return kzalloc(sizeof(struct tty_struct), GFP_KERNEL);
}
-static void tty_buffer_free_all(struct tty_struct *);
-
/**
* free_tty_struct - free a disused tty
* @tty: tty struct to free
return 0;
}
-/*
- * Tty buffer allocation management
- */
-
-/**
- * tty_buffer_free_all - free buffers used by a tty
- * @tty: tty to free from
- *
- * Remove all the buffers pending on a tty whether queued with data
- * or in the free ring. Must be called when the tty is no longer in use
- *
- * Locking: none
- */
-
-static void tty_buffer_free_all(struct tty_struct *tty)
-{
- struct tty_buffer *thead;
- while ((thead = tty->buf.head) != NULL) {
- tty->buf.head = thead->next;
- kfree(thead);
- }
- while ((thead = tty->buf.free) != NULL) {
- tty->buf.free = thead->next;
- kfree(thead);
- }
- tty->buf.tail = NULL;
- tty->buf.memory_used = 0;
-}
-
-/**
- * tty_buffer_init - prepare a tty buffer structure
- * @tty: tty to initialise
- *
- * Set up the initial state of the buffer management for a tty device.
- * Must be called before the other tty buffer functions are used.
- *
- * Locking: none
- */
-
-static void tty_buffer_init(struct tty_struct *tty)
-{
- spin_lock_init(&tty->buf.lock);
- tty->buf.head = NULL;
- tty->buf.tail = NULL;
- tty->buf.free = NULL;
- tty->buf.memory_used = 0;
-}
-
-/**
- * tty_buffer_alloc - allocate a tty buffer
- * @tty: tty device
- * @size: desired size (characters)
- *
- * Allocate a new tty buffer to hold the desired number of characters.
- * Return NULL if out of memory or the allocation would exceed the
- * per device queue
- *
- * Locking: Caller must hold tty->buf.lock
- */
-
-static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size)
-{
- struct tty_buffer *p;
-
- if (tty->buf.memory_used + size > 65536)
- return NULL;
- p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC);
- if (p == NULL)
- return NULL;
- p->used = 0;
- p->size = size;
- p->next = NULL;
- p->commit = 0;
- p->read = 0;
- p->char_buf_ptr = (char *)(p->data);
- p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size;
- tty->buf.memory_used += size;
- return p;
-}
-
-/**
- * tty_buffer_free - free a tty buffer
- * @tty: tty owning the buffer
- * @b: the buffer to free
- *
- * Free a tty buffer, or add it to the free list according to our
- * internal strategy
- *
- * Locking: Caller must hold tty->buf.lock
- */
-
-static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b)
-{
- /* Dumb strategy for now - should keep some stats */
- tty->buf.memory_used -= b->size;
- WARN_ON(tty->buf.memory_used < 0);
-
- if (b->size >= 512)
- kfree(b);
- else {
- b->next = tty->buf.free;
- tty->buf.free = b;
- }
-}
-
-/**
- * __tty_buffer_flush - flush full tty buffers
- * @tty: tty to flush
- *
- * flush all the buffers containing receive data. Caller must
- * hold the buffer lock and must have ensured no parallel flush to
- * ldisc is running.
- *
- * Locking: Caller must hold tty->buf.lock
- */
-
-static void __tty_buffer_flush(struct tty_struct *tty)
-{
- struct tty_buffer *thead;
-
- while ((thead = tty->buf.head) != NULL) {
- tty->buf.head = thead->next;
- tty_buffer_free(tty, thead);
- }
- tty->buf.tail = NULL;
-}
-
-/**
- * tty_buffer_flush - flush full tty buffers
- * @tty: tty to flush
- *
- * flush all the buffers containing receive data. If the buffer is
- * being processed by flush_to_ldisc then we defer the processing
- * to that function
- *
- * Locking: none
- */
-
-static void tty_buffer_flush(struct tty_struct *tty)
-{
- unsigned long flags;
- spin_lock_irqsave(&tty->buf.lock, flags);
-
- /* If the data is being pushed to the tty layer then we can't
- process it here. Instead set a flag and the flush_to_ldisc
- path will process the flush request before it exits */
- if (test_bit(TTY_FLUSHING, &tty->flags)) {
- set_bit(TTY_FLUSHPENDING, &tty->flags);
- spin_unlock_irqrestore(&tty->buf.lock, flags);
- wait_event(tty->read_wait,
- test_bit(TTY_FLUSHPENDING, &tty->flags) == 0);
- return;
- } else
- __tty_buffer_flush(tty);
- spin_unlock_irqrestore(&tty->buf.lock, flags);
-}
-
-/**
- * tty_buffer_find - find a free tty buffer
- * @tty: tty owning the buffer
- * @size: characters wanted
- *
- * Locate an existing suitable tty buffer or if we are lacking one then
- * allocate a new one. We round our buffers off in 256 character chunks
- * to get better allocation behaviour.
