From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f52.google.com (mail-wm1-f52.google.com [209.85.128.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EE6C727AC48 for ; Sat, 6 Jun 2026 06:11:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.52 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780726288; cv=none; b=ixwrawTQxtuHwvx3cBkdd7AFp4uBAq4D9CVVr4v+fKrK2UZZtSxEfdL/tW0wAdgDBFT3K2WqxJ2XKB+zI6SRaLQHQtCZQ17SLc+hK027fN2zak0BD6tre1FRtTT9FdOkaRc6z0rP3Cu0DmrEWj21GqQRQ2uZiawA6nC7ha4MkIg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780726288; c=relaxed/simple; bh=QtIkhOcb4XuSPNMSHsQTam2xRok/IOw4SC1HUoDCl24=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZzL/nc6l2i6uKh89bkcnFSXoXsUPJ3Obw69MqV0VsLiLeA8Zw2vAxSYO+p0Vk6bytthUvD/3AOExI/KFfZdh3zmY3cvaCBWUj19LWqq/PfQvKrC2neUV5YYSN66DULm30XUZVUPWzo5Ew0H0fwzJU11kBeW4JN6BiK0HlgH8B34= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=KLy12Jix; arc=none smtp.client-ip=209.85.128.52 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="KLy12Jix" Received: by mail-wm1-f52.google.com with SMTP id 5b1f17b1804b1-490b4e1ade7so28379615e9.0 for ; Fri, 05 Jun 2026 23:11:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1780726285; x=1781331085; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=T2cQgCHbxQom2kVIv1Cvt6Y9CPEs8rn7euaXGTL0+j8=; b=KLy12Jixz2tIbG+Bqx2kFQDR1LkeBX0JuY4LIwcqjeHo/va6TrWxNBoa91zM34FCyk mObgIC48xiVoCBi1ZPIGlgQOHQyn9emWUrVDOWqYaBFvhEZXDTOeeUhpLL6+rJIwshLr aKffAjaazH/1LOg2AqAoqWohc3YFEKEv/DxJevSlqg9zFJ078PjbTzLwj+enA8sbMdV9 jpud3TmpWZmn+ufBFbxMUfcGTKX1l+POePF59aR2eaSzdSYgy7WHLLc+/yaRg8ft43ID nKTwCh5PVm9JUyDWNm8XB6Ha2WzeIkTh3i356Tr5YC4NvrM4K/q+hVxk9XvOEFi6IqtH L2RQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780726285; x=1781331085; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=T2cQgCHbxQom2kVIv1Cvt6Y9CPEs8rn7euaXGTL0+j8=; b=FLrDrY8+tZCAgLwx9Wey0ZAXTTkDFk75vV9nQpYZZ25znxDsLrJ+71xHKoBRfzgdi7 uYz1jyZkE5Ign7GuMRN0dONaqVsZsyRtMVGanwnbyX1d0dA6A8uuwx5z9CANoSa/RZYt VTI/0xCcXnafc57cp8/7fNvuOGp6OwZWzC9NW6/Q3zUhS5oQZdt8Q9l+gPJlxuZIZNXm Ds9Nga2N8uI0yFnv/TCveGhxjjTMKCqIf9HIgfhsRn+irf8wE8B5aP0JoxJl0PJWRn5m QgGzNTnXR4z2Kq1vVTbrv6WZLT7MRA4jCVNToVPW68En5oxSud9kj79Ji1yiND3GTHKm t1aQ== X-Gm-Message-State: AOJu0YwOptQr9X/VGgI4inxQoEQhZAGk6XbzzSnBfxIvvb1uN1Wetk3D nDiOrdqZi4pj+TAS9873m9fCbkRF5pONTAwM0lj7KTZTP0g23rYt0llz X-Gm-Gg: Acq92OEzt8oFEZTV5Twge/8sZmmPPMbR8U3D2fA/8NnRqxP3wkflhXXqjT9fI9QIU3y 2O5pJy/0eKhbPg3TE8/zFwOmYBWKbBHK38uUv1ET7PI/hnUVsVdp8gNu24sX6vpyoUlRv7g76Se hGRty1+MODBdJMdCkw5Kem+zPo4ABdUBiSYWKjuKAkyhlepxpP04KdFM81GIaTXFnkzdrgbEx38 KEWqcjWpkZnvw4GwVkhvsPkF5yAz479UYxo+W8s007oJKaWumjVRNzpbrU46XGmeXIU6I541SZ/ JVigsvN7RMjklU0Trr0Xu3WRsc76vUuMUPm7TKgTYQ+ysbnho3mcQK1m9OWhqTQqzTv0IRyHUSw B6cazWNdRYpbgOYIKT5u7a+MDGmpTSMNAYz1A3jBvI5BAUi9tIJZGxkhopTu7l1HzrbLttwlgRr 6k2BSwU8LuNQ14ixVliFSGer8YR6pAe2xh1JxaEExb X-Received: by 2002:a05:600c:a117:b0:490:c2a3:3302 with SMTP id 5b1f17b1804b1-490c2a3336dmr71973635e9.35.1780726285175; Fri, 05 Jun 2026 23:11:25 -0700 (PDT) Received: from localhost ([212.73.77.104]) by smtp.gmail.com with UTF8SMTPSA id 5b1f17b1804b1-490bc39e024sm273433555e9.4.2026.06.05.23.11.