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TTY: move ldisc data from tty_struct: locks 

atomic_write_lock is not n_tty specific, so move it up in the
tty_struct.

And since these are the last ones to move, remove also the comment
saying there are some ldisc' members. There are none now.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiri Slaby 2012-10-18 22:26:42 +02:00 committed by Greg Kroah-Hartman
parent ba2e68ac61
commit bddc7152f6
3 changed files with 73 additions and 65 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

123
drivers/tty/n_tty.c
View File

@ -96,6 +96,11 @@ struct n_tty_data {
int canon_data;
unsigned long canon_head;
unsigned int canon_column;
struct mutex atomic_read_lock;
struct mutex output_lock;
struct mutex echo_lock;
spinlock_t read_lock;
};
static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
@ -171,14 +176,15 @@ static void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty)
static void put_tty_queue(unsigned char c, struct tty_struct *tty)
{
struct n_tty_data *ldata = tty->disc_data;
unsigned long flags;
/*
* The problem of stomping on the buffers ends here.
* Why didn't anyone see this one coming? --AJK
*/
spin_lock_irqsave(&tty->read_lock, flags);
spin_lock_irqsave(&ldata->read_lock, flags);
put_tty_queue_nolock(c, tty);
spin_unlock_irqrestore(&tty->read_lock, flags);
spin_unlock_irqrestore(&ldata->read_lock, flags);
}
/**
@ -212,13 +218,13 @@ static void reset_buffer_flags(struct tty_struct *tty)
struct n_tty_data *ldata = tty->disc_data;
unsigned long flags;
spin_lock_irqsave(&tty->read_lock, flags);
spin_lock_irqsave(&ldata->read_lock, flags);
ldata->read_head = ldata->read_tail = ldata->read_cnt = 0;
spin_unlock_irqrestore(&tty->read_lock, flags);
spin_unlock_irqrestore(&ldata->read_lock, flags);
mutex_lock(&tty->echo_lock);
mutex_lock(&ldata->echo_lock);
ldata->echo_pos = ldata->echo_cnt = ldata->echo_overrun = 0;
mutex_unlock(&tty->echo_lock);
mutex_unlock(&ldata->echo_lock);
ldata->canon_head = ldata->canon_data = ldata->erasing = 0;
bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
@ -270,7 +276,7 @@ static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
unsigned long flags;
ssize_t n = 0;
spin_lock_irqsave(&tty->read_lock, flags);
spin_lock_irqsave(&ldata->read_lock, flags);
if (!ldata->icanon) {
n = ldata->read_cnt;
} else if (ldata->canon_data) {
@ -278,7 +284,7 @@ static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
ldata->canon_head - ldata->read_tail :
ldata->canon_head + (N_TTY_BUF_SIZE - ldata->read_tail);
}
spin_unlock_irqrestore(&tty->read_lock, flags);
spin_unlock_irqrestore(&ldata->read_lock, flags);
return n;
}
@ -408,14 +414,15 @@ static int do_output_char(unsigned char c, struct tty_struct *tty, int space)
static int process_output(unsigned char c, struct tty_struct *tty)
{
struct n_tty_data *ldata = tty->disc_data;
int space, retval;
mutex_lock(&tty->output_lock);
mutex_lock(&ldata->output_lock);
space = tty_write_room(tty);
retval = do_output_char(c, tty, space);
mutex_unlock(&tty->output_lock);
mutex_unlock(&ldata->output_lock);
if (retval < 0)
return -1;
else
@ -449,11 +456,11 @@ static ssize_t process_output_block(struct tty_struct *tty,
int i;
const unsigned char *cp;
mutex_lock(&tty->output_lock);
mutex_lock(&ldata->output_lock);
space = tty_write_room(tty);
if (!space) {
mutex_unlock(&tty->output_lock);
mutex_unlock(&ldata->output_lock);
return 0;
}
if (nr > space)
@ -496,7 +503,7 @@ static ssize_t process_output_block(struct tty_struct *tty,
break_out:
i = tty->ops->write(tty, buf, i);
mutex_unlock(&tty->output_lock);
mutex_unlock(&ldata->output_lock);
return i;
}
@ -536,8 +543,8 @@ static void process_echoes(struct tty_struct *tty)
if (!ldata->echo_cnt)
return;
mutex_lock(&tty->output_lock);
mutex_lock(&tty->echo_lock);
mutex_lock(&ldata->output_lock);
mutex_lock(&ldata->echo_lock);
space = tty_write_room(tty);
@ -682,8 +689,8 @@ static void process_echoes(struct tty_struct *tty)
ldata->echo_overrun = 0;
}
mutex_unlock(&tty->echo_lock);
mutex_unlock(&tty->output_lock);
mutex_unlock(&ldata->echo_lock);
mutex_unlock(&ldata->output_lock);
if (tty->ops->flush_chars)
tty->ops->flush_chars(tty);
