From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-98.freemail.mail.aliyun.com (out30-98.freemail.mail.aliyun.com [115.124.30.98]) (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 D911B1947D; Mon, 4 Mar 2024 09:00:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.98 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709542851; cv=none; b=isjfbUTU8c48NpCiFgoj3tKbqDkZ2JSMPl4n5ivZUCS37YgdwahYr/fPFev6mJeID/IRiLPSmEIdrwC1hEYJdAMpiGUDRacP0dYLlIkqWGc6CnvY7CbxlD9exdoZKD5Vlkbn2hiEVh2oZcRmA6J42/xYDr/VZYldmoxfb4tUafE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709542851; c=relaxed/simple; bh=kC/i6dh8xeQ/wHc0EIZeXuT9EMYEzuM7Q48zQ/NMRt8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ZL4nnIIdnPx/Vt+uoksaNxC3Ya1NwOHzIw75bZT5rUPR4icsasTEaMbfJi9wl8s/dQevfC6AW4PrxJ3XvIrxJeJpLYqnamDa9coCF02XwCr+p5F1YcMWUheuUEBaaL5jAHhOGdx5ynG5Wxo3woYiz37hHeiBwsvNgfSR/dGJ8qc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=OUuCtk7v; arc=none smtp.client-ip=115.124.30.98 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="OUuCtk7v" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1709542838; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=9ahmIqK5qlatgPE40+G4aT0KoQpIaQEigate3V7w1Vc=; b=OUuCtk7vX/VZh0Df8GOtfvT4l2HYinkxHUd8copLJ063CIz5dyNmusQxjNaqNTmxrvoJkILnSFxs9QrIDskIGIEInmM809uxX+4FlK1Ug1rkiLKdaO/wZciByOSOI7+Ipfd//udgMwe5qCc2nmUgrWP2LcvZFPuTfwKNVltfGJI= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R211e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045192;MF=guwen@linux.alibaba.com;NM=1;PH=DS;RN=14;SR=0;TI=SMTPD_---0W1mkySt_1709542837; Received: from 30.221.132.253(mailfrom:guwen@linux.alibaba.com fp:SMTPD_---0W1mkySt_1709542837) by smtp.aliyun-inc.com; Mon, 04 Mar 2024 17:00:38 +0800 Message-ID: <71aa847b-2edc-44a2-beb7-3610bf744937@linux.alibaba.com> Date: Mon, 4 Mar 2024 17:00:36 +0800 Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH][next] net/smc: Avoid -Wflex-array-member-not-at-end warnings To: "Gustavo A. R. Silva" , Wenjia Zhang , Jan Karcher , "D. Wythe" , Tony Lu , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: linux-s390@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Kees Cook References: From: Wen Gu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2024/3/2 02:40, Gustavo A. R. Silva wrote: > -Wflex-array-member-not-at-end is coming in GCC-14, and we are getting > ready to enable it globally. > > There are currently a couple of objects in `struct smc_clc_msg_proposal_area` > that contain a couple of flexible structures: > > struct smc_clc_msg_proposal_area { > ... > struct smc_clc_v2_extension pclc_v2_ext; > ... > struct smc_clc_smcd_v2_extension pclc_smcd_v2_ext; > ... > }; > > So, in order to avoid ending up with a couple of flexible-array members > in the middle of a struct, we use the `struct_group_tagged()` helper to > separate the flexible array from the rest of the members in the flexible > structure: > > struct smc_clc_smcd_v2_extension { > struct_group_tagged(smc_clc_smcd_v2_extension_hdr, hdr, > u8 system_eid[SMC_MAX_EID_LEN]; > u8 reserved[16]; > ); > struct smc_clc_smcd_gid_chid gidchid[]; > }; > > With the change