From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 2BB64A32; Sun, 17 Dec 2023 02:03:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="1SC7We7T" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Sender:Reply-To:Content-ID:Content-Description; bh=wSxaOslInFaYonzYXDSErFQurFpPyX2ZAWJ45tnIxmU=; b=1SC7We7TfTkAliYcUVp07bbaHo sEKhmoTHHkl+lZeeuq9Z7k5SLs66o8RXWdkUTSw5Oeq9lzilQeiRBzD1RjJNTlkQVm8jBq+9Gdmwm KabnLTExPA5zrWt5QpMWLVPPujApVtez+zmVUASsNzhEmHS2ihFLO4Ln82TRfsxa2DcrblKgUs5nx WpdAA1sz91RwOztxpm9W+v+TSAu68OhQ/QojCdTyo4ZbRnBDg1xU/eST1X1ZYQuxAEUHc2Lxha7Gx uS0PFSz9HfrcyX/rekKwkv2RFIHwbpDY+YaJTi4qSskTQbef8Un5o0/Z7mOgzjxqbPat2iVmaFI6e hR/Pb9lw==; Received: from [50.53.46.231] (helo=[192.168.254.15]) by bombadil.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1rEgVF-0070Vy-0E; Sun, 17 Dec 2023 02:03:37 +0000 Message-ID: <8625718c-b8c2-448b-a2a8-7153aa74ce29@infradead.org> Date: Sat, 16 Dec 2023 18:03:36 -0800 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 46/50] preempt.h: Kill dependency on list.h Content-Language: en-US To: Kent Overstreet , Matthew Wilcox Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, tglx@linutronix.de, x86@kernel.org, tj@kernel.org, peterz@infradead.org, mathieu.desnoyers@efficios.com, paulmck@kernel.org, keescook@chromium.org, dave.hansen@linux.intel.com, mingo@redhat.com, will@kernel.org, longman@redhat.com, boqun.feng@gmail.com, brauner@kernel.org References: <20231216024834.3510073-1-kent.overstreet@linux.dev> <20231216033552.3553579-1-kent.overstreet@linux.dev> <20231216033552.3553579-3-kent.overstreet@linux.dev> <20231216223522.s4skrclervsskx32@moria.home.lan> <82ed43c2-2a9d-4c5e-8ccd-8078397b7953@infradead.org> <20231217002028.shjg6p7wa2cmtkq2@moria.home.lan> From: Randy Dunlap In-Reply-To: <20231217002028.shjg6p7wa2cmtkq2@moria.home.lan> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 12/16/23 16:20, Kent Overstreet wrote: > On Sun, Dec 17, 2023 at 12:18:17AM +0000, Matthew Wilcox wrote: >> On Sat, Dec 16, 2023 at 04:04:43PM -0800, Randy Dunlap wrote: >>> >>> >>> On 12/16/23 14:35, Kent Overstreet wrote: >>>> On Sat, Dec 16, 2023 at 06:13:41AM +0000, Matthew Wilcox wrote: >>>>> On Fri, Dec 15, 2023 at 10:35:47PM -0500, Kent Overstreet wrote: >>>>>> - INIT_HLIST_NODE(¬ifier->link); >>>>>> + /* INIT_HLIST_NODE() open coded, to avoid dependency on list.h */ >>>>>> + notifier->link.next = NULL; >>>>>> + notifier->link.pprev = NULL; >>>>> >>>>> Arguably INIT_HLIST_NODE() belongs in types.h -- we already have >>>>> RCUREF_INIT() and ATOMIC_INIT() in there. >>>> >>>> I think I'd prefer to keep types.h as minimal as possible - as soon as >>>> we start putting non type stuff in there people won't know what the >>>> distinction is and it'll grow. >>>> >>>> preempt.h is a bit unusual too, normally we'd just split out a _types.h >>>> header there but it's not so easy to split up usefully. >>>> >>> >>> I don't feel like I have NAK power, but if I did, I would NAK >>> open coding of INIT_HLIST_HEAD() or anything like it. >>> I would expect some $maintainer to do likewise, but I could be >>> surprised. >> >> There is another solution here (although I prefer moving INIT_HLIST_HEAD >> into types.h). The preprocessor allows redefinitions as long as the two >> definitions match exactly. So you can copy INIT_HLIST_HEAD into >> preempt.h and if the definition ever changes, we'll notice. > > I like it. Possible to revert 490d6ab170c9 ? although with something list this inserted: struct hlist_node *_p = h; and then use _p instead of h (or the old macro's 'ptr') The code looks the same to me, although I could have mucked something up: https://godbolt.org/z/z76nsqGx3 although Andrew prefers inlines for type checking. -- #Randy https://people.kernel.org/tglx/notes-about-netiquette https://subspace.kernel.org/etiquette.html