@ -748,12 +755,14 @@ static void add_echo_byte(unsigned char c, struct tty_struct *tty)
static void echo_move_back_col(struct tty_struct *tty)
{
mutex_lock(&tty->echo_lock);
struct n_tty_data *ldata = tty->disc_data;
mutex_lock(&ldata->echo_lock);
add_echo_byte(ECHO_OP_START, tty);
add_echo_byte(ECHO_OP_MOVE_BACK_COL, tty);
mutex_unlock(&tty->echo_lock);
mutex_unlock(&ldata->echo_lock);
}
/**
@ -768,12 +777,14 @@ static void echo_move_back_col(struct tty_struct *tty)
static void echo_set_canon_col(struct tty_struct *tty)
{
mutex_lock(&tty->echo_lock);
struct n_tty_data *ldata = tty->disc_data;
mutex_lock(&ldata->echo_lock);
add_echo_byte(ECHO_OP_START, tty);
add_echo_byte(ECHO_OP_SET_CANON_COL, tty);
mutex_unlock(&tty->echo_lock);
mutex_unlock(&ldata->echo_lock);
}
/**
@ -796,7 +807,9 @@ static void echo_set_canon_col(struct tty_struct *tty)
static void echo_erase_tab(unsigned int num_chars, int after_tab,
struct tty_struct *tty)
{
mutex_lock(&tty->echo_lock);
struct n_tty_data *ldata = tty->disc_data;
mutex_lock(&ldata->echo_lock);
add_echo_byte(ECHO_OP_START, tty);
add_echo_byte(ECHO_OP_ERASE_TAB, tty);
@ -810,7 +823,7 @@ static void echo_erase_tab(unsigned int num_chars, int after_tab,
add_echo_byte(num_chars, tty);
mutex_unlock(&tty->echo_lock);
mutex_unlock(&ldata->echo_lock);
}
/**
@ -828,7 +841,9 @@ static void echo_erase_tab(unsigned int num_chars, int after_tab,
static void echo_char_raw(unsigned char c, struct tty_struct *tty)
{
mutex_lock(&tty->echo_lock);
struct n_tty_data *ldata = tty->disc_data;
mutex_lock(&ldata->echo_lock);
if (c == ECHO_OP_START) {
add_echo_byte(ECHO_OP_START, tty);
@ -837,7 +852,7 @@ static void echo_char_raw(unsigned char c, struct tty_struct *tty)
add_echo_byte(c, tty);
}
mutex_unlock(&tty->echo_lock);
mutex_unlock(&ldata->echo_lock);
}
/**
@ -856,7 +871,9 @@ static void echo_char_raw(unsigned char c, struct tty_struct *tty)
static void echo_char(unsigned char c, struct tty_struct *tty)
{
mutex_lock(&tty->echo_lock);
struct n_tty_data *ldata = tty->disc_data;
mutex_lock(&ldata->echo_lock);
if (c == ECHO_OP_START) {
add_echo_byte(ECHO_OP_START, tty);
@ -867,7 +884,7 @@ static void echo_char(unsigned char c, struct tty_struct *tty)
add_echo_byte(c, tty);
}
mutex_unlock(&tty->echo_lock);
mutex_unlock(&ldata->echo_lock);
}
/**
@ -914,19 +931,19 @@ static void eraser(unsigned char c, struct tty_struct *tty)
kill_type = WERASE;
else {
if (!L_ECHO(tty)) {
spin_lock_irqsave(&tty->read_lock, flags);
spin_lock_irqsave(&ldata->read_lock, flags);
ldata->read_cnt -= ((ldata->read_head - ldata->canon_head) &
(N_TTY_BUF_SIZE - 1));
ldata->read_head = ldata->canon_head;
spin_unlock_irqrestore(&tty->read_lock, flags);
spin_unlock_irqrestore(&ldata->read_lock, flags);
return;
}
if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) {
spin_lock_irqsave(&tty->read_lock, flags);
spin_lock_irqsave(&ldata->read_lock, flags);
ldata->read_cnt -= ((ldata->read_head - ldata->canon_head) &
(N_TTY_BUF_SIZE - 1));
ldata->read_head = ldata->canon_head;
spin_unlock_irqrestore(&tty->read_lock, flags);
spin_unlock_irqrestore(&ldata->read_lock, flags);
finish_erasing(tty);
echo_char(KILL_CHAR(tty), tty);
/* Add a newline if ECHOK is on and ECHOKE is off. */
@ -960,10 +977,10 @@ static void eraser(unsigned char c, struct tty_struct *tty)
break;
}
cnt = (ldata->read_head - head) & (N_TTY_BUF_SIZE-1);
spin_lock_irqsave(&tty->read_lock, flags);
spin_lock_irqsave(&ldata->read_lock, flags);
ldata->read_head = head;
ldata->read_cnt -= cnt;
spin_unlock_irqrestore(&tty->read_lock, flags);
spin_unlock_irqrestore(&ldata->read_lock, flags);
if (L_ECHO(tty)) {
if (L_ECHOPRT(tty)) {
if (!ldata->erasing) {
@ -1338,12 +1355,12 @@ static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
put_tty_queue(c, tty);
handle_newline:
spin_lock_irqsave(&tty->read_lock, flags);
spin_lock_irqsave(&ldata->read_lock, flags);
set_bit(ldata->read_head, ldata->read_flags);
put_tty_queue_nolock(c, tty);
ldata->canon_head = ldata->read_head;
ldata->canon_data++;
spin_unlock_irqrestore(&tty->read_lock, flags);
spin_unlock_irqrestore(&ldata->read_lock, flags);
kill_fasync(&tty->fasync, SIGIO, POLL_IN);
if (waitqueue_active(&tty->read_wait))
