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@ -45,7 +45,6 @@ enum {
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*/
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static DEFINE_RAW_SPINLOCK(tty_ldiscs_lock);
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static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait);
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/* Line disc dispatch table */
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static struct tty_ldisc_ops *tty_ldiscs[NR_LDISCS];
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@ -153,7 +152,7 @@ static void put_ldops(struct tty_ldisc_ops *ldops)
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* takes tty_ldiscs_lock to guard against ldisc races
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*/
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static struct tty_ldisc *tty_ldisc_get(int disc)
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static struct tty_ldisc *tty_ldisc_get(struct tty_struct *tty, int disc)
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{
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struct tty_ldisc *ld;
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struct tty_ldisc_ops *ldops;
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@ -180,8 +179,7 @@ static struct tty_ldisc *tty_ldisc_get(int disc)
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}
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ld->ops = ldops;
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atomic_set(&ld->users, 1);
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init_waitqueue_head(&ld->wq_idle);
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ld->tty = tty;
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return ld;
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}
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@ -193,20 +191,11 @@ static struct tty_ldisc *tty_ldisc_get(int disc)
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*/
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static inline void tty_ldisc_put(struct tty_ldisc *ld)
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{
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unsigned long flags;
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if (WARN_ON_ONCE(!ld))
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return;
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raw_spin_lock_irqsave(&tty_ldiscs_lock, flags);
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/* unreleased reader reference(s) will cause this WARN */
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WARN_ON(!atomic_dec_and_test(&ld->users));
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ld->ops->refcount--;
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module_put(ld->ops->owner);
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put_ldops(ld->ops);
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kfree(ld);
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raw_spin_unlock_irqrestore(&tty_ldiscs_lock, flags);
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}
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static void *tty_ldiscs_seq_start(struct seq_file *m, loff_t *pos)
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@ -257,34 +246,6 @@ const struct file_operations tty_ldiscs_proc_fops = {
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.release = seq_release,
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};
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/**
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* tty_ldisc_try - internal helper
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* @tty: the tty
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*
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* Make a single attempt to grab and bump the refcount on
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* the tty ldisc. Return 0 on failure or 1 on success. This is
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* used to implement both the waiting and non waiting versions
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* of tty_ldisc_ref
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*
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* Locking: takes tty_ldiscs_lock
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*/
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static struct tty_ldisc *tty_ldisc_try(struct tty_struct *tty)
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{
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unsigned long flags;
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struct tty_ldisc *ld;
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/* FIXME: this allows reference acquire after TTY_LDISC is cleared */
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raw_spin_lock_irqsave(&tty_ldiscs_lock, flags);
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ld = NULL;
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if (test_bit(TTY_LDISC, &tty->flags) && tty->ldisc) {
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ld = tty->ldisc;
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atomic_inc(&ld->users);
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}
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raw_spin_unlock_irqrestore(&tty_ldiscs_lock, flags);
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return ld;
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}
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/**
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* tty_ldisc_ref_wait - wait for the tty ldisc
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* @tty: tty device
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@ -298,16 +259,15 @@ static struct tty_ldisc *tty_ldisc_try(struct tty_struct *tty)
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* against a discipline change, such as an existing ldisc reference
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* (which we check for)
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*
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* Locking: call functions take tty_ldiscs_lock
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* Note: only callable from a file_operations routine (which
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* guarantees tty->ldisc != NULL when the lock is acquired).
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*/
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struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty)
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{
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struct tty_ldisc *ld;
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/* wait_event is a macro */
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wait_event(tty_ldisc_wait, (ld = tty_ldisc_try(tty)) != NULL);
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return ld;
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ldsem_down_read(&tty->ldisc_sem, MAX_SCHEDULE_TIMEOUT);
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WARN_ON(!tty->ldisc);
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return tty->ldisc;
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}
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EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait);
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@ -318,13 +278,18 @@ EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait);
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* Dereference the line discipline for the terminal and take a
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* reference to it. If the line discipline is in flux then
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* return NULL. Can be called from IRQ and timer functions.
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*
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* Locking: called functions take tty_ldiscs_lock
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*/
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struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty)
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|
{
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|
return tty_ldisc_try(tty);
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struct tty_ldisc *ld = NULL;
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if (ldsem_down_read_trylock(&tty->ldisc_sem)) {
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ld = tty->ldisc;
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if (!ld)
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|
ldsem_up_read(&tty->ldisc_sem);
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}
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return ld;
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}
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EXPORT_SYMBOL_GPL(tty_ldisc_ref);
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@ -334,27 +299,11 @@ EXPORT_SYMBOL_GPL(tty_ldisc_ref);
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*
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* Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May
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* be called in IRQ context.