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 05 Jun 2026 23:11:24 -0700 (PDT) From: Askar Safin To: linux-fsdevel@vger.kernel.org, Christian Brauner , Alexander Viro , Jan Kara Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org, netdev@vger.kernel.org, fuse-devel@lists.linux.dev, ltp@lists.linux.it, Linus Torvalds , Matthew Wilcox , Jens Axboe , Christoph Hellwig , David Howells , Andrew Morton , David Hildenbrand , Pedro Falcato , Miklos Szeredi , Andy Lutomirski , Collin Funk , David Laight , Stefan Metzmacher , Steven Rostedt , The 8472 , Willy Tarreau , Joanne Koong , patches@lists.linux.dev Subject: [PATCH 1/5] vmsplice: open-code do_writev and do_readv Date: Sat, 6 Jun 2026 06:10:27 +0000 Message-ID: <20260606061031.3744880-2-safinaskar@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260606061031.3744880-1-safinaskar@gmail.com> References: <20260606061031.3744880-1-safinaskar@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit My previous vmsplice patch did the following mistake: I did "CLASS(fd, f)(fd)", then did some checks on resulting "struct file", then passed numeric (!) file descriptor to a function. This is somewhat okay in this particular case, but I still think this is code smell, so I fix this by open-coding do_writev and do_readv. Also I insert a comment to warn other developers to keep do_writev and do_readv in sync with vmsplice(2). Signed-off-by: Askar Safin --- fs/read_write.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/fs/read_write.c b/fs/read_write.c index 1e5444f4d..e224e7cb8 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1070,6 +1070,7 @@ static ssize_t vfs_writev(struct file *file, const struct iovec __user *vec, static ssize_t do_readv(unsigned long fd, const struct iovec __user *vec, unsigned long vlen, rwf_t flags) { + /* All future changes to this function should be kept in sync with vmsplice(2). */ CLASS(fd_pos, f)(fd); ssize_t ret = -EBADF; @@ -1093,6 +1094,7 @@ static ssize_t do_readv(unsigned long fd, const struct iovec __user *vec, static ssize_t do_writev(unsigned long fd, const struct iovec __user *vec, unsigned long vlen, rwf_t flags) { + /* All future changes to this function should be kept in sync with vmsplice(2). */ CLASS(fd_pos, f)(fd); ssize_t ret = -EBADF; @@ -1226,14 +1228,24 @@ SYSCALL_DEFINE4(vmsplice, unsigned long, fd, const struct iovec __user *, vec, if (fd_empty(f)) return -EBADF; - /* We do do_writev/do_readv, so it is okay to pass "false" here */ + /* We do vfs_writev/vfs_readv, so it is okay to pass "false" here */ if (!get_pipe_info(fd_file(f), /* for_splice = */ false)) return -EBADF; - if (fd_file(f)->f_mode & FMODE_WRITE) - return do_writev(fd, vec, vlen, (flags & SPLICE_F_NONBLOCK) ? RWF_NOWAIT : 0); - else - return do_readv(fd, vec, vlen, (flags & SPLICE_F_NONBLOCK) ? RWF_NOWAIT : 0); + if (fd_file(f)->f_mode & FMODE_WRITE) { + ssize_t ret = vfs_writev(fd_file(f), vec, vlen, NULL, (flags & SPLICE_F_NONBLOCK) ? RWF_NOWAIT : 0); + if (ret > 0) + add_wchar(current, ret); + inc_syscw(current); + return ret; + } else { + ssize_t ret = vfs_readv(fd_file(f), vec, vlen, NULL, (flags & SPLICE_F_NONBLOCK) ? RWF_NOWAIT : 0); + + if (ret > 0) + add_rchar(current, ret); + inc_syscr(current); + return ret; + } } /* -- 2.47.3