From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 14FF917E0; Wed, 30 Apr 2025 06:58:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745996316; cv=none; b=Htb5y6H5OKa8IFOCLmMNadbYSgz+frkJ4GOMxgPEZSKRbEJkzpFSZH6TTu9iqvWOaeFD/X2awpRayUs6RdZcqEDASIoVMk7AkTiWmHusvz4cJd7QpwM4xW6jdNKr/cB3bg1l0NPIQ9Zy/PkDMXCvDTtnoqTHKAqhA5DEwB0eXPk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745996316; c=relaxed/simple; bh=7CUhpQ9+zIhyv0GvZjAoVHD9ajVOAIWKqnDgeOZSAdA=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=N77b7B/MEHkXupArjD94LmRy3q0IxvMZOMg8cCRT3L5kCodwseV9/pDwiruWqzxSjRdUoXvFpBPTjgmWAc3pz4GVWUl9yeK+OSSUCocmK0vWo/0+KmE8XwGBqI259c2vFiqEbOVOCVEDdI+5KYcDVM+y+snssd6tqz0zaLpnCbQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=WQPZ9YhE; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=xh7ZqCgV; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="WQPZ9YhE"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="xh7ZqCgV" From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1745996313; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=UBgDD27NsLa3RNSfaO8xNkStzEbW1eu3yXOUdjUkJfA=; b=WQPZ9YhEzgOWDJ04IOSVvahwwt2m/mtd68TP/cYb8lUMTtj1sbLgxpdrhcnuRjHlCxlajZ RQPpyaMjbNzZExn/43jyVw0MAV60M5VCE+4Wla824MHBvGRA026q/DqGtVI6aguWauKgU6 Jb9CjTM3USxThLTeIGWmw8Ti+15vSum/QX5iGVHQ59R0y8AcF98uiae783qs37yUXMsm8v h4ze8g5PfcEVaBW2LGi1d3e+z5xHowbj8Fu8Dj4PJX+EQJYphGea/2bYykvksBDjpc80sE b5IPR9TLPaxz8OGCfzNsVbnU21G2R2tG8uexUhKwTF/O6gcDj6MteWd/X3mJaQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1745996313; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=UBgDD27NsLa3RNSfaO8xNkStzEbW1eu3yXOUdjUkJfA=; b=xh7ZqCgVTbQ7h+QZGKcm2N9MxrIQp+fmQ2rvlcWtJlgeoQD09XcMYs1UPk7bBOsKVRtB/O ucKcWBDz5gBIW+Bw== To: John Stultz , Su Hui Cc: sboyd@kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [PATCH 3/3] alarmtimer: switch spin_{lock,unlock}_irqsave() to guard() In-Reply-To: References: <20250424144819.24884-1-suhui@nfschina.com> <20250424144819.24884-4-suhui@nfschina.com> Date: Wed, 30 Apr 2025 08:58:27 +0200 Message-ID: <87y0vip23w.ffs@tglx> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On Thu, Apr 24 2025 at 16:59, John Stultz wrote: > On Thu, Apr 24, 2025 at 7:48=E2=80=AFAM Su Hui wrote: >> - spin_unlock_irqrestore(&freezer_delta_lock, flags); >> + scoped_guard(spinlock_irqsave, &freezer_delta_lock) { >> + min =3D freezer_delta; >> + expires =3D freezer_expires; >> + type =3D freezer_alarmtype; >> + freezer_delta =3D 0; >> + } > > I'm not necessarily opposed, but I'm not sure we're gaining much here. >> @@ -352,13 +347,13 @@ EXPORT_SYMBOL_GPL(alarm_init); >> void alarm_start(struct alarm *alarm, ktime_t start) >> { >> struct alarm_base *base =3D &alarm_bases[alarm->type]; >> - unsigned long flags; >> >> - spin_lock_irqsave(&base->lock, flags); >> - alarm->node.expires =3D start; >> - alarmtimer_enqueue(base, alarm); >> - hrtimer_start(&alarm->timer, alarm->node.expires, HRTIMER_MODE_A= BS); >> - spin_unlock_irqrestore(&base->lock, flags); >> + scoped_guard(spinlock_irqsave, &base->lock) { >> + alarm->node.expires =3D start; >> + alarmtimer_enqueue(base, alarm); >> + hrtimer_start(&alarm->timer, alarm->node.expires, >> + HRTIMER_MODE_ABS); >> + } > > Similarly, this just seems more like churn, than making the code > particularly more clear. I disagree. scoped_guard() is actually superior as it makes it visually entirely clear what the actual scope of the spin lock protected code is. That's the whole point. Especially in alarm_suspend() this would end up with a mix of scoped guards and open coded spinlock regions. That's obstructing the reading flow. I'll bring them back for consistency when applying the series. Thanks, tglx