- *
- * Locking: Caller must hold tty->buf.lock
- */
-
-static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size)
-{
- struct tty_buffer **tbh = &tty->buf.free;
- while ((*tbh) != NULL) {
- struct tty_buffer *t = *tbh;
- if (t->size >= size) {
- *tbh = t->next;
- t->next = NULL;
- t->used = 0;
- t->commit = 0;
- t->read = 0;
- tty->buf.memory_used += t->size;
- return t;
- }
- tbh = &((*tbh)->next);
- }
- /* Round the buffer size out */
- size = (size + 0xFF) & ~0xFF;
- return tty_buffer_alloc(tty, size);
- /* Should possibly check if this fails for the largest buffer we
- have queued and recycle that ? */
-}
-
-/**
- * tty_buffer_request_room - grow tty buffer if needed
- * @tty: tty structure
- * @size: size desired
- *
- * Make at least size bytes of linear space available for the tty
- * buffer. If we fail return the size we managed to find.
- *
- * Locking: Takes tty->buf.lock
- */
-int tty_buffer_request_room(struct tty_struct *tty, size_t size)
-{
- struct tty_buffer *b, *n;
- int left;
- unsigned long flags;
-
- spin_lock_irqsave(&tty->buf.lock, flags);
-
- /* OPTIMISATION: We could keep a per tty "zero" sized buffer to
- remove this conditional if its worth it. This would be invisible
- to the callers */
- if ((b = tty->buf.tail) != NULL)
- left = b->size - b->used;
- else
- left = 0;
-
- if (left < size) {
- /* This is the slow path - looking for new buffers to use */
- if ((n = tty_buffer_find(tty, size)) != NULL) {
- if (b != NULL) {
- b->next = n;
- b->commit = b->used;
- } else
- tty->buf.head = n;
- tty->buf.tail = n;
- } else
- size = left;
- }
-
- spin_unlock_irqrestore(&tty->buf.lock, flags);
- return size;
-}
-EXPORT_SYMBOL_GPL(tty_buffer_request_room);
-
-/**
- * tty_insert_flip_string - Add characters to the tty buffer
- * @tty: tty structure
- * @chars: characters
- * @size: size
- *
- * Queue a series of bytes to the tty buffering. All the characters
- * passed are marked as without error. Returns the number added.
- *
- * Locking: Called functions may take tty->buf.lock
- */
-
-int tty_insert_flip_string(struct tty_struct *tty, const unsigned char *chars,
- size_t size)
-{
- int copied = 0;
- do {
- int space = tty_buffer_request_room(tty, size - copied);
- struct tty_buffer *tb = tty->buf.tail;
- /* If there is no space then tb may be NULL */
- if (unlikely(space == 0))
- break;
- memcpy(tb->char_buf_ptr + tb->used, chars, space);
- memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space);
- tb->used += space;
- copied += space;
- chars += space;
- /* There is a small chance that we need to split the data over
- several buffers. If this is the case we must loop */
- } while (unlikely(size > copied));
- return copied;
-}
-EXPORT_SYMBOL(tty_insert_flip_string);
-
-/**
- * tty_insert_flip_string_flags - Add characters to the tty buffer
- * @tty: tty structure
- * @chars: characters
- * @flags: flag bytes
- * @size: size
- *
- * Queue a series of bytes to the tty buffering. For each character
- * the flags array indicates the status of the character. Returns the
- * number added.
