Cregit: Linux 6.13: tty

Contributors: 10
Author	Tokens	Token Proportion	Commits	Commit Proportion
Peter Hurley	60	30.93%	9	31.03%
Jiri Slaby	47	24.23%	1	3.45%
Linus Torvalds (pre-git)	30	15.46%	5	17.24%
Alan Cox	28	14.43%	3	10.34%
Jiri Slaby (SUSE)	18	9.28%	5	17.24%
Ilpo Järvinen	5	2.58%	2	6.90%
Ingo Molnar	3	1.55%	1	3.45%
Greg Kroah-Hartman	1	0.52%	1	3.45%
Paul Fulghum	1	0.52%	1	3.45%
Linus Torvalds	1	0.52%	1	3.45%
Total	194		29

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_TTY_BUFFER_H
#define _LINUX_TTY_BUFFER_H

#include <linux/atomic.h>
#include <linux/llist.h>
#include <linux/mutex.h>
#include <linux/workqueue.h>

struct tty_buffer {
	union {
		struct tty_buffer *next;
		struct llist_node free;
	};
	unsigned int used;
	unsigned int size;
	unsigned int commit;
	unsigned int lookahead;		/* Lazy update on recv, can become less than "read" */
	unsigned int read;
	bool flags;
	/* Data points here */
	u8 data[] __aligned(sizeof(unsigned long));
};

static inline u8 *char_buf_ptr(struct tty_buffer *b, unsigned int ofs)
{
	return b->data + ofs;
}

static inline u8 *flag_buf_ptr(struct tty_buffer *b, unsigned int ofs)
{
	return char_buf_ptr(b, ofs) + b->size;
}

struct tty_bufhead {
	struct tty_buffer *head;	/* Queue head */
	struct work_struct work;
	struct mutex	   lock;
	atomic_t	   priority;
	struct tty_buffer sentinel;
	struct llist_head free;		/* Free queue head */
	atomic_t	   mem_used;    /* In-use buffers excluding free list */
	int		   mem_limit;
	struct tty_buffer *tail;	/* Active buffer */
};

/*
 * When a break, frame error, or parity error happens, these codes are
 * stuffed into the flags buffer.
 */
#define TTY_NORMAL	0
#define TTY_BREAK	1
#define TTY_FRAME	2
#define TTY_PARITY	3
#define TTY_OVERRUN	4

#endif

tty_buffer.h