Merge tag 'tty-5.11-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial fixes from Greg KH:
 "Here are three small tty/serial fixes for 5.11-rc5 to resolve reported
  problems:

   - two patches to fix up writing to ttys with splice

   - mvebu-uart driver fix for reported problem

  All of these have been in linux-next with no reported problems"

* tag 'tty-5.11-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  tty: fix up hung_up_tty_write() conversion
  tty: implement write_iter
  serial: mvebu-uart: fix tx lost characters at power off

Author: torvalds

drivers/tty/serial/mvebu-uart.c

@@ -648,6 +648,14 @@ static void wait_for_xmitr(struct uart_port *port)
 				  (val & STAT_TX_RDY(port)), 1, 10000);
 }
 
+static void wait_for_xmite(struct uart_port *port)
+{
+	u32 val;
+
+	readl_poll_timeout_atomic(port->membase + UART_STAT, val,
+				  (val & STAT_TX_EMP), 1, 10000);
+}
+
 static void mvebu_uart_console_putchar(struct uart_port *port, int ch)
 {
 	wait_for_xmitr(port);
@@ -675,7 +683,7 @@ static void mvebu_uart_console_write(struct console *co, const char *s,
 
 	uart_console_write(port, s, count, mvebu_uart_console_putchar);
 
-	wait_for_xmitr(port);
+	wait_for_xmite(port);
 
 	if (ier)
 		writel(ier, port->membase + UART_CTRL(port));

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);
@@ -438,8 +437,7 @@ static ssize_t hung_up_tty_read(struct file *file, char __user *buf,
 	return 0;
 }
 
-static ssize_t hung_up_tty_write(struct file *file, const char __user *buf,
-				 size_t count, loff_t *ppos)
+static ssize_t hung_up_tty_write(struct kiocb *iocb, struct iov_iter *from)
 {
 	return -EIO;
 }
@@ -478,7 +476,8 @@ 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 +490,8 @@ 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,
@@ -503,7 +503,7 @@ static const struct file_operations console_fops = {
 static const struct file_operations hung_up_tty_fops = {
 	.llseek		= no_llseek,
 	.read		= hung_up_tty_read,
-	.write		= hung_up_tty_write,
+	.write_iter	= hung_up_tty_write,
 	.poll		= hung_up_tty_poll,
 	.unlocked_ioctl	= hung_up_tty_ioctl,
 	.compat_ioctl	= hung_up_tty_compat_ioctl,
@@ -606,9 +606,9 @@ 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 */
@@ -901,9 +901,9 @@ 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;
 
@@ -955,14 +955,20 @@ 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;
@@ -1022,9 +1028,9 @@ 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;
@@ -1038,17 +1044,16 @@ static ssize_t tty_write(struct file *file, const char __user *buf,
 		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);
+		return hung_up_tty_write(iocb, from);
 	if (!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;
 
@@ -1059,11 +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);
 }
 
 /*
@@ -2295,7 +2300,7 @@ 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;