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path: root/drivers/tty/n_tty.c
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-rw-r--r--drivers/tty/n_tty.c1739
1 files changed, 1030 insertions, 709 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 19083efa231..f44f1ba762c 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -49,6 +49,8 @@
#include <linux/file.h>
#include <linux/uaccess.h>
#include <linux/module.h>
+#include <linux/ratelimit.h>
+#include <linux/vmalloc.h>
/* number of characters left in xmit buffer before select has we have room */
@@ -73,36 +75,83 @@
#define ECHO_OP_SET_CANON_COL 0x81
#define ECHO_OP_ERASE_TAB 0x82
+#define ECHO_COMMIT_WATERMARK 256
+#define ECHO_BLOCK 256
+#define ECHO_DISCARD_WATERMARK N_TTY_BUF_SIZE - (ECHO_BLOCK + 32)
+
+
+#undef N_TTY_TRACE
+#ifdef N_TTY_TRACE
+# define n_tty_trace(f, args...) trace_printk(f, ##args)
+#else
+# define n_tty_trace(f, args...)
+#endif
+
struct n_tty_data {
- unsigned int column;
+ /* producer-published */
+ size_t read_head;
+ size_t canon_head;
+ size_t echo_head;
+ size_t echo_commit;
+ size_t echo_mark;
+ DECLARE_BITMAP(char_map, 256);
+
+ /* private to n_tty_receive_overrun (single-threaded) */
unsigned long overrun_time;
int num_overrun;
+ /* non-atomic */
+ bool no_room;
+
+ /* must hold exclusive termios_rwsem to reset these */
unsigned char lnext:1, erasing:1, raw:1, real_raw:1, icanon:1;
- unsigned char echo_overrun:1;
+ unsigned char push:1;
- DECLARE_BITMAP(process_char_map, 256);
+ /* shared by producer and consumer */
+ char read_buf[N_TTY_BUF_SIZE];
DECLARE_BITMAP(read_flags, N_TTY_BUF_SIZE);
+ unsigned char echo_buf[N_TTY_BUF_SIZE];
- char *read_buf;
- int read_head;
- int read_tail;
- int read_cnt;
+ int minimum_to_wake;
- unsigned char *echo_buf;
- unsigned int echo_pos;
- unsigned int echo_cnt;
+ /* consumer-published */
+ size_t read_tail;
+ size_t line_start;
- int canon_data;
- unsigned long canon_head;
+ /* protected by output lock */
+ unsigned int column;
unsigned int canon_column;
+ size_t echo_tail;
struct mutex atomic_read_lock;
struct mutex output_lock;
- struct mutex echo_lock;
- spinlock_t read_lock;
};
+static inline size_t read_cnt(struct n_tty_data *ldata)
+{
+ return ldata->read_head - ldata->read_tail;
+}
+
+static inline unsigned char read_buf(struct n_tty_data *ldata, size_t i)
+{
+ return ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)];
+}
+
+static inline unsigned char *read_buf_addr(struct n_tty_data *ldata, size_t i)
+{
+ return &ldata->read_buf[i & (N_TTY_BUF_SIZE - 1)];
+}
+
+static inline unsigned char echo_buf(struct n_tty_data *ldata, size_t i)
+{
+ return ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)];
+}
+
+static inline unsigned char *echo_buf_addr(struct n_tty_data *ldata, size_t i)
+{
+ return &ldata->echo_buf[i & (N_TTY_BUF_SIZE - 1)];
+}
+
static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
unsigned char __user *ptr)
{
@@ -112,30 +161,18 @@ static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
return put_user(x, ptr);
}
-/**
- * n_tty_set__room - receive space
- * @tty: terminal
- *
- * Called by the driver to find out how much data it is
- * permitted to feed to the line discipline without any being lost
- * and thus to manage flow control. Not serialized. Answers for the
- * "instant".
- */
-
-static void n_tty_set_room(struct tty_struct *tty)
+static int receive_room(struct tty_struct *tty)
{
struct n_tty_data *ldata = tty->disc_data;
int left;
- int old_left;
- /* ldata->read_cnt is not read locked ? */
if (I_PARMRK(tty)) {
/* Multiply read_cnt by 3, since each byte might take up to
* three times as many spaces when PARMRK is set (depending on
* its flags, e.g. parity error). */
- left = N_TTY_BUF_SIZE - ldata->read_cnt * 3 - 1;
+ left = N_TTY_BUF_SIZE - read_cnt(ldata) * 3 - 1;
} else
- left = N_TTY_BUF_SIZE - ldata->read_cnt - 1;
+ left = N_TTY_BUF_SIZE - read_cnt(ldata) - 1;
/*
* If we are doing input canonicalization, and there are no
@@ -144,120 +181,208 @@ static void n_tty_set_room(struct tty_struct *tty)
* characters will be beeped.
*/
if (left <= 0)
- left = ldata->icanon && !ldata->canon_data;
- old_left = tty->receive_room;
- tty->receive_room = left;
+ left = ldata->icanon && ldata->canon_head == ldata->read_tail;
+
+ return left;
+}
+
+/**
+ * n_tty_set_room - receive space
+ * @tty: terminal
+ *
+ * Re-schedules the flip buffer work if space just became available.
+ *
+ * Caller holds exclusive termios_rwsem
+ * or
+ * n_tty_read()/consumer path:
+ * holds non-exclusive termios_rwsem
+ */
+
+static void n_tty_set_room(struct tty_struct *tty)
+{
+ struct n_tty_data *ldata = tty->disc_data;
/* Did this open up the receive buffer? We may need to flip */
- if (left && !old_left) {
+ if (unlikely(ldata->no_room) && receive_room(tty)) {
+ ldata->no_room = 0;
+
WARN_RATELIMIT(tty->port->itty == NULL,
"scheduling with invalid itty\n");
- schedule_work(&tty->port->buf.work);
+ /* see if ldisc has been killed - if so, this means that
+ * even though the ldisc has been halted and ->buf.work
+ * cancelled, ->buf.work is about to be rescheduled
+ */
+ WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags),
+ "scheduling buffer work for halted ldisc\n");
+ queue_work(system_unbound_wq, &tty->port->buf.work);
}
}
-static void put_tty_queue_nolock(unsigned char c, struct n_tty_data *ldata)
+static ssize_t chars_in_buffer(struct tty_struct *tty)
{
- if (ldata->read_cnt < N_TTY_BUF_SIZE) {
- ldata->read_buf[ldata->read_head] = c;
- ldata->read_head = (ldata->read_head + 1) & (N_TTY_BUF_SIZE-1);
- ldata->read_cnt++;
- }
+ struct n_tty_data *ldata = tty->disc_data;
+ ssize_t n = 0;
+
+ if (!ldata->icanon)
+ n = read_cnt(ldata);
+ else
+ n = ldata->canon_head - ldata->read_tail;
+ return n;
}
/**
- * put_tty_queue - add character to tty
- * @c: character
- * @ldata: n_tty data
+ * n_tty_write_wakeup - asynchronous I/O notifier
+ * @tty: tty device
*
- * Add a character to the tty read_buf queue. This is done under the
- * read_lock to serialize character addition and also to protect us
- * against parallel reads or flushes
+ * Required for the ptys, serial driver etc. since processes
+ * that attach themselves to the master and rely on ASYNC
+ * IO must be woken up
*/
-static void put_tty_queue(unsigned char c, struct n_tty_data *ldata)
+static void n_tty_write_wakeup(struct tty_struct *tty)
{
- unsigned long flags;
+ if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags))
+ kill_fasync(&tty->fasync, SIGIO, POLL_OUT);
+}
+
+static void n_tty_check_throttle(struct tty_struct *tty)
+{
+ if (tty->driver->type == TTY_DRIVER_TYPE_PTY)
+ return;
/*
- * The problem of stomping on the buffers ends here.
- * Why didn't anyone see this one coming? --AJK
- */
- spin_lock_irqsave(&ldata->read_lock, flags);
- put_tty_queue_nolock(c, ldata);
- spin_unlock_irqrestore(&ldata->read_lock, flags);
+ * Check the remaining room for the input canonicalization
+ * mode. We don't want to throttle the driver if we're in
+ * canonical mode and don't have a newline yet!
+ */
+ while (1) {
+ int throttled;
+ tty_set_flow_change(tty, TTY_THROTTLE_SAFE);
+ if (receive_room(tty) >= TTY_THRESHOLD_THROTTLE)
+ break;
+ throttled = tty_throttle_safe(tty);
+ if (!throttled)
+ break;
+ }
+ __tty_set_flow_change(tty, 0);
+}
+
+static void n_tty_check_unthrottle(struct tty_struct *tty)
+{
+ if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
+ tty->link->ldisc->ops->write_wakeup == n_tty_write_wakeup) {
+ if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE)
+ return;
+ if (!tty->count)
+ return;
+ n_tty_set_room(tty);
+ n_tty_write_wakeup(tty->link);
+ if (waitqueue_active(&tty->link->write_wait))
+ wake_up_interruptible_poll(&tty->link->write_wait, POLLOUT);
+ return;
+ }
+
+ /* If there is enough space in the read buffer now, let the
+ * low-level driver know. We use chars_in_buffer() to
+ * check the buffer, as it now knows about canonical mode.