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*
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* Locking: takes tty_ldiscs_lock
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*/
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void tty_ldisc_deref(struct tty_ldisc *ld)
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{
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unsigned long flags;
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if (WARN_ON_ONCE(!ld))
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return;
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raw_spin_lock_irqsave(&tty_ldiscs_lock, flags);
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/*
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* WARNs if one-too-many reader references were released
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* - the last reference must be released with tty_ldisc_put
|
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|
*/
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WARN_ON(atomic_dec_and_test(&ld->users));
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raw_spin_unlock_irqrestore(&tty_ldiscs_lock, flags);
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if (waitqueue_active(&ld->wq_idle))
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wake_up(&ld->wq_idle);
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ldsem_up_read(&ld->tty->ldisc_sem);
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}
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|
EXPORT_SYMBOL_GPL(tty_ldisc_deref);
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|
@ -437,27 +386,6 @@ static void __lockfunc tty_ldisc_enable_pair(struct tty_struct *tty,
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tty_ldisc_unlock_pair(tty, tty2);
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}
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/**
|
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|
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* tty_ldisc_enable - allow ldisc use
|
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|
* @tty: terminal to activate ldisc on
|
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|
*
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|
|
* Set the TTY_LDISC flag when the line discipline can be called
|
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|
|
* again. Do necessary wakeups for existing sleepers. Clear the LDISC
|
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* changing flag to indicate any ldisc change is now over.
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*
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|
* Note: nobody should set the TTY_LDISC bit except via this function.
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|
* Clearing directly is allowed.
|
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|
|
*/
|
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|
|
static void tty_ldisc_enable(struct tty_struct *tty)
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|
|
{
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|
|
clear_bit(TTY_LDISC_HALTED, &tty->flags);
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|
|
set_bit(TTY_LDISC, &tty->flags);
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|
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clear_bit(TTY_LDISC_CHANGING, &tty->flags);
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|
|
wake_up(&tty_ldisc_wait);
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|
|
}
|
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|
|
/**
|
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|
|
* tty_ldisc_flush - flush line discipline queue
|
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|
|
* @tty: tty
|
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|
|
@ -555,14 +483,14 @@ static void tty_ldisc_restore(struct tty_struct *tty, struct tty_ldisc *old)
|
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|
|
int r;
|
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|
|
/* There is an outstanding reference here so this is safe */
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old = tty_ldisc_get(old->ops->num);
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|
old = tty_ldisc_get(tty, old->ops->num);
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|
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WARN_ON(IS_ERR(old));
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|
|
tty->ldisc = old;
|
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|
|
tty_set_termios_ldisc(tty, old->ops->num);
|
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|
|
if (tty_ldisc_open(tty, old) < 0) {
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|
|
tty_ldisc_put(old);
|
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|
|
|
/* This driver is always present */
|
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|
|
|
new_ldisc = tty_ldisc_get(N_TTY);
|
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|
|
|
new_ldisc = tty_ldisc_get(tty, N_TTY);
|
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|
|
|
if (IS_ERR(new_ldisc))
|
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|
|
|
panic("n_tty: get");
|
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|
|
|
tty->ldisc = new_ldisc;
|
|
|
|
@ -575,101 +503,6 @@ static void tty_ldisc_restore(struct tty_struct *tty, struct tty_ldisc *old)
|
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|
}
|
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|
|
|
}
|
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|
|
|
|
|
|
|
|
/**
|
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|
|
|
* tty_ldisc_wait_idle - wait for the ldisc to become idle
|
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|
|
* @tty: tty to wait for
|
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|
|
* @timeout: for how long to wait at most
|
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|
|
*
|
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|
|
* Wait for the line discipline to become idle. The discipline must
|
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|
|
* have been halted for this to guarantee it remains idle.
