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=-16.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 E5889C282C2 for ; Wed, 23 Jan 2019 14:19:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A54EA20870 for ; Wed, 23 Jan 2019 14:19:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="NXRcGOp5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726820AbfAWOTb (ORCPT ); Wed, 23 Jan 2019 09:19:31 -0500 Received: from mail-qt1-f201.google.com ([209.85.160.201]:48577 "EHLO mail-qt1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726200AbfAWOT3 (ORCPT ); Wed, 23 Jan 2019 09:19:29 -0500 Received: by mail-qt1-f201.google.com with SMTP id q3so2521361qtq.15 for ; Wed, 23 Jan 2019 06:19:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=lauieMoR6mplnrnDEREtCol1sUo9ohBTLyuY9w4HtBk=; b=NXRcGOp5W5Ssjdh3Im3Z6KMuxPIaY9k5ldjq4SRdmNCOnYgCcA5lIJLgLRLj36spUX UbMAcl+XB4V4C6lt9183RWMPeYmk540xiY2xVHZxA7pY+42d2MgiejxOa9Y6IgH95SGV nTKW346QZR2DroQ/8eYPtxcU/Hj3CsdDh0TvVRF6Ociu/5f7Je6KbSZ9Ruv0CSwg5EwJ tgfUVQXfOmvVogpiVDfWgk8sj2bgzrqetbaPWo+X3rdYa4y1yHPar9/HIRUwVZK8qFiv 1MoDIgCfpStQSaOMi16hRjHmzeVRvPs1NhUOd1vdXGeMCXoHtZvwKRja+lpUPM3k9xwz Dlcg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=lauieMoR6mplnrnDEREtCol1sUo9ohBTLyuY9w4HtBk=; b=O5g+yvNVqk1SlFb3H9dBVs41BosPBdzEoNOUnhEWFlTOIpbxHf8wpS7svUtVHePd5k pxyjBFESW71xTlXGh8cxU4m+zA6p5zV/E9wgif3nyGoy0jp2F92jOKIbkzDWooeptq6n Y3H9jlm3z/qncCY2VO7RqEP1PfcLjM36uKV4rIlBOIZtDSpvSePigUtUc5A3A9etkCSP 2wLDR0Yaud1c65LZc0iUbLfgrDyj3MSUq/Pj6IzBVCnTLBFldpNNEyJ17bf0BCyY1mLr ba94OWBrpIG65G7O5S60qWfSVApfybm1u7mFYPCL8/ct4hTFOOeDjavzy+rJ8IE9TG9m PhdQ== X-Gm-Message-State: AJcUukcchhpyrv/Sbh+E9gi2rUlcES1cKMQ57j465St5yr8y92GfuPTe 5hBtHXLvdajJeJZN6JrBOTkqNi9Vgg== X-Google-Smtp-Source: ALg8bN6uQhEi6JiUzSDcrTrYhpjw86tPlBRanZqgED1nJ/llFX5lNdsCGTm29Inx0W31X+gU+g32wKfqYA== X-Received: by 2002:aed:39c7:: with SMTP id m65mr1644915qte.2.1548253168224; Wed, 23 Jan 2019 06:19:28 -0800 (PST) Date: Wed, 23 Jan 2019 15:19:18 +0100 In-Reply-To: <20190123141918.238286-1-jannh@google.com> Message-Id: <20190123141918.238286-2-jannh@google.com> Mime-Version: 1.0 References: <20190123141918.238286-1-jannh@google.com> X-Mailer: git-send-email 2.20.1.321.g9e740568ce-goog Subject: [PATCH v2 2/2] pipe: stop using ->can_merge From: Jann Horn To: Al Viro , Miklos Szeredi , Jens Axboe , Jens Axboe , jannh@google.com Cc: Eric Biggers , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Kees Cook Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Al Viro pointed out that since there is only one pipe buffer type to which new data can be appended, it isn't necessary to have a ->can_merge field in struct pipe_buf_operations, we can just check for a magic type. Suggested-by: Al Viro Signed-off-by: Jann Horn --- fs/pipe.c | 20 ++++++++++++++++---- fs/splice.c | 4 ---- include/linux/pipe_fs_i.h | 7 ------- kernel/relay.c | 1 - kernel/trace/trace.c | 2 -- net/smc/smc_rx.c | 1 - 6 files changed, 16 insertions(+), 19 deletions(-) diff --git a/fs/pipe.c b/fs/pipe.c index c51750ed4011..0ff09b490ddf 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -226,8 +226,8 @@ void generic_pipe_buf_release(struct pipe_inode_info *pipe, } EXPORT_SYMBOL(generic_pipe_buf_release); +/* New data written to a pipe may be appended to a buffer with this type. */ static const struct pipe_buf_operations anon_pipe_buf_ops = { - .can_merge = 1, .confirm = generic_pipe_buf_confirm, .release = anon_pipe_buf_release, .steal = anon_pipe_buf_steal, @@ -235,7 +235,6 @@ static const struct pipe_buf_operations anon_pipe_buf_ops = { }; static const struct pipe_buf_operations anon_pipe_buf_nomerge_ops = { - .can_merge = 0, .confirm = generic_pipe_buf_confirm, .release = anon_pipe_buf_release, .steal = anon_pipe_buf_steal, @@ -243,19 +242,32 @@ static const struct pipe_buf_operations anon_pipe_buf_nomerge_ops = { }; static const struct pipe_buf_operations packet_pipe_buf_ops = { - .can_merge = 0, .confirm = generic_pipe_buf_confirm, .release = anon_pipe_buf_release, .steal = anon_pipe_buf_steal, .get = generic_pipe_buf_get, }; +/** + * pipe_buf_mark_unmergeable - mark a &struct pipe_buffer as unmergeable + * @buf: the buffer to mark + * + * Description: + * This function ensures that no future writes will be merged into the + * given &struct