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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 4AD8BC433ED for ; Sat, 17 Apr 2021 02:37:43 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B39DA61003 for ; Sat, 17 Apr 2021 02:37:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B39DA61003 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:59158 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lXaq5-0005Ug-M2 for qemu-devel@archiver.kernel.org; Fri, 16 Apr 2021 22:37:41 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35052) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lXap8-0004wg-09; Fri, 16 Apr 2021 22:36:42 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:2075) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lXap4-0000VS-Oo; Fri, 16 Apr 2021 22:36:41 -0400 Received: from dggeml406-hub.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4FMcbX3C9fzRWxZ; Sat, 17 Apr 2021 10:34:16 +0800 (CST) Received: from dggpemm500023.china.huawei.com (7.185.36.83) by dggeml406-hub.china.huawei.com (10.3.17.50) with Microsoft SMTP Server (TLS) id 14.3.498.0; Sat, 17 Apr 2021 10:36:24 +0800 Received: from [10.174.187.128] (10.174.187.128) by dggpemm500023.china.huawei.com (7.185.36.83) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2106.2; Sat, 17 Apr 2021 10:36:20 +0800 Subject: Re: [RFC PATCH v2 1/6] device_tree: Add qemu_fdt_add_path To: David Gibson References: <20210413080745.33004-1-wangyanan55@huawei.com> <20210413080745.33004-2-wangyanan55@huawei.com> From: "wangyanan (Y)" Message-ID: Date: Sat, 17 Apr 2021 10:36:20 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Originating-IP: [10.174.187.128] X-ClientProxiedBy: dggeme713-chm.china.huawei.com (10.1.199.109) To dggpemm500023.china.huawei.com (7.185.36.83) X-CFilter-Loop: Reflected Received-SPF: pass client-ip=45.249.212.188; envelope-from=wangyanan55@huawei.com; helo=szxga02-in.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Andrew Jones , "Michael S . Tsirkin" , wanghaibin.wang@huawei.com, qemu-devel@nongnu.org, Shannon Zhao , qemu-arm@nongnu.org, Alistair Francis , prime.zeng@hisilicon.com, yangyicong@huawei.com, yuzenghui@huawei.com, Igor Mammedov , zhukeqian1@huawei.com, Jiajie Li Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi David, On 2021/4/16 12:52, David Gibson wrote: > On Tue, Apr 13, 2021 at 04:07:40PM +0800, Yanan Wang wrote: >> From: Andrew Jones >> >> qemu_fdt_add_path() works like qemu_fdt_add_subnode(), except >> it also adds any missing subnodes in the path. We also tweak >> an error message of qemu_fdt_add_subnode(). >> >> We'll make use of this new function in a coming patch. >> >> Signed-off-by: Andrew Jones >> Signed-off-by: Yanan Wang >> --- >> include/sysemu/device_tree.h | 1 + >> softmmu/device_tree.c | 45 ++++++++++++++++++++++++++++++++++-- >> 2 files changed, 44 insertions(+), 2 deletions(-) >> >> diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h >> index 8a2fe55622..ef060a9759 100644 >> --- a/include/sysemu/device_tree.h >> +++ b/include/sysemu/device_tree.h >> @@ -121,6 +121,7 @@ uint32_t qemu_fdt_get_phandle(void *fdt, const char *path); >> uint32_t qemu_fdt_alloc_phandle(void *fdt); >> int qemu_fdt_nop_node(void *fdt, const char *node_path); >> int qemu_fdt_add_subnode(void *fdt, const char *name); >> +int qemu_fdt_add_path(void *fdt, const char *path); >> >> #define qemu_fdt_setprop_cells(fdt, node_path, property, ...) \ >> do { \ >> diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c >> index 2691c58cf6..8592c7aa1b 100644 >> --- a/softmmu/device_tree.c >> +++ b/softmmu/device_tree.c >> @@ -541,8 +541,8 @@ int qemu_fdt_add_subnode(void *fdt, const char *name) >> >> retval = fdt_add_subnode(fdt, parent, basename); >> if (retval < 0) { >> - error_report("FDT: Failed to create subnode %s: %s", name, >> - fdt_strerror(retval)); >> + error_report("%s: Failed to create subnode %s: %s", >> + __func__, name, fdt_strerror(retval)); >> exit(1); >> } >> >> @@ -550,6 +550,47 @@ int qemu_fdt_add_subnode(void *fdt, const char *name) >> return retval; >> } >> >> +/* >> + * Like qemu_fdt_add_subnode(), but will add all missing >> + * subnodes in the path. >> + */ >> +int qemu_fdt_add_path(void *fdt, const char *path) >> +{ >> + char *dupname, *basename, *p; >> + int parent, retval = -1; >> + >> + if (path[0] != '/') { >> + return retval; >> + } >> + >> + parent = fdt_path_offset(fdt, "/"); > Getting the offset for "/" is never needed - it's always 0. Thanks, will fix it. >> + p = dupname = g_strdup(path); > You shouldn't need the strdup(), see below. > >> + >> + while (p) { >> + *p = '/'; >> + basename = p + 1; >> + p = strchr(p + 1, '/'); >> + if (p) { >> + *p = '\0'; >> + } >> + retval = fdt_path_offset(fdt, dupname); > The fdt_path_offset_namelen() function exists *exactly* so that you > can look up partial parths without having to mangle your input > string. Just set the namelen right, and it will ignore anything to > the right of that. Function fdt_path_offset_namelen() seems more reasonable. After we call qemu_fdt_add_path() to add "/cpus/cpu-map/socket0/core0" successfully, if we want to add another path like "/cpus/cpu-map/socket0/core1" we will get the error -FDT_ERR_NOTFOUND for each partial path. But actually "/cpus/cpu-map/socket0" already exists, so by using fdt_path_offset_namelen() with right namelen we can avoid the error retval for this part. >> + if (retval < 0 && retval != -FDT_ERR_NOTFOUND) { >> + error_report("%s: Invalid path %s: %s", >> + __func__, path, fdt_strerror(retval)); > If you're getting an error other than FDT_ERR_NOTFOUND here, chances > are it's not an invalid path, but a corrupted fdt blob or something > else. Right, there can be variable reasons for the fail in addition to the invalid path. >> + exit(1); >> + } else if (retval == -FDT_ERR_NOTFOUND) { >> + retval = fdt_add_subnode(fdt, parent, basename); >> + if (retval < 0) { >> + break; >> + } I found another question here. If path "/cpus/cpu-map/socket0/core0" has already been added, when we want to add another path "/cpus/cpu-map/socket0/core1" and go here with retval = fdt_add_subnode(fdt, parent, "cpus"), then retval will be -FDT_ERR_EXISTS, but we can't just break the loop in this case. Am I right of the explanation ? Thanks, Yanan >> + } >> + parent = retval; >> + } >> + >> + g_free(dupname); >> + return retval; >> +} >> + >> void qemu_fdt_dumpdtb(void *fdt, int size) >> { >> const char *dumpdtb = current_machine->dumpdtb;