|
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|
|
|
*/
|
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|
|
static int tty_ldisc_wait_idle(struct tty_struct *tty, long timeout)
|
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|
|
|
{
|
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|
|
|
long ret;
|
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|
|
ret = wait_event_timeout(tty->ldisc->wq_idle,
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|
|
atomic_read(&tty->ldisc->users) == 1, timeout);
|
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|
|
return ret > 0 ? 0 : -EBUSY;
|
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|
|
}
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* tty_ldisc_halt - shut down the line discipline
|
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|
|
* @tty: tty device
|
|
|
|
|
* @o_tty: paired pty device (can be NULL)
|
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|
|
* @timeout: # of jiffies to wait for ldisc refs to be released
|
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|
|
|
*
|
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|
|
|
* Shut down the line discipline and work queue for this tty device and
|
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|
|
* its paired pty (if exists). Clearing the TTY_LDISC flag ensures
|
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|
|
* no further references can be obtained, while waiting for existing
|
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|
|
|
* references to be released ensures no more data is fed to the ldisc.
|
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|
|
|
*
|
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|
|
|
* You need to do a 'flush_scheduled_work()' (outside the ldisc_mutex)
|
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|
|
|
* in order to make sure any currently executing ldisc work is also
|
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|
|
* flushed.
|
|
|
|
|
*/
|
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|
|
|
|
|
|
|
|
static int tty_ldisc_halt(struct tty_struct *tty, struct tty_struct *o_tty,
|
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|
|
|
long timeout)
|
|
|
|
|
{
|
|
|
|
|
int retval;
|
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|
|
|
|
|
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|
|
clear_bit(TTY_LDISC, &tty->flags);
|
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|
|
if (o_tty)
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|
|
clear_bit(TTY_LDISC, &o_tty->flags);
|
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|
|
|
|
|
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|
|
retval = tty_ldisc_wait_idle(tty, timeout);
|
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|
|
|
if (!retval && o_tty)
|
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|
|
|
retval = tty_ldisc_wait_idle(o_tty, timeout);
|
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|
|
|
if (retval)
|
|
|
|
|
return retval;
|
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|
|
|
|
|
|
|
|
set_bit(TTY_LDISC_HALTED, &tty->flags);
|
|
|
|
|
if (o_tty)
|
|
|
|
|
set_bit(TTY_LDISC_HALTED, &o_tty->flags);
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* tty_ldisc_hangup_halt - halt the line discipline for hangup
|
|
|
|
|
* @tty: tty being hung up
|
|
|
|
|
*
|
|
|
|
|
* Shut down the line discipline and work queue for the tty device
|
|
|
|
|
* being hungup. Clear the TTY_LDISC flag to ensure no further
|
|
|
|
|
* references can be obtained and wait for remaining references to be
|
|
|
|
|
* released to ensure no more data is fed to this ldisc.
|
|
|
|
|
* Caller must hold legacy and ->ldisc_mutex.
|
|
|
|
|
*
|
|
|
|
|
* NB: tty_set_ldisc() is prevented from changing the ldisc concurrently
|
|
|
|
|
* with this function by checking the TTY_HUPPING flag.
|
|
|
|
|
*/
|
|
|
|
|
static bool tty_ldisc_hangup_halt(struct tty_struct *tty)
|
|
|
|
|
{
|
|
|
|
|
char cur_n[TASK_COMM_LEN], tty_n[64];
|
|
|
|
|
long timeout = 3 * HZ;
|
|
|
|
|
|
|
|
|
|
clear_bit(TTY_LDISC, &tty->flags);
|
|
|
|
|
|
|
|
|
|
if (tty->ldisc) { /* Not yet closed */
|
|
|
|
|
tty_unlock(tty);
|
|
|
|
|
|
|
|
|
|
while (tty_ldisc_wait_idle(tty, timeout) == -EBUSY) {
|
|
|
|
|
timeout = MAX_SCHEDULE_TIMEOUT;
|
|
|
|
|
printk_ratelimited(KERN_WARNING
|
|
|
|
|
"%s: waiting (%s) for %s took too long, but we keep waiting...\n",
|
|
|
|
|
__func__, get_task_comm(cur_n, current),
|
|
|
|
|
tty_name(tty, tty_n));
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
set_bit(TTY_LDISC_HALTED, &tty->flags);
|
|
|
|
|
|
|
|
|
|
/* must reacquire both locks and preserve lock order */
|
|
|
|
|
mutex_unlock(&tty->ldisc_mutex);
|
|
|
|
|
tty_lock(tty);
|
|
|
|
|
mutex_lock(&tty->ldisc_mutex);
|
|
|
|
|
}
|
|
|
|
|
return !!tty->ldisc;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* tty_set_ldisc - set line discipline
|
|
|
|
|
* @tty: the terminal to set
|
|
|
|
@ -679,103 +512,47 @@ static bool tty_ldisc_hangup_halt(struct tty_struct *tty)
|
|
|
|
|
* context. The ldisc change logic has to protect itself against any
|
|
|
|
|
* overlapping ldisc change (including on the other end of pty pairs),
|
|
|
|
|
* the close of one side of a tty/pty pair, and eventually hangup.