+ * Otherwise, if the driver is throttled and the line is
+ * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode,
+ * we won't get any more characters.
+ */
+
+ while (1) {
+ int unthrottled;
+ tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE);
+ if (chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE)
+ break;
+ if (!tty->count)
+ break;
+ n_tty_set_room(tty);
+ unthrottled = tty_unthrottle_safe(tty);
+ if (!unthrottled)
+ break;
+ }
+ __tty_set_flow_change(tty, 0);
}
/**
- * check_unthrottle - allow new receive data
- * @tty; tty device
+ * put_tty_queue - add character to tty
+ * @c: character
+ * @ldata: n_tty data
*
- * Check whether to call the driver unthrottle functions
+ * Add a character to the tty read_buf queue.
*
- * Can sleep, may be called under the atomic_read_lock mutex but
- * this is not guaranteed.
+ * n_tty_receive_buf()/producer path:
+ * caller holds non-exclusive termios_rwsem
+ * modifies read_head
+ *
+ * read_head is only considered 'published' if canonical mode is
+ * not active.
*/
-static void check_unthrottle(struct tty_struct *tty)
+
+static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata)
{
- if (tty->count)
- tty_unthrottle(tty);
+ *read_buf_addr(ldata, ldata->read_head++) = c;
}
/**
* reset_buffer_flags - reset buffer state
* @tty: terminal to reset
*
- * Reset the read buffer counters, clear the flags,
- * and make sure the driver is unthrottled. Called
- * from n_tty_open() and n_tty_flush_buffer().
+ * Reset the read buffer counters and clear the flags.
+ * Called from n_tty_open() and n_tty_flush_buffer().
*
- * Locking: tty_read_lock for read fields.
+ * Locking: caller holds exclusive termios_rwsem
+ * (or locking is not required)
*/
-static void reset_buffer_flags(struct tty_struct *tty)
+static void reset_buffer_flags(struct n_tty_data *ldata)
{
- struct n_tty_data *ldata = tty->disc_data;
- unsigned long flags;
+ ldata->read_head = ldata->canon_head = ldata->read_tail = 0;
+ ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0;
+ ldata->echo_mark = 0;
+ ldata->line_start = 0;
- spin_lock_irqsave(&ldata->read_lock, flags);
- ldata->read_head = ldata->read_tail = ldata->read_cnt = 0;
- spin_unlock_irqrestore(&ldata->read_lock, flags);
+ ldata->erasing = 0;
+ bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
+ ldata->push = 0;
+}
- mutex_lock(&ldata->echo_lock);
- ldata->echo_pos = ldata->echo_cnt = ldata->echo_overrun = 0;
- mutex_unlock(&ldata->echo_lock);
+static void n_tty_packet_mode_flush(struct tty_struct *tty)
+{
+ unsigned long flags;
- ldata->canon_head = ldata->canon_data = ldata->erasing = 0;
- bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
- n_tty_set_room(tty);
+ spin_lock_irqsave(&tty->ctrl_lock, flags);
+ if (tty->link->packet) {
+ tty->ctrl_status |= TIOCPKT_FLUSHREAD;
+ if (waitqueue_active(&tty->link->read_wait))
+ wake_up_interruptible(&tty->link->read_wait);
+ }
+ spin_unlock_irqrestore(&tty->ctrl_lock, flags);
}
/**
* n_tty_flush_buffer - clean input queue
* @tty: terminal device
*
- * Flush the input buffer. Called when the line discipline is
- * being closed, when the tty layer wants the buffer flushed (eg
- * at hangup) or when the N_TTY line discipline internally has to
- * clean the pending queue (for example some signals).
+ * Flush the input buffer. Called when the tty layer wants the
+ * buffer flushed (eg at hangup) or when the N_TTY line discipline
+ * internally has to clean the pending queue (for example some signals).
+ *
+ * Holds termios_rwsem to exclude producer/consumer while
+ * buffer indices are reset.
*
- * Locking: ctrl_lock, read_lock.
+ * Locking: ctrl_lock, exclusive termios_rwsem
*/
static void n_tty_flush_buffer(struct tty_struct *tty)
{
- unsigned long flags;
- /* clear everything and unthrottle the driver */
- reset_buffer_flags(tty);
-
- if (!tty->link)
- return;
+ down_write(&tty->termios_rwsem);
+ reset_buffer_flags(tty->disc_data);
+ n_tty_set_room(tty);
- spin_lock_irqsave(&tty->ctrl_lock, flags);
- if (tty->link->packet) {
- tty->ctrl_status |= TIOCPKT_FLUSHREAD;
- wake_up_interruptible(&tty->link->read_wait);
- }
- spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+ if (tty->link)
+ n_tty_packet_mode_flush(tty);
+ up_write(&tty->termios_rwsem);
}
/**
@@ -267,24 +392,18 @@ static void n_tty_flush_buffer(struct tty_struct *tty)
* Report the number of characters buffered to be delivered to user
* at this instant in time.
*
- * Locking: read_lock
+ * Locking: exclusive termios_rwsem
*/
static ssize_t n_tty_chars_in_buffer(struct tty_struct *tty)
{
- struct n_tty_data *ldata = tty->disc_data;
- unsigned long flags;
- ssize_t n = 0;
+ ssize_t n;
- spin_lock_irqsave(&ldata->read_lock, flags);
- if (!ldata->icanon) {
- n = ldata->read_cnt;
- } else if (ldata->canon_data) {
- n = (ldata->canon_head > ldata->read_tail) ?
- ldata->canon_head - ldata->read_tail :
- ldata->canon_head + (N_TTY_BUF_SIZE - ldata->read_tail);
- }
- spin_unlock_irqrestore(&ldata->read_lock, flags);
+ WARN_ONCE(1, "%s is deprecated and scheduled for removal.", __func__);
+
+ down_write(&tty->termios_rwsem);
+ n = chars_in_buffer(tty);
+ up_write(&tty->termios_rwsem);
return n;
}
@@ -529,33 +648,23 @@ break_out:
* are prioritized. Also, when control characters are echoed with a
* prefixed "^", the pair is treated atomically and thus not separated.
*
- * Locking: output_lock to protect column state and space left,
- * echo_lock to protect the echo buffer
+ * Locking: callers must hold output_lock
*/
-static void process_echoes(struct tty_struct *tty)
+static size_t __process_echoes(struct tty_struct *tty)
{
struct n_tty_data *ldata = tty->disc_data;
- int space, nr;
+ int space, old_space;
+ size_t tail;
unsigned char c;
- unsigned char *cp, *buf_end;
- if (!ldata->echo_cnt)
- return;
+ old_space = space = tty_write_room(tty);
- mutex_lock(&ldata->output_lock);
- mutex_lock(&ldata->echo_lock);
-
- space = tty_write_room(tty);
-
- buf_end = ldata->echo_buf + N_TTY_BUF_SIZE;
- cp = ldata->echo_buf + ldata->echo_pos;
- nr = ldata->echo_cnt;
- while (nr > 0) {
- c = *cp;
+ tail = ldata->echo_tail;
+ while (ldata->echo_commit != tail) {
+ c = echo_buf(ldata, tail);
if (c == ECHO_OP_START) {
unsigned char op;
- unsigned char *opp;
int no_space_left = 0;
/*
@@ -563,18 +672,13 @@ static void process_echoes(struct tty_struct *tty)
* operation, get the next byte, which is either the
* op code or a control character value.