described above, we now declare objects of the type of > the tagged struct without embedding flexible arrays in the middle of > another struct: > > struct smc_clc_msg_proposal_area { > ... > struct smc_clc_v2_extension_hdr pclc_v2_ext; > ... > struct smc_clc_smcd_v2_extension_hdr pclc_smcd_v2_ext; > ... > }; > > We also use `container_of()` when we need to retrieve a pointer to the > flexible structures. > > So, with these changes, fix the following warnings: > > In file included from net/smc/af_smc.c:42: > net/smc/smc_clc.h:186:49: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] > 186 | struct smc_clc_v2_extension pclc_v2_ext; > | ^~~~~~~~~~~ > net/smc/smc_clc.h:188:49: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] > 188 | struct smc_clc_smcd_v2_extension pclc_smcd_v2_ext; > | ^~~~~~~~~~~~~~~~ > > Signed-off-by: Gustavo A. R. Silva > --- > net/smc/smc_clc.c | 5 +++-- > net/smc/smc_clc.h | 24 ++++++++++++++---------- > 2 files changed, 17 insertions(+), 12 deletions(-) > > diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c > index e55026c7529c..3094cfa1c458 100644 > --- a/net/smc/smc_clc.c > +++ b/net/smc/smc_clc.c > @@ -853,8 +853,9 @@ int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini) > pclc_smcd = &pclc->pclc_smcd; > pclc_prfx = &pclc->pclc_prfx; > ipv6_prfx = pclc->pclc_prfx_ipv6; > - v2_ext = &pclc->pclc_v2_ext; > - smcd_v2_ext = &pclc->pclc_smcd_v2_ext; > + v2_ext = container_of(&pclc->pclc_v2_ext, struct smc_clc_v2_extension, _hdr); > + smcd_v2_ext = container_of(&pclc->pclc_smcd_v2_ext, > + struct smc_clc_smcd_v2_extension, hdr); > gidchids = pclc->pclc_gidchids; > trl = &pclc->pclc_trl; > > diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h > index 7cc7070b9772..5b91a1947078 100644 > --- a/net/smc/smc_clc.h > +++ b/net/smc/smc_clc.h > @@ -134,12 +134,14 @@ struct smc_clc_smcd_gid_chid { > */ > > struct smc_clc_v2_extension { > - struct smc_clnt_opts_area_hdr hdr; > - u8 roce[16]; /* RoCEv2 GID */ > - u8 max_conns; > - u8 max_links; > - __be16 feature_mask; > - u8 reserved[12]; > + struct_group_tagged(smc_clc_v2_extension_hdr, _hdr, > + struct smc_clnt_opts_area_hdr hdr; > + u8 roce[16]; /* RoCEv2 GID */ > + u8 max_conns; > + u8 max_links; > + __be16 feature_mask; > + u8 reserved[12]; > + ); > u8 user_eids[][SMC_MAX_EID_LEN]; > }; > > @@ -159,8 +161,10 @@ struct smc_clc_msg_smcd { /* SMC-D GID information */ > }; > > struct smc_clc_smcd_v2_extension { > - u8 system_eid[SMC_MAX_EID_LEN]; > - u8 reserved[16]; > + struct_group_tagged(smc_clc_smcd_v2_extension_hdr, hdr, > + u8 system_eid[SMC_MAX_EID_LEN]; > + u8 reserved[16]; > + ); > struct smc_clc_smcd_gid_chid gidchid[]; > }; > > @@ -183,9 +187,9 @@ struct smc_clc_msg_proposal_area { > struct smc_clc_msg_smcd pclc_smcd; > struct smc_clc_msg_proposal_prefix pclc_prfx; > struct smc_clc_ipv6_prefix pclc_prfx_ipv6[SMC_CLC_MAX_V6_PREFIX]; > - struct smc_clc_v2_extension pclc_v2_ext; > + struct smc_clc_v2_extension_hdr pclc_v2_ext; > u8 user_eids[SMC_CLC_MAX_UEID][SMC_MAX_EID_LEN]; > - struct smc_clc_smcd_v2_extension pclc_smcd_v2_ext; > + struct smc_clc_smcd_v2_extension_hdr pclc_smcd_v2_ext; > struct