drivers/tty/vt/vt_ioctl.c

Source file repositories/reference/linux-study-clean/drivers/tty/vt/vt_ioctl.c

File Facts

System
Linux kernel
Corpus path
drivers/tty/vt/vt_ioctl.c
Extension
.c
Size
30518 bytes
Lines
1316
Domain
Driver Families
Bucket
drivers/tty
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct vt_event_wait {
	struct list_head list;
	struct vt_event event;
	int done;
};

static LIST_HEAD(vt_events);
static DEFINE_SPINLOCK(vt_event_lock);
static DECLARE_WAIT_QUEUE_HEAD(vt_event_waitqueue);

/**
 *	vt_event_post
 *	@event: the event that occurred
 *	@old: old console
 *	@new: new console
 *
 *	Post an VT event to interested VT handlers
 */

void vt_event_post(unsigned int event, unsigned int old, unsigned int new)
{
	struct list_head *pos, *head;
	unsigned long flags;
	int wake = 0;

	spin_lock_irqsave(&vt_event_lock, flags);
	head = &vt_events;

	list_for_each(pos, head) {
		struct vt_event_wait *ve = list_entry(pos,
						struct vt_event_wait, list);
		if (!(ve->event.event & event))
			continue;
		ve->event.event = event;
		/* kernel view is consoles 0..n-1, user space view is
		   console 1..n with 0 meaning current, so we must bias */
		ve->event.oldev = old + 1;
		ve->event.newev = new + 1;
		wake = 1;
		ve->done = 1;
	}
	spin_unlock_irqrestore(&vt_event_lock, flags);
	if (wake)
		wake_up_interruptible(&vt_event_waitqueue);
}

static void __vt_event_queue(struct vt_event_wait *vw)
{
	unsigned long flags;
	/* Prepare the event */
	INIT_LIST_HEAD(&vw->list);
	vw->done = 0;
	/* Queue our event */
	spin_lock_irqsave(&vt_event_lock, flags);
	list_add(&vw->list, &vt_events);
	spin_unlock_irqrestore(&vt_event_lock, flags);
}

static void __vt_event_wait(struct vt_event_wait *vw)
{
	/* Wait for it to pass */
	wait_event_interruptible(vt_event_waitqueue, vw->done);
}

static void __vt_event_dequeue(struct vt_event_wait *vw)
{
	unsigned long flags;

	/* Dequeue it */
	spin_lock_irqsave(&vt_event_lock, flags);
	list_del(&vw->list);
	spin_unlock_irqrestore(&vt_event_lock, flags);
}

/**
 *	vt_event_wait		-	wait for an event
 *	@vw: our event
 *
 *	Waits for an event to occur which completes our vt_event_wait
 *	structure. On return the structure has wv->done set to 1 for success
 *	or 0 if some event such as a signal ended the wait.
 */

static void vt_event_wait(struct vt_event_wait *vw)
{
	__vt_event_queue(vw);
	__vt_event_wait(vw);
	__vt_event_dequeue(vw);
}

Annotation

Implementation Notes