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=-6.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 CBAB6C04EB8 for ; Wed, 12 Dec 2018 07:57:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 82D172086D for ; Wed, 12 Dec 2018 07:57:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 82D172086D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726678AbeLLH50 (ORCPT ); Wed, 12 Dec 2018 02:57:26 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:33972 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726251AbeLLH5Y (ORCPT ); Wed, 12 Dec 2018 02:57:24 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id BF88940216E5; Wed, 12 Dec 2018 07:57:22 +0000 (UTC) Received: from localhost (unknown [10.64.242.21]) by smtp.corp.redhat.com (Postfix) with ESMTP id AFB2C170E4; Wed, 12 Dec 2018 07:57:21 +0000 (UTC) Date: Wed, 12 Dec 2018 16:57:20 +0900 (JST) Message-Id: <20181212.165720.1203400724538830403.yamato@redhat.com> To: serge@hallyn.com Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH resend] eventfd: make eventfd files distinguishable in /proc/$PID/fd From: Masatake YAMATO In-Reply-To: <20181211230914.GA2677@mail.hallyn.com> References: <20181209183546.5550-1-yamato@redhat.com> <20181211230914.GA2677@mail.hallyn.com> Organization: Red Hat Japan, Inc. Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Wed, 12 Dec 2018 07:57:22 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Wed, 12 Dec 2018 07:57:22 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'yamato@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 11 Dec 2018 17:09:14 -0600, "Serge E. Hallyn" wrote: > On Mon, Dec 10, 2018 at 03:35:46AM +0900, Masatake YAMATO wrote: >> Finding endpoints of an IPC channel is one of essential task to >> understand how a user program works. Procfs and netlink socket provide >> enough hints to find endpoints for IPC channels like pipes, unix >> sockets, and pseudo terminals. However, there is no simple way to find >> endpoints for an eventfd file from userland. An inode number doesn't >> hint. Unlike pipe, all eventfd files shares one inode object. >> >> To provide the way to find endpoints of an eventfd file, this patch >> adds eventfd identifiers to the output of 'ls -l /proc/$pid/fd' like: >> >> ... >> lrwx------. 1 qemu qemu 64 May 20 04:49 93 -> 'anon_inode:[eventfd:130]' >> lrwx------. 1 qemu qemu 64 May 20 04:49 94 -> 'anon_inode:[eventfd:131]' >> ... >> >> Here "130" and "131" are added as identifiers newly added. >> In the case that ida_simple_get returns an error, this change doesn't add >> an identifier; just use "[eventfd]" as before. >> >> Signed-off-by: Masatake YAMATO > > I'm going to love this when I need it :) Thanks. > > Acked-by: Serge Hallyn > Thank you for replying. This is the first time getting replying since my first post, Mon, 21 May 2018 05:18:23 +0900. Can I expect my patch is merged to the mainline? Or should I do something more? Masatake YAMATO >> --- >> fs/eventfd.c | 14 +++++++++++++- >> 1 file changed, 13 insertions(+), 1 deletion(-) >> >> diff --git a/fs/eventfd.c b/fs/eventfd.c >> index 08d3bd602f73..c18952948110 100644 >> --- a/fs/eventfd.c >> +++ b/fs/eventfd.c >> @@ -21,6 +21,11 @@ >> #include >> #include >> #include >> +#include >> + >> +/* Worst case buffer size needed for holding an integer. */ >> +#define ITOA_MAX_LEN 12 >> +DEFINE_IDA(eventfd_ida); >> >> struct eventfd_ctx { >> struct kref kref; >> @@ -35,6 +40,7 @@ struct eventfd_ctx { >> */ >> __u64 count; >> unsigned int flags; >> + int id; >> }; >> >> /** >> @@ -69,6 +75,8 @@ EXPORT_SYMBOL_GPL(eventfd_signal); >> >> static void eventfd_free_ctx(struct eventfd_ctx *ctx) >> { >> + if (ctx->id >= 0) >> + ida_simple_remove(&eventfd_ida, ctx->id); >> kfree(ctx); >> } >> >> @@ -384,6 +392,7 @@ static int do_eventfd(unsigned int count, int flags) >> { >> struct eventfd_ctx *ctx; >> int fd; >> + char name[1 + 8 + ITOA_MAX_LEN + 1 + 1] = "[eventfd]"; >> >> /* Check the EFD_* constants for consistency. */ >> BUILD_BUG_ON(EFD_CLOEXEC != O_CLOEXEC); >> @@ -400,8 +409,11 @@ static int do_eventfd(unsigned int count, int flags) >> init_waitqueue_head(&ctx->wqh); >> ctx->count = count; >> ctx->flags = flags; >> + ctx->id = ida_simple_get(&eventfd_ida, 0, 0, GFP_KERNEL); >> >> - fd = anon_inode_getfd("[eventfd]", &eventfd_fops, ctx, >> + if (ctx->id >= 0) >> + snprintf(name, sizeof(name), "[eventfd:%d]", ctx->id); >> + fd = anon_inode_getfd(name, &eventfd_fops, ctx, >> O_RDWR | (flags & EFD_SHARED_FCNTL_FLAGS)); >> if (fd < 0) >> eventfd_free_ctx(ctx); >> -- >> 2.17.0