From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 93F452C3273; Mon, 30 Jun 2025 17:25:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751304300; cv=none; b=feLGTdTuQlx1mt8Qhl+zapIu0BqPBSMFQ2KuzmQsDLrJtFb/57gx3xBtA9avk07FjsIiKXJlaIMi1SKqTHTTuxV5YQ6yoaviFq1VaumMMkxT0KPqDimSYLROGnWImR0IRzhyuUt5H7cZCuZdVmGJDSlbkw3TCFPb6l/48ErCqos= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751304300; c=relaxed/simple; bh=uehCu0PQ3Rt5UP3Eqg8DxWd06wirGlh5cnhD9O7bFeg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fXyNK8N4nvLmoyuajOVfXO3XbAaEKLZcbHFVorNHLUkeg80cwM/ANQO1/f32E8KtQeuJ8PsrauVT6ftdjq/9P8TglVgJSBIcjnJNDfF5MaLzN7xV7DNtHjJFNmc8Qn1a4wIJHknEQp4aRVlTV4MBrpXTn4YuyOb135b+31kXcis= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b=YETbN4qM; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="YETbN4qM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E5EEC4CEE3; Mon, 30 Jun 2025 17:24:59 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="YETbN4qM" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1751304298; 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: in-reply-to:in-reply-to:references:references; bh=mmwZNE2u/jLWQ97nyzsa8bOnYBvTHITQRZ6hjwPm9kM=; b=YETbN4qM+f1cBb669m1/hT7Q4hRI2+0z525cA9bYYlRfOYah39n5n+zgwzsVs0gbBi9NIU M0yaSxKCDBssANSv6sXIfguOLhdf2+vNn3N+VpC3WaXidp2KGUdR6N0dutVq2bSHWVo22D ft0Ay9OF7nLQl4y180ov5VQDK1aOpS8= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 21b57f64 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Mon, 30 Jun 2025 17:24:57 +0000 (UTC) Date: Mon, 30 Jun 2025 19:24:33 +0200 From: "Jason A. Donenfeld" To: Yury Norov Cc: Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , wireguard@lists.zx2c4.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] wireguard: queueing: simplify wg_cpumask_next_online() Message-ID: References: <20250619145501.351951-1-yury.norov@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250619145501.351951-1-yury.norov@gmail.com> On Thu, Jun 19, 2025 at 10:54:59AM -0400, Yury Norov wrote: > From: Yury Norov [NVIDIA] > > wg_cpumask_choose_online() opencodes cpumask_nth(). Use it and make the > function significantly simpler. While there, fix opencoded cpu_online() > too. > > Signed-off-by: Yury Norov [NVIDIA] > --- > v1: https://lore.kernel.org/all/20250604233656.41896-1-yury.norov@gmail.com/ > v2: > - fix 'cpu' undeclared; > - change subject (Jason); > - keep the original function structure (Jason); > > drivers/net/wireguard/queueing.h | 13 ++++--------- > 1 file changed, 4 insertions(+), 9 deletions(-) > > diff --git a/drivers/net/wireguard/queueing.h b/drivers/net/wireguard/queueing.h > index 7eb76724b3ed..56314f98b6ba 100644 > --- a/drivers/net/wireguard/queueing.h > +++ b/drivers/net/wireguard/queueing.h > @@ -104,16 +104,11 @@ static inline void wg_reset_packet(struct sk_buff *skb, bool encapsulating) > > static inline int wg_cpumask_choose_online(int *stored_cpu, unsigned int id) > { > - unsigned int cpu = *stored_cpu, cpu_index, i; > + unsigned int cpu = *stored_cpu; > + > + if (unlikely(cpu >= nr_cpu_ids || !cpu_online(cpu))) > + cpu = *stored_cpu = cpumask_nth(id % num_online_cpus(), cpu_online_mask); I was about to apply this but then it occurred to me: what happens if cpu_online_mask changes (shrinks) after num_online_cpus() is evaluated? cpumask_nth() will then return nr_cpu_ids? Jason