- *
- * Locking: Called functions may take tty->buf.lock
- */
-
-int tty_insert_flip_string_flags(struct tty_struct *tty,
- const unsigned char *chars, const char *flags, size_t size)
-{
- int copied = 0;
- do {
- int space = tty_buffer_request_room(tty, size - copied);
- struct tty_buffer *tb = tty->buf.tail;
- /* If there is no space then tb may be NULL */
- if (unlikely(space == 0))
- break;
- memcpy(tb->char_buf_ptr + tb->used, chars, space);
- memcpy(tb->flag_buf_ptr + tb->used, flags, space);
- tb->used += space;
- copied += space;
- chars += space;
- flags += space;
- /* There is a small chance that we need to split the data over
- several buffers. If this is the case we must loop */
- } while (unlikely(size > copied));
- return copied;
-}
-EXPORT_SYMBOL(tty_insert_flip_string_flags);
-
-/**
- * tty_schedule_flip - push characters to ldisc
- * @tty: tty to push from
- *
- * Takes any pending buffers and transfers their ownership to the
- * ldisc side of the queue. It then schedules those characters for
- * processing by the line discipline.
- *
- * Locking: Takes tty->buf.lock
- */
-
-void tty_schedule_flip(struct tty_struct *tty)
-{
- unsigned long flags;
- spin_lock_irqsave(&tty->buf.lock, flags);
- if (tty->buf.tail != NULL)
- tty->buf.tail->commit = tty->buf.tail->used;
- spin_unlock_irqrestore(&tty->buf.lock, flags);
- schedule_delayed_work(&tty->buf.work, 1);
-}
-EXPORT_SYMBOL(tty_schedule_flip);
-
-/**
- * tty_prepare_flip_string - make room for characters
- * @tty: tty
- * @chars: return pointer for character write area
- * @size: desired size
- *
- * Prepare a block of space in the buffer for data. Returns the length
- * available and buffer pointer to the space which is now allocated and
- * accounted for as ready for normal characters. This is used for drivers
- * that need their own block copy routines into the buffer. There is no
- * guarantee the buffer is a DMA target!
- *
- * Locking: May call functions taking tty->buf.lock
- */
-
-int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars,
- size_t size)
-{
- int space = tty_buffer_request_room(tty, size);
- if (likely(space)) {
- struct tty_buffer *tb = tty->buf.tail;
- *chars = tb->char_buf_ptr + tb->used;
- memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space);
- tb->used += space;
- }
- return space;
-}
-
-EXPORT_SYMBOL_GPL(tty_prepare_flip_string);
-
-/**
- * tty_prepare_flip_string_flags - make room for characters
- * @tty: tty
- * @chars: return pointer for character write area
- * @flags: return pointer for status flag write area
- * @size: desired size
- *
- * Prepare a block of space in the buffer for data. Returns the length
- * available and buffer pointer to the space which is now allocated and
- * accounted for as ready for characters. This is used for drivers
- * that need their own block copy routines into the buffer. There is no
- * guarantee the buffer is a DMA target!
- *
- * Locking: May call functions taking tty->buf.lock
- */
-
-int tty_prepare_flip_string_flags(struct tty_struct *tty,
- unsigned char **chars, char **flags, size_t size)
-{
- int space = tty_buffer_request_room(tty, size);
- if (likely(space)) {
- struct tty_buffer *tb = tty->buf.tail;
- *chars = tb->char_buf_ptr + tb->used;
- *flags = tb->flag_buf_ptr + tb->used;
- tb->used += space;
- }
- return space;
-}
-
-EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags);
-
-
-
/**
* get_tty_driver - find device of a tty
* @dev_t: device identifier
struct tty_ldisc *ld;
int closecount = 0, n;
unsigned long flags;
+ int refs = 0;
if (!tty)
return;
if (tty->session) {
do_each_pid_task(tty->session, PIDTYPE_SID, p) {
spin_lock_irq(&p->sighand->siglock);
- if (p->signal->tty == tty)
+ if (p->signal->tty == tty) {
p->signal->tty = NULL;
+ /* We defer the dereferences outside fo
+ the tasklist lock */
+ refs++;
+ }
if (!p->signal->leader) {
spin_unlock_irq(&p->sighand->siglock);
continue;
tty->ctrl_status = 0;
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+ /* Account for the p->signal references we killed */
+ while (refs--)
+ tty_kref_put(tty);
+
/*
* If one of the devices matches a console pointer, we
