From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1CB10EE644C for ; Fri, 15 Sep 2023 09:15:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232633AbjIOJPD (ORCPT ); Fri, 15 Sep 2023 05:15:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59438 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232435AbjIOJPC (ORCPT ); Fri, 15 Sep 2023 05:15:02 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B26F898; Fri, 15 Sep 2023 02:14:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1694769297; x=1726305297; h=date:from:to:cc:subject:in-reply-to:message-id: references:mime-version; bh=CeM5K/VFy1Wo5gVfxA3wNMmKSXfxOKlo5AiwsitcOPU=; b=QKu/Qfg7k9YKzEvDyxKE8KgRWcAxAMRZFkD0FAsLkEDh5DCUncMAp9Yn DZitoJySSofuZXjv912bKUbEADbG0ShZ+Z4jvyEA9lTLgUfjrcQ6pYtMR j3/ChGt/jOON3CUX0VLBGU3u5lOXYxT+dEv9MB5wejNc7Z7j2GARE4oMw 9FlcV3nDE4jfPzeM3S7vz7zPLht98jooimzTF9LndeT+/yfXV7FPmH5Tq 9okpZR19ZoVgfTIaXfe8dC4s49hhFfXYpK2vgLqovXtCtsXOmuXnAFgei dDuOJzKqNy0MO5CyqavR41Ioq2Sd4AK7o4M/bKexskvHI/dYdIU8BOIzp Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10833"; a="369523756" X-IronPort-AV: E=Sophos;i="6.02,148,1688454000"; d="scan'208";a="369523756" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Sep 2023 02:14:57 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10833"; a="744905421" X-IronPort-AV: E=Sophos;i="6.02,148,1688454000"; d="scan'208";a="744905421" Received: from srdoo-mobl1.ger.corp.intel.com ([10.252.38.99]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Sep 2023 02:14:54 -0700 Date: Fri, 15 Sep 2023 12:14:52 +0300 (EEST) From: =?ISO-8859-15?Q?Ilpo_J=E4rvinen?= To: John Ogness cc: Greg Kroah-Hartman , Jiri Slaby , linux-serial , Petr Mladek , Thomas Gleixner , LKML , Andy Shevchenko Subject: Re: [PATCH tty v1 07/74] serial: 8250_dma: Use port lock wrappers In-Reply-To: <20230914183831.587273-8-john.ogness@linutronix.de> Message-ID: <2410ffe1-d89c-8598-3e41-8ba2454088d@linux.intel.com> References: <20230914183831.587273-1-john.ogness@linutronix.de> <20230914183831.587273-8-john.ogness@linutronix.de> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="8323329-2032124865-1694769296=:2347" Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323329-2032124865-1694769296=:2347 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 8BIT On Thu, 14 Sep 2023, John Ogness wrote: > From: Thomas Gleixner > > When a serial port is used for kernel console output, then all > modifications to the UART registers which are done from other contexts, > e.g. getty, termios, are interference points for the kernel console. > > So far this has been ignored and the printk output is based on the > principle of hope. The rework of the console infrastructure which aims to > support threaded and atomic consoles, requires to mark sections which > modify the UART registers as unsafe. This allows the atomic write function > to make informed decisions and eventually to restore operational state. It > also allows to prevent the regular UART code from modifying UART registers > while printk output is in progress. > > All modifications of UART registers are guarded by the UART port lock, > which provides an obvious synchronization point with the console > infrastructure. > > To avoid adding this functionality to all UART drivers, wrap the > spin_[un]lock*() invocations for uart_port::lock into helper functions > which just contain the spin_[un]lock*() invocations for now. In a > subsequent step these helpers will gain the console synchronization > mechanisms. > > Converted with coccinelle. No functional change. > > Signed-off-by: Thomas Gleixner > --- > drivers/tty/serial/8250/8250_dma.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c > index 7fa66501792d..8b30ca8fdd3f 100644 > --- a/drivers/tty/serial/8250/8250_dma.c > +++ b/drivers/tty/serial/8250/8250_dma.c > @@ -22,7 +22,7 @@ static void __dma_tx_complete(void *param) > dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr, > UART_XMIT_SIZE, DMA_TO_DEVICE); > > - spin_lock_irqsave(&p->port.lock, flags); > + uart_port_lock_irqsave(&p->port, &flags); > > dma->tx_running = 0; > > @@ -35,7 +35,7 @@ static void __dma_tx_complete(void *param) > if (ret || !dma->tx_running) > serial8250_set_THRI(p); > > - spin_unlock_irqrestore(&p->port.lock, flags); > + uart_port_unlock_irqrestore(&p->port, flags); > } > > static void __dma_rx_complete(struct uart_8250_port *p) > @@ -70,7 +70,7 @@ static void dma_rx_complete(void *param) > struct uart_8250_dma *dma = p->dma; > unsigned long flags; > > - spin_lock_irqsave(&p->port.lock, flags); > + uart_port_lock_irqsave(&p->port, &flags); > if (dma->rx_running) > __dma_rx_complete(p); > > @@ -80,7 +80,7 @@ static void dma_rx_complete(void *param) > */ > if (!dma->rx_running && (serial_lsr_in(p) & UART_LSR_DR)) > p->dma->rx_dma(p); > - spin_unlock_irqrestore(&p->port.lock, flags); > + uart_port_unlock_irqrestore(&p->port, flags); > } > > int serial8250_tx_dma(struct uart_8250_port *p) Reviewed-by: Ilpo Järvinen -- i. --8323329-2032124865-1694769296=:2347--