|
|
|
|
|
*
|
|
|
|
|
* Locking: takes tty_ldiscs_lock, termios_mutex
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
int tty_set_ldisc(struct tty_struct *tty, int ldisc)
|
|
|
|
|
{
|
|
|
|
|
int retval;
|
|
|
|
|
struct tty_ldisc *o_ldisc, *new_ldisc;
|
|
|
|
|
struct tty_struct *o_tty;
|
|
|
|
|
struct tty_struct *o_tty = tty->link;
|
|
|
|
|
|
|
|
|
|
new_ldisc = tty_ldisc_get(ldisc);
|
|
|
|
|
new_ldisc = tty_ldisc_get(tty, ldisc);
|
|
|
|
|
if (IS_ERR(new_ldisc))
|
|
|
|
|
return PTR_ERR(new_ldisc);
|
|
|
|
|
|
|
|
|
|
tty_lock(tty);
|
|
|
|
|
/*
|
|
|
|
|
* We need to look at the tty locking here for pty/tty pairs
|
|
|
|
|
* when both sides try to change in parallel.
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
o_tty = tty->link; /* o_tty is the pty side or NULL */
|
|
|
|
|
|
|
|
|
|
retval = tty_ldisc_lock_pair_timeout(tty, o_tty, 5 * HZ);
|
|
|
|
|
if (retval) {
|
|
|
|
|
tty_ldisc_put(new_ldisc);
|
|
|
|
|
return retval;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Check the no-op case
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
if (tty->ldisc->ops->num == ldisc) {
|
|
|
|
|
tty_unlock(tty);
|
|
|
|
|
tty_ldisc_enable_pair(tty, o_tty);
|
|
|
|
|
tty_ldisc_put(new_ldisc);
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
mutex_lock(&tty->ldisc_mutex);
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* We could be midstream of another ldisc change which has
|
|
|
|
|
* dropped the lock during processing. If so we need to wait.
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
while (test_bit(TTY_LDISC_CHANGING, &tty->flags)) {
|
|
|
|
|
mutex_unlock(&tty->ldisc_mutex);
|
|
|
|
|
tty_unlock(tty);
|
|
|
|
|
wait_event(tty_ldisc_wait,
|
|
|
|
|
test_bit(TTY_LDISC_CHANGING, &tty->flags) == 0);
|
|
|
|
|
tty_lock(tty);
|
|
|
|
|
mutex_lock(&tty->ldisc_mutex);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
set_bit(TTY_LDISC_CHANGING, &tty->flags);
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* No more input please, we are switching. The new ldisc
|
|
|
|
|
* will update this value in the ldisc open function
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
/* FIXME: why 'shutoff' input if the ldisc is locked? */
|
|
|
|
|
tty->receive_room = 0;
|
|
|
|
|
|
|
|
|
|
o_ldisc = tty->ldisc;
|
|
|
|
|
|
|
|
|
|
tty_unlock(tty);
|
|
|
|
|
/*
|
|
|
|
|
* Make sure we don't change while someone holds a
|
|
|
|
|
* reference to the line discipline. The TTY_LDISC bit
|
|
|
|
|
* prevents anyone taking a reference once it is clear.
|
|
|
|
|
* We need the lock to avoid racing reference takers.
|
|
|
|
|
*
|
|
|
|
|
* We must clear the TTY_LDISC bit here to avoid a livelock
|
|
|
|
|
* with a userspace app continually trying to use the tty in
|
|
|
|
|
* parallel to the change and re-referencing the tty.
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
retval = tty_ldisc_halt(tty, o_tty, 5 * HZ);
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Wait for hangup to complete, if pending.
|
|
|
|
|
* We must drop the mutex here in case a hangup is also in process.