* cannot just call hangup() because that will cause
EXPORT_SYMBOL(tty_vhangup);
+/**
+ * tty_vhangup_self - process vhangup for own ctty
+ *
+ * Perform a vhangup on the current controlling tty
+ */
+
+void tty_vhangup_self(void)
+{
+ struct tty_struct *tty;
+
+ tty = get_current_tty();
+ if (tty) {
+ tty_vhangup(tty);
+ tty_kref_put(tty);
+ }
+}
+
/**
* tty_hung_up_p - was tty hung up
* @filp: file pointer of tty
struct pid *tty_pgrp = NULL;
- mutex_lock(&tty_mutex);
tty = get_current_tty();
if (tty) {
tty_pgrp = get_pid(tty->pgrp);
lock_kernel();
- mutex_unlock(&tty_mutex);
- /* XXX: here we race, there is nothing protecting tty */
if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY)
tty_vhangup(tty);
unlock_kernel();
+ tty_kref_put(tty);
} else if (on_exit) {
struct pid *old_pgrp;
spin_lock_irq(¤t->sighand->siglock);
kill_pgrp(old_pgrp, SIGCONT, on_exit);
put_pid(old_pgrp);
}
- mutex_unlock(&tty_mutex);
return;
}
if (tty_pgrp) {
current->signal->tty_old_pgrp = NULL;
spin_unlock_irq(¤t->sighand->siglock);
- mutex_lock(&tty_mutex);
- /* It is possible that do_tty_hangup has free'd this tty */
tty = get_current_tty();
if (tty) {
unsigned long flags;
tty->session = NULL;
tty->pgrp = NULL;
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+ tty_kref_put(tty);
} else {
#ifdef TTY_DEBUG_HANGUP
printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
" = NULL", tty);
#endif
}
- mutex_unlock(&tty_mutex);
/* Now clear signal->tty under the lock */
read_lock(&tasklist_lock);
return ret;
}
+/**
+ * tty_write_message - write a message to a certain tty, not just the console.
+ * @tty: the destination tty_struct
+ * @msg: the message to write
+ *
+ * This is used for messages that need to be redirected to a specific tty.
+ * We don't put it into the syslog queue right now maybe in the future if
+ * really needed.
+ *
+ * We must still hold the BKL and test the CLOSING flag for the moment.
+ */
+
+void tty_write_message(struct tty_struct *tty, char *msg)
+{
+ lock_kernel();
+ if (tty) {
+ mutex_lock(&tty->atomic_write_lock);
+ if (tty->ops->write && !test_bit(TTY_CLOSING, &tty->flags))
+ tty->ops->write(tty, msg, strlen(msg));
+ tty_write_unlock(tty);
+ }
+ unlock_kernel();
+ return;
+}
+
/**
* tty_write - write method for tty device file
return tty_write(file, buf, count, ppos);
}
-void tty_port_init(struct tty_port *port)
-{
- memset(port, 0, sizeof(*port));
- init_waitqueue_head(&port->open_wait);
- init_waitqueue_head(&port->close_wait);
- mutex_init(&port->mutex);
- port->close_delay = (50 * HZ) / 100;
- port->closing_wait = (3000 * HZ) / 100;
-}
-EXPORT_SYMBOL(tty_port_init);
-
-int tty_port_alloc_xmit_buf(struct tty_port *port)
-{
- /* We may sleep in get_zeroed_page() */
- mutex_lock(&port->mutex);
- if (port->xmit_buf == NULL)
- port->xmit_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL);
- mutex_unlock(&port->mutex);
- if (port->xmit_buf == NULL)
- return -ENOMEM;
- return 0;
-}
-EXPORT_SYMBOL(tty_port_alloc_xmit_buf);
-
-void tty_port_free_xmit_buf(struct tty_port *port)
-{
- mutex_lock(&port->mutex);
- if (port->xmit_buf != NULL) {
- free_page((unsigned long)port->xmit_buf);
- port->xmit_buf = NULL;
- }
- mutex_unlock(&port->mutex);
-}
-EXPORT_SYMBOL(tty_port_free_xmit_buf);
-
-
static char ptychar[] = "pqrstuvwxyzabcde";
/**
* init_dev - initialise a tty device
* @driver: tty driver we are opening a device on
* @idx: device index
- * @tty: returned tty structure
+ * @ret_tty: returned tty structure
+ * @first_ok: ok to open a new device (used by ptmx)
*
* Prepare a tty device. This may not be a "new" clean device but
* could also be an active device. The pty drivers require special
*/
static int init_dev(struct tty_driver *driver, int idx,
- struct tty_struct **ret_tty)
+ struct tty_struct **ret_tty, int first_ok)
{
struct tty_struct *tty, *o_tty;
struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc;
}
if (tty) goto fast_track;
+ if (driver->subtype == PTY_TYPE_MASTER &&
+ (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) {
+ retval = -EIO;
+ goto end_init;
+ }
/*
* First time open is complex, especially for PTY devices.
