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 87CED330B09 for ; Thu, 26 Mar 2026 10:31:48 +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=1774521108; cv=none; b=gM0hBF1FnxNjdrh17mIEu1+NPtsgvF0o7lNEIj1+WS/L8OupVDfIyweNQVkr/pU9unVATtZ4OE1bNa9bfs3OPi8IRWxBgMPc2rAN5FgGGotD/NKAYCsIlkH7Phg4acHyGw9wMSM+rg2ajdem4mjI5rEdd2CLza2gJLntQktMRQs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774521108; c=relaxed/simple; bh=SLTmm83ZZ/udKMXkHuHAbn9PFLN9jOvoZZ+tIAmKVVg=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=D0KTcSicBdQ+LDcdZq52dJY/jOxqXcsDkQpgPDdEUOELb1NCBNCUmay1ARnzue4n7iA3SNAJ5tMMmqMMWOhmKSUPcZ9mENEvCrWrcP10ZqHwcXdxTS4Kce2oMSbwd7z63G98JeURQdwXRR2tksGkLSXX96+fU175Jr65v8ktLhM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=e6lzebq7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="e6lzebq7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F232C19423; Thu, 26 Mar 2026 10:31:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774521108; bh=SLTmm83ZZ/udKMXkHuHAbn9PFLN9jOvoZZ+tIAmKVVg=; h=Date:Subject:To:References:From:In-Reply-To:From; b=e6lzebq7vEUZ5LYf4L/ZhNZ4QQvcaUT3YSNGNSKvxFwRCzB4ZKKTM5eGgeScHjb6F 4wRNDojiK4PFDKCtMbaJv+eqwNQeOF8caKgm0lmF07iaugHUKJqnKAxy3EvZpGep0M B2R8tXBuC7NXkuRt+TL0BCE+H+03b75D1Ks2FOaMIe/ghDWY9wh6obbDLmqaeyca+x F0G+Pn6yUU0daHOhMF335PJCdFgApYMYTo9EIPyC9MXYWo+piuIq4S6rQgEpupGqre OzmrLaQOjunfZ7WmaxjvwIi2XI0S+1QDGT9o9WoC1Q53B2q0uVju8sBo/5hF3H2rVI aqQz2jAH3PiyQ== Message-ID: <2690c97e-8911-4172-a8db-32e61cab495b@kernel.org> Date: Thu, 26 Mar 2026 11:31:45 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] w1: simplify allocation of w1_master To: Rosen Penev , linux-kernel@vger.kernel.org References: <20260324021537.14191-1-rosenp@gmail.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 24/03/2026 03:15, Rosen Penev wrote: > Convert bus_master to a flexible array member as it's being used as one > with the old C89 + 1 pointer trick. > > Signed-off-by: Rosen Penev > --- > drivers/w1/w1_int.c | 4 +--- > include/linux/w1.h | 4 ++-- > 2 files changed, 3 insertions(+), 5 deletions(-) > > diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c > index 19a0ea28e9f3..a0bb97608564 100644 > --- a/drivers/w1/w1_int.c > +++ b/drivers/w1/w1_int.c > @@ -31,12 +31,10 @@ static struct w1_master *w1_alloc_dev(u32 id, int slave_count, int slave_ttl, > /* > * We are in process context(kernel thread), so can sleep. > */ > - dev = kzalloc(sizeof(struct w1_master) + sizeof(struct w1_bus_master), GFP_KERNEL); > + dev = kzalloc_flex(*dev, bus_master, 1); > if (!dev) > return NULL; > > - dev->bus_master = (struct w1_bus_master *)(dev + 1); > - > dev->owner = THIS_MODULE; > dev->max_slave_count = slave_count; > dev->slave_count = 0; > diff --git a/include/linux/w1.h b/include/linux/w1.h > index 064805bfae3f..7379a9ddefc0 100644 > --- a/include/linux/w1.h > +++ b/include/linux/w1.h > @@ -236,9 +236,9 @@ struct w1_master { > struct device_driver *driver; > struct device dev; > > - struct w1_bus_master *bus_master; > - > u32 seq; > + > + struct w1_bus_master bus_master[]; Code does not use it as flexible array member, does it? Why this cannot be just two kzalloc's - one for w1_master and then next for bus_master? Or embed it directly (composition) in w1_master? Best regards, Krzysztof