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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 C824EC433E1 for ; Wed, 24 Jun 2020 13:21:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A806220C09 for ; Wed, 24 Jun 2020 13:21:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389445AbgFXNU7 (ORCPT ); Wed, 24 Jun 2020 09:20:59 -0400 Received: from mga09.intel.com ([134.134.136.24]:14085 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387687AbgFXNU5 (ORCPT ); Wed, 24 Jun 2020 09:20:57 -0400 IronPort-SDR: dhq/oymItepQ3iYKtIX4FXrPxaxnGJAgpXFABLcF1dzrVZZF2rYyuDc2gVrovvlsO93AKIKVKS 4sS0Obk5TMcQ== X-IronPort-AV: E=McAfee;i="6000,8403,9661"; a="145958119" X-IronPort-AV: E=Sophos;i="5.75,275,1589266800"; d="scan'208";a="145958119" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jun 2020 06:20:55 -0700 IronPort-SDR: BY5EJYm6T9Uz5+auy6YyodqB73Oa5pKcLMtEMuL7y+bmne7kG8UtBXZs7FalPeclp8y7xLziU8 UZhPYFH4lT0g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,275,1589266800"; d="scan'208";a="311639730" Received: from linux.intel.com ([10.54.29.200]) by fmsmga002.fm.intel.com with ESMTP; 24 Jun 2020 06:20:54 -0700 Received: from [10.249.228.248] (abudanko-mobl.ccr.corp.intel.com [10.249.228.248]) by linux.intel.com (Postfix) with ESMTP id B58275805B5; Wed, 24 Jun 2020 06:20:52 -0700 (PDT) Subject: Re: [PATCH v8 03/13] perf evlist: implement control command handling functions To: Jiri Olsa Cc: Arnaldo Carvalho de Melo , Namhyung Kim , Alexander Shishkin , Peter Zijlstra , Ingo Molnar , Andi Kleen , linux-kernel References: <0781a077-aa82-5b4a-273e-c17372a72b93@linux.intel.com> <20200623145613.GI2619137@krava> From: Alexey Budankov Organization: Intel Corp. Message-ID: <3ab05af5-b882-ffde-8311-307b6c373fd3@linux.intel.com> Date: Wed, 24 Jun 2020 16:20:51 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <20200623145613.GI2619137@krava> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23.06.2020 17:56, Jiri Olsa wrote: > On Wed, Jun 17, 2020 at 11:36:46AM +0300, Alexey Budankov wrote: > > SNIP > >> +static int evlist__ctlfd_recv(struct evlist *evlist, enum evlist_ctl_cmd *cmd, >> + char *cmd_data, size_t data_size) >> +{ >> + int err; >> + char c; >> + size_t bytes_read = 0; >> + >> + memset(cmd_data, 0, data_size--); >> + >> + do { >> + err = read(evlist->ctl_fd.fd, &c, 1); >> + if (err > 0) { >> + if (c == '\n' || c == '\0') >> + break; >> + cmd_data[bytes_read++] = c; >> + if (bytes_read == data_size) >> + break; >> + } else { >> + if (err == -1) >> + pr_err("Failed to read from ctlfd %d: %m\n", evlist->ctl_fd.fd); >> + break; >> + } >> + } while (1); >> + >> + pr_debug("Message from ctl_fd: \"%s%s\"\n", cmd_data, >> + bytes_read == data_size ? "" : c == '\n' ? "\\n" : "\\0"); > > do you want to display the message above only if (err > 0) ? I do, only for err >= 0. For err == -1 there is already the error message. > >> + >> + if (err > 0) { >> + if (!strncmp(cmd_data, EVLIST_CTL_CMD_ENABLE_TAG, >> + strlen(EVLIST_CTL_CMD_ENABLE_TAG))) { >> + *cmd = EVLIST_CTL_CMD_ENABLE; >> + } else if (!strncmp(cmd_data, EVLIST_CTL_CMD_DISABLE_TAG, >> + strlen(EVLIST_CTL_CMD_DISABLE_TAG))) { >> + *cmd = EVLIST_CTL_CMD_DISABLE; >> + } >> + } >> + >> + return err; >> +} > > SNIP > >> + int ctlfd_pos = evlist->ctl_fd.pos; >> + struct pollfd *entries = evlist->core.pollfd.entries; >> + >> + if (ctlfd_pos == -1 || !entries[ctlfd_pos].revents) >> + return 0; >> + >> + if (entries[ctlfd_pos].revents & POLLIN) { >> + err = evlist__ctlfd_recv(evlist, cmd, cmd_data, >> + EVLIST_CTL_CMD_MAX_LEN); >> + if (err > 0) { >> + switch (*cmd) { >> + case EVLIST_CTL_CMD_ENABLE: >> + evlist__enable(evlist); >> + break; >> + case EVLIST_CTL_CMD_DISABLE: >> + evlist__disable(evlist); >> + break; >> + case EVLIST_CTL_CMD_ACK: >> + case EVLIST_CTL_CMD_UNSUPPORTED: >> + default: >> + pr_debug("ctlfd: unsupported %d\n", *cmd); >> + break; >> + } >> + if (!(*cmd == EVLIST_CTL_CMD_ACK || *cmd == EVLIST_CTL_CMD_UNSUPPORTED)) >> + evlist__ctlfd_ack(evlist); >> + } >> + } >> + >> + if (entries[ctlfd_pos].revents & (POLLHUP | POLLERR)) >> + evlist__finalize_ctlfd(evlist); > > should this error be propagated via err? I don't think so. Currently it returns 0 only and there is no need to stop collection or skip processing in caller in this case. ~Alexey > > jirka >