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
mutex_unlock(&tty->ldisc_mutex);
|
|
|
|
|
|
|
|
|
|
flush_work(&tty->hangup_work);
|
|
|
|
|
|
|
|
|
|
tty_lock(tty);
|
|
|
|
|
mutex_lock(&tty->ldisc_mutex);
|
|
|
|
|
|
|
|
|
|
/* handle wait idle failure locked */
|
|
|
|
|
if (retval) {
|
|
|
|
|
tty_ldisc_put(new_ldisc);
|
|
|
|
|
goto enable;
|
|
|
|
|
}
|
|
|
|
|
/* FIXME: for testing only */
|
|
|
|
|
WARN_ON(test_bit(TTY_HUPPED, &tty->flags));
|
|
|
|
|
|
|
|
|
|
if (test_bit(TTY_HUPPING, &tty->flags)) {
|
|
|
|
|
/* We were raced by the hangup method. It will have stomped
|
|
|
|
|
the ldisc data and closed the ldisc down */
|
|
|
|
|
clear_bit(TTY_LDISC_CHANGING, &tty->flags);
|
|
|
|
|
mutex_unlock(&tty->ldisc_mutex);
|
|
|
|
|
tty_ldisc_enable_pair(tty, o_tty);
|
|
|
|
|
tty_ldisc_put(new_ldisc);
|
|
|
|
|
tty_unlock(tty);
|
|
|
|
|
return -EIO;
|
|
|
|
@ -804,14 +581,10 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
|
|
|
|
|
|
|
|
|
|
tty_ldisc_put(o_ldisc);
|
|
|
|
|
|
|
|
|
|
enable:
|
|
|
|
|
/*
|
|
|
|
|
* Allow ldisc referencing to occur again
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
tty_ldisc_enable(tty);
|
|
|
|
|
if (o_tty)
|
|
|
|
|
tty_ldisc_enable(o_tty);
|
|
|
|
|
tty_ldisc_enable_pair(tty, o_tty);
|
|
|
|
|
|
|
|
|
|
/* Restart the work queue in case no characters kick it off. Safe if
|
|
|
|
|
already running */
|
|
|
|
@ -819,7 +592,6 @@ enable:
|
|
|
|
|
if (o_tty)
|
|
|
|
|
schedule_work(&o_tty->port->buf.work);
|
|
|
|
|
|
|
|
|
|
mutex_unlock(&tty->ldisc_mutex);
|
|
|
|
|
tty_unlock(tty);
|
|
|
|
|
return retval;
|
|
|
|
|
}
|
|
|
|
@ -852,7 +624,7 @@ static void tty_reset_termios(struct tty_struct *tty)
|
|
|
|
|
|
|
|
|
|
static int tty_ldisc_reinit(struct tty_struct *tty, int ldisc)
|
|
|
|
|
{
|
|
|
|
|
struct tty_ldisc *ld = tty_ldisc_get(ldisc);
|
|
|
|
|
struct tty_ldisc *ld = tty_ldisc_get(tty, ldisc);
|
|
|
|
|
|
|
|
|
|
if (IS_ERR(ld))
|
|
|
|
|
return -1;
|
|
|
|
@ -891,14 +663,8 @@ void tty_ldisc_hangup(struct tty_struct *tty)
|
|
|
|
|
|
|
|
|
|
tty_ldisc_debug(tty, "closing ldisc: %p\n", tty->ldisc);
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* FIXME! What are the locking issues here? This may me overdoing
|
|
|
|
|
* things... This question is especially important now that we've
|
|
|
|
|
* removed the irqlock.
|
|
|
|
|
*/
|
|
|
|
|
ld = tty_ldisc_ref(tty);
|
|
|
|
|
if (ld != NULL) {
|
|
|
|
|
/* We may have no line discipline at this point */
|
|
|
|
|
if (ld->ops->flush_buffer)
|
|
|
|
|
ld->ops->flush_buffer(tty);
|
|
|
|
|
tty_driver_flush_buffer(tty);
|
|
|
|
@ -909,21 +675,22 @@ void tty_ldisc_hangup(struct tty_struct *tty)
|
|
|
|
|
ld->ops->hangup(tty);
|
|
|
|
|
tty_ldisc_deref(ld);
|
|
|
|
|
}
|
|
|
|
|
/*
|
|
|
|
|
* FIXME: Once we trust the LDISC code better we can wait here for
|
|
|
|
|
* ldisc completion and fix the driver call race
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
|
|
|
|
|
wake_up_interruptible_poll(&tty->read_wait, POLLIN);
|
|
|
|
|
|
|
|
|
|
tty_unlock(tty);
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Shutdown the current line discipline, and reset it to
|
|
|
|
|
* N_TTY if need be.
