Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751430AbdGPPMM (ORCPT ); Sun, 16 Jul 2017 11:12:12 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:33698 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751354AbdGPPMB (ORCPT ); Sun, 16 Jul 2017 11:12:01 -0400 Message-Id: <20170716151156.981556142@gmail.com> User-Agent: quilt/0.65 Date: Sun, 16 Jul 2017 17:18:26 +0100 From: Okash Khawaja To: Greg Kroah-Hartman , Jiri Slaby , Samuel Thibault , Alan Cox , linux-kernel@vger.kernel.org Cc: William Hubbs , Chris Brannon , Kirk Reiser , speakup@linux-speakup.org, devel@driverdev.osuosl.org, Okash Khawaja Subject: [patch 2/2] staging: speakup: safely register and unregister ldisc References: <20170716161824.794118123@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=18_safely_register_and_unregister_ldisc Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2461 Lines: 69 This patch makes use of functions added in the previous patch. It registers ldisc during init of main speakup module and unregisters it during exit. It also removes the code to register ldisc every time a synth module is loaded. This way we only register the ldisc once when main speakup module is loaded. Since main speakup module is required by all synth modules, it is only unloaded when all synths have been unloaded. Therefore we unregister the ldisc once, when all speakup related references to the ldisc have returned. In unlikely scenario of something outside speakup using the ldisc, the ldisc refcount check in tty_unregister_ldisc will ensure that it is not unregistered while in use. The function to register ldisc doesn't cause speakup init function to fail. That is different from current behaviour where failure to register ldisc results in failure to load the specific synth module. This is because speakup module is also required by those synths which don't use tty and ldisc. We don't want to prevent those modules from loading when ldisc fails to register. The synth modules will correctly fail when trying to set N_SPEAKUP to tty, if ldisc registrationi had failed. Signed-off-by: Okash Khawaja --- drivers/staging/speakup/main.c | 2 ++ drivers/staging/speakup/spk_ttyio.c | 8 ++------ 2 files changed, 4 insertions(+), 6 deletions(-) --- a/drivers/staging/speakup/main.c +++ b/drivers/staging/speakup/main.c @@ -2315,6 +2315,7 @@ static void __exit speakup_exit(void) mutex_lock(&spk_mutex); synth_release(); mutex_unlock(&spk_mutex); + spk_ttyio_unregister_ldisc(); speakup_kobj_exit(); @@ -2377,6 +2378,7 @@ static int __init speakup_init(void) if (err) goto error_kobjects; + spk_ttyio_register_ldisc(); synth_init(synth_name); speakup_register_devsynth(); /* --- a/drivers/staging/speakup/spk_ttyio.c +++ b/drivers/staging/speakup/spk_ttyio.c @@ -154,12 +154,6 @@ static int spk_ttyio_initialise_ldisc(st struct ktermios tmp_termios; dev_t dev; - ret = tty_register_ldisc(N_SPEAKUP, &spk_ttyio_ldisc_ops); - if (ret) { - pr_err("Error registering line discipline.\n"); - return ret; - } - ret = get_dev_to_use(synth, &dev); if (ret) return ret; @@ -196,6 +190,8 @@ static int spk_ttyio_initialise_ldisc(st tty_unlock(tty); ret = tty_set_ldisc(tty, N_SPEAKUP); + if (ret) + pr_err("speakup: Failed to set N_SPEAKUP on tty\n"); return ret; }