mirror of
https://github.com/torvalds/linux
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d8c215adbf
If two processes are opening the same line, the second to get into line_open() will decide that it doesn't need to do anything (correctly) or wait for anything. The latter, unfortunately, is incorrect - the first opener might not be through yet. We need to have exclusion covering the entire line_init(), including the blocking parts. Moreover, the next patch will need to widen the exclusion on mconsole side of things, also including the blocking bits, so let's just convert that sucker to mutex... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
98 lines
3 KiB
C
98 lines
3 KiB
C
/*
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* Copyright (C) 2001, 2002 Jeff Dike (jdike@karaya.com)
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* Licensed under the GPL
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*/
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#ifndef __LINE_H__
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#define __LINE_H__
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#include "linux/list.h"
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#include "linux/workqueue.h"
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#include "linux/tty.h"
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#include "linux/interrupt.h"
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#include "linux/spinlock.h"
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#include "linux/mutex.h"
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#include "chan_user.h"
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#include "mconsole_kern.h"
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/* There's only one modifiable field in this - .mc.list */
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struct line_driver {
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const char *name;
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const char *device_name;
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const short major;
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const short minor_start;
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const short type;
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const short subtype;
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const int read_irq;
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const char *read_irq_name;
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const int write_irq;
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const char *write_irq_name;
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struct mc_device mc;
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};
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struct line {
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struct tty_struct *tty;
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struct mutex count_lock;
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unsigned long count;
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int valid;
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char *init_str;
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struct list_head chan_list;
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/*This lock is actually, mostly, local to*/
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spinlock_t lock;
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int throttled;
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/* Yes, this is a real circular buffer.
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* XXX: And this should become a struct kfifo!
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*
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* buffer points to a buffer allocated on demand, of length
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* LINE_BUFSIZE, head to the start of the ring, tail to the end.*/
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char *buffer;
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char *head;
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char *tail;
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int sigio;
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struct delayed_work task;
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const struct line_driver *driver;
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int have_irq;
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};
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extern void line_close(struct tty_struct *tty, struct file * filp);
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extern int line_open(struct line *lines, struct tty_struct *tty);
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extern int line_setup(char **conf, unsigned nlines, char **def,
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char *init, char *name);
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extern int line_write(struct tty_struct *tty, const unsigned char *buf,
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int len);
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extern int line_put_char(struct tty_struct *tty, unsigned char ch);
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extern void line_set_termios(struct tty_struct *tty, struct ktermios * old);
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extern int line_chars_in_buffer(struct tty_struct *tty);
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extern void line_flush_buffer(struct tty_struct *tty);
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extern void line_flush_chars(struct tty_struct *tty);
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extern int line_write_room(struct tty_struct *tty);
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extern int line_ioctl(struct tty_struct *tty, unsigned int cmd,
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unsigned long arg);
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extern void line_throttle(struct tty_struct *tty);
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extern void line_unthrottle(struct tty_struct *tty);
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extern char *add_xterm_umid(char *base);
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extern int line_setup_irq(int fd, int input, int output, struct line *line,
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void *data);
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extern void line_close_chan(struct line *line);
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extern struct tty_driver *register_lines(struct line_driver *line_driver,
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const struct tty_operations *driver,
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struct line *lines, int nlines);
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extern void lines_init(struct line *lines, int nlines, struct chan_opts *opts);
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extern void close_lines(struct line *lines, int nlines);
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extern int line_config(struct line *lines, unsigned int sizeof_lines,
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char *str, const struct chan_opts *opts,
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char **error_out);
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extern int line_id(char **str, int *start_out, int *end_out);
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extern int line_remove(struct line *lines, unsigned int sizeof_lines, int n,
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char **error_out);
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extern int line_get_config(char *dev, struct line *lines,
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unsigned int sizeof_lines, char *str,
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int size, char **error_out);
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#endif
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