From patchwork Mon Mar 1 16:05:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 389727 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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham 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 1F5D2C433E0 for ; Mon, 1 Mar 2021 18:20:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E757364F3B for ; Mon, 1 Mar 2021 18:20:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239582AbhCASTy (ORCPT ); Mon, 1 Mar 2021 13:19:54 -0500 Received: from mail.kernel.org ([198.145.29.99]:60792 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238479AbhCASNx (ORCPT ); Mon, 1 Mar 2021 13:13:53 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4E7CD650B5; Mon, 1 Mar 2021 17:40:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1614620425; bh=XjxSP4gTK0DUqbdh6+kze/ZU1l3SZVJox4fJHvNI6/8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OkflpFP6q4cfSOzrVZwqzz8DFk28JB8jwuOiS3nbQ7ecY5QOapK1gCKJvROTGtP0w ZPUOvE1yLyocvHS62nBEvgki6mHmNhbRS7MVaWgeyMkg14UGJP3D+AVM8UOlNOh5zS L69nudYKBHz6RTqE451tPLe96PTaK1bpRCKbgDfQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Oliver Giles , Christoph Hellwig , Al Viro , Linus Torvalds , Sasha Levin Subject: [PATCH 5.11 149/775] tty: implement read_iter Date: Mon, 1 Mar 2021 17:05:17 +0100 Message-Id: <20210301161209.012290354@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210301161201.679371205@linuxfoundation.org> References: <20210301161201.679371205@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Linus Torvalds [ Upstream commit dd78b0c483e33225e0e0782b0ed887129b00f956 ] Now that the ldisc read() function takes kernel pointers, it's fairly straightforward to make the tty file operations use .read_iter() instead of .read(). That automatically gives us vread() and friends, and also makes it possible to do .splice_read() on ttys again. Fixes: 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops") Reported-by: Oliver Giles Cc: Christoph Hellwig Cc: Greg Kroah-Hartman Cc: Al Viro Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- drivers/tty/tty_io.c | 36 ++++++++++++++++++------------------ 1 file changed, 18 insertions(+), 18 deletions(-) diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 0c11c65d27431..623738d8e32c8 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -142,7 +142,7 @@ LIST_HEAD(tty_drivers); /* linked list of tty drivers */ /* Mutex to protect creating and releasing a tty */ DEFINE_MUTEX(tty_mutex); -static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); +static ssize_t tty_read(struct kiocb *, struct iov_iter *); static ssize_t tty_write(struct kiocb *, struct iov_iter *); static __poll_t tty_poll(struct file *, poll_table *); static int tty_open(struct inode *, struct file *); @@ -473,8 +473,9 @@ static void tty_show_fdinfo(struct seq_file *m, struct file *file) static const struct file_operations tty_fops = { .llseek = no_llseek, - .read = tty_read, + .read_iter = tty_read, .write_iter = tty_write, + .splice_read = generic_file_splice_read, .splice_write = iter_file_splice_write, .poll = tty_poll, .unlocked_ioctl = tty_ioctl, @@ -487,8 +488,9 @@ static const struct file_operations tty_fops = { static const struct file_operations console_fops = { .llseek = no_llseek, - .read = tty_read, + .read_iter = tty_read, .write_iter = redirected_tty_write, + .splice_read = generic_file_splice_read, .splice_write = iter_file_splice_write, .poll = tty_poll, .unlocked_ioctl = tty_ioctl, @@ -840,16 +842,17 @@ static void tty_update_time(struct timespec64 *time) * data or clears the cookie. The cookie may be something that the * ldisc maintains state for and needs to free. */ -static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty, struct file *file, - char __user *buf, size_t count) +static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty, + struct file *file, struct iov_iter *to) { int retval = 0; void *cookie = NULL; unsigned long offset = 0; char kernel_buf[64]; + size_t count = iov_iter_count(to); do { - int size, uncopied; + int size, copied; size = count > sizeof(kernel_buf) ? sizeof(kernel_buf) : count; size = ld->ops->read(tty, file, kernel_buf, size, &cookie, offset); @@ -865,10 +868,9 @@ static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty, struct return size; } - uncopied = copy_to_user(buf+offset, kernel_buf, size); - size -= uncopied; - offset += size; - count -= size; + copied = copy_to_iter(kernel_buf, size, to); + offset += copied; + count -= copied; /* * If the user copy failed, we still need to do another ->read() @@ -876,7 +878,7 @@ static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty, struct * * But make sure size is zeroed. */ - if (unlikely(uncopied)) { + if (unlikely(copied != size)) { count = 0; retval = -EFAULT; } @@ -903,10 +905,10 @@ static int iterate_tty_read(struct tty_ldisc *ld, struct tty_struct *tty, struct * read calls may be outstanding in parallel. */ -static ssize_t tty_read(struct file *file, char __user *buf, size_t count, - loff_t *ppos) +static ssize_t tty_read(struct kiocb *iocb, struct iov_iter *to) { int i; + struct file *file = iocb->ki_filp; struct inode *inode = file_inode(file); struct tty_struct *tty = file_tty(file); struct tty_ldisc *ld; @@ -919,11 +921,9 @@ static ssize_t tty_read(struct file *file, char __user *buf, size_t count, /* We want to wait for the line discipline to sort out in this situation */ ld = tty_ldisc_ref_wait(tty); - if (!ld) - return hung_up_tty_read(file, buf, count, ppos); i = -EIO; - if (ld->ops->read) - i = iterate_tty_read(ld, tty, file, buf, count); + if (ld && ld->ops->read) + i = iterate_tty_read(ld, tty, file, to); tty_ldisc_deref(ld); if (i > 0) @@ -2945,7 +2945,7 @@ static long tty_compat_ioctl(struct file *file, unsigned int cmd, static int this_tty(const void *t, struct file *file, unsigned fd) { - if (likely(file->f_op->read != tty_read)) + if (likely(file->f_op->read_iter != tty_read)) return 0; return file_tty(file) != t ? 0 : fd + 1; }