*/
- opp = cp + 1;
- if (opp == buf_end)
- opp -= N_TTY_BUF_SIZE;
- op = *opp;
+ op = echo_buf(ldata, tail + 1);
switch (op) {
unsigned int num_chars, num_bs;
case ECHO_OP_ERASE_TAB:
- if (++opp == buf_end)
- opp -= N_TTY_BUF_SIZE;
- num_chars = *opp;
+ num_chars = echo_buf(ldata, tail + 2);
/*
* Determine how many columns to go back
@@ -600,21 +704,18 @@ static void process_echoes(struct tty_struct *tty)
if (ldata->column > 0)
ldata->column--;
}
- cp += 3;
- nr -= 3;
+ tail += 3;
break;
case ECHO_OP_SET_CANON_COL:
ldata->canon_column = ldata->column;
- cp += 2;
- nr -= 2;
+ tail += 2;
break;
case ECHO_OP_MOVE_BACK_COL:
if (ldata->column > 0)
ldata->column--;
- cp += 2;
- nr -= 2;
+ tail += 2;
break;
case ECHO_OP_START:
@@ -626,8 +727,7 @@ static void process_echoes(struct tty_struct *tty)
tty_put_char(tty, ECHO_OP_START);
ldata->column++;
space--;
- cp += 2;
- nr -= 2;
+ tail += 2;
break;
default:
@@ -648,15 +748,13 @@ static void process_echoes(struct tty_struct *tty)
tty_put_char(tty, op ^ 0100);
ldata->column += 2;
space -= 2;
- cp += 2;
- nr -= 2;
+ tail += 2;
}
if (no_space_left)
break;
} else {
- if (O_OPOST(tty) &&
- !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) {
+ if (O_OPOST(tty)) {
int retval = do_output_char(c, tty, space);
if (retval < 0)
break;
@@ -667,80 +765,96 @@ static void process_echoes(struct tty_struct *tty)
tty_put_char(tty, c);
space -= 1;
}
- cp += 1;
- nr -= 1;
+ tail += 1;
}
-
- /* When end of circular buffer reached, wrap around */
- if (cp >= buf_end)
- cp -= N_TTY_BUF_SIZE;
}
- if (nr == 0) {
- ldata->echo_pos = 0;
- ldata->echo_cnt = 0;
- ldata->echo_overrun = 0;
- } else {
- int num_processed = ldata->echo_cnt - nr;
- ldata->echo_pos += num_processed;
- ldata->echo_pos &= N_TTY_BUF_SIZE - 1;
- ldata->echo_cnt = nr;
- if (num_processed > 0)
- ldata->echo_overrun = 0;
+ /* If the echo buffer is nearly full (so that the possibility exists
+ * of echo overrun before the next commit), then discard enough
+ * data at the tail to prevent a subsequent overrun */
+ while (ldata->echo_commit - tail >= ECHO_DISCARD_WATERMARK) {
+ if (echo_buf(ldata, tail) == ECHO_OP_START) {
+ if (echo_buf(ldata, tail + 1) == ECHO_OP_ERASE_TAB)
+ tail += 3;
+ else
+ tail += 2;
+ } else
+ tail++;
}
- mutex_unlock(&ldata->echo_lock);
+ ldata->echo_tail = tail;
+ return old_space - space;
+}
+
+static void commit_echoes(struct tty_struct *tty)
+{
+ struct n_tty_data *ldata = tty->disc_data;
+ size_t nr, old, echoed;
+ size_t head;
+
+ head = ldata->echo_head;
+ ldata->echo_mark = head;
+ old = ldata->echo_commit - ldata->echo_tail;
+
+ /* Process committed echoes if the accumulated # of bytes
+ * is over the threshold (and try again each time another
+ * block is accumulated) */
+ nr = head - ldata->echo_tail;
+ if (nr < ECHO_COMMIT_WATERMARK || (nr % ECHO_BLOCK > old % ECHO_BLOCK))
+ return;
+
+ mutex_lock(&ldata->output_lock);
+ ldata->echo_commit = head;
+ echoed = __process_echoes(tty);
+ mutex_unlock(&ldata->output_lock);
+
+ if (echoed && tty->ops->flush_chars)
+ tty->ops->flush_chars(tty);
+}
+
+static void process_echoes(struct tty_struct *tty)
+{
+ struct n_tty_data *ldata = tty->disc_data;
+ size_t echoed;
+
+ if (ldata->echo_mark == ldata->echo_tail)
+ return;
+
+ mutex_lock(&ldata->output_lock);
+ ldata->echo_commit = ldata->echo_mark;
+ echoed = __process_echoes(tty);
mutex_unlock(&ldata->output_lock);
- if (tty->ops->flush_chars)
+ if (echoed && tty->ops->flush_chars)
tty->ops->flush_chars(tty);
}
+/* NB: echo_mark and echo_head should be equivalent here */
+static void flush_echoes(struct tty_struct *tty)
+{
+ struct n_tty_data *ldata = tty->disc_data;
+
+ if ((!L_ECHO(tty) && !L_ECHONL(tty)) ||
+ ldata->echo_commit == ldata->echo_head)
+ return;
+
+ mutex_lock(&ldata->output_lock);
+ ldata->echo_commit = ldata->echo_head;
+ __process_echoes(tty);
+ mutex_unlock(&ldata->output_lock);
+}
+
/**
* add_echo_byte - add a byte to the echo buffer
* @c: unicode byte to echo
* @ldata: n_tty data
*
* Add a character or operation byte to the echo buffer.
- *
- * Should be called under the echo lock to protect the echo buffer.
*/
-static void add_echo_byte(unsigned char c, struct n_tty_data *ldata)
+static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata)
{
- int new_byte_pos;
-
- if (ldata->echo_cnt == N_TTY_BUF_SIZE) {
- /* Circular buffer is already at capacity */
- new_byte_pos = ldata->echo_pos;
-
- /*
- * Since the buffer start position needs to be advanced,
- * be sure to step by a whole operation byte group.
- */
- if (ldata->echo_buf[ldata->echo_pos] == ECHO_OP_START) {
- if (ldata->echo_buf[(ldata->echo_pos + 1) &
- (N_TTY_BUF_SIZE - 1)] ==
- ECHO_OP_ERASE_TAB) {
- ldata->echo_pos += 3;
- ldata->echo_cnt -= 2;
- } else {
- ldata->echo_pos += 2;
- ldata->echo_cnt -= 1;
- }
- } else {
- ldata->echo_pos++;
- }
- ldata->echo_pos &= N_TTY_BUF_SIZE - 1;
-
- ldata->echo_overrun = 1;
- } else {
- new_byte_pos = ldata->echo_pos + ldata->echo_cnt;
- new_byte_pos &= N_TTY_BUF_SIZE - 1;
- ldata->echo_cnt++;
- }
-
- ldata->echo_buf[new_byte_pos] = c;
+ *echo_buf_addr(ldata, ldata->echo_head++) = c;
}
/**
@@ -748,16 +862,12 @@ static void add_echo_byte(unsigned char c, struct n_tty_data *ldata)
* @ldata: n_tty data
*
* Add an operation to the echo buffer to move back one column.
- *
- * Locking: echo_lock to protect the echo buffer
*/
static void echo_move_back_col(struct n_tty_data *ldata)
{
- mutex_lock(&ldata->echo_lock);
add_echo_byte(ECHO_OP_START, ldata);
add_echo_byte(ECHO_OP_MOVE_BACK_COL, ldata);
- mutex_unlock(&ldata->echo_lock);
}
/**
@@ -766,16 +876,12 @@ static void echo_move_back_col(struct n_tty_data *ldata)
*
* Add an operation to the echo buffer to set the canon column
* to the current column.
- *
- * Locking: echo_lock to protect the echo buffer
*/
static void echo_set_canon_col(struct n_tty_data *ldata)
{
- mutex_lock(&ldata->echo_lock);
add_echo_byte(ECHO_OP_START, ldata);
add_echo_byte(ECHO_OP_SET_CANON_COL, ldata);
- mutex_unlock(&ldata->echo_lock);
}
/**
@@ -791,15 +897,11 @@ static void echo_set_canon_col(struct n_tty_data *ldata)
* of input. This information will be used later, along with
* canon column (if applicable), to go back the correct number
* of columns.
- *
- * Locking: echo_lock to protect the echo buffer
*/
static void echo_erase_tab(unsigned int num_chars, int after_tab,
struct n_tty_data *ldata)
{
- mutex_lock(&ldata->echo_lock);
-
add_echo_byte(ECHO_OP_START, ldata);
add_echo_byte(ECHO_OP_ERASE_TAB, ldata);
@@ -811,8 +913,6 @@ static void echo_erase_tab(unsigned int num_chars, int after_tab,
num_chars |= 0x80;
add_echo_byte(num_chars, ldata);
-
- mutex_unlock(&ldata->echo_lock);
}
/**
@@ -824,20 +924,16 @@ static void echo_erase_tab(unsigned int num_chars, int after_tab,
* L_ECHO(tty) is true. Called from the driver receive_buf path.
*
* This variant does not treat control characters specially.
- *
- * Locking: echo_lock to protect the echo buffer
*/
static void echo_char_raw(unsigned char c, struct n_tty_data *ldata)
{
- mutex_lock(&ldata->echo_lock);
if (c == ECHO_OP_START) {
add_echo_byte(ECHO_OP_START, ldata);
add_echo_byte(ECHO_OP_START, ldata);
} else {
add_echo_byte(c, ldata);
}
- mutex_unlock(&ldata->echo_lock);
}
/**
@@ -850,16 +946,12 @@ static void echo_char_raw(unsigned char c, struct n_tty_data *ldata)
*
* This variant tags control characters to be echoed as "^X"
* (where X is the letter representing the control char).
- *
- * Locking: echo_lock to protect the echo buffer
*/
static void echo_char(unsigned char c, struct tty_struct *tty)
{
struct n_tty_data *ldata = tty->disc_data;
- mutex_lock(&ldata->echo_lock);
-
if (c == ECHO_OP_START) {
add_echo_byte(ECHO_OP_START, ldata);
add_echo_byte(ECHO_OP_START, ldata);
@@ -868,8 +960,6 @@ static void echo_char(unsigned char c, struct tty_struct *tty)
add_echo_byte(ECHO_OP_START, ldata);
add_echo_byte(c, ldata);
}
-
- mutex_unlock(&ldata->echo_lock);
}
/**
@@ -894,17 +984,22 @@ static inline void finish_erasing(struct n_tty_data *ldata)
* present in the stream from the driver layer. Handles the complexities
* of UTF-8 multibyte symbols.
