From mboxrd@z Thu Jan 1 00:00:00 1970 From: Viresh Kumar Subject: [PATCH 19/25] tty: serial: pnx8xxx: drop uart_port->lock before calling tty_flip_buffer_push() Date: Fri, 16 Aug 2013 17:13:20 +0530 Message-ID: <4de8e95b2a8289b4f9556bb0a663fb6b967b98d2.1376651114.git.viresh.kumar@linaro.org> References: Return-path: Received: from mail-pd0-f170.google.com ([209.85.192.170]:63818 "EHLO mail-pd0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754258Ab3HPLpl (ORCPT ); Fri, 16 Aug 2013 07:45:41 -0400 Received: by mail-pd0-f170.google.com with SMTP id x10so2159565pdj.15 for ; Fri, 16 Aug 2013 04:45:41 -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/pnx8xxx_uart.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/tty/serial/pnx8xxx_uart.c b/drivers/tty/serial/pnx8xxx_uart.c index 7e277a5..8db7482 100644 --- a/drivers/tty/serial/pnx8xxx_uart.c +++ b/drivers/tty/serial/pnx8xxx_uart.c @@ -237,7 +237,10 @@ static void pnx8xxx_rx_chars(struct pnx8xxx_port *sport) status = FIFO_TO_SM(serial_in(sport, PNX8XXX_FIFO)) | ISTAT_TO_SM(serial_in(sport, PNX8XXX_ISTAT)); } + + spin_unlock(&sport->port.lock); tty_flip_buffer_push(&sport->port.state->port); + spin_lock(&sport->port.lock); } static void pnx8xxx_tx_chars(struct pnx8xxx_port *sport) -- 1.7.12.rc2.18.g61b472e