smc_clc_smcd_gid_chid > pclc_gidchids[SMCD_CLC_MAX_V2_GID_ENTRIES]; > struct smc_clc_msg_trail pclc_trl; Thank you! Gustavo. This patch can fix this warning well, just the name '*_hdr' might not be very accurate, but I don't have a good idea ATM. Besides, I am wondering if this can be fixed by moving user_eids of smc_clc_msg_proposal_area into smc_clc_v2_extension, and pclc_gidchids of smc_clc_msg_proposal_area into smc_clc_smcd_v2_extension. so that we can avoid to use the flexible-array in smc_clc_v2_extension and smc_clc_smcd_v2_extension. diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c index e55026c7529c..971b4677b84d 100644 --- a/net/smc/smc_clc.c +++ b/net/smc/smc_clc.c @@ -855,7 +855,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini) ipv6_prfx = pclc->pclc_prfx_ipv6; v2_ext = &pclc->pclc_v2_ext; smcd_v2_ext = &pclc->pclc_smcd_v2_ext; - gidchids = pclc->pclc_gidchids; + gidchids = pclc->pclc_smcd_v2_ext.gidchid; trl = &pclc->pclc_trl; pclc_base->hdr.version = SMC_V2; diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h index 7cc7070b9772..36c8432af73e 100644 --- a/net/smc/smc_clc.h +++ b/net/smc/smc_clc.h @@ -133,6 +133,14 @@ struct smc_clc_smcd_gid_chid { * (https://www.ibm.com/support/pages/node/6326337) */ +#define SMC_CLC_MAX_V6_PREFIX 8 +#define SMC_CLC_MAX_UEID 8 +#define SMCD_CLC_MAX_V2_GID_ENTRIES 8 /* max # of CHID-GID entries in CLC + * proposal SMC-Dv2 extension. + * each ISM device takes one entry and + * each Emulated-ISM takes two entries + */ + struct smc_clc_v2_extension { struct smc_clnt_opts_area_hdr hdr; u8 roce[16]; /* RoCEv2 GID */ @@ -140,7 +148,7 @@ struct smc_clc_v2_extension { u8 max_links; __be16 feature_mask; u8 reserved[12]; - u8 user_eids[][SMC_MAX_EID_LEN]; + u8 user_eids[SMC_CLC_MAX_UEID][SMC_MAX_EID_LEN]; }; struct smc_clc_msg_proposal_prefix { /* prefix part of clc proposal message*/ @@ -161,7 +169,7 @@ struct smc_clc_msg_smcd { /* SMC-D GID information */ struct smc_clc_smcd_v2_extension { u8 system_eid[SMC_MAX_EID_LEN]; u8 reserved[16]; - struct smc_clc_smcd_gid_chid gidchid[]; + struct smc_clc_smcd_gid_chid gidchid[SMCD_CLC_MAX_V2_GID_ENTRIES]; }; struct smc_clc_msg_proposal { /* clc proposal message sent by Linux */ @@ -170,24 +178,13 @@ struct smc_clc_msg_proposal { /* clc proposal message sent by Linux */ __be16 iparea_offset; /* offset to IP address information area */ } __aligned(4); -#define SMC_CLC_MAX_V6_PREFIX 8 -#define SMC_CLC_MAX_UEID 8 -#define SMCD_CLC_MAX_V2_GID_ENTRIES 8 /* max # of CHID-GID entries in CLC - * proposal SMC-Dv2 extension. - * each ISM device takes one entry and - * each Emulated-ISM takes two entries - */ - struct smc_clc_msg_proposal_area { struct smc_clc_msg_proposal pclc_base; struct smc_clc_msg_smcd pclc_smcd; struct smc_clc_msg_proposal_prefix pclc_prfx; struct smc_clc_ipv6_prefix pclc_prfx_ipv6[SMC_CLC_MAX_V6_PREFIX]; struct smc_clc_v2_extension pclc_v2_ext; - u8 user_eids[SMC_CLC_MAX_UEID][SMC_MAX_EID_LEN]; struct smc_clc_smcd_v2_extension pclc_smcd_v2_ext; - struct smc_clc_smcd_gid_chid - pclc_gidchids[SMCD_CLC_MAX_V2_GID_ENTRIES]; struct smc_clc_msg_trail pclc_trl; }; Thanks! Wen Gu