* This code guarantees that either everything succeeds and the
o_tty = alloc_tty_struct();
if (!o_tty)
goto free_mem_out;
+ if (!try_module_get(driver->other->owner)) {
+ /* This cannot in fact currently happen */
+ free_tty_struct(o_tty);
+ o_tty = NULL;
+ goto free_mem_out;
+ }
initialize_tty_struct(o_tty);
o_tty->driver = driver->other;
o_tty->ops = driver->ops;
if (retval)
goto release_mem_out;
- goto success;
+ goto success;
/*
* This fast open can be used if the tty is already open.
/* Release locally allocated memory ... nothing placed in slots */
free_mem_out:
kfree(o_tp);
- if (o_tty)
+ if (o_tty) {
+ module_put(o_tty->driver->owner);
free_tty_struct(o_tty);
+ }
kfree(ltp);
kfree(tp);
free_tty_struct(tty);
goto end_init;
}
+void tty_free_termios(struct tty_struct *tty)
+{
+ struct ktermios *tp;
+ int idx = tty->index;
+ /* Kill this flag and push into drivers for locking etc */
+ if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
+ /* FIXME: Locking on ->termios array */
+ tp = tty->termios;
+ tty->driver->termios[idx] = NULL;
+ kfree(tp);
+
+ tp = tty->termios_locked;
+ tty->driver->termios_locked[idx] = NULL;
+ kfree(tp);
+ }
+}
+EXPORT_SYMBOL(tty_free_termios);
+
+void tty_shutdown(struct tty_struct *tty)
+{
+ tty->driver->ttys[tty->index] = NULL;
+ tty_free_termios(tty);
+}
+EXPORT_SYMBOL(tty_shutdown);
+
/**
* release_one_tty - release tty structure memory
+ * @kref: kref of tty we are obliterating
*
* Releases memory associated with a tty structure, and clears out the
* driver table slots. This function is called when a device is no longer
* tty_mutex - sometimes only
* takes the file list lock internally when working on the list
* of ttys that the driver keeps.
- * FIXME: should we require tty_mutex is held here ??
*/
-static void release_one_tty(struct tty_struct *tty, int idx)
+static void release_one_tty(struct kref *kref)
{
- int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM;
- struct ktermios *tp;
-
- if (!devpts)
- tty->driver->ttys[idx] = NULL;
-
- if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) {
- tp = tty->termios;
- if (!devpts)
- tty->driver->termios[idx] = NULL;
- kfree(tp);
-
- tp = tty->termios_locked;
- if (!devpts)
- tty->driver->termios_locked[idx] = NULL;
- kfree(tp);
- }
-
+ struct tty_struct *tty = container_of(kref, struct tty_struct, kref);
+ struct tty_driver *driver = tty->driver;
+ if (tty->ops->shutdown)
+ tty->ops->shutdown(tty);
+ else
+ tty_shutdown(tty);
tty->magic = 0;
+ /* FIXME: locking on tty->driver->refcount */
tty->driver->refcount--;
+ module_put(driver->owner);
file_list_lock();
list_del_init(&tty->tty_files);
free_tty_struct(tty);
}
+/**
+ * tty_kref_put - release a tty kref
+ * @tty: tty device
+ *
+ * Release a reference to a tty device and if need be let the kref
+ * layer destruct the object for us
+ */
+
+void tty_kref_put(struct tty_struct *tty)
+{
+ if (tty)
+ kref_put(&tty->kref, release_one_tty);
+}
+EXPORT_SYMBOL(tty_kref_put);
+
/**
* release_tty - release tty structure memory
*
* takes the file list lock internally when working on the list
* of ttys that the driver keeps.
