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 C10E826156B for ; Thu, 13 Mar 2025 08:44:36 +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=1741855478; cv=none; b=h7bP3qy91as8+k7vIpQ7mRmSDukuYTcceucC8yJvBbSDMSUQkKhwgJSMTB9uMfWkmr8pN4HBuOatm2wBspPa7/aqLV+cWPx6tDsOJu/bLKhKuA3r9HGVF6XDZXZFFKESdJPySWdYQq/HZVM880bxxVro1Wdunu2Ca8eLOZo3/0o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741855478; c=relaxed/simple; bh=pjhXZ5mkdKGtF7dOyIO0Xl30xgfDbOJ2tgP+dlGEawg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=j2wz3urFWh3nADRD7C1bmZF7Y+hIyCzCuWakqD5FHummQ/jN097vI45dmcKt9dA+jY5BpqCa8/jNgyuWfl5gN7JcslDo1fYWCDB668v6JA3Shbr0XQLPc66wb3L5KIB8V1NKdOjKv0ptUGysz91XRmX/e0TDNn1qYWfMsU6CWVI= 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=O9ugxHfA; 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="O9ugxHfA" 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=J93E6Vw3VK+dqosx/C38S2yEZoCxKiYDJPynkA042n4=; b=O9ugxHfAgY3WEudjUwN0Ar0xeU TbQNuDG9GefuP6cngv+wsY6/MzAfDSdqFiTuFFHLWP+l7kE9W2/W556UQe82tzHSzdY1jSk/Z0tuT W4h048ZXziXn9X3yWtR28bPmcZ5/O1+ZVTZM1BQLbgfCgBnyXvDp+S4xreX5JVpY1/mE5L/AA7Qsx nPMk4TlVD6/3Yo+5/ZyRPj1ZATrLoaqAGFQHtKqzeoNlatq5xVsjj6jOCdLGV9hCGu8phkz5p2e+D xqYlKFgxMEWuwZjK5sEMIWNwbA3CZYdvkFHWejT5KWGmM3wDf6FxCKjGUdGcAMJg3LkpHxvGIDJYJ yCZf1EQQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1tseB9-0000000AabG-2B0j; Thu, 13 Mar 2025 08:44:35 +0000 Date: Thu, 13 Mar 2025 01:44:35 -0700 From: Christoph Hellwig To: Hannes Reinecke Cc: Christoph Hellwig , Matthew Wilcox , Jakub Kicinski , Andrew Morton , netdev@vger.kernel.org, Vlastimil Babka , linux-mm@kvack.org Subject: Re: [PATCH] mm: Decline to manipulate the refcount on a slab page Message-ID: References: <20250310143544.1216127-1-willy@infradead.org> <20250311111511.2531b260@kernel.org> <4fc21641-e258-474b-9409-4949fe2fda2d@suse.de> <9af6dff3-adce-40f8-8649-282212acad9e@suse.de> <17f4795a-f6c8-4e6c-ba31-c65eab18efd1@suse.de> Precedence: bulk X-Mailing-List: netdev@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: <17f4795a-f6c8-4e6c-ba31-c65eab18efd1@suse.de> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Thu, Mar 13, 2025 at 09:34:39AM +0100, Hannes Reinecke wrote: > nvmf_connect_command_prep() returns a kmalloced buffer. Yes. > That is stored in a bvec in _nvme_submit_sync_cmd() via > blk_mq_rq_map_kern()->bio_map_kern(). > And from that point on we are dealing with bvecs (iterators > and all), and losing the information that the page referenced > is a slab page. Yes. But so does every other consomer of the block layer that passes slab memory, of which there are quite a few. Various internal scsi and nvme command come to mind, as does the XFS buffer cache. > The argument is that the network layer expected a kvec iterator > when slab pages are referred to, not a bvec iterator. It doesn't. It just doesn't want you to use ->sendpage.