Merge tag 'v3.7-rc1' into staging/for_v3.8

Linux 3.7-rc1

* tag 'v3.7-rc1': (9579 commits)
  Linux 3.7-rc1
  x86, boot: Explicitly include autoconf.h for hostprogs
  perf: Fix UAPI fallout
  ARM: config: make sure that platforms are ordered by option string
  ARM: config: sort select statements alphanumerically
  UAPI: (Scripted) Disintegrate include/linux/byteorder
  UAPI: (Scripted) Disintegrate include/linux
  UAPI: Unexport linux/blk_types.h
  UAPI: Unexport part of linux/ppp-comp.h
  perf: Handle new rbtree implementation
  procfs: don't need a PATH_MAX allocation to hold a string representation of an int
  vfs: embed struct filename inside of names_cache allocation if possible
  audit: make audit_inode take struct filename
  vfs: make path_openat take a struct filename pointer
  vfs: turn do_path_lookup into wrapper around struct filename variant
  audit: allow audit code to satisfy getname requests from its names_list
  vfs: define struct filename and have getname() return it
  btrfs: Fix compilation with user namespace support enabled
  userns: Fix posix_acl_file_xattr_userns gid conversion
  userns: Properly print bluetooth socket uids
  ...

1 files changed, 24 insertions, 5 deletions

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index ee1c268f5f9..8c0b7b42319 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -92,10 +92,18 @@ static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
 
 static void n_tty_set_room(struct tty_struct *tty)
 {
-	/* tty->read_cnt is not read locked ? */
-	int	left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
+	int left;
 	int old_left;
 
+	/* tty->read_cnt is not read locked ? */
+	if (I_PARMRK(tty)) {
+		/* Multiply read_cnt by 3, since each byte might take up to
+		 * three times as many spaces when PARMRK is set (depending on
+		 * its flags, e.g. parity error). */
+		left = N_TTY_BUF_SIZE - tty->read_cnt * 3 - 1;
+	} else
+		left = N_TTY_BUF_SIZE - tty->read_cnt - 1;
+
 	/*
 	 * If we are doing input canonicalization, and there are no
 	 * pending newlines, let characters through without limit, so
@@ -1432,6 +1440,12 @@ static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
 	 */
 	if (tty->receive_room < TTY_THRESHOLD_THROTTLE)
 		tty_throttle(tty);
+
+        /* FIXME: there is a tiny race here if the receive room check runs
+           before the other work executes and empties the buffer (upping
+           the receiving room and unthrottling. We then throttle and get
+           stuck. This has been observed and traced down by Vincent Pillet/
+           We need to address this when we sort out out the rx path locking */
 }
 
 int is_ignored(int sig)
@@ -1460,7 +1474,7 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
 	BUG_ON(!tty);
 
 	if (old)
-		canon_change = (old->c_lflag ^ tty->termios->c_lflag) & ICANON;
+		canon_change = (old->c_lflag ^ tty->termios.c_lflag) & ICANON;
 	if (canon_change) {
 		memset(&tty->read_flags, 0, sizeof tty->read_flags);
 		tty->canon_head = tty->read_tail;
@@ -1728,7 +1742,8 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
 
 do_it_again:
 
-	BUG_ON(!tty->read_buf);
+	if (WARN_ON(!tty->read_buf))
+		return -EAGAIN;
 
 	c = job_control(tty, file);
 	if (c < 0)
@@ -1832,13 +1847,13 @@ do_it_again:
 
 		if (tty->icanon && !L_EXTPROC(tty)) {
 			/* N.B. avoid overrun if nr == 0 */
+			spin_lock_irqsave(&tty->read_lock, flags);
 			while (nr && tty->read_cnt) {
 				int eol;
 
 				eol = test_and_clear_bit(tty->read_tail,
 						tty->read_flags);
 				c = tty->read_buf[tty->read_tail];
-				spin_lock_irqsave(&tty->read_lock, flags);
 				tty->read_tail = ((tty->read_tail+1) &
 						  (N_TTY_BUF_SIZE-1));
 				tty->read_cnt--;
@@ -1856,15 +1871,19 @@ do_it_again:
 					if (tty_put_user(tty, c, b++)) {
 						retval = -EFAULT;
 						b--;
+						spin_lock_irqsave(&tty->read_lock, flags);
 						break;
 					}
 					nr--;
 				}
 				if (eol) {
 					tty_audit_push(tty);
+					spin_lock_irqsave(&tty->read_lock, flags);
 					break;
 				}
+				spin_lock_irqsave(&tty->read_lock, flags);
 			}
+			spin_unlock_irqrestore(&tty->read_lock, flags);
 			if (retval)
 				break;
 		} else {