* FIXME: should we require tty_mutex is held here ??
+ *
*/
static void release_tty(struct tty_struct *tty, int idx)
{
- struct tty_driver *driver = tty->driver;
+ /* This should always be true but check for the moment */
+ WARN_ON(tty->index != idx);
if (tty->link)
- release_one_tty(tty->link, idx);
- release_one_tty(tty, idx);
- module_put(driver->owner);
+ tty_kref_put(tty->link);
+ tty_kref_put(tty);
}
/*
}
/**
- * tty_open - open a tty device
+ * __tty_open - open a tty device
* @inode: inode of device file
* @filp: file pointer to tty
*
index = tty->index;
filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */
/* noctty = 1; */
+ /* FIXME: Should we take a driver reference ? */
+ tty_kref_put(tty);
goto got_driver;
}
#ifdef CONFIG_VT
return -ENODEV;
}
got_driver:
- retval = init_dev(driver, index, &tty);
+ retval = init_dev(driver, index, &tty, 0);
mutex_unlock(&tty_mutex);
if (retval)
return retval;
return index;
mutex_lock(&tty_mutex);
- retval = init_dev(ptm_driver, index, &tty);
+ retval = init_dev(ptm_driver, index, &tty, 1);
mutex_unlock(&tty_mutex);
if (retval)
/* For a PTY we need to lock the tty side */
mutex_lock(&real_tty->termios_mutex);
- if (!memcmp(ws, &tty->winsize, sizeof(*ws)))
+ if (!memcmp(ws, &real_tty->winsize, sizeof(*ws)))
goto done;
/* Get the PID values and reference them so we can
avoid holding the tty ctrl lock while sending signals */
case TIOCSTI:
return tiocsti(tty, p);
case TIOCGWINSZ:
- return tiocgwinsz(tty, p);
+ return tiocgwinsz(real_tty, p);
case TIOCSWINSZ:
return tiocswinsz(tty, real_tty, p);
case TIOCCONS:
return put_user(tty->ldisc.ops->num, (int __user *)p);
case TIOCSETD:
return tiocsetd(tty, p);
-#ifdef CONFIG_VT
- case TIOCLINUX:
- return tioclinux(tty, arg);
-#endif
/*
* Break handling
*/
EXPORT_SYMBOL(do_SAK);
-/**
- * flush_to_ldisc
- * @work: tty structure passed from work queue.
- *
- * This routine is called out of the software interrupt to flush data
- * from the buffer chain to the line discipline.
- *
- * Locking: holds tty->buf.lock to guard buffer list. Drops the lock
- * while invoking the line discipline receive_buf method. The
- * receive_buf method is single threaded for each tty instance.
- */
-
-static void flush_to_ldisc(struct work_struct *work)
-{
- struct tty_struct *tty =
- container_of(work, struct tty_struct, buf.work.work);
- unsigned long flags;
- struct tty_ldisc *disc;
- struct tty_buffer *tbuf, *head;
- char *char_buf;
- unsigned char *flag_buf;
-
- disc = tty_ldisc_ref(tty);
- if (disc == NULL) /* !TTY_LDISC */
- return;
-
- spin_lock_irqsave(&tty->buf.lock, flags);
- /* So we know a flush is running */
- set_bit(TTY_FLUSHING, &tty->flags);
- head = tty->buf.head;
- if (head != NULL) {
- tty->buf.head = NULL;
- for (;;) {
- int count = head->commit - head->read;
- if (!count) {
- if (head->next == NULL)
- break;
- tbuf = head;
- head = head->next;
- tty_buffer_free(tty, tbuf);
- continue;
- }
- /* Ldisc or user is trying to flush the buffers
- we are feeding to the ldisc, stop feeding the
- line discipline as we want to empty the queue */
- if (test_bit(TTY_FLUSHPENDING, &tty->flags))
- break;
- if (!tty->receive_room) {
- schedule_delayed_work(&tty->buf.work, 1);
- break;
- }
- if (count > tty->receive_room)
- count = tty->receive_room;
- char_buf = head->char_buf_ptr + head->read;
- flag_buf = head->flag_buf_ptr + head->read;
- head->read += count;
- spin_unlock_irqrestore(&tty->buf.lock, flags);
- disc->ops->receive_buf(tty, char_buf,
- flag_buf, count);
- spin_lock_irqsave(&tty->buf.lock, flags);
- }
- /* Restore the queue head */
- tty->buf.head = head;
- }
- /* We may have a deferred request to flush the input buffer,
- if so pull the chain under the lock and empty the queue */
- if (test_bit(TTY_FLUSHPENDING, &tty->flags)) {
- __tty_buffer_flush(tty);
- clear_bit(TTY_FLUSHPENDING, &tty->flags);
- wake_up(&tty->read_wait);
- }
- clear_bit(TTY_FLUSHING, &tty->flags);
- spin_unlock_irqrestore(&tty->buf.lock, flags);
-
- tty_ldisc_deref(disc);
-}
-
-/**
- * tty_flip_buffer_push - terminal
- * @tty: tty to push
- *
- * Queue a push of the terminal flip buffers to the line discipline. This
- * function must not be called from IRQ context if tty->low_latency is set.
