From patchwork Tue Sep 29 19:01:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 1373572 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=default header.b=K3kaRVQu; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4C17s000vfz9sSJ for ; Wed, 30 Sep 2020 04:56:19 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728367AbgI2S4R (ORCPT ); Tue, 29 Sep 2020 14:56:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:60412 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727740AbgI2S4Q (ORCPT ); Tue, 29 Sep 2020 14:56:16 -0400 Received: from embeddedor (187-162-31-110.static.axtel.net [187.162.31.110]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C9A622076D; Tue, 29 Sep 2020 18:56:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601405775; bh=B4LAoCA5W+8yr4Ajd8NMhnc+SSJLU315huDeq+kqHT0=; h=Date:From:To:Cc:Subject:From; b=K3kaRVQui+deC0532ckd9YNAnVhOcaqYzyqkRIy1t5X9hEm7PTeEMXip/Y0isOHre dUXVtpwqhw0FMn56Tj9t/8gSeVLwjY6xrqk7TLaueetVHjsoVMNui6tScT/IO4QTT7 QBtev1ZKwIOco3iXvT+6s1BvGgR373hV3pMkdw7w= Date: Tue, 29 Sep 2020 14:01:56 -0500 From: "Gustavo A. R. Silva" To: Jeff Kirsher , "David S. Miller" , Jakub Kicinski Cc: intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" , linux-hardening@vger.kernel.org Subject: [PATCH][next] ice: Replace one-element array with flexible-array member Message-ID: <20200929190156.GA25604@embeddedor> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. Refactor the code according to the use of a flexible-array member in struct ice_res_tracker, instead of a one-element array and use the struct_size() helper to calculate the size for the allocations. Also, notice that the code below suggests that, currently, two too many bytes are being allocated with devm_kzalloc(), as the total number of entries (pf->irq_tracker->num_entries) for pf->irq_tracker->list[] is _vectors_ and sizeof(*pf->irq_tracker) also includes the size of the one-element array _list_ in struct ice_res_tracker. drivers/net/ethernet/intel/ice/ice_main.c:3511: 3511 /* populate SW interrupts pool with number of OS granted IRQs. */ 3512 pf->num_avail_sw_msix = (u16)vectors; 3513 pf->irq_tracker->num_entries = (u16)vectors; 3514 pf->irq_tracker->end = pf->irq_tracker->num_entries; With this change, the right amount of dynamic memory is now allocated because, contrary to one-element arrays which occupy at least as much space as a single object of the type, flexible-array members don't occupy such space in the containing structure. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://www.kernel.org/doc/html/v5.9-rc1/process/deprecated.html#zero-length-and-one-element-arrays Built-tested-by: kernel test robot Signed-off-by: Gustavo A. R. Silva --- drivers/net/ethernet/intel/ice/ice.h | 2 +- drivers/net/ethernet/intel/ice/ice_main.c | 6 +++--- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h index 65583f0a1797..a4c84faa36d6 100644 --- a/drivers/net/ethernet/intel/ice/ice.h +++ b/drivers/net/ethernet/intel/ice/ice.h @@ -164,7 +164,7 @@ struct ice_tc_cfg { struct ice_res_tracker { u16 num_entries; u16 end; - u16 list[1]; + u16 list[]; }; struct ice_qs_cfg { diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c index 2297ee7dba26..f6a7a23615eb 100644 --- a/drivers/net/ethernet/intel/ice/ice_main.c +++ b/drivers/net/ethernet/intel/ice/ice_main.c @@ -3500,9 +3500,9 @@ static int ice_init_interrupt_scheme(struct ice_pf *pf) return vectors; /* set up vector assignment tracking */ - pf->irq_tracker = - devm_kzalloc(ice_pf_to_dev(pf), sizeof(*pf->irq_tracker) + - (sizeof(u16) * vectors), GFP_KERNEL); + pf->irq_tracker = devm_kzalloc(ice_pf_to_dev(pf), + struct_size(pf->irq_tracker, list, vectors), + GFP_KERNEL); if (!pf->irq_tracker) { ice_dis_msix(pf); return -ENOMEM;