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 X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 256B1C433E0 for ; Mon, 8 Feb 2021 19:21:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D16D764E74 for ; Mon, 8 Feb 2021 19:21:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236118AbhBHTVK (ORCPT ); Mon, 8 Feb 2021 14:21:10 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:38158 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235184AbhBHSAG (ORCPT ); Mon, 8 Feb 2021 13:00:06 -0500 From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1612807155; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=d/K1nflfjUlbsBR3cGwm/oQjA++u+sJaiD0qsOu7S2s=; b=CHIBhRcS9EzzfV/puEcjPtfyZq14OpnWy94x/5xqEeK0HD9eFrDljq/dTT6dy9ZKTjviFQ MGHzHOyVpa+QPrQiyqsLPjFWCxz57fKJcRkuSQ3TbSfeA8aC4CEMg63jOGQy36tON9WnhH FXCPhxIkc1tjeFdI1nWXgbFNmAqSIg3Gf5rxY58W12Ogf3RrKvmv5LNEl0Exa1gbdGVtE2 /FUi6oQ+L25oJhzHFKLgX2xd+fgMgs6Io1bEFCOnsDAaM0QaxgGZqHXkqxNVDdkrufn0Jx 1y60ALM6UeklQge91NhzcJ4O/AqhCekCvRCVLJwGTk/0KnOBa4Nc34PWbgbnag== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1612807155; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=d/K1nflfjUlbsBR3cGwm/oQjA++u+sJaiD0qsOu7S2s=; b=4wR+m38B5LyACURm932IzQakUfaUt5rUysmpS8y054un9uavzWSlLGMvv9GSXfneHTzHA6 a3f2+iCqIeMEA0BQ== To: linux-kernel@vger.kernel.org Cc: Thomas Gleixner , Sebastian Andrzej Siewior , Miguel Ojeda Sandonis Subject: [PATCH] auxdisplay: Remove in_interrupt() usage. Date: Mon, 8 Feb 2021 18:58:24 +0100 Message-Id: <20210208175824.381484-1-bigeasy@linutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org charlcd_write() is invoked as a VFS->write() callback and as such it is always invoked from preemptible context and may sleep. charlcd_puts() is invoked from register/unregister callback which is preemtible. The reboot notifier callback is also invoked from preemptible context. Therefore there is no need to use `in_interrupt()' to figure out if it is save to sleep because it always is. Using `schedule()' to schedule (an be friendly to others) is discouraged and `cond_resched()' should be used instead. Remove `in_interrupt()' and use `cond_resched()' to schedule every 32 iteration if needed. Cc: Miguel Ojeda Sandonis Signed-off-by: Sebastian Andrzej Siewior --- drivers/auxdisplay/charlcd.c | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-) diff --git a/drivers/auxdisplay/charlcd.c b/drivers/auxdisplay/charlcd.c index f43430e9dceed..fbfce95919f72 100644 --- a/drivers/auxdisplay/charlcd.c +++ b/drivers/auxdisplay/charlcd.c @@ -470,12 +470,8 @@ static ssize_t charlcd_write(struct file *file, const = char __user *buf, char c; =20 for (; count-- > 0; (*ppos)++, tmp++) { - if (!in_interrupt() && (((count + 1) & 0x1f) =3D=3D 0)) - /* - * let's be a little nice with other processes - * that need some CPU - */ - schedule(); + if (((count + 1) & 0x1f) =3D=3D 0) + cond_resched(); =20 if (get_user(c, tmp)) return -EFAULT; @@ -537,12 +533,8 @@ static void charlcd_puts(struct charlcd *lcd, const ch= ar *s) int count =3D strlen(s); =20 for (; count-- > 0; tmp++) { - if (!in_interrupt() && (((count + 1) & 0x1f) =3D=3D 0)) - /* - * let's be a little nice with other processes - * that need some CPU - */ - schedule(); + if (((count + 1) & 0x1f) =3D=3D 0) + cond_resched(); =20 charlcd_write_char(lcd, *tmp); } --=20 2.30.0