*
- * Locking: read_lock for tty buffers
+ * n_tty_receive_buf()/producer path:
+ * caller holds non-exclusive termios_rwsem
+ * modifies read_head
+ *
+ * Modifying the read_head is not considered a publish in this context
+ * because canonical mode is active -- only canon_head publishes
*/
static void eraser(unsigned char c, struct tty_struct *tty)
{
struct n_tty_data *ldata = tty->disc_data;
enum { ERASE, WERASE, KILL } kill_type;
- int head, seen_alnums, cnt;
- unsigned long flags;
+ size_t head;
+ size_t cnt;
+ int seen_alnums;
- /* FIXME: locking needed ? */
if (ldata->read_head == ldata->canon_head) {
/* process_output('\a', tty); */ /* what do you think? */
return;
@@ -915,19 +1010,11 @@ static void eraser(unsigned char c, struct tty_struct *tty)
kill_type = WERASE;
else {
if (!L_ECHO(tty)) {
- 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(&ldata->read_lock, flags);
return;
}
if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) {
- 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(&ldata->read_lock, flags);
finish_erasing(ldata);
echo_char(KILL_CHAR(tty), tty);
/* Add a newline if ECHOK is on and ECHOKE is off. */
@@ -939,14 +1026,13 @@ static void eraser(unsigned char c, struct tty_struct *tty)
}
seen_alnums = 0;
- /* FIXME: Locking ?? */
while (ldata->read_head != ldata->canon_head) {
head = ldata->read_head;
/* erase a single possibly multibyte character */
do {
- head = (head - 1) & (N_TTY_BUF_SIZE-1);
- c = ldata->read_buf[head];
+ head--;
+ c = read_buf(ldata, head);
} while (is_continuation(c, tty) && head != ldata->canon_head);
/* do not partially erase */
@@ -960,11 +1046,8 @@ static void eraser(unsigned char c, struct tty_struct *tty)
else if (seen_alnums)
break;
}
- cnt = (ldata->read_head - head) & (N_TTY_BUF_SIZE-1);
- spin_lock_irqsave(&ldata->read_lock, flags);
+ cnt = ldata->read_head - head;
ldata->read_head = head;
- ldata->read_cnt -= cnt;
- spin_unlock_irqrestore(&ldata->read_lock, flags);
if (L_ECHO(tty)) {
if (L_ECHOPRT(tty)) {
if (!ldata->erasing) {
@@ -974,9 +1057,8 @@ static void eraser(unsigned char c, struct tty_struct *tty)
/* if cnt > 1, output a multi-byte character */
echo_char(c, tty);
while (--cnt > 0) {
- head = (head+1) & (N_TTY_BUF_SIZE-1);
- echo_char_raw(ldata->read_buf[head],
- ldata);
+ head++;
+ echo_char_raw(read_buf(ldata, head), ldata);
echo_move_back_col(ldata);
}
} else if (kill_type == ERASE && !L_ECHOE(tty)) {
@@ -984,7 +1066,7 @@ static void eraser(unsigned char c, struct tty_struct *tty)
} else if (c == '\t') {
unsigned int num_chars = 0;
int after_tab = 0;
- unsigned long tail = ldata->read_head;
+ size_t tail = ldata->read_head;
/*
* Count the columns used for characters
@@ -994,8 +1076,8 @@ static void eraser(unsigned char c, struct tty_struct *tty)
* number of columns.
*/
while (tail != ldata->canon_head) {
- tail = (tail-1) & (N_TTY_BUF_SIZE-1);
- c = ldata->read_buf[tail];
+ tail--;
+ c = read_buf(ldata, tail);
if (c == '\t') {
after_tab = 1;
break;
@@ -1031,23 +1113,19 @@ static void eraser(unsigned char c, struct tty_struct *tty)
* isig - handle the ISIG optio
* @sig: signal
* @tty: terminal
- * @flush: force flush
*
- * Called when a signal is being sent due to terminal input. This
- * may caus terminal flushing to take place according to the termios
- * settings and character used. Called from the driver receive_buf
- * path so serialized.
+ * Called when a signal is being sent due to terminal input.
+ * Called from the driver receive_buf path so serialized.
*
- * Locking: ctrl_lock, read_lock (both via flush buffer)
+ * Locking: ctrl_lock
*/
-static inline void isig(int sig, struct tty_struct *tty, int flush)
+static void isig(int sig, struct tty_struct *tty)
{
- if (tty->pgrp)
- kill_pgrp(tty->pgrp, sig, 1);
- if (flush || !L_NOFLSH(tty)) {
- n_tty_flush_buffer(tty);
- tty_driver_flush_buffer(tty);
+ struct pid *tty_pgrp = tty_get_pgrp(tty);
+ if (tty_pgrp) {
+ kill_pgrp(tty_pgrp, sig, 1);
+ put_pid(tty_pgrp);
}
}
@@ -1058,17 +1136,28 @@ static inline void isig(int sig, struct tty_struct *tty, int flush)
* An RS232 break event has been hit in the incoming bitstream. This
* can cause a variety of events depending upon the termios settings.
*
- * Called from the receive_buf path so single threaded.
+ * n_tty_receive_buf()/producer path:
+ * caller holds non-exclusive termios_rwsem
+ * publishes read_head via put_tty_queue()
+ *
+ * Note: may get exclusive termios_rwsem if flushing input buffer
*/
-static inline void n_tty_receive_break(struct tty_struct *tty)
+static void n_tty_receive_break(struct tty_struct *tty)
{
struct n_tty_data *ldata = tty->disc_data;
if (I_IGNBRK(tty))
return;
if (I_BRKINT(tty)) {
- isig(SIGINT, tty, 1);
+ isig(SIGINT, tty);
+ if (!L_NOFLSH(tty)) {
+ /* flushing needs exclusive termios_rwsem */
+ up_read(&tty->termios_rwsem);
+ n_tty_flush_buffer(tty);
+ tty_driver_flush_buffer(tty);
+ down_read(&tty->termios_rwsem);
+ }
return;
}
if (I_PARMRK(tty)) {
@@ -1076,7 +1165,8 @@ static inline void n_tty_receive_break(struct tty_struct *tty)
put_tty_queue('\0', ldata);
}
put_tty_queue('\0', ldata);
- wake_up_interruptible(&tty->read_wait);
+ if (waitqueue_active(&tty->read_wait))
+ wake_up_interruptible(&tty->read_wait);
}
/**
@@ -1092,7 +1182,7 @@ static inline void n_tty_receive_break(struct tty_struct *tty)
* private.
*/
-static inline void n_tty_receive_overrun(struct tty_struct *tty)
+static void n_tty_receive_overrun(struct tty_struct *tty)
{
struct n_tty_data *ldata = tty->disc_data;
char buf[64];
@@ -1114,24 +1204,50 @@ static inline void n_tty_receive_overrun(struct tty_struct *tty)
* @c: character
*
* Process a parity error and queue the right data to indicate
- * the error case if necessary. Locking as per n_tty_receive_buf.
+ * the error case if necessary.
+ *
+ * n_tty_receive_buf()/producer path:
+ * caller holds non-exclusive termios_rwsem
+ * publishes read_head via put_tty_queue()
*/
-static inline void n_tty_receive_parity_error(struct tty_struct *tty,
- unsigned char c)
+static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c)
{
struct n_tty_data *ldata = tty->disc_data;
- if (I_IGNPAR(tty))
- return;
- if (I_PARMRK(tty)) {
- put_tty_queue('\377', ldata);
- put_tty_queue('\0', ldata);
- put_tty_queue(c, ldata);
- } else if (I_INPCK(tty))
- put_tty_queue('\0', ldata);
- else
+ if (I_INPCK(tty)) {
+ if (I_IGNPAR(tty))
+ return;
+ if (I_PARMRK(tty)) {
+ put_tty_queue('\377', ldata);
+ put_tty_queue('\0', ldata);
+ put_tty_queue(c, ldata);
+ } else
+ put_tty_queue('\0', ldata);
+ } else
put_tty_queue(c, ldata);
- wake_up_interruptible(&tty->read_wait);
+ if (waitqueue_active(&tty->read_wait))
+ wake_up_interruptible(&tty->read_wait);
+}
+
+static void
+n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c)
+{
+ if (!L_NOFLSH(tty)) {
+ /* flushing needs exclusive termios_rwsem */
+ up_read(&tty->termios_rwsem);
+ n_tty_flush_buffer(tty);
+ tty_driver_flush_buffer(tty);
+ down_read(&tty->termios_rwsem);
+ }
+ if (I_IXON(tty))
+ start_tty(tty);
+ if (L_ECHO(tty)) {
+ echo_char(c, tty);
+ commit_echoes(tty);
+ } else
+ process_echoes(tty);
+ isig(signal, tty);
+ return;
}
/**
@@ -1142,123 +1258,53 @@ static inline void n_tty_receive_parity_error(struct tty_struct *tty,
* Process an individual character of input received from the driver.
* This is serialized with respect to itself by the rules for the
* driver above.