pipe_buffer. This is necessary when multiple pipe buffers + * share the same backing page. + */ void pipe_buf_mark_unmergeable(struct pipe_buffer *buf) { if (buf->ops == &anon_pipe_buf_ops) buf->ops = &anon_pipe_buf_nomerge_ops; } +static bool pipe_buf_can_merge(struct pipe_buffer *buf) +{ + return buf->ops == &anon_pipe_buf_ops; +} + static ssize_t pipe_read(struct kiocb *iocb, struct iov_iter *to) { @@ -393,7 +405,7 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from) struct pipe_buffer *buf = pipe->bufs + lastbuf; int offset = buf->offset + buf->len; - if (buf->ops->can_merge && offset + chars <= PAGE_SIZE) { + if (pipe_buf_can_merge(buf) && offset + chars <= PAGE_SIZE) { ret = pipe_buf_confirm(pipe, buf); if (ret) goto out; diff --git a/fs/splice.c b/fs/splice.c index 90c29675d573..fc71e9733f7a 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -138,7 +138,6 @@ static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe, } const struct pipe_buf_operations page_cache_pipe_buf_ops = { - .can_merge = 0, .confirm = page_cache_pipe_buf_confirm, .release = page_cache_pipe_buf_release, .steal = page_cache_pipe_buf_steal, @@ -156,7 +155,6 @@ static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, } static const struct pipe_buf_operations user_page_pipe_buf_ops = { - .can_merge = 0, .confirm = generic_pipe_buf_confirm, .release = page_cache_pipe_buf_release, .steal = user_page_pipe_buf_steal, @@ -326,7 +324,6 @@ ssize_t generic_file_splice_read(struct file *in, loff_t *ppos, EXPORT_SYMBOL(generic_file_splice_read); const struct pipe_buf_operations default_pipe_buf_ops = { - .can_merge = 0, .confirm = generic_pipe_buf_confirm, .release = generic_pipe_buf_release, .steal = generic_pipe_buf_steal, @@ -341,7 +338,6 @@ static int generic_pipe_buf_nosteal(struct pipe_inode_info *pipe, /* Pipe buffer operations for a socket and similar. */ const struct pipe_buf_operations nosteal_pipe_buf_ops = { - .can_merge = 0, .confirm = generic_pipe_buf_confirm, .release = generic_pipe_buf_release, .steal = generic_pipe_buf_nosteal, diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h index 3ecd7ea212ae..787d224ff43e 100644 --- a/include/linux/pipe_fs_i.h +++ b/include/linux/pipe_fs_i.h @@ -73,13 +73,6 @@ struct pipe_inode_info { * in fs/pipe.c for the pipe and generic variants of these hooks. */ struct pipe_buf_operations { - /* - * This is set to 1, if the generic pipe read/write may coalesce - * data into an existing buffer. If this is set to 0, a new pipe - * page segment is always used for new data. - */ - int can_merge; - /* * ->confirm() verifies that the data in the pipe buffer is there * and that the contents are good. If the pages in the pipe belong diff --git a/kernel/relay.c b/kernel/relay.c index 04f248644e06..db3e419c25a6 100644 --- a/kernel/relay.c +++ b/kernel/relay.c @@ -1175,7 +1175,6 @@ static void relay_pipe_buf_release(struct pipe_inode_info *pipe, } static const struct pipe_buf_operations relay_pipe_buf_ops = { - .can_merge = 0, .confirm = generic_pipe_buf_confirm, .release = relay_pipe_buf_release, .steal = generic_pipe_buf_steal, diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index c521b7347482..f380139e972c 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5823,7 +5823,6 @@ static void tracing_spd_release_pipe(struct splice_pipe_desc *spd, } static const struct pipe_buf_operations tracing_pipe_buf_ops = { - .can_merge = 0, .confirm = generic_pipe_buf_confirm, .release = generic_pipe_buf_release, .steal = generic_pipe_buf_steal, @@ -6843,7 +6842,6 @@ static void buffer_pipe_buf_get(struct pipe_inode_info *pipe, /* Pipe buffer operations for a buffer. */ static const struct pipe_buf_operations buffer_pipe_buf_ops = { - .can_merge = 0, .confirm = generic_pipe_buf_confirm, .release = buffer_pipe_buf_release, .steal = generic_pipe_buf_steal, diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c index bbcf0fe4ae10..413a6abf227e 100644 --- a/net/smc/smc_rx.c +++ b/net/smc/smc_rx.c @@ -136,7 +136,6 @@ static int smc_rx_pipe_buf_nosteal(struct pipe_inode_info *pipe, } static const struct pipe_buf_operations smc_pipe_ops = { - .can_merge = 0, .confirm = generic_pipe_buf_confirm, .release = smc_rx_pipe_buf_release, .steal = smc_rx_pipe_buf_nosteal, -- 2.20.1.321.g9e740568ce-goog