From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f45.google.com (mail-wr1-f45.google.com [209.85.221.45]) (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 B2B6037B41E for ; Thu, 25 Jun 2026 08:35:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.45 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782376516; cv=none; b=ex+WdjpM0REOytT2z+YclYe53Y0PjjwDkKNrPgFBWAbkt3R++nC6MjDauZecUlyu5J+ZbfOpeIroZPj12DoC7DEd0J1Rron4jD/XgawzstZymb9kR4UYmAy3iUhqp7pnHaYk7r6G+5vRijiE+csj9jwESGNr9w+YBzauQdLzLTA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782376516; c=relaxed/simple; bh=QtIkhOcb4XuSPNMSHsQTam2xRok/IOw4SC1HUoDCl24=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gljhm2Z+xYM+M56ZoQyoJcOmGqgc/eeDiepK14NKg3cnGOb2CFpOslG68xjHexOGRqqKBq+VXefzqt0+xC2kOtQb/whxpPLSu7eQcOTQ+KmFTSe6Qzr1+yKFskudBC6v++/iZ0OupFggwjViodK5Zi/aa33zmS7VvBnvF/vHc/M= 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=IvVtfjAn; arc=none smtp.client-ip=209.85.221.45 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="IvVtfjAn" Received: by mail-wr1-f45.google.com with SMTP id ffacd0b85a97d-46cacc39191so253576f8f.0 for ; Thu, 25 Jun 2026 01:35:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1782376513; x=1782981313; 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=IvVtfjAnKaBK/0oQMtnLDiuV4uWEGKXPXAe+AlxRHG6MnbRdOnwIUfAKJjX57utGZS RA93kED8fJa9O5rFjZ+0xpmGWVHSGJekcF4QjLRE+9tIfLia59YTnsl5uCFNeaniCHYM 5ZzmM6WJ/eA/ZQgbCsLgjOKHc5QpvB8SEkaetLP6sDVxwCT9Xbf79YBfNv/qFqmFb1eR GqdtIomwz2L9o19YnNZzwc8yfe+1sOCd2S9kf+44M9mXX/WaaS9HEOsL1d9bD/AsSE7U LxGhViFq3CN1cDSLLxRgrgwei7VAOJ71DV4FvcjrUCQB/zwz2D3jyNKU/qsz7in7C5lc AwHQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782376513; x=1782981313; 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=Z0VuYLUmUtjJ4S3mDarcrMtU+ZMjlbZVaRbERKUvxZol9j6xk9Kmhe90hFi5Q6ruds 0hgnWquhhFetnij/vlAL3gZfkXS4jN5GZn7PxMqpKfwpWtluG9H+I/oOpf/e1KnW5WjT v8FpIfgwkwtfqceaFaqoVvYF27tKcJD06dKUziplgLjIctr6ffYbhvr/dUdDTMiw1eK1 iLjZ0KxekxzRUI4+OJgLWK+6EyvyDYpKwDY5a+qGlFq9sMgW3Bjk5V8XiCWv1y6flx3k BLWC8PqYLo81hfri/kxwuPmxt/EE065KPZgxFrmXzMbGRefCC9rlh1nrDvQEuhFC3gey NEYg== X-Forwarded-Encrypted: i=1; AHgh+RrkxBrQp5r2AOX2X75EgBZ60LYk7URjRPAsWhv+hagxbOjw9LjOCXFh9bjZFbc3aNRSOJX0dKaOREg=@vger.kernel.org X-Gm-Message-State: AOJu0Yw5perEifMqJWqfGAHIzES4CQAbOKYm9jqtK0nsVkNg2pq59uVL 2HyHoA3nsYzRQgPdKgZaj77AfsA5is4rmi3NntdCV3DdtTqaxx9Vcjcb X-Gm-Gg: AfdE7cmvXQI/AbS7r+WQDKBKVCkavpArmH2vSGQ1vWmJFqu7gI/u9GFJqozMsDexCY8 TemP6y+oZkUkX54cYTrXjCl5Hb6gblJldu5Kdnw8bWOgIQwp7h5gOKDqywMsvI6ZrO+g1ufHtne VD96LhRvbHi64J27YjYVjieeIibVQVi/B5BfkXG0gPaoE42zR28Nk98sS4EAyi25plz++FlehNg ljHBTkiBWL0khBFqmEe60BTWKOEcDlqCJBxn9fkIikqn2duoVlm50DHqLJsp/TXVkKsbUC3vCnR 60ejV63YdipBC0yBUlxTRC4wkrO5X9vV4O+Zb0Yba1i/4a91UH7TQwy1JmnCkOM5F3E00QchGsq AiSveVEg1buWSyuVQLZMuGrs3iYUyyFN3mXC8MTy/1dRjzKm5KUkiraROet1iITlsBiwiYTB/NJ KR/QI6hR+F X-Received: by 2002:a05:6000:4603:b0:460:602f:85a6 with SMTP id ffacd0b85a97d-46da34965dbmr2376831f8f.0.1782376512951; Thu, 25 Jun 2026 01:35:12 -0700 (PDT) Received: from localhost ([212.73.77.104]) by smtp.gmail.com with UTF8SMTPSA id ffacd0b85a97d-46c9ed7491esm9926887f8f.37.2026.06.25.01.35.09 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 25 Jun 2026 01:35:11 -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, 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 , The 8472 , Willy Tarreau , Joanne Koong , Val Packett , Andrei Vagin , patches@lists.linux.dev Subject: [PATCH v2 1/7] vmsplice: open-code do_writev and do_readv Date: Thu, 25 Jun 2026 08:34:03 +0000 Message-ID: <20260625083409.3769242-2-safinaskar@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260625083409.3769242-1-safinaskar@gmail.com> References: <20260625083409.3769242-1-safinaskar@gmail.com> Precedence: bulk X-Mailing-List: linux-api@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