+ *
+ * n_tty_receive_buf()/producer path:
+ * caller holds non-exclusive termios_rwsem
+ * publishes canon_head if canonical mode is active
+ * otherwise, publishes read_head via put_tty_queue()
+ *
+ * Returns 1 if LNEXT was received, else returns 0
*/
-static inline void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
+static int
+n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
{
struct n_tty_data *ldata = tty->disc_data;
- unsigned long flags;
- int parmrk;
-
- if (ldata->raw) {
- put_tty_queue(c, ldata);
- return;
- }
-
- if (I_ISTRIP(tty))
- c &= 0x7f;
- if (I_IUCLC(tty) && L_IEXTEN(tty))
- c = tolower(c);
-
- if (L_EXTPROC(tty)) {
- put_tty_queue(c, ldata);
- return;
- }
-
- if (tty->stopped && !tty->flow_stopped && I_IXON(tty) &&
- I_IXANY(tty) && c != START_CHAR(tty) && c != STOP_CHAR(tty) &&
- c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) && c != SUSP_CHAR(tty)) {
- start_tty(tty);
- process_echoes(tty);
- }
-
- if (tty->closing) {
- if (I_IXON(tty)) {
- if (c == START_CHAR(tty)) {
- start_tty(tty);
- process_echoes(tty);
- } else if (c == STOP_CHAR(tty))
- stop_tty(tty);
- }
- return;
- }
-
- /*
- * If the previous character was LNEXT, or we know that this
- * character is not one of the characters that we'll have to
- * handle specially, do shortcut processing to speed things
- * up.
- */
- if (!test_bit(c, ldata->process_char_map) || ldata->lnext) {
- ldata->lnext = 0;
- parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
- if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) {
- /* beep if no space */
- if (L_ECHO(tty))
- process_output('\a', tty);
- return;
- }
- if (L_ECHO(tty)) {
- finish_erasing(ldata);
- /* Record the column of first canon char. */
- if (ldata->canon_head == ldata->read_head)
- echo_set_canon_col(ldata);
- echo_char(c, tty);
- process_echoes(tty);
- }
- if (parmrk)
- put_tty_queue(c, ldata);
- put_tty_queue(c, ldata);
- return;
- }
if (I_IXON(tty)) {
if (c == START_CHAR(tty)) {
start_tty(tty);
process_echoes(tty);
- return;
+ return 0;
}
if (c == STOP_CHAR(tty)) {
stop_tty(tty);
- return;
+ return 0;
}
}
if (L_ISIG(tty)) {
- int signal;
- signal = SIGINT;
- if (c == INTR_CHAR(tty))
- goto send_signal;
- signal = SIGQUIT;
- if (c == QUIT_CHAR(tty))
- goto send_signal;
- signal = SIGTSTP;
- if (c == SUSP_CHAR(tty)) {
-send_signal:
- /*
- * Note that we do not use isig() here because we want
- * the order to be:
- * 1) flush, 2) echo, 3) signal
- */
- if (!L_NOFLSH(tty)) {
- n_tty_flush_buffer(tty);
- tty_driver_flush_buffer(tty);
- }
- if (I_IXON(tty))
- start_tty(tty);
- if (L_ECHO(tty)) {
- echo_char(c, tty);
- process_echoes(tty);
- }
- if (tty->pgrp)
- kill_pgrp(tty->pgrp, signal, 1);
- return;
+ if (c == INTR_CHAR(tty)) {
+ n_tty_receive_signal_char(tty, SIGINT, c);
+ return 0;
+ } else if (c == QUIT_CHAR(tty)) {
+ n_tty_receive_signal_char(tty, SIGQUIT, c);
+ return 0;
+ } else if (c == SUSP_CHAR(tty)) {
+ n_tty_receive_signal_char(tty, SIGTSTP, c);
+ return 0;
}
}
+ if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) {
+ start_tty(tty);
+ process_echoes(tty);
+ }
+
if (c == '\r') {
if (I_IGNCR(tty))
- return;
+ return 0;
if (I_ICRNL(tty))
c = '\n';
} else if (c == '\n' && I_INLCR(tty))
@@ -1268,8 +1314,8 @@ send_signal:
if (c == ERASE_CHAR(tty) || c == KILL_CHAR(tty) ||
(c == WERASE_CHAR(tty) && L_IEXTEN(tty))) {
eraser(c, tty);
- process_echoes(tty);
- return;
+ commit_echoes(tty);
+ return 0;
}
if (c == LNEXT_CHAR(tty) && L_IEXTEN(tty)) {
ldata->lnext = 1;
@@ -1278,54 +1324,37 @@ send_signal:
if (L_ECHOCTL(tty)) {
echo_char_raw('^', ldata);
echo_char_raw('\b', ldata);
- process_echoes(tty);
+ commit_echoes(tty);
}
}
- return;
+ return 1;
}
- if (c == REPRINT_CHAR(tty) && L_ECHO(tty) &&
- L_IEXTEN(tty)) {
- unsigned long tail = ldata->canon_head;
+ if (c == REPRINT_CHAR(tty) && L_ECHO(tty) && L_IEXTEN(tty)) {
+ size_t tail = ldata->canon_head;
finish_erasing(ldata);
echo_char(c, tty);
echo_char_raw('\n', ldata);
while (tail != ldata->read_head) {
- echo_char(ldata->read_buf[tail], tty);
- tail = (tail+1) & (N_TTY_BUF_SIZE-1);
+ echo_char(read_buf(ldata, tail), tty);
+ tail++;
}
- process_echoes(tty);
- return;
+ commit_echoes(tty);
+ return 0;
}
if (c == '\n') {
- if (ldata->read_cnt >= N_TTY_BUF_SIZE) {
- if (L_ECHO(tty))
- process_output('\a', tty);
- return;
- }
if (L_ECHO(tty) || L_ECHONL(tty)) {
echo_char_raw('\n', ldata);
- process_echoes(tty);
+ commit_echoes(tty);
}
goto handle_newline;
}
if (c == EOF_CHAR(tty)) {
- if (ldata->read_cnt >= N_TTY_BUF_SIZE)
- return;
- if (ldata->canon_head != ldata->read_head)
- set_bit(TTY_PUSH, &tty->flags);
c = __DISABLED_CHAR;
goto handle_newline;
}
if ((c == EOL_CHAR(tty)) ||
(c == EOL2_CHAR(tty) && L_IEXTEN(tty))) {
- parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty))
- ? 1 : 0;
- if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk)) {
- if (L_ECHO(tty))
- process_output('\a', tty);
- return;
- }
/*
* XXX are EOL_CHAR and EOL2_CHAR echoed?!?
*/
@@ -1334,36 +1363,26 @@ send_signal:
if (ldata->canon_head == ldata->read_head)
echo_set_canon_col(ldata);
echo_char(c, tty);
- process_echoes(tty);
+ commit_echoes(tty);
}
/*
* XXX does PARMRK doubling happen for
* EOL_CHAR and EOL2_CHAR?
*/
- if (parmrk)
+ if (c == (unsigned char) '\377' && I_PARMRK(tty))
put_tty_queue(c, ldata);
handle_newline:
- spin_lock_irqsave(&ldata->read_lock, flags);
- set_bit(ldata->read_head, ldata->read_flags);
- put_tty_queue_nolock(c, ldata);
+ set_bit(ldata->read_head & (N_TTY_BUF_SIZE - 1), ldata->read_flags);
+ put_tty_queue(c, ldata);
ldata->canon_head = ldata->read_head;
- ldata->canon_data++;
- 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);
- return;
+ return 0;
}
}
- parmrk = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0;
- if (ldata->read_cnt >= (N_TTY_BUF_SIZE - parmrk - 1)) {
- /* beep if no space */
- if (L_ECHO(tty))
- process_output('\a', tty);
- return;
- }
if (L_ECHO(tty)) {
finish_erasing(ldata);
if (c == '\n')
@@ -1374,29 +1393,122 @@ handle_newline:
echo_set_canon_col(ldata);
echo_char(c, tty);
}
- process_echoes(tty);
+ commit_echoes(tty);
}
- if (parmrk)
+ /* PARMRK doubling check */
+ if (c == (unsigned char) '\377' && I_PARMRK(tty))
put_tty_queue(c, ldata);
put_tty_queue(c, ldata);
+ return 0;
}
+static inline void
+n_tty_receive_char_inline(struct tty_struct *tty, unsigned char c)
+{
+ struct n_tty_data *ldata = tty->disc_data;
-/**
- * n_tty_write_wakeup - asynchronous I/O notifier
- * @tty: tty device
- *
- * Required for the ptys, serial driver etc. since processes
- * that attach themselves to the master and rely on ASYNC
- * IO must be woken up
- */
+ if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) {
+ start_tty(tty);
+ process_echoes(tty);
+ }
+ if (L_ECHO(tty)) {
+ finish_erasing(ldata);
+ /* Record the column of first canon char. */
+ if (ldata->canon_head == ldata->read_head)
+ echo_set_canon_col(ldata);
+ echo_char(c, tty);
+ commit_echoes(tty);
+ }
+ /* PARMRK doubling check */
+ if (c == (unsigned char) '\377' && I_PARMRK(tty))
+ put_tty_queue(c, ldata);
+ put_tty_queue(c, ldata);
+}
-static void n_tty_write_wakeup(struct tty_struct *tty)
+static void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
{
- if (tty->fasync && test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags))
