From patchwork Thu Jan 21 09:00:15 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 368402 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,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, 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 14CA5C433E0 for ; Thu, 21 Jan 2021 09:01:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C4F01239D0 for ; Thu, 21 Jan 2021 09:01:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726668AbhAUJBZ (ORCPT ); Thu, 21 Jan 2021 04:01:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:36584 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728340AbhAUJBO (ORCPT ); Thu, 21 Jan 2021 04:01:14 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id C776722473; Thu, 21 Jan 2021 09:00:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1611219631; bh=K7tHFWmO+SytEv9K8H586UnBlSIX0eYSPupIZD2/lq8=; h=From:To:Cc:Subject:Date:From; b=1j7+qNnNzQTcRAq7KRiWv060duDdC7S1RHZDks/qVz0sgJtat7+aN85GQGoUHbYbJ K8B2GwXc3JPw/mW64/f0p63X/6IymaL7iWqVnFrPOt/GmxyqGwL5KcQTmD+0vG/80k QF1mxmbjfE/2o3zW+qm+T/4cMusQszOUmingrTxc= From: Greg Kroah-Hartman To: jirislaby@kernel.org, linux-serial@vger.kernel.org Cc: gregkh@linuxfoundation.org, hch@lst.de, viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org, ohw.giles@gmail.com, r.karszniewicz@phytec.de, Linus Torvalds Subject: [PATCH 1/6] tty: implement write_iter Date: Thu, 21 Jan 2021 10:00:15 +0100 Message-Id: <20210121090020.3147058-1-gregkh@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org From: Linus Torvalds This makes the tty layer use the .write_iter() function instead of the traditional .write() functionality. That allows writev(), but more importantly also makes it possible to enable .splice_write() for ttys, reinstating the "splice to tty" functionality that was lost in commit 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops"). 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 Reported-by: Jiri Slaby Signed-off-by: Linus Torvalds Reviewed-by: Jiri Slaby --- drivers/tty/tty_io.c | 48 ++++++++++++++++++++++++-------------------- 1 file changed, 26 insertions(+), 22 deletions(-) diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 56ade99ef99f..338bc4ef5549 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -143,9 +143,8 @@ LIST_HEAD(tty_drivers); /* linked list of tty drivers */ DEFINE_MUTEX(tty_mutex); static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); -static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *); -ssize_t redirected_tty_write(struct file *, const char __user *, - size_t, loff_t *); +static ssize_t tty_write(struct kiocb *, struct iov_iter *); +ssize_t redirected_tty_write(struct kiocb *, struct iov_iter *); static __poll_t tty_poll(struct file *, poll_table *); static int tty_open(struct inode *, struct file *); long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg); @@ -478,7 +477,8 @@ 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, - .write = tty_write, + .write_iter = tty_write, + .splice_write = iter_file_splice_write, .poll = tty_poll, .unlocked_ioctl = tty_ioctl, .compat_ioctl = tty_compat_ioctl, @@ -491,7 +491,8 @@ static const struct file_operations tty_fops = { static const struct file_operations console_fops = { .llseek = no_llseek, .read = tty_read, - .write = redirected_tty_write, + .write_iter = redirected_tty_write, + .splice_write = iter_file_splice_write, .poll = tty_poll, .unlocked_ioctl = tty_ioctl, .compat_ioctl = tty_compat_ioctl, @@ -607,9 +608,9 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session) /* This breaks for file handles being sent over AF_UNIX sockets ? */ list_for_each_entry(priv, &tty->tty_files, list) { filp = priv->file; - if (filp->f_op->write == redirected_tty_write) + if (filp->f_op->write_iter == redirected_tty_write) cons_filp = filp; - if (filp->f_op->write != tty_write) + if (filp->f_op->write_iter != tty_write) continue; closecount++; __tty_fasync(-1, filp, 0); /* can't block */ @@ -902,9 +903,9 @@ static inline ssize_t do_tty_write( ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t), struct tty_struct *tty, struct file *file, - const char __user *buf, - size_t count) + struct iov_iter *from) { + size_t count = iov_iter_count(from); ssize_t ret, written = 0; unsigned int chunk; @@ -956,14 +957,20 @@ static inline ssize_t do_tty_write( size_t size = count; if (size > chunk) size = chunk; + ret = -EFAULT; - if (copy_from_user(tty->write_buf, buf, size)) + if (copy_from_iter(tty->write_buf, size, from) != size) break; + ret = write(tty, file, tty->write_buf, size); if (ret <= 0) break; + + /* FIXME! Have Al check this! */ + if (ret != size) + iov_iter_revert(from, size-ret); + written += ret; - buf += ret; count -= ret; if (!count) break; @@ -1023,9 +1030,9 @@ void tty_write_message(struct tty_struct *tty, char *msg) * write method will not be invoked in parallel for each device. */ -static ssize_t tty_write(struct file *file, const char __user *buf, - size_t count, loff_t *ppos) +static ssize_t tty_write(struct kiocb *iocb, struct iov_iter *from) { + struct file *file = iocb->ki_filp; struct tty_struct *tty = file_tty(file); struct tty_ldisc *ld; ssize_t ret; @@ -1038,18 +1045,15 @@ static ssize_t tty_write(struct file *file, const char __user *buf, if (tty->ops->write_room == NULL) tty_err(tty, "missing write_room method\n"); ld = tty_ldisc_ref_wait(tty); - if (!ld) - return hung_up_tty_write(file, buf, count, ppos); - if (!ld->ops->write) + if (!ld || !ld->ops->write) ret = -EIO; else - ret = do_tty_write(ld->ops->write, tty, file, buf, count); + ret = do_tty_write(ld->ops->write, tty, file, from); tty_ldisc_deref(ld); return ret; } -ssize_t redirected_tty_write(struct file *file, const char __user *buf, - size_t count, loff_t *ppos) +ssize_t redirected_tty_write(struct kiocb *iocb, struct iov_iter *iter) { struct file *p = NULL; @@ -1060,11 +1064,11 @@ ssize_t redirected_tty_write(struct file *file, const char __user *buf, if (p) { ssize_t res; - res = vfs_write(p, buf, count, &p->f_pos); + res = vfs_iocb_iter_write(p, iocb, iter); fput(p); return res; } - return tty_write(file, buf, count, ppos); + return tty_write(iocb, iter); } /** @@ -2293,7 +2297,7 @@ static int tioccons(struct file *file) { if (!capable(CAP_SYS_ADMIN)) return -EPERM; - if (file->f_op->write == redirected_tty_write) { + if (file->f_op->write_iter == redirected_tty_write) { struct file *f; spin_lock(&redirect_lock); f = redirect;