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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 7FC2CC742AE for ; Fri, 12 Jul 2019 09:07:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6382020863 for ; Fri, 12 Jul 2019 09:07:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726266AbfGLJHT (ORCPT ); Fri, 12 Jul 2019 05:07:19 -0400 Received: from mout.kundenserver.de ([212.227.17.13]:56347 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726169AbfGLJHS (ORCPT ); Fri, 12 Jul 2019 05:07:18 -0400 Received: from threadripper.lan ([149.172.19.189]) by mrelayeu.kundenserver.de (mreue106 [212.227.15.145]) with ESMTPA (Nemesis) id 1MeC5x-1iN7Ph3SwZ-00bI7H; Fri, 12 Jul 2019 11:07:06 +0200 From: Arnd Bergmann To: Vishal Kulkarni , "David S. Miller" Cc: Arnd Bergmann , Rahul Lakkireddy , Ganesh Goudar , Alexios Zavras , Arjun Vynipadath , Surendra Mobiya , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com Subject: [PATCH] [net-next] cxgb4: reduce kernel stack usage in cudbg_collect_mem_region() Date: Fri, 12 Jul 2019 11:06:33 +0200 Message-Id: <20190712090700.317887-1-arnd@arndb.de> X-Mailer: git-send-email 2.20.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Provags-ID: V03:K1:rxFNf2Aki8qaWD5BAHF9dJ6RZq9YGgkpHy8CO9HIEVlm7go4NVx kHFABxf69KKsV1nhzdGT3E9nhL8b1dNpvlMeZZl2UMJi8iAayuR+sj7oa0MEnBelfmAdzn5 GmHu8AwVCwbo0qLCZAdAoclelQrmU9yj0DnBAzqUoCo/zn600t8P2zAcHHKnKHoneepLFiT ZS5YgzKSe3u0GNUA3I0FA== X-UI-Out-Filterresults: notjunk:1;V03:K0:O+AX6q867+c=:MXtjbU0XZTwkG7PWMjzQ0V v5o84QhB/JLoRjYCRSyrVPpQt+fH7M0kpZkVaBCVVUDGAjEiOpR7zF32Qu8hpWd9fjVvUf+3U KM3P5kDvJKPYVl3RNOaGzcaB+KUav3WF3hQGBcRQ5oavMoyr1ROzkS4UD91aZIX2VOC3hywPN LYXBXODKbJrhtm+gVfyHZhr/oM6QSpKV/T5aq/hwkkYKNdUKbAZJjTKKOFSMqbZU3W5wl4l5K ZJxws379F6lkAaRSSwgkC5q6yPaDxukpzkb9aX+7ySDAfmcwkFaSsdzP1N5SybF+TievuvcO/ xAc46xFlboH0LUsMWBjvT+8Tz1tvqK6rWkdCl5ZyP2V1wbYA449wJ76Y3yBQ0oGcl8oHUNR0D Kop6dogBbjIbIZi5nMcsuNvvy7tMBy+Netj1OMEEVl6wb4nBNmFVdgApLQJTZvL46Zz8H0xof qE1VEvSdhbZrWfi05TsMs99NoV7+Qy+L6/1lNyUu76iUnhD5uIwFA7A+n+Xhek2p5XjU0BGkI tF4JPjQp/fIRI8zPkQVqPvfyzoJEDDwO9YAjwz3be7/QnXITG8dOE0e4oVwWEoMqAT8kgruzR MSEhW1VvhgmwaDaQTK+1rSNFglRTIvh2/oPX9zMp5nrcR5Cy0QuxN6c5EYSv314nMM002t7JP 6gxHomwy6vEHdQnQ/6HHOVawvNPEXHrEQQhC7lP46W6BLahCkwhrAMjYv+Qknyg2uvGCER0Qw vIforeros4ovfVwG0LyxQ5Y7toEmy3zMX/nf4g== Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The cudbg_collect_mem_region() and cudbg_read_fw_mem() both use several hundred kilobytes of kernel stack space. One gets inlined into the other, which causes the stack usage to be combined beyond the warning limit when building with clang: drivers/net/ethernet/chelsio/cxgb4/cudbg_lib.c:1057:12: error: stack frame size of 1244 bytes in function 'cudbg_collect_mem_region' [-Werror,-Wframe-larger-than=] Restructuring cudbg_collect_mem_region() lets clang do the same optimization that gcc does and reuse the stack slots as it can see that the large variables are never used together. A better fix might be to avoid using cudbg_meminfo on the stack altogether, but that requires a larger rewrite. Fixes: a1c69520f785 ("cxgb4: collect MC memory dump") Signed-off-by: Arnd Bergmann --- .../net/ethernet/chelsio/cxgb4/cudbg_lib.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/chelsio/cxgb4/cudbg_lib.c b/drivers/net/ethernet/chelsio/cxgb4/cudbg_lib.c index a76529a7662d..c2e92786608b 100644 --- a/drivers/net/ethernet/chelsio/cxgb4/cudbg_lib.c +++ b/drivers/net/ethernet/chelsio/cxgb4/cudbg_lib.c @@ -1054,14 +1054,12 @@ static void cudbg_t4_fwcache(struct cudbg_init *pdbg_init, } } -static int cudbg_collect_mem_region(struct cudbg_init *pdbg_init, - struct cudbg_buffer *dbg_buff, - struct cudbg_error *cudbg_err, - u8 mem_type) +static unsigned long cudbg_mem_region_size(struct cudbg_init *pdbg_init, + struct cudbg_error *cudbg_err, + u8 mem_type) { struct adapter *padap = pdbg_init->adap; struct cudbg_meminfo mem_info; - unsigned long size; u8 mc_idx; int rc; @@ -1075,7 +1073,16 @@ static int cudbg_collect_mem_region(struct cudbg_init *pdbg_init, if (rc) return rc; - size = mem_info.avail[mc_idx].limit - mem_info.avail[mc_idx].base; + return mem_info.avail[mc_idx].limit - mem_info.avail[mc_idx].base; +} + +static int cudbg_collect_mem_region(struct cudbg_init *pdbg_init, + struct cudbg_buffer *dbg_buff, + struct cudbg_error *cudbg_err, + u8 mem_type) +{ + unsigned long size = cudbg_mem_region_size(pdbg_init, cudbg_err, mem_type); + return cudbg_read_fw_mem(pdbg_init, dbg_buff, mem_type, size, cudbg_err); } -- 2.20.0