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 E976D3CA497; Wed, 19 Aug 2026 05:59:35 +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=1787119181; cv=none; b=HkcaqIkx5hNQO58fMSXZFJ+coyUTvLDKrzopwDB/o2j62Xud8yqEVEcP5RoNAl/gd7dp8Krm5uD6U8lO8a4Bh/xV7mCXa0Vnu/CqzxMTlhHq+oa+cNhm4W89hHJnM8H59sZElbYmQndK2+Fx5yN6FyMwkKtx3AtLeAjt2HYN1MI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787119181; c=relaxed/simple; bh=zImk7JyRxEsZI02lK0HI5YsjZLjwlFYZoROVY6CkpD8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=c8fISx54B8pIrXJijTZuvFnjsAC95H5aE1r7pypuUyNBgx5ZwB9Bi9So372sAI/2Atx/AmXXDjStiTjvNe6APgTFfjH20uS0Aia2qYF4wl5iIoXvruxs+mytQ0czxDjddXeNcjQvLPc53nJ0QONjrG6+5+Ow6tigzb71ueqfsJE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (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=AKQoAUlp; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (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="AKQoAUlp" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=h1/Jq2qHgrQSYqbMlUYbjKMlu16WUscv+y1zxCO55Cw=; b=AKQoAUlp6NIKg56ZsFYR0aTyHE pUrkdYHpX0MNDaLeMcstq8d3LoBk95uBtLvBWIcG3cBOozMtWqGqlhBuKKLYKi/4euHB+pWkcEX5j uh74COjqv450qS/D381ttfcZA+Eap8MtksxK4kTEd87E/t6maLlLn4BhoDI8PkyRDUCPvYNYmyHvc mswrUpuY586QnTRXAH/q3kBak4rB+ux2A6U+MBGzeWT9NS/2eCgceYk/VzdnhAW/FynIjdI+hnnv+ 5PdSRuHVQ6GXrI5PNZ1m8jVE29qH1DptcodLq+aJhJguqkClN0kgu9Xn0NbdT1qbCt6/YSvuC5ZNE T7riaOfg==; Received: from hch by bombadil.infradead.org with local (Exim 4.99.1 #2 (Red Hat Linux)) id 1wwZKl-000000093aA-3H6p; Wed, 19 Aug 2026 05:59:31 +0000 Date: Tue, 18 Aug 2026 22:59:31 -0700 From: Christoph Hellwig To: NeilBrown Cc: Ameer Hamza , cel@kernel.org, jlayton@kernel.org, okorniev@redhat.com, Dai.Ngo@oracle.com, tom@talpey.com, trondmy@kernel.org, anna@kernel.org, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, alexander.motin@truenas.com, caleb.stjohn@truenas.com Subject: Re: [PATCH 1/2] NFSD: Use nfsd_iter_read() when ->splice_read is not zero-copy Message-ID: References: <20260817210811.3984663-1-ameer.hamza@truenas.com> <20260817210811.3984663-2-ameer.hamza@truenas.com> <178709365192.2852630.5607658976022815566@noble.neil.brown.name> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <178709365192.2852630.5607658976022815566@noble.neil.brown.name> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Wed, Aug 19, 2026 at 08:54:11AM +1000, NeilBrown wrote: > I think that if we are going to do this then we should do it properly > and make it easy to detect these cases. That's a big IFF. The splice fallback is a generate case. And no, we should not add flags and big blobs of NFSD code to work around it, there's simply no point in optimizing for some LLM generated ext4 on fake DAX bullshit.