- *
- * In the event of the queue being busy for flipping the work will be
- * held off and retried later.
- *
- * Locking: tty buffer lock. Driver locks in low latency mode.
- */
-
-void tty_flip_buffer_push(struct tty_struct *tty)
-{
- unsigned long flags;
- spin_lock_irqsave(&tty->buf.lock, flags);
- if (tty->buf.tail != NULL)
- tty->buf.tail->commit = tty->buf.tail->used;
- spin_unlock_irqrestore(&tty->buf.lock, flags);
-
- if (tty->low_latency)
- flush_to_ldisc(&tty->buf.work.work);
- else
- schedule_delayed_work(&tty->buf.work, 1);
-}
-
-EXPORT_SYMBOL(tty_flip_buffer_push);
-
-
/**
* initialize_tty_struct
* @tty: tty to initialize
static void initialize_tty_struct(struct tty_struct *tty)
{
memset(tty, 0, sizeof(struct tty_struct));
+ kref_init(&tty->kref);
tty->magic = TTY_MAGIC;
tty_ldisc_init(tty);
tty->session = NULL;
tty->overrun_time = jiffies;
tty->buf.head = tty->buf.tail = NULL;
tty_buffer_init(tty);
- INIT_DELAYED_WORK(&tty->buf.work, flush_to_ldisc);
mutex_init(&tty->termios_mutex);
init_waitqueue_head(&tty->write_wait);
init_waitqueue_head(&tty->read_wait);
void proc_clear_tty(struct task_struct *p)
{
+ struct tty_struct *tty;
spin_lock_irq(&p->sighand->siglock);
+ tty = p->signal->tty;
p->signal->tty = NULL;
spin_unlock_irq(&p->sighand->siglock);
+ tty_kref_put(tty);
}
/* Called under the sighand lock */
tty->pgrp = get_pid(task_pgrp(tsk));
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
tty->session = get_pid(task_session(tsk));
+ if (tsk->signal->tty) {
+ printk(KERN_DEBUG "tty not NULL!!\n");
+ tty_kref_put(tsk->signal->tty);
+ }
}
put_pid(tsk->signal->tty_old_pgrp);
- tsk->signal->tty = tty;
+ tsk->signal->tty = tty_kref_get(tty);
tsk->signal->tty_old_pgrp = NULL;
}
struct tty_struct *get_current_tty(void)
{
struct tty_struct *tty;
- WARN_ON_ONCE(!mutex_is_locked(&tty_mutex));
- tty = current->signal->tty;
- /*
- * session->tty can be changed/cleared from under us, make sure we
- * issue the load. The obtained pointer, when not NULL, is valid as
- * long as we hold tty_mutex.
- */
- barrier();
+ unsigned long flags;
+
+ spin_lock_irqsave(¤t->sighand->siglock, flags);
+ tty = tty_kref_get(current->signal->tty);
+ spin_unlock_irqrestore(¤t->sighand->siglock, flags);
return tty;
}
EXPORT_SYMBOL_GPL(get_current_tty);
projects / linux-2.6-omap-h63xx.git / blobdiff