|
|
|
|
|
*
|
|
|
|
|
* Avoid racing set_ldisc or tty_ldisc_release
|
|
|
|
|
*/
|
|
|
|
|
mutex_lock(&tty->ldisc_mutex);
|
|
|
|
|
tty_ldisc_lock_pair(tty, tty->link);
|
|
|
|
|
tty_lock(tty);
|
|
|
|
|
|
|
|
|
|
if (tty_ldisc_hangup_halt(tty)) {
|
|
|
|
|
if (tty->ldisc) {
|
|
|
|
|
|
|
|
|
|
/* At this point we have a halted ldisc; we want to close it and
|
|
|
|
|
reopen a new ldisc. We could defer the reopen to the next
|
|
|
|
@ -942,9 +709,8 @@ void tty_ldisc_hangup(struct tty_struct *tty)
|
|
|
|
|
BUG_ON(tty_ldisc_reinit(tty, N_TTY));
|
|
|
|
|
WARN_ON(tty_ldisc_open(tty, tty->ldisc));
|
|
|
|
|
}
|
|
|
|
|
tty_ldisc_enable(tty);
|
|
|
|
|
}
|
|
|
|
|
mutex_unlock(&tty->ldisc_mutex);
|
|
|
|
|
tty_ldisc_enable_pair(tty, tty->link);
|
|
|
|
|
if (reset)
|
|
|
|
|
tty_reset_termios(tty);
|
|
|
|
|
|
|
|
|
@ -976,15 +742,12 @@ int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty)
|
|
|
|
|
tty_ldisc_close(tty, ld);
|
|
|
|
|
return retval;
|
|
|
|
|
}
|
|
|
|
|
tty_ldisc_enable(o_tty);
|
|
|
|
|
}
|
|
|
|
|
tty_ldisc_enable(tty);
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static void tty_ldisc_kill(struct tty_struct *tty)
|
|
|
|
|
{
|
|
|
|
|
mutex_lock(&tty->ldisc_mutex);
|
|
|
|
|
/*
|
|
|
|
|
* Now kill off the ldisc
|
|
|
|
|
*/
|
|
|
|
@ -995,7 +758,6 @@ static void tty_ldisc_kill(struct tty_struct *tty)
|
|
|
|
|
|
|
|
|
|
/* Ensure the next open requests the N_TTY ldisc */
|
|
|
|
|
tty_set_termios_ldisc(tty, N_TTY);
|
|
|
|
|
mutex_unlock(&tty->ldisc_mutex);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
@ -1017,15 +779,16 @@ void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty)
|
|
|
|
|
|
|
|
|
|
tty_ldisc_debug(tty, "closing ldisc: %p\n", tty->ldisc);
|
|
|
|
|
|
|
|
|
|
tty_ldisc_halt(tty, o_tty, MAX_SCHEDULE_TIMEOUT);
|
|
|
|
|
|
|
|
|
|
tty_ldisc_lock_pair(tty, o_tty);
|
|
|
|
|
tty_lock_pair(tty, o_tty);
|
|
|
|
|
/* This will need doing differently if we need to lock */
|
|
|
|
|
|
|
|
|
|
tty_ldisc_kill(tty);
|
|
|
|
|
if (o_tty)
|
|
|
|
|
tty_ldisc_kill(o_tty);
|
|
|
|
|
|
|
|
|
|
tty_unlock_pair(tty, o_tty);
|
|
|
|
|
tty_ldisc_unlock_pair(tty, o_tty);
|
|
|
|
|
|
|
|
|
|
/* And the memory resources remaining (buffers, termios) will be
|
|
|
|
|
disposed of when the kref hits zero */
|
|
|
|
|
|
|
|
|
@ -1042,7 +805,7 @@ void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty)
|
|
|
|
|
|
|
|
|
|
void tty_ldisc_init(struct tty_struct *tty)
|
|
|
|
|
{
|
|
|
|
|
struct tty_ldisc *ld = tty_ldisc_get(N_TTY);
|
|
|
|
|
struct tty_ldisc *ld = tty_ldisc_get(tty, N_TTY);
|
|
|
|
|
if (IS_ERR(ld))
|
|
|
|
|
panic("n_tty: init_tty");
|
|
|
|
|
tty->ldisc = ld;
|
|
|
|
|