From: Peter Hurley Subject: [PATCH -next 12/27] tty: Document check_tty_count() requires tty_lock held Date: Thu, 16 Oct 2014 16:25:10 -0400 Message-ID: <1413491125-20134-13-git-send-email-peter@hurleysoftware.com> References: <1413491125-20134-1-git-send-email-peter@hurleysoftware.com> Return-path: In-Reply-To: <1413491125-20134-1-git-send-email-peter@hurleysoftware.com> Sender: linux-kernel-owner@vger.kernel.org To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, Jiri Slaby , linux-serial@vger.kernel.org, One Thousand Gnomes , Peter Hurley List-Id: linux-serial@vger.kernel.org Holding the tty_lock() is necessary to prevent concurrent changes to the tty count that may cause it to differ from the open file list count. The tty_lock() is already held at all call sites. NB: Note that the check for the pty master tty count is safe because the slave's tty_lock() is held while decrementing the pty master tty count. Signed-off-by: Peter Hurley --- drivers/tty/tty_io.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 50118ce..5c09cc4 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -275,6 +275,7 @@ int tty_paranoia_check(struct tty_struct *tty, struct inode *inode, return 0; } +/* Caller must hold tty_lock */ static int check_tty_count(struct tty_struct *tty, const char *routine) { #ifdef CHECK_TTY_COUNT -- 2.1.1