From patchwork Wed Jan 22 16:02:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 11346011 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D67BE921 for ; Wed, 22 Jan 2020 16:02:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B54B424125 for ; Wed, 22 Jan 2020 16:02:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="0H/shxhD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725933AbgAVQCh (ORCPT ); Wed, 22 Jan 2020 11:02:37 -0500 Received: from mail-il1-f194.google.com ([209.85.166.194]:40457 "EHLO mail-il1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726170AbgAVQCg (ORCPT ); Wed, 22 Jan 2020 11:02:36 -0500 Received: by mail-il1-f194.google.com with SMTP id c4so5523641ilo.7 for ; Wed, 22 Jan 2020 08:02:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=AA0wwvnZ0n7WrhC9fHpAGgP3kCVdarewU7fTNKHf4vo=; b=0H/shxhDH59wMOxesQPvrDjl4FFa3J+m4nL2lmrNnii35gnausf6qcIR1qKVyzVQla PYNxtpP1C7/+l2tphwffssWW/Q0vGMFwDSPhXC3vsaazpFg2veEUYPiOhlx3NPln4jDZ TVB/ZG+CNBGX3priGF4NMP2ShNa8rdk24z7mkGPlc5HX3USTp5/9aaPfXwijftQW7c01 NsF6pxF5ScY8hSZhjZ6Eq4NYpX7FJiRHQfA6gNeKAgGrVz/DOa9VjsN0klyJQTedOsN7 LYNRD+/CIhPRe/S52R1Yv2GbiGd97uxMwCoWgKPskjngNYVNaKt13jq1yfjaeuHd7u0x ZeGg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=AA0wwvnZ0n7WrhC9fHpAGgP3kCVdarewU7fTNKHf4vo=; b=GvJNMaIVYm2fHZElrYIMxl9IjlRFgjTvKfJEJCojh4wRWm1UEt/Z1ZhgDJb0Zb/a6v RE+SyWztvrHglIb0HSsvWNCE5eVHbs6/dOUCB5vtPWR5i+PHxIASQznE12NCbktQabZX BKb5C3nmtCHRhPS9n8guLAzv2YgxfKOAUgIJ2w3PDmuywFl0ASOAnf1WAbzk239WWMX+ nZ15JXDl4/Tb2lilE4stAq9ewh85+bGbg8GriUHawSfcK6lZ4UuOsFdo2Zj7IXS1oAhu ceNWh0B8gZA9r4O8B1HMV7CcHqXUCS0j2AR5lrkS26lIHVGMoZQTdJOlNBw1kDihozme Q4Tw== X-Gm-Message-State: APjAAAXPIBQiuiR0AxkrBaN3VWnhRYRx6azc/CdRCdgPQkKndFULr92B H/QkkKt72t6D2pGL0sM0mi9B5w== X-Google-Smtp-Source: APXvYqyxzuH48HGZqrrug9el5aUKeMAz9hgaD7zTffei2y597qUlMlA4wHMTMSSmUeNtc91J/df1Sg== X-Received: by 2002:a05:6e02:f0f:: with SMTP id x15mr8446354ilj.298.1579708955822; Wed, 22 Jan 2020 08:02:35 -0800 (PST) Received: from x1.localdomain ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id v206sm796924iod.41.2020.01.22.08.02.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Jan 2020 08:02:35 -0800 (PST) From: Jens Axboe To: io-uring@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, Jens Axboe Subject: [PATCH 2/3] eventpoll: support non-blocking do_epoll_ctl() calls Date: Wed, 22 Jan 2020 09:02:30 -0700 Message-Id: <20200122160231.11876-3-axboe@kernel.dk> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200122160231.11876-1-axboe@kernel.dk> References: <20200122160231.11876-1-axboe@kernel.dk> MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Also make it available outside of epoll, along with the helper that decides if we need to copy the passed in epoll_event. Signed-off-by: Jens Axboe --- fs/eventpoll.c | 42 ++++++++++++++++++++++++++++----------- include/linux/eventpoll.h | 9 +++++++++ 2 files changed, 39 insertions(+), 12 deletions(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index cd848e8d08e2..162af749ea50 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -354,12 +354,6 @@ static inline struct epitem *ep_item_from_epqueue(poll_table *p) return container_of(p, struct ep_pqueue, pt)->epi; } -/* Tells if the epoll_ctl(2) operation needs an event copy from userspace */ -static inline int ep_op_has_event(int op) -{ - return op != EPOLL_CTL_DEL; -} - /* Initialize the poll safe wake up structure */ static void ep_nested_calls_init(struct nested_calls *ncalls) { @@ -2074,7 +2068,20 @@ SYSCALL_DEFINE1(epoll_create, int, size) return do_epoll_create(0); } -static int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds) +static inline int epoll_mutex_lock(struct mutex *mutex, int depth, + bool nonblock) +{ + if (!nonblock) { + mutex_lock_nested(mutex, depth); + return 0; + } + if (!mutex_trylock(mutex)) + return 0; + return -EAGAIN; +} + +int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds, + bool nonblock) { int error; int full_check = 0; @@ -2145,13 +2152,17 @@ static int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds) * deep wakeup paths from forming in parallel through multiple * EPOLL_CTL_ADD operations. */ - mutex_lock_nested(&ep->mtx, 0); + error = epoll_mutex_lock(&ep->mtx, 0, nonblock); + if (error) + goto error_tgt_fput; if (op == EPOLL_CTL_ADD) { if (!list_empty(&f.file->f_ep_links) || is_file_epoll(tf.file)) { full_check = 1; mutex_unlock(&ep->mtx); - mutex_lock(&epmutex); + error = epoll_mutex_lock(&epmutex, 0, nonblock); + if (error) + goto error_tgt_fput; if (is_file_epoll(tf.file)) { error = -ELOOP; if (ep_loop_check(ep, tf.file) != 0) { @@ -2161,10 +2172,17 @@ static int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds) } else list_add(&tf.file->f_tfile_llink, &tfile_check_list); - mutex_lock_nested(&ep->mtx, 0); + error = epoll_mutex_lock(&ep->mtx, 0, nonblock); + if (error) { +out_del: + list_del(&tf.file->f_tfile_llink); + goto error_tgt_fput; + } if (is_file_epoll(tf.file)) { tep = tf.file->private_data; - mutex_lock_nested(&tep->mtx, 1); + error = epoll_mutex_lock(&tep->mtx, 1, nonblock); + if (error) + goto out_del; } } } @@ -2233,7 +2251,7 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd, copy_from_user(&epds, event, sizeof(struct epoll_event))) return -EFAULT; - return do_epoll_ctl(epfd, op, fd, &epds); + return do_epoll_ctl(epfd, op, fd, &epds, false); } /* diff --git a/include/linux/eventpoll.h b/include/linux/eventpoll.h index bc6d79b00c4e..8f000fada5a4 100644 --- a/include/linux/eventpoll.h +++ b/include/linux/eventpoll.h @@ -61,6 +61,15 @@ static inline void eventpoll_release(struct file *file) eventpoll_release_file(file); } +int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds, + bool nonblock); + +/* Tells if the epoll_ctl(2) operation needs an event copy from userspace */ +static inline int ep_op_has_event(int op) +{ + return op != EPOLL_CTL_DEL; +} + #else static inline void eventpoll_init_file(struct file *file) {}