Commit aa1ebc9c authored by Jiri Slaby (SUSE)'s avatar Jiri Slaby (SUSE) Committed by Greg Kroah-Hartman
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tty: n_tty: extract n_tty_continue_cookie() from n_tty_read() 



n_tty_read() is a very long function doing too much of different stuff.
Extract the "cookie" (continuation read) handling to a separate
function: n_tty_continue_cookie().

Signed-off-by: default avatarJiri Slaby (SUSE) <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250317070046.24386-10-jirislaby@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 67e781f5

drivers/tty/n_tty.c

+36 −30
Original line number Diff line number Diff line
@@ -2111,6 +2111,39 @@ static int job_control(struct tty_struct *tty, struct file *file) 
	return __tty_check_change(tty, SIGTTIN);

}



/*

 * We still hold the atomic_read_lock and the termios_rwsem, and can just

 * continue to copy data.

 */

static ssize_t n_tty_continue_cookie(struct tty_struct *tty, u8 *kbuf,

				   size_t nr, void **cookie)

{

	struct n_tty_data *ldata = tty->disc_data;

	u8 *kb = kbuf;



	if (ldata->icanon && !L_EXTPROC(tty)) {

		/*

		 * If we have filled the user buffer, see if we should skip an

		 * EOF character before releasing the lock and returning done.

		 */

		if (!nr)

			canon_skip_eof(ldata);

		else if (canon_copy_from_read_buf(tty, &kb, &nr))

			return kb - kbuf;

	} else {

		if (copy_from_read_buf(tty, &kb, &nr))

			return kb - kbuf;

	}



	/* No more data - release locks and stop retries */

	n_tty_kick_worker(tty);

	n_tty_check_unthrottle(tty);

	up_read(&tty->termios_rwsem);

	mutex_unlock(&ldata->atomic_read_lock);

	*cookie = NULL;



	return kb - kbuf;

}



/**

 * n_tty_read		-	read function for tty
@@ -2144,36 +2177,9 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, u8 *kbuf, 
	bool packet;

	size_t old_tail;



	/*

	 * Is this a continuation of a read started earler?

	 *

	 * If so, we still hold the atomic_read_lock and the

	 * termios_rwsem, and can just continue to copy data.

	 */

	if (*cookie) {

		if (ldata->icanon && !L_EXTPROC(tty)) {

			/*

			 * If we have filled the user buffer, see

			 * if we should skip an EOF character before

			 * releasing the lock and returning done.

			 */

			if (!nr)

				canon_skip_eof(ldata);

			else if (canon_copy_from_read_buf(tty, &kb, &nr))

				return kb - kbuf;

		} else {

			if (copy_from_read_buf(tty, &kb, &nr))

				return kb - kbuf;

		}



		/* No more data - release locks and stop retries */

		n_tty_kick_worker(tty);

		n_tty_check_unthrottle(tty);

		up_read(&tty->termios_rwsem);

		mutex_unlock(&ldata->atomic_read_lock);

		*cookie = NULL;

		return kb - kbuf;

	}

	/* Is this a continuation of a read started earlier? */

	if (*cookie)

		return n_tty_continue_cookie(tty, kbuf, nr, cookie);



	retval = job_control(tty, file);

	if (retval < 0)