty->read_tail = (tty->read_tail + n) & (N_TTY_BUF_SIZE-1);
 		tty->read_cnt -= n;
 		/* Turn single EOF into zero-length read */
-		if (L_EXTPROC(tty) && tty->icanon && n == 1) {
-			if (!tty->read_cnt && (*b)[n-1] == EOF_CHAR(tty))
-				n--;
-		}
+		if (L_EXTPROC(tty) && tty->icanon && is_eof && !tty->read_cnt)
+			n = 0;
 		spin_unlock_irqrestore(&tty->read_lock, flags);
 		*b += n;
 		*nr -= n;