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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 A75C5C433E0 for ; Tue, 23 Jun 2020 14:56:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8014A20774 for ; Tue, 23 Jun 2020 14:56:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="MytTFs78" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732959AbgFWO4X (ORCPT ); Tue, 23 Jun 2020 10:56:23 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:22116 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732738AbgFWO4W (ORCPT ); Tue, 23 Jun 2020 10:56:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1592924181; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=HWZ8wEpT9WswtfFYl1mP0fDjlJkStWexSarfhsNNRC0=; b=MytTFs78qblUUAb3LS1o1IE2e0poK3sc874kg/TAWtmipF3gXHW5hbhMT2/XWwKFJRQ1qV R1CenIMCh8Gp4XCxAG6JY35fEFDGDMR5gemAk3Lf7Xe40FOn7A5+gszjBUWM4pjLeZxnh6 8FULF18pNo+8+1souc3RLp2dwg9MmtM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-89-DnVl22kUO86pHT5MRq57aQ-1; Tue, 23 Jun 2020 10:56:17 -0400 X-MC-Unique: DnVl22kUO86pHT5MRq57aQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E88FD801503; Tue, 23 Jun 2020 14:56:15 +0000 (UTC) Received: from krava (unknown [10.40.192.77]) by smtp.corp.redhat.com (Postfix) with SMTP id 21FEF7CAA3; Tue, 23 Jun 2020 14:56:13 +0000 (UTC) Date: Tue, 23 Jun 2020 16:56:13 +0200 From: Jiri Olsa To: Alexey Budankov Cc: Arnaldo Carvalho de Melo , Namhyung Kim , Alexander Shishkin , Peter Zijlstra , Ingo Molnar , Andi Kleen , linux-kernel Subject: Re: [PATCH v8 03/13] perf evlist: implement control command handling functions Message-ID: <20200623145613.GI2619137@krava> References: <0781a077-aa82-5b4a-273e-c17372a72b93@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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) ? > + > + 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? jirka