From mboxrd@z Thu Jan 1 00:00:00 1970 From: Viresh Kumar Subject: [PATCH 13/25] tty: serial: mcf: drop uart_port->lock before calling tty_flip_buffer_push() Date: Fri, 16 Aug 2013 17:13:14 +0530 Message-ID: <5128c7c0bba9d7626e42255ec44b8f500b65235e.1376651114.git.viresh.kumar@linaro.org> References: Return-path: Received: from mail-pa0-f46.google.com ([209.85.220.46]:45847 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754258Ab3HPLpD (ORCPT ); Fri, 16 Aug 2013 07:45:03 -0400 Received: by mail-pa0-f46.google.com with SMTP id fa1so1790957pad.33 for ; Fri, 16 Aug 2013 04:45:02 -0700 (PDT) In-Reply-To: In-Reply-To: References: Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: gregkh@linuxfoundation.org, jslaby@suse.cz Cc: linaro-kernel@lists.linaro.org, patches@linaro.org, linux-serial@vger.kernel.org, Viresh Kumar The -rt patch triggers a lockdep warning for serial drivers if tty_flip_buffer_push() is called with uart_port->lock locked. This never shows up on UP kernels. Release the port lock before calling tty_flip_buffer_push() and reacquire it after the call. Similar stuff was already done for few other drivers in the past, like: commit 2389b272168ceec056ca1d8a870a97fa9c26e11a Author: Thomas Gleixner Date: Tue May 29 21:53:50 2007 +0100 [ARM] 4417/1: Serial: Fix AMBA drivers locking Signed-off-by: Viresh Kumar --- drivers/tty/serial/mcf.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/tty/serial/mcf.c b/drivers/tty/serial/mcf.c index 65be0c0..62c8fdf 100644 --- a/drivers/tty/serial/mcf.c +++ b/drivers/tty/serial/mcf.c @@ -324,7 +324,9 @@ static void mcf_rx_chars(struct mcf_uart *pp) uart_insert_char(port, status, MCFUART_USR_RXOVERRUN, ch, flag); } + spin_unlock(&port->lock); tty_flip_buffer_push(&port->state->port); + spin_lock(&port->lock); } /****************************************************************************/ -- 1.7.12.rc2.18.g61b472e