- kill_fasync(&tty->fasync, SIGIO, POLL_OUT);
+ n_tty_receive_char_inline(tty, c);
+}
+
+static inline void
+n_tty_receive_char_fast(struct tty_struct *tty, unsigned char c)
+{
+ struct n_tty_data *ldata = tty->disc_data;
+
+ if (tty->stopped && !tty->flow_stopped && I_IXON(tty) && I_IXANY(tty)) {
+ start_tty(tty);
+ process_echoes(tty);
+ }
+ if (L_ECHO(tty)) {
+ finish_erasing(ldata);
+ /* Record the column of first canon char. */
+ if (ldata->canon_head == ldata->read_head)
+ echo_set_canon_col(ldata);
+ echo_char(c, tty);
+ commit_echoes(tty);
+ }
+ put_tty_queue(c, ldata);
+}
+
+static void n_tty_receive_char_closing(struct tty_struct *tty, unsigned char c)
+{
+ if (I_ISTRIP(tty))
+ c &= 0x7f;
+ if (I_IUCLC(tty) && L_IEXTEN(tty))
+ c = tolower(c);
+
+ if (I_IXON(tty)) {
+ if (c == STOP_CHAR(tty))
+ stop_tty(tty);
+ else if (c == START_CHAR(tty) ||
+ (tty->stopped && !tty->flow_stopped && I_IXANY(tty) &&
+ c != INTR_CHAR(tty) && c != QUIT_CHAR(tty) &&
+ c != SUSP_CHAR(tty))) {
+ start_tty(tty);
+ process_echoes(tty);
+ }
+ }
+}
+
+static void
+n_tty_receive_char_flagged(struct tty_struct *tty, unsigned char c, char flag)
+{
+ char buf[64];
+
+ switch (flag) {
+ case TTY_BREAK:
+ n_tty_receive_break(tty);
+ break;
+ case TTY_PARITY:
+ case TTY_FRAME:
+ n_tty_receive_parity_error(tty, c);
+ break;
+ case TTY_OVERRUN:
+ n_tty_receive_overrun(tty);
+ break;
+ default:
+ printk(KERN_ERR "%s: unknown flag %d\n",
+ tty_name(tty, buf), flag);
+ break;
+ }
+}
+
+static void
+n_tty_receive_char_lnext(struct tty_struct *tty, unsigned char c, char flag)
+{
+ struct n_tty_data *ldata = tty->disc_data;
+
+ ldata->lnext = 0;
+ if (likely(flag == TTY_NORMAL)) {
+ if (I_ISTRIP(tty))
+ c &= 0x7f;
+ if (I_IUCLC(tty) && L_IEXTEN(tty))
+ c = tolower(c);
+ n_tty_receive_char(tty, c);
+ } else
+ n_tty_receive_char_flagged(tty, c, flag);
}
/**
@@ -1410,86 +1522,209 @@ static void n_tty_write_wakeup(struct tty_struct *tty)
* been received. This function must be called from soft contexts
* not from interrupt context. The driver is responsible for making
* calls one at a time and in order (or using flush_to_ldisc)
+ *
+ * n_tty_receive_buf()/producer path:
+ * claims non-exclusive termios_rwsem
+ * publishes read_head and canon_head
*/
-static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
- char *fp, int count)
+static void
+n_tty_receive_buf_real_raw(struct tty_struct *tty, const unsigned char *cp,
+ char *fp, int count)
{
struct n_tty_data *ldata = tty->disc_data;
- const unsigned char *p;
- char *f, flags = TTY_NORMAL;
- int i;
- char buf[64];
- unsigned long cpuflags;
-
- if (ldata->real_raw) {
- 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);
- 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;
- cp += i;
- count -= i;
-
- i = min(N_TTY_BUF_SIZE - ldata->read_cnt,
- N_TTY_BUF_SIZE - ldata->read_head);
- i = min(count, i);
- 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(&ldata->read_lock, cpuflags);
- } else {
- for (i = count, p = cp, f = fp; i; i--, p++) {
- if (f)
- flags = *f++;
- switch (flags) {
- case TTY_NORMAL:
- n_tty_receive_char(tty, *p);
- break;
- case TTY_BREAK:
- n_tty_receive_break(tty);
- break;
- case TTY_PARITY:
- case TTY_FRAME:
- n_tty_receive_parity_error(tty, *p);
- break;
- case TTY_OVERRUN:
- n_tty_receive_overrun(tty);
- break;
- default:
- printk(KERN_ERR "%s: unknown flag %d\n",
- tty_name(tty, buf), flags);
- break;
+ size_t n, head;
+
+ head = ldata->read_head & (N_TTY_BUF_SIZE - 1);
+ n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head);
+ n = min_t(size_t, count, n);
+ memcpy(read_buf_addr(ldata, head), cp, n);
+ ldata->read_head += n;
+ cp += n;
+ count -= n;
+
+ head = ldata->read_head & (N_TTY_BUF_SIZE - 1);
+ n = N_TTY_BUF_SIZE - max(read_cnt(ldata), head);
+ n = min_t(size_t, count, n);
+ memcpy(read_buf_addr(ldata, head), cp, n);
+ ldata->read_head += n;
+}
+
+static void
+n_tty_receive_buf_raw(struct tty_struct *tty, const unsigned char *cp,
+ char *fp, int count)
+{
+ struct n_tty_data *ldata = tty->disc_data;
+ char flag = TTY_NORMAL;
+
+ while (count--) {
+ if (fp)
+ flag = *fp++;
+ if (likely(flag == TTY_NORMAL))
+ put_tty_queue(*cp++, ldata);
+ else
+ n_tty_receive_char_flagged(tty, *cp++, flag);
+ }
+}
+
+static void
+n_tty_receive_buf_closing(struct tty_struct *tty, const unsigned char *cp,
+ char *fp, int count)
+{
+ char flag = TTY_NORMAL;
+
+ while (count--) {
+ if (fp)
+ flag = *fp++;
+ if (likely(flag == TTY_NORMAL))
+ n_tty_receive_char_closing(tty, *cp++);
+ else
+ n_tty_receive_char_flagged(tty, *cp++, flag);
+ }
+}
+
+static void
+n_tty_receive_buf_standard(struct tty_struct *tty, const unsigned char *cp,
+ char *fp, int count)
+{
+ struct n_tty_data *ldata = tty->disc_data;
+ char flag = TTY_NORMAL;
+
+ while (count--) {
+ if (fp)
+ flag = *fp++;
+ if (likely(flag == TTY_NORMAL)) {
+ unsigned char c = *cp++;
+
+ if (I_ISTRIP(tty))
+ c &= 0x7f;
+ if (I_IUCLC(tty) && L_IEXTEN(tty))
+ c = tolower(c);
+ if (L_EXTPROC(tty)) {
+ put_tty_queue(c, ldata);
+ continue;
+ }
+ if (!test_bit(c, ldata->char_map))
+ n_tty_receive_char_inline(tty, c);
+ else if (n_tty_receive_char_special(tty, c) && count) {
+ if (fp)
+ flag = *fp++;
+ n_tty_receive_char_lnext(tty, *cp++, flag);
+ count--;
}
+ } else
+ n_tty_receive_char_flagged(tty, *cp++, flag);
+ }
+}
+
+static void
+n_tty_receive_buf_fast(struct tty_struct *tty, const unsigned char *cp,
+ char *fp, int count)
+{
+ struct n_tty_data *ldata = tty->disc_data;
+ char flag = TTY_NORMAL;
+
+ while (count--) {
+ if (fp)
+ flag = *fp++;
+ if (likely(flag == TTY_NORMAL)) {
+ unsigned char c = *cp++;
+
+ if (!test_bit(c, ldata->char_map))
+ n_tty_receive_char_fast(tty, c);
+ else if (n_tty_receive_char_special(tty, c) && count) {
+ if (fp)
+ flag = *fp++;
+ n_tty_receive_char_lnext(tty, *cp++, flag);
+ count--;
+ }
+ } else
+ n_tty_receive_char_flagged(tty, *cp++, flag);
+ }
+}
+
+static void __receive_buf(struct tty_struct *tty, const unsigned char *cp,
+ char *fp, int count)
+{
+ struct n_tty_data *ldata = tty->disc_data;
+ bool preops = I_ISTRIP(tty) || (I_IUCLC(tty) && L_IEXTEN(tty));
+
+ if (ldata->real_raw)
+ n_tty_receive_buf_real_raw(tty, cp, fp, count);
+ else if (ldata->raw || (L_EXTPROC(tty) && !preops))
+ n_tty_receive_buf_raw(tty, cp, fp, count);
+ else if (tty->closing && !L_EXTPROC(tty))
+ n_tty_receive_buf_closing(tty, cp, fp, count);
+ else {
+ if (ldata->lnext) {
+ char flag = TTY_NORMAL;
+
+ if (fp)
+ flag = *fp++;
+ n_tty_receive_char_lnext(tty, *cp++, flag);
+ count--;
}
+
+ if (!preops && !I_PARMRK(tty))
+ n_tty_receive_buf_fast(tty, cp, fp, count);
+ else
+ n_tty_receive_buf_standard(tty, cp, fp, count);
+
+ flush_echoes(tty);
if (tty->ops->flush_chars)
tty->ops->flush_chars(tty);
}
- n_tty_set_room(tty);
-
- if ((!ldata->icanon && (ldata->read_cnt >= tty->minimum_to_wake)) ||
+ if ((!ldata->icanon && (read_cnt(ldata) >= ldata->minimum_to_wake)) ||
L_EXTPROC(tty)) {
kill_fasync(&tty->fasync, SIGIO, POLL_IN);
if (waitqueue_active(&tty->read_wait))
wake_up_interruptible(&tty->read_wait);
}
+}
- /*
- * Check the remaining room for the input canonicalization
- * mode. We don't want to throttle the driver if we're in
- * canonical mode and don't have a newline yet!