wake_up_interruptible(&tty->read_wait);
@ -1417,7 +1434,7 @@ static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
unsigned long cpuflags;
if (ldata->real_raw) {
spin_lock_irqsave(&tty->read_lock, cpuflags);
spin_lock_irqsave(&ldata->read_lock, cpuflags);
i = min(N_TTY_BUF_SIZE - ldata->read_cnt,
N_TTY_BUF_SIZE - ldata->read_head);
i = min(count, i);
@ -1433,7 +1450,7 @@ static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
memcpy(ldata->read_buf + ldata->read_head, cp, i);
ldata->read_head = (ldata->read_head + i) & (N_TTY_BUF_SIZE-1);
ldata->read_cnt += i;
spin_unlock_irqrestore(&tty->read_lock, cpuflags);
spin_unlock_irqrestore(&ldata->read_lock, cpuflags);
} else {
for (i = count, p = cp, f = fp; i; i--, p++) {
if (f)
@ -1626,6 +1643,10 @@ static int n_tty_open(struct tty_struct *tty)
goto err;
ldata->overrun_time = jiffies;
mutex_init(&ldata->atomic_read_lock);
mutex_init(&ldata->output_lock);
mutex_init(&ldata->echo_lock);
spin_lock_init(&ldata->read_lock);
/* These are ugly. Currently a malloc failure here can panic */
ldata->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
@ -1677,7 +1698,7 @@ static inline int input_available_p(struct tty_struct *tty, int amt)
* buffer, and once to drain the space from the (physical) beginning of
* the buffer to head pointer.
*
* Called under the tty->atomic_read_lock sem
* Called under the ldata->atomic_read_lock sem
*
*/
@ -1693,10 +1714,10 @@ static int copy_from_read_buf(struct tty_struct *tty,
bool is_eof;
retval = 0;
spin_lock_irqsave(&tty->read_lock, flags);
spin_lock_irqsave(&ldata->read_lock, flags);
n = min(ldata->read_cnt, N_TTY_BUF_SIZE - ldata->read_tail);
n = min(*nr, n);
spin_unlock_irqrestore(&tty->read_lock, flags);
spin_unlock_irqrestore(&ldata->read_lock, flags);
if (n) {
retval = copy_to_user(*b, &ldata->read_buf[ldata->read_tail], n);
n -= retval;
@ -1704,13 +1725,13 @@ static int copy_from_read_buf(struct tty_struct *tty,
ldata->read_buf[ldata->read_tail] == EOF_CHAR(tty);
tty_audit_add_data(tty, &ldata->read_buf[ldata->read_tail], n,
ldata->icanon);
spin_lock_irqsave(&tty->read_lock, flags);
spin_lock_irqsave(&ldata->read_lock, flags);
ldata->read_tail = (ldata->read_tail + n) & (N_TTY_BUF_SIZE-1);
ldata->read_cnt -= n;
/* Turn single EOF into zero-length read */
if (L_EXTPROC(tty) && ldata->icanon && is_eof && !ldata->read_cnt)
n = 0;
spin_unlock_irqrestore(&tty->read_lock, flags);
spin_unlock_irqrestore(&ldata->read_lock, flags);
*b += n;
*nr -= n;
}
@ -1818,10 +1839,10 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
* Internal serialization of reads.
*/
if (file->f_flags & O_NONBLOCK) {
if (!mutex_trylock(&tty->atomic_read_lock))
if (!mutex_trylock(&ldata->atomic_read_lock))
return -EAGAIN;
} else {
if (mutex_lock_interruptible(&tty->atomic_read_lock))
if (mutex_lock_interruptible(&ldata->atomic_read_lock))
return -ERESTARTSYS;
}
packet = tty->packet;
@ -1890,7 +1911,7 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
if (ldata->icanon && !L_EXTPROC(tty)) {
/* N.B. avoid overrun if nr == 0 */
spin_lock_irqsave(&tty->read_lock, flags);
spin_lock_irqsave(&ldata->read_lock, flags);
while (nr && ldata->read_cnt) {
int eol;
@ -1908,25 +1929,25 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
if (--ldata->canon_data < 0)
ldata->canon_data = 0;
}
spin_unlock_irqrestore(&tty->read_lock, flags);
spin_unlock_irqrestore(&ldata->read_lock, flags);
if (!eol || (c != __DISABLED_CHAR)) {
if (tty_put_user(tty, c, b++)) {
retval = -EFAULT;
b--;
spin_lock_irqsave(&tty->read_lock, flags);
spin_lock_irqsave(&ldata->read_lock, flags);
break;
}
nr--;
}
if (eol) {
tty_audit_push(tty);
spin_lock_irqsave(&tty->read_lock, flags);
spin_lock_irqsave(&ldata->read_lock, flags);
break;
}
spin_lock_irqsave(&tty->read_lock, flags);
spin_lock_irqsave(&ldata->read_lock, flags);
}
spin_unlock_irqrestore(&tty->read_lock, flags);
spin_unlock_irqrestore(&ldata->read_lock, flags);
if (retval)
break;
} else {
@ -1958,7 +1979,7 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
if (time)
timeout = time;
}
mutex_unlock(&tty->atomic_read_lock);
mutex_unlock(&ldata->atomic_read_lock);
remove_wait_queue(&tty->read_wait, &wait);
if (!waitqueue_active(&tty->read_wait))

