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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1A233C43334 for ; Tue, 7 Jun 2022 08:06:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238021AbiFGIGr (ORCPT ); Tue, 7 Jun 2022 04:06:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44044 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238000AbiFGIGo (ORCPT ); Tue, 7 Jun 2022 04:06:44 -0400 Received: from out1.migadu.com (out1.migadu.com [IPv6:2001:41d0:2:863f::]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE2A8B82DA; Tue, 7 Jun 2022 01:06:39 -0700 (PDT) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1654589198; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=klVOdmR1nU7hPRaqNMeN8/4eylLm3n3KJl/eiNUtm0o=; b=HxqJGVj9AWEXmaTuJYwqAghzOqYCKWtZjzq5XUfX8XIfvgZzRHJak4kUBr4KLoGXwbNuVJ DqnaAk8Y4CnHz8rU7nit+jqCQnVERRBvVKhH0zyeFrVyLXchdffcqg8P2nzsDIkQYd6WOK 9BmlK2+vbR9mEjoN20otm7nkxGZmFds= From: Hao Xu To: io-uring@vger.kernel.org Cc: Jens Axboe , Pavel Begunkov , linux-fsdevel@vger.kernel.org, Alexander Viro , Andrew Morton , Luis Chamberlain , Kuniyuki Iwashima Subject: [PATCH 2/5] pipe: add trylock helpers for pipe lock Date: Tue, 7 Jun 2022 16:06:16 +0800 Message-Id: <20220607080619.513187-3-hao.xu@linux.dev> In-Reply-To: <20220607080619.513187-1-hao.xu@linux.dev> References: <20220607080619.513187-1-hao.xu@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org From: Hao Xu Add two helpers pipe_trylock() and pipe_double_trylock(), they are used in nonblock splice(pipe to pipe) scenario in next patches. Signed-off-by: Hao Xu --- fs/pipe.c | 29 +++++++++++++++++++++++++++++ include/linux/pipe_fs_i.h | 2 ++ 2 files changed, 31 insertions(+) diff --git a/fs/pipe.c b/fs/pipe.c index 74ae9fafd25a..033736eb61fb 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -98,6 +98,11 @@ void pipe_unlock(struct pipe_inode_info *pipe) } EXPORT_SYMBOL(pipe_unlock); +int pipe_trylock(struct pipe_inode_info *pipe) +{ + return mutex_trylock(&pipe->mutex); +} + static inline void __pipe_lock(struct pipe_inode_info *pipe) { mutex_lock_nested(&pipe->mutex, I_MUTEX_PARENT); @@ -122,6 +127,30 @@ void pipe_double_lock(struct pipe_inode_info *pipe1, } } +int pipe_double_trylock(struct pipe_inode_info *pipe1, + struct pipe_inode_info *pipe2) +{ + BUG_ON(pipe1 == pipe2); + + if (pipe1 < pipe2) { + if (!pipe_trylock(pipe1)) + return 0; + if (!pipe_trylock(pipe2)) { + pipe_unlock(pipe1); + return 0; + } + } else { + if (!pipe_trylock(pipe2)) + return 0; + if (!pipe_trylock(pipe1)) { + pipe_unlock(pipe2); + return 0; + } + } + + return 1; +} + static void anon_pipe_buf_release(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h index cb0fd633a610..78dc2c7c999f 100644 --- a/include/linux/pipe_fs_i.h +++ b/include/linux/pipe_fs_i.h @@ -235,8 +235,10 @@ static inline bool pipe_buf_try_steal(struct pipe_inode_info *pipe, /* Pipe lock and unlock operations */ void pipe_lock(struct pipe_inode_info *); +int pipe_trylock(struct pipe_inode_info *); void pipe_unlock(struct pipe_inode_info *); void pipe_double_lock(struct pipe_inode_info *, struct pipe_inode_info *); +int pipe_double_trylock(struct pipe_inode_info *, struct pipe_inode_info *); /* Wait for a pipe to be readable/writable while dropping the pipe lock */ void pipe_wait_readable(struct pipe_inode_info *); -- 2.25.1