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n_tty: Move buffers into n_tty_data 

Reduce pointer reloading and improve locality-of-reference;
allocate read_buf and echo_buf within struct n_tty_data.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Hurley 2013-06-15 10:21:19 -04:00 committed by Greg Kroah-Hartman
parent 8cb06c9838
commit 20bafb3d23
1 changed files with 9 additions and 16 deletions
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25
drivers/tty/n_tty.c
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@ -105,9 +105,9 @@ struct n_tty_data {
unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1; unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1;
/* shared by producer and consumer */ /* shared by producer and consumer */
char *read_buf; char read_buf[N_TTY_BUF_SIZE];
DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE); DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE);
unsigned char *echo_buf; unsigned char echo_buf[N_TTY_BUF_SIZE];
int minimum_to_wake; int minimum_to_wake;
@ -1695,9 +1695,7 @@ static void n_tty_close(struct tty_struct *tty)
if (tty->link) if (tty->link)
n_tty_packet_mode_flush(tty); n_tty_packet_mode_flush(tty);
kfree(ldata->read_buf); vfree(ldata);
kfree(ldata->echo_buf);
kfree(ldata);
tty->disc_data = NULL; tty->disc_data = NULL;
} }
@ -1715,7 +1713,8 @@ static int n_tty_open(struct tty_struct *tty)
{ {
struct n_tty_data *ldata; struct n_tty_data *ldata;
ldata = kzalloc(sizeof(*ldata), GFP_KERNEL); /* Currently a malloc failure here can panic */
ldata = vmalloc(sizeof(*ldata));
if (!ldata) if (!ldata)
goto err; goto err;
@ -1723,16 +1722,14 @@ static int n_tty_open(struct tty_struct *tty)
mutex_init(&ldata->atomic_read_lock); mutex_init(&ldata->atomic_read_lock);
mutex_init(&ldata->output_lock); mutex_init(&ldata->output_lock);
/* These are ugly. Currently a malloc failure here can panic */
ldata->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
ldata->echo_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
if (!ldata->read_buf || !ldata->echo_buf)
goto err_free_bufs;
tty->disc_data = ldata; tty->disc_data = ldata;
reset_buffer_flags(tty->disc_data); reset_buffer_flags(tty->disc_data);
ldata->column = 0; ldata->column = 0;
ldata->canon_column = 0;
ldata->minimum_to_wake = 1; ldata->minimum_to_wake = 1;
ldata->num_overrun = 0;
ldata->no_room = 0;
ldata->lnext = 0;
tty->closing = 0; tty->closing = 0;
/* indicate buffer work may resume */ /* indicate buffer work may resume */
clear_bit(TTY_LDISC_HALTED, &tty->flags); clear_bit(TTY_LDISC_HALTED, &tty->flags);
@ -1740,10 +1737,6 @@ static int n_tty_open(struct tty_struct *tty)
tty_unthrottle(tty); tty_unthrottle(tty);
return 0; return 0;
err_free_bufs:
kfree(ldata->read_buf);
kfree(ldata->echo_buf);
kfree(ldata);
err: err:
return -ENOMEM; return -ENOMEM;
} }