- */
- if (tty->receive_room < TTY_THRESHOLD_THROTTLE)
- tty_throttle(tty);
+static int
+n_tty_receive_buf_common(struct tty_struct *tty, const unsigned char *cp,
+ char *fp, int count, int flow)
+{
+ struct n_tty_data *ldata = tty->disc_data;
+ int room, n, rcvd = 0;
+
+ down_read(&tty->termios_rwsem);
+
+ while (1) {
+ room = receive_room(tty);
+ n = min(count, room);
+ if (!n) {
+ if (flow && !room)
+ ldata->no_room = 1;
+ break;
+ }
+ __receive_buf(tty, cp, fp, n);
+ cp += n;
+ if (fp)
+ fp += n;
+ count -= n;
+ rcvd += n;
+ }
- /* FIXME: there is a tiny race here if the receive room check runs
- before the other work executes and empties the buffer (upping
- the receiving room and unthrottling. We then throttle and get
- stuck. This has been observed and traced down by Vincent Pillet/
- We need to address this when we sort out out the rx path locking */
+ tty->receive_room = room;
+ n_tty_check_throttle(tty);
+ up_read(&tty->termios_rwsem);
+
+ return rcvd;
+}
+
+static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
+ char *fp, int count)
+{
+ n_tty_receive_buf_common(tty, cp, fp, count, 0);
+}
+
+static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp,
+ char *fp, int count)
+{
+ return n_tty_receive_buf_common(tty, cp, fp, count, 1);
}
int is_ignored(int sig)
@@ -1509,72 +1744,67 @@ int is_ignored(int sig)
* guaranteed that this function will not be re-entered or in progress
* when the ldisc is closed.
*
- * Locking: Caller holds tty->termios_mutex
+ * Locking: Caller holds tty->termios_rwsem
*/
static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
{
struct n_tty_data *ldata = tty->disc_data;
- int canon_change = 1;
- if (old)
- canon_change = (old->c_lflag ^ tty->termios.c_lflag) & ICANON;
- if (canon_change) {
+ if (!old || (old->c_lflag ^ tty->termios.c_lflag) & ICANON) {
bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE);
- ldata->canon_head = ldata->read_tail;
- ldata->canon_data = 0;
+ ldata->line_start = ldata->read_tail;
+ if (!L_ICANON(tty) || !read_cnt(ldata)) {
+ ldata->canon_head = ldata->read_tail;
+ ldata->push = 0;
+ } else {
+ set_bit((ldata->read_head - 1) & (N_TTY_BUF_SIZE - 1),
+ ldata->read_flags);
+ ldata->canon_head = ldata->read_head;
+ ldata->push = 1;
+ }
ldata->erasing = 0;
+ ldata->lnext = 0;
}
- if (canon_change && !L_ICANON(tty) && ldata->read_cnt)
- wake_up_interruptible(&tty->read_wait);
-
ldata->icanon = (L_ICANON(tty) != 0);
- if (test_bit(TTY_HW_COOK_IN, &tty->flags)) {
- ldata->raw = 1;
- ldata->real_raw = 1;
- n_tty_set_room(tty);
- return;
- }
+
if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) ||
I_ICRNL(tty) || I_INLCR(tty) || L_ICANON(tty) ||
I_IXON(tty) || L_ISIG(tty) || L_ECHO(tty) ||
I_PARMRK(tty)) {
- bitmap_zero(ldata->process_char_map, 256);
+ bitmap_zero(ldata->char_map, 256);
if (I_IGNCR(tty) || I_ICRNL(tty))
- set_bit('\r', ldata->process_char_map);
+ set_bit('\r', ldata->char_map);
if (I_INLCR(tty))
- set_bit('\n', ldata->process_char_map);
+ set_bit('\n', ldata->char_map);
if (L_ICANON(tty)) {
- set_bit(ERASE_CHAR(tty), ldata->process_char_map);
- set_bit(KILL_CHAR(tty), ldata->process_char_map);
- set_bit(EOF_CHAR(tty), ldata->process_char_map);
- set_bit('\n', ldata->process_char_map);
- set_bit(EOL_CHAR(tty), ldata->process_char_map);
+ set_bit(ERASE_CHAR(tty), ldata->char_map);
+ set_bit(KILL_CHAR(tty), ldata->char_map);
+ set_bit(EOF_CHAR(tty), ldata->char_map);
+ set_bit('\n', ldata->char_map);
+ set_bit(EOL_CHAR(tty), ldata->char_map);
if (L_IEXTEN(tty)) {
- set_bit(WERASE_CHAR(tty),
- ldata->process_char_map);
- set_bit(LNEXT_CHAR(tty),
- ldata->process_char_map);
- set_bit(EOL2_CHAR(tty),
- ldata->process_char_map);
+ set_bit(WERASE_CHAR(tty), ldata->char_map);
+ set_bit(LNEXT_CHAR(tty), ldata->char_map);
+ set_bit(EOL2_CHAR(tty), ldata->char_map);
if (L_ECHO(tty))
set_bit(REPRINT_CHAR(tty),
- ldata->process_char_map);
+ ldata->char_map);
}
}
if (I_IXON(tty)) {
- set_bit(START_CHAR(tty), ldata->process_char_map);
- set_bit(STOP_CHAR(tty), ldata->process_char_map);
+ set_bit(START_CHAR(tty), ldata->char_map);
+ set_bit(STOP_CHAR(tty), ldata->char_map);
}
if (L_ISIG(tty)) {
- set_bit(INTR_CHAR(tty), ldata->process_char_map);
- set_bit(QUIT_CHAR(tty), ldata->process_char_map);
- set_bit(SUSP_CHAR(tty), ldata->process_char_map);
+ set_bit(INTR_CHAR(tty), ldata->char_map);
+ set_bit(QUIT_CHAR(tty), ldata->char_map);
+ set_bit(SUSP_CHAR(tty), ldata->char_map);
}
- clear_bit(__DISABLED_CHAR, ldata->process_char_map);
+ clear_bit(__DISABLED_CHAR, ldata->char_map);
ldata->raw = 0;
ldata->real_raw = 0;
} else {
@@ -1587,9 +1817,20 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
ldata->real_raw = 0;
}
n_tty_set_room(tty);
+ /*
+ * Fix tty hang when I_IXON(tty) is cleared, but the tty
+ * been stopped by STOP_CHAR(tty) before it.
