![Peter Hurley](/assets/img/avatar_default.png)
Lockless flip buffers require atomically updating the bytes-in-use watermark. The pty driver also peeks at the watermark value to limit memory consumption to a much lower value than the default; query the watermark with new fn, tty_buffer_space_avail(). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
36 lines
1.3 KiB
C
36 lines
1.3 KiB
C
#ifndef _LINUX_TTY_FLIP_H
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#define _LINUX_TTY_FLIP_H
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extern int tty_buffer_space_avail(struct tty_port *port);
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extern int tty_buffer_request_room(struct tty_port *port, size_t size);
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extern int tty_insert_flip_string_flags(struct tty_port *port,
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const unsigned char *chars, const char *flags, size_t size);
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extern int tty_insert_flip_string_fixed_flag(struct tty_port *port,
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const unsigned char *chars, char flag, size_t size);
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extern int tty_prepare_flip_string(struct tty_port *port,
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unsigned char **chars, size_t size);
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extern int tty_prepare_flip_string_flags(struct tty_port *port,
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unsigned char **chars, char **flags, size_t size);
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extern void tty_flip_buffer_push(struct tty_port *port);
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void tty_schedule_flip(struct tty_port *port);
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static inline int tty_insert_flip_char(struct tty_port *port,
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unsigned char ch, char flag)
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{
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struct tty_buffer *tb = port->buf.tail;
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if (tb && tb->used < tb->size) {
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*flag_buf_ptr(tb, tb->used) = flag;
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*char_buf_ptr(tb, tb->used++) = ch;
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return 1;
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}
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return tty_insert_flip_string_flags(port, &ch, &flag, 1);
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}
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static inline int tty_insert_flip_string(struct tty_port *port,
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const unsigned char *chars, size_t size)
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{
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return tty_insert_flip_string_fixed_flag(port, chars, TTY_NORMAL, size);
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}
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#endif /* _LINUX_TTY_FLIP_H */
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