From patchwork Sat Feb 6 04:40:59 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Tony Nguyen X-Patchwork-Id: 378384 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E8562C433E0 for ; Sat, 6 Feb 2021 04:50:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B02D664F9B for ; Sat, 6 Feb 2021 04:50:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231757AbhBFEuF (ORCPT ); Fri, 5 Feb 2021 23:50:05 -0500 Received: from mga18.intel.com ([134.134.136.126]:21611 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231206AbhBFErA (ORCPT ); Fri, 5 Feb 2021 23:47:00 -0500 IronPort-SDR: x0Rl6jp+TW0ykcE3P8LFA94IisWPGjKd7JkxkiYU4+mY1pfoWUhrhD7+051Xi2PsMxYar3xqLR km6V1NWx2ozg== X-IronPort-AV: E=McAfee;i="6000,8403,9886"; a="169194696" X-IronPort-AV: E=Sophos;i="5.81,156,1610438400"; d="scan'208";a="169194696" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Feb 2021 20:40:12 -0800 IronPort-SDR: mxU7vjp3C5XEyCaF1VjQd1R0L+qIF/m8rRmlNc2FLGJ0y5aYZH6HSXX8uPM8Seeb7AEMJw67Zn EU5r3PF6r1Zg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.81,156,1610438400"; d="scan'208";a="434751067" Received: from anguy11-desk2.jf.intel.com ([10.166.244.147]) by orsmga001.jf.intel.com with ESMTP; 05 Feb 2021 20:40:12 -0800 From: Tony Nguyen To: davem@davemloft.net, kuba@kernel.org Cc: "Gustavo A. R. Silva" , netdev@vger.kernel.org, sassmann@redhat.com, anthony.l.nguyen@intel.com, kernel test robot , Tony Brelinski Subject: [PATCH net-next v2 09/11] ice: Replace one-element array with flexible-array member Date: Fri, 5 Feb 2021 20:40:59 -0800 Message-Id: <20210206044101.636242-10-anthony.l.nguyen@intel.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210206044101.636242-1-anthony.l.nguyen@intel.com> References: <20210206044101.636242-1-anthony.l.nguyen@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: "Gustavo A. R. Silva" 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 Tested-by: Tony Brelinski Signed-off-by: Tony Nguyen --- 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 fa1e128c24ec..fca428c879ec 100644 --- a/drivers/net/ethernet/intel/ice/ice.h +++ b/drivers/net/ethernet/intel/ice/ice.h @@ -166,7 +166,7 @@ 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 643fbc8d6b6a..f6177591978d 100644 --- a/drivers/net/ethernet/intel/ice/ice_main.c +++ b/drivers/net/ethernet/intel/ice/ice_main.c @@ -3495,9 +3495,9 @@ 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;