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 3D3391E865; Tue, 12 Mar 2024 22:30:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710282636; cv=none; b=OKVU2GVRI8FfQ64wXalRzXdM2vvLItK/xnTM6eKs3iNwNLxLzPmo/R3aMkgmg6m4fEtVJ92Kc516VYqlaY9f9KFrs0BmM5026dMx9kUgr/RXVNnZfg6rmdcqTB0Kg542OhotuZwTSp7JGIFwSIzU8Ss/fNQYQcWKykiKS/Ijoxo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710282636; c=relaxed/simple; bh=Q4tyCFUdRMFy/X4/dbjE7LKOIJOM3K5KGJRp8+K4Jks=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ZoCQnOjzAw6hUu8/E4rs/uL9TzJWSb8eAypjTbEgSpYl72Wfpe93p846AMfDm/nNuw4/DpYzmvvxXuacKPhla3vy/wHqPcT8BM1qZv9EmdXN9F3nZdMoP48j0+M3jRZ+G7BuxHRbK+/03OhI5LTZ52n5KBErPKfsA9T3HE9BU70= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=VYx9FtyN; arc=none smtp.client-ip=198.137.202.133 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=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="VYx9FtyN" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Transfer-Encoding :Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=vUPdcFP0avBFD0D2L9KZnUUP8B4bZ3OA1degYExs78g=; b=VYx9FtyNGU0EntIZoMxKthvM/f icFD2IBK/Wte2zcPsuHmrMtsgCb59mHSoW7aJPaJl7/hZiXzewCRZXgSkK34obujy0w+Zzmt1v5EO CdtWMPLTmkdJl8m5X1qxz/odqUHGakhZMi595VfItyvA1l9RZY9RqjWtAWTf3aJad/t3XL22cRq90 SOeJ709hIQmRWY1oZbIzSKQ04pNv4SfLdlJ1kxzU57NGw/UWZEiz68I68RpDPPjVBGOLAd94be4No 6j7p+JBb3jqzQxGLUtC1sHv83+COKOJsqwIWp6hzEudGFSQDkfg1D95bGDIVYJ/JY1erRntte3o/p xtkwLFdA==; Received: from hch by bombadil.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1rkAdk-00000007qTc-2vub; Tue, 12 Mar 2024 22:30:32 +0000 Date: Tue, 12 Mar 2024 15:30:32 -0700 From: Christoph Hellwig To: Mike Snitzer Cc: Christoph Hellwig , Linus Torvalds , Jens Axboe , Johannes Weiner , "linux-block@vger.kernel.org" , dm-devel@lists.linux.dev Subject: Re: [GIT PULL] Block updates for 6.9-rc1 Message-ID: References: <20240311235023.GA1205@cmpxchg.org> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Tue, Mar 12, 2024 at 06:22:21PM -0400, Mike Snitzer wrote: > > The real problem is that we combine the limits while we shouldn't. > > Every since we've supported immutable biovecs and do the splitting > > down in blk-mq there is no point to even inherit such limits in the > > upper drivers. > > immutable biovecs, late splitting and blk-mq aren't a factor. > > dm-crypt has to contend with the crypto subsystem and HW crypto > engines that have their own constraints. Yes, they are. The limit for underlying device does not matter for an upper devіce as it will split later. And that's not just my opinion, you also clearly stated that in the commit adding the limits (586b286b110e94e). We should have stopped inheriting all these limits only relevant for splitting when we switched to immutable bvecs. I don't know why we didn't, but a big part of that might be that we never made clear which limits these are.