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tty: n_tty: extract n_tty_continue_cookie() from n_tty_read()

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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: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20250317070046.24386-10-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiri Slaby (SUSE)
2025-03-17 08:00:24 +01:00
committed by Greg Kroah-Hartman
parent 67e781f568
commit aa1ebc9cff
1 changed files with 36 additions and 30 deletions
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66
drivers/tty/n_tty.c
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@@ -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)