4
drivers/tty/tty_io.c
View File

@ -2939,11 +2939,7 @@ void initialize_tty_struct(struct tty_struct *tty,
init_waitqueue_head(&tty->write_wait);
init_waitqueue_head(&tty->read_wait);
INIT_WORK(&tty->hangup_work, do_tty_hangup);
mutex_init(&tty->atomic_read_lock);
mutex_init(&tty->atomic_write_lock);
mutex_init(&tty->output_lock);
mutex_init(&tty->echo_lock);
spin_lock_init(&tty->read_lock);
spin_lock_init(&tty->ctrl_lock);
INIT_LIST_HEAD(&tty->tty_files);
INIT_WORK(&tty->SAK_work, do_SAK_work);

11
include/linux/tty.h
View File

@ -235,6 +235,7 @@ struct tty_struct {
struct mutex ldisc_mutex;
struct tty_ldisc *ldisc;
struct mutex atomic_write_lock;
struct mutex legacy_mutex;
struct mutex termios_mutex;
spinlock_t ctrl_lock;
@ -265,20 +266,10 @@ struct tty_struct {
#define N_TTY_BUF_SIZE 4096
/*
* The following is data for the N_TTY line discipline. For
* historical reasons, this is included in the tty structure.
* Mostly locked by the BKL.
*/
unsigned char closing:1;
unsigned short minimum_to_wake;
struct mutex atomic_read_lock;
struct mutex atomic_write_lock;
struct mutex output_lock;
struct mutex echo_lock;
unsigned char *write_buf;
int write_cnt;
spinlock_t read_lock;
/* If the tty has a pending do_SAK, queue it here - akpm */
struct work_struct SAK_work;
struct tty_port *port;