From patchwork Mon Oct 12 12:33:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= X-Patchwork-Id: 269839 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 861BCC43467 for ; Mon, 12 Oct 2020 12:34:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4245D20757 for ; Mon, 12 Oct 2020 12:34:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388500AbgJLMeL (ORCPT ); Mon, 12 Oct 2020 08:34:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48900 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388503AbgJLMeL (ORCPT ); Mon, 12 Oct 2020 08:34:11 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9F0CCC0613D5 for ; Mon, 12 Oct 2020 05:34:10 -0700 (PDT) Received: from pty.hi.pengutronix.de ([2001:67c:670:100:1d::c5]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kRx1f-0001Ex-N7; Mon, 12 Oct 2020 14:34:03 +0200 Received: from ukl by pty.hi.pengutronix.de with local (Exim 4.89) (envelope-from ) id 1kRx1c-0007So-Tr; Mon, 12 Oct 2020 14:34:00 +0200 From: =?utf-8?q?Uwe_Kleine-K=C3=B6nig?= To: Jacek Anaszewski , Pavel Machek , Dan Murphy , Greg Kroah-Hartman , Jiri Slaby Cc: Johan Hovold , linux-leds@vger.kernel.org, linux-serial@vger.kernel.org, kernel@pengutronix.de, linux-kernel@vger.kernel.org Subject: [PATCH v8 1/3] tty: rename tty_kopen() and add new function tty_kopen_shared() Date: Mon, 12 Oct 2020 14:33:56 +0200 Message-Id: <20201012123358.1475928-2-u.kleine-koenig@pengutronix.de> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201012123358.1475928-1-u.kleine-koenig@pengutronix.de> References: <20201012123358.1475928-1-u.kleine-koenig@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c5 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-serial@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org Introduce a new function tty_kopen_shared() that yields a struct tty_struct. The semantic difference to tty_kopen() is that the tty is expected to be used already. So rename tty_kopen() to tty_kopen_exclusive() for clearness, adapt the single user and put the common code in a new static helper function. tty_kopen_shared is to be used to implement an LED trigger for tty devices in one of the next patches. Signed-off-by: Uwe Kleine-König --- drivers/accessibility/speakup/spk_ttyio.c | 2 +- drivers/tty/tty_io.c | 56 +++++++++++++++-------- include/linux/tty.h | 5 +- 3 files changed, 42 insertions(+), 21 deletions(-) diff --git a/drivers/accessibility/speakup/spk_ttyio.c b/drivers/accessibility/speakup/spk_ttyio.c index a831ff64f8ba..991b21017a01 100644 --- a/drivers/accessibility/speakup/spk_ttyio.c +++ b/drivers/accessibility/speakup/spk_ttyio.c @@ -149,7 +149,7 @@ static int spk_ttyio_initialise_ldisc(struct spk_synth *synth) if (ret) return ret; - tty = tty_kopen(dev); + tty = tty_kopen_exclusive(dev); if (IS_ERR(tty)) return PTR_ERR(tty); diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index ceed72c9a88f..8aede3d2c1e0 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -1871,22 +1871,7 @@ static struct tty_driver *tty_lookup_driver(dev_t device, struct file *filp, return driver; } -/** - * tty_kopen - open a tty device for kernel - * @device: dev_t of device to open - * - * Opens tty exclusively for kernel. Performs the driver lookup, - * makes sure it's not already opened and performs the first-time - * tty initialization. - * - * Returns the locked initialized &tty_struct - * - * Claims the global tty_mutex to serialize: - * - concurrent first-time tty initialization - * - concurrent tty driver removal w/ lookup - * - concurrent tty removal from driver table - */ -struct tty_struct *tty_kopen(dev_t device) +static struct tty_struct *tty_kopen(dev_t device, int shared) { struct tty_struct *tty; struct tty_driver *driver; @@ -1901,7 +1886,7 @@ struct tty_struct *tty_kopen(dev_t device) /* check whether we're reopening an existing tty */ tty = tty_driver_lookup_tty(driver, NULL, index); - if (IS_ERR(tty)) + if (IS_ERR(tty) || shared) goto out; if (tty) { @@ -1919,7 +1904,42 @@ struct tty_struct *tty_kopen(dev_t device) tty_driver_kref_put(driver); return tty; } -EXPORT_SYMBOL_GPL(tty_kopen); + +/** + * tty_kopen_exclusive - open a tty device for kernel + * @device: dev_t of device to open + * + * Opens tty exclusively for kernel. Performs the driver lookup, + * makes sure it's not already opened and performs the first-time + * tty initialization. + * + * Returns the locked initialized &tty_struct + * + * Claims the global tty_mutex to serialize: + * - concurrent first-time tty initialization + * - concurrent tty driver removal w/ lookup + * - concurrent tty removal from driver table + */ +struct tty_struct *tty_kopen_exclusive(dev_t device) +{ + return tty_kopen(device, 0); +} +EXPORT_SYMBOL_GPL(tty_kopen_exclusive); + +/** + * tty_kopen_shared - open a tty device for shared in-kernel use + * @device: dev_t of device to open + * + * Opens an already existing tty for in-kernel use. Compared to + * tty_kopen_exclusive() above it doesn't ensure to be the only user. + * + * Locking is identical to tty_kopen() above. + */ +struct tty_struct *tty_kopen_shared(dev_t device) +{ + return tty_kopen(device, 1); +} +EXPORT_SYMBOL_GPL(tty_kopen_shared); /** * tty_open_by_driver - open a tty device diff --git a/include/linux/tty.h b/include/linux/tty.h index a99e9b8e4e31..c867d6fe67c4 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -413,7 +413,8 @@ extern struct tty_struct *get_current_tty(void); /* tty_io.c */ extern int __init tty_init(void); extern const char *tty_name(const struct tty_struct *tty); -extern struct tty_struct *tty_kopen(dev_t device); +extern struct tty_struct *tty_kopen_exclusive(dev_t device); +extern struct tty_struct *tty_kopen_shared(dev_t device); extern void tty_kclose(struct tty_struct *tty); extern int tty_dev_name_to_number(const char *name, dev_t *number); extern int tty_ldisc_lock(struct tty_struct *tty, unsigned long timeout); @@ -438,7 +439,7 @@ static inline int __init tty_init(void) { return 0; } static inline const char *tty_name(const struct tty_struct *tty) { return "(none)"; } -static inline struct tty_struct *tty_kopen(dev_t device) +static inline struct tty_struct *tty_kopen_exclusive(dev_t device) { return ERR_PTR(-ENODEV); } static inline void tty_kclose(struct tty_struct *tty) { }