From mboxrd@z Thu Jan 1 00:00:00 1970 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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT 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 A8A0BC43381 for ; Fri, 8 Mar 2019 13:27:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 725502087C for ; Fri, 8 Mar 2019 13:27:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726692AbfCHN1c (ORCPT ); Fri, 8 Mar 2019 08:27:32 -0500 Received: from verein.lst.de ([213.95.11.211]:53841 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726420AbfCHN1b (ORCPT ); Fri, 8 Mar 2019 08:27:31 -0500 Received: by newverein.lst.de (Postfix, from userid 2407) id E62D568C4E; Fri, 8 Mar 2019 14:27:27 +0100 (CET) Date: Fri, 8 Mar 2019 14:27:27 +0100 From: Christoph Hellwig To: "Gustavo A. R. Silva" Cc: James Smart , Christoph Hellwig , Sagi Grimberg , linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] nvmet-fc: use zero-sized array and struct_size() in kzalloc() Message-ID: <20190308132727.GC18218@lst.de> References: <20190223185108.GA6706@embeddedor> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190223185108.GA6706@embeddedor> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org James, can you take a look at this one? On Sat, Feb 23, 2019 at 12:51:08PM -0600, Gustavo A. R. Silva wrote: > Update the code to use a zero-sized array instead of a pointer in > structure nvmet_fc_tgt_queue and use struct_size() in kzalloc(). > > Notice that one of the more common cases of allocation size calculations > is finding the size of a structure that has a zero-sized array at the end, > along with memory for some number of elements for that array. For example: > > struct foo { > int stuff; > struct boo entry[]; > }; > > instance = kzalloc(sizeof(struct foo) + sizeof(struct boo) * count, GFP_KERNEL); > > Instead of leaving these open-coded and prone to type mistakes, we can now > use the new struct_size() helper: > > instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL); > > This code was detected with the help of Coccinelle. > > Signed-off-by: Gustavo A. R. Silva > --- > drivers/nvme/target/fc.c | 7 ++----- > 1 file changed, 2 insertions(+), 5 deletions(-) > > diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c > index 1e9654f04c60..23baec38f97e 100644 > --- a/drivers/nvme/target/fc.c > +++ b/drivers/nvme/target/fc.c > @@ -128,12 +128,12 @@ struct nvmet_fc_tgt_queue { > struct nvmet_cq nvme_cq; > struct nvmet_sq nvme_sq; > struct nvmet_fc_tgt_assoc *assoc; > - struct nvmet_fc_fcp_iod *fod; /* array of fcp_iods */ > struct list_head fod_list; > struct list_head pending_cmd_list; > struct list_head avail_defer_list; > struct workqueue_struct *work_q; > struct kref ref; > + struct nvmet_fc_fcp_iod fod[]; /* array of fcp_iods */ > } __aligned(sizeof(unsigned long long)); > > struct nvmet_fc_tgt_assoc { > @@ -588,9 +588,7 @@ nvmet_fc_alloc_target_queue(struct nvmet_fc_tgt_assoc *assoc, > if (qid > NVMET_NR_QUEUES) > return NULL; > > - queue = kzalloc((sizeof(*queue) + > - (sizeof(struct nvmet_fc_fcp_iod) * sqsize)), > - GFP_KERNEL); > + queue = kzalloc(struct_size(queue, fod, sqsize), GFP_KERNEL); > if (!queue) > return NULL; > > @@ -603,7 +601,6 @@ nvmet_fc_alloc_target_queue(struct nvmet_fc_tgt_assoc *assoc, > if (!queue->work_q) > goto out_a_put; > > - queue->fod = (struct nvmet_fc_fcp_iod *)&queue[1]; > queue->qid = qid; > queue->sqsize = sqsize; > queue->assoc = assoc; > -- > 2.20.1 ---end quoted text---