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linux-next/include/linux/tty_flip.h
Peter Hurley acc0f67f30 tty: Halve flip buffer GFP_ATOMIC memory consumption
tty flip buffers use GFP_ATOMIC allocations for received data
which is to be processed by the line discipline. For each byte
received, an extra byte is used to indicate the error status of
that byte.

Instead, if the received data is error-free, encode the entire
buffer without status bytes.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-09 11:09:24 -08:00

42 lines
1.4 KiB
C

#ifndef _LINUX_TTY_FLIP_H
#define _LINUX_TTY_FLIP_H
extern int tty_buffer_set_limit(struct tty_port *port, int limit);
extern int tty_buffer_space_avail(struct tty_port *port);
extern int tty_buffer_request_room(struct tty_port *port, size_t size);
extern int tty_insert_flip_string_flags(struct tty_port *port,
const unsigned char *chars, const char *flags, size_t size);
extern int tty_insert_flip_string_fixed_flag(struct tty_port *port,
const unsigned char *chars, char flag, size_t size);
extern int tty_prepare_flip_string(struct tty_port *port,
unsigned char **chars, size_t size);
extern void tty_flip_buffer_push(struct tty_port *port);
void tty_schedule_flip(struct tty_port *port);
static inline int tty_insert_flip_char(struct tty_port *port,
unsigned char ch, char flag)
{
struct tty_buffer *tb = port->buf.tail;
int change;
change = (tb->flags & TTYB_NORMAL) && (flag != TTY_NORMAL);
if (!change && tb->used < tb->size) {
if (~tb->flags & TTYB_NORMAL)
*flag_buf_ptr(tb, tb->used) = flag;
*char_buf_ptr(tb, tb->used++) = ch;
return 1;
}
return tty_insert_flip_string_flags(port, &ch, &flag, 1);
}
static inline int tty_insert_flip_string(struct tty_port *port,
const unsigned char *chars, size_t size)
{
return tty_insert_flip_string_fixed_flag(port, chars, TTY_NORMAL, size);
}
extern void tty_buffer_lock_exclusive(struct tty_port *port);
extern void tty_buffer_unlock_exclusive(struct tty_port *port);
#endif /* _LINUX_TTY_FLIP_H */