+ */
+ if (!I_IXON(tty) && old && (old->c_iflag & IXON) && !tty->flow_stopped) {
+ start_tty(tty);
+ process_echoes(tty);
+ }
+
/* The termios change make the tty ready for I/O */
- wake_up_interruptible(&tty->write_wait);
- wake_up_interruptible(&tty->read_wait);
+ if (waitqueue_active(&tty->write_wait))
+ wake_up_interruptible(&tty->write_wait);
+ if (waitqueue_active(&tty->read_wait))
+ wake_up_interruptible(&tty->read_wait);
}
/**
@@ -1606,10 +1847,10 @@ static void n_tty_close(struct tty_struct *tty)
{
struct n_tty_data *ldata = tty->disc_data;
- n_tty_flush_buffer(tty);
- kfree(ldata->read_buf);
- kfree(ldata->echo_buf);
- kfree(ldata);
+ if (tty->link)
+ n_tty_packet_mode_flush(tty);
+
+ vfree(ldata);
tty->disc_data = NULL;
}
@@ -1627,51 +1868,43 @@ static int n_tty_open(struct tty_struct *tty)
{
struct n_tty_data *ldata;
- ldata = kzalloc(sizeof(*ldata), GFP_KERNEL);
+ /* Currently a malloc failure here can panic */
+ ldata = vmalloc(sizeof(*ldata));
if (!ldata)
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);
- 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;
- reset_buffer_flags(tty);
- tty_unthrottle(tty);
+ reset_buffer_flags(tty->disc_data);
ldata->column = 0;
- n_tty_set_termios(tty, NULL);
- tty->minimum_to_wake = 1;
+ ldata->canon_column = 0;
+ ldata->minimum_to_wake = 1;
+ ldata->num_overrun = 0;
+ ldata->no_room = 0;
+ ldata->lnext = 0;
tty->closing = 0;
+ /* indicate buffer work may resume */
+ clear_bit(TTY_LDISC_HALTED, &tty->flags);
+ n_tty_set_termios(tty, NULL);
+ tty_unthrottle(tty);
return 0;
-err_free_bufs:
- kfree(ldata->read_buf);
- kfree(ldata->echo_buf);
- kfree(ldata);
err:
return -ENOMEM;
}
-static inline int input_available_p(struct tty_struct *tty, int amt)
+static inline int input_available_p(struct tty_struct *tty, int poll)
{
struct n_tty_data *ldata = tty->disc_data;
+ int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1;
- tty_flush_to_ldisc(tty);
- if (ldata->icanon && !L_EXTPROC(tty)) {
- if (ldata->canon_data)
- return 1;
- } else if (ldata->read_cnt >= (amt ? amt : 1))
- return 1;
-
- return 0;
+ if (ldata->icanon && !L_EXTPROC(tty))
+ return ldata->canon_head != ldata->read_tail;
+ else
+ return read_cnt(ldata) >= amt;
}
/**
@@ -1689,6 +1922,9 @@ static inline int input_available_p(struct tty_struct *tty, int amt)
*
* Called under the ldata->atomic_read_lock sem
*
+ * n_tty_read()/consumer path:
+ * caller holds non-exclusive termios_rwsem
+ * read_tail published
*/
static int copy_from_read_buf(struct tty_struct *tty,
@@ -1699,34 +1935,126 @@ static int copy_from_read_buf(struct tty_struct *tty,
struct n_tty_data *ldata = tty->disc_data;
int retval;
size_t n;
- unsigned long flags;
bool is_eof;
+ size_t tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1);
retval = 0;
- spin_lock_irqsave(&ldata->read_lock, flags);
- n = min(ldata->read_cnt, N_TTY_BUF_SIZE - ldata->read_tail);
+ n = min(read_cnt(ldata), N_TTY_BUF_SIZE - tail);
n = min(*nr, n);
- spin_unlock_irqrestore(&ldata->read_lock, flags);
if (n) {
- retval = copy_to_user(*b, &ldata->read_buf[ldata->read_tail], n);
+ retval = copy_to_user(*b, read_buf_addr(ldata, tail), n);
n -= retval;
- is_eof = n == 1 &&
- ldata->read_buf[ldata->read_tail] == EOF_CHAR(tty);
- tty_audit_add_data(tty, &ldata->read_buf[ldata->read_tail], n,
+ is_eof = n == 1 && read_buf(ldata, tail) == EOF_CHAR(tty);
+ tty_audit_add_data(tty, read_buf_addr(ldata, tail), n,
ldata->icanon);
- spin_lock_irqsave(&ldata->read_lock, flags);
- ldata->read_tail = (ldata->read_tail + n) & (N_TTY_BUF_SIZE-1);
- ldata->read_cnt -= n;
+ ldata->read_tail += n;
/* Turn single EOF into zero-length read */
- if (L_EXTPROC(tty) && ldata->icanon && is_eof && !ldata->read_cnt)
+ if (L_EXTPROC(tty) && ldata->icanon && is_eof && !read_cnt(ldata))
n = 0;
- spin_unlock_irqrestore(&ldata->read_lock, flags);
*b += n;
*nr -= n;
}
return retval;
}
+/**
+ * canon_copy_from_read_buf - copy read data in canonical mode
+ * @tty: terminal device
+ * @b: user data
+ * @nr: size of data
+ *
+ * Helper function for n_tty_read. It is only called when ICANON is on;
+ * it copies one line of input up to and including the line-delimiting
+ * character into the user-space buffer.
+ *
+ * NB: When termios is changed from non-canonical to canonical mode and
+ * the read buffer contains data, n_tty_set_termios() simulates an EOF
+ * push (as if C-d were input) _without_ the DISABLED_CHAR in the buffer.
+ * This causes data already processed as input to be immediately available
+ * as input although a newline has not been received.
+ *
+ * Called under the atomic_read_lock mutex
+ *
+ * n_tty_read()/consumer path:
+ * caller holds non-exclusive termios_rwsem
+ * read_tail published
+ */
+
+static int canon_copy_from_read_buf(struct tty_struct *tty,
+ unsigned char __user **b,
+ size_t *nr)
+{
+ struct n_tty_data *ldata = tty->disc_data;
+ size_t n, size, more, c;
+ size_t eol;
+ size_t tail;
+ int ret, found = 0;
+ bool eof_push = 0;
+
+ /* N.B. avoid overrun if nr == 0 */
+ n = min(*nr, read_cnt(ldata));
+ if (!n)
+ return 0;
+
+ tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1);
+ size = min_t(size_t, tail + n, N_TTY_BUF_SIZE);
+
+ n_tty_trace("%s: nr:%zu tail:%zu n:%zu size:%zu\n",
+ __func__, *nr, tail, n, size);
+
+ eol = find_next_bit(ldata->read_flags, size, tail);
+ more = n - (size - tail);
+ if (eol == N_TTY_BUF_SIZE && more) {
+ /* scan wrapped without finding set bit */
+ eol = find_next_bit(ldata->read_flags, more, 0);
+ if (eol != more)
+ found = 1;
+ } else if (eol != size)
+ found = 1;
+
+ size = N_TTY_BUF_SIZE - tail;
+ n = eol - tail;
+ if (n > 4096)
+ n += 4096;
+ n += found;
+ c = n;
+
+ if (found && !ldata->push && read_buf(ldata, eol) == __DISABLED_CHAR) {
+ n--;
+ eof_push = !n && ldata->read_tail != ldata->line_start;
+ }
+
+ n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n",
+ __func__, eol, found, n, c, size, more);
+
+ if (n > size) {
+ ret = copy_to_user(*b, read_buf_addr(ldata, tail), size);
+ if (ret)
+ return -EFAULT;
+ ret = copy_to_user(*b + size, ldata->read_buf, n - size);
+ } else
+ ret = copy_to_user(*b, read_buf_addr(ldata, tail), n);
+
+ if (ret)
+ return -EFAULT;
+ *b += n;
+ *nr -= n;
+
+ if (found)
+ clear_bit(eol, ldata->read_flags);
+ smp_mb__after_atomic();
+ ldata->read_tail += c;
+
+ if (found) {
+ if (!ldata->push)
+ ldata->line_start = ldata->read_tail;
+ else
+ ldata->push = 0;
+ tty_audit_push(tty);
+ }
+ return eof_push ? -EAGAIN : 0;
+}
+
extern ssize_t redirected_tty_write(struct file *, const char __user *,
size_t, loff_t *);
@@ -1739,10 +2067,9 @@ extern ssize_t redirected_tty_write(struct file *, const char __user *,
* and if appropriate send any needed signals and return a negative
* error code if action should be taken.
*
- * FIXME:
- * Locking: None - redirected write test is safe, testing
- * current->signal should possibly lock current->sighand
- * pgrp locking ?
+ * Locking: redirected write test is safe
+ * current->signal->tty check is safe
+ * ctrl_lock to safely reference tty->pgrp
*/
static int job_control(struct tty_struct *tty, struct file *file)
@@ -1752,19 +2079,22 @@ static int job_control(struct tty_struct *tty, struct file *file)
/* NOTE: not yet done after every sleep pending a thorough
check of the logic of this change. -- jlc */
/* don't stop on /dev/console */
- if (file->f_op->write != redirected_tty_write &&
- current->signal->tty == tty) {
- if (!tty->pgrp)
- printk(KERN_ERR "n_tty_read: no tty->pgrp!\n");
- else if (task_pgrp(current) != tty->pgrp) {
- if (is_ignored(SIGTTIN) ||
- is_current_pgrp_orphaned())
- return -EIO;
- kill_pgrp(task_pgrp(current), SIGTTIN, 1);
- set_thread_flag(TIF_SIGPENDING);
- return -ERESTARTSYS;
- }
+ if (file->f_op->write == redirected_tty_write ||
+ current->signal->tty != tty)
+ return 0;
+
+ spin_lock_irq(&tty->ctrl_lock);
+ if (!tty->pgrp)
+ printk(KERN_ERR "n_tty_read: no tty->pgrp!\n");
+ else if (task_pgrp(current) != tty->pgrp) {
+ spin_unlock_irq(&tty->ctrl_lock);
+ if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned())
+ return -EIO;
+ kill_pgrp(task_pgrp(current), SIGTTIN, 1);
+ set_thread_flag(TIF_SIGPENDING);
+ return -ERESTARTSYS;
}
+ spin_unlock_irq(&tty->ctrl_lock);
return 0;
}
@@ -1782,6 +2112,10 @@ static int job_control(struct tty_struct *tty, struct file *file)
* a hangup. Always called in user context, may sleep.
*
* This code must be sure never to sleep through a hangup.
+ *
+ * n_tty_read()/consumer path:
+ * claims non-exclusive termios_rwsem
+ * publishes read_tail
*/
static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
@@ -1793,47 +2127,44 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
int c;
int minimum, time;
ssize_t retval = 0;
- ssize_t size;
long timeout;
unsigned long flags;
int packet;
-do_it_again:
c = job_control(tty, file);
if (c < 0)
return c;
+ /*
+ * Internal serialization of reads.
+ */
+ if (file->f_flags & O_NONBLOCK) {
+ if (!mutex_trylock(&ldata->atomic_read_lock))
+ return -EAGAIN;
+ } else {
+ if (mutex_lock_interruptible(&ldata->atomic_read_lock))
+ return -ERESTARTSYS;
+ }
+
+ down_read(&tty->termios_rwsem);
+
minimum = time = 0;
timeout = MAX_SCHEDULE_TIMEOUT;
if (!ldata->icanon) {
- time = (HZ / 10) * TIME_CHAR(tty);
minimum = MIN_CHAR(tty);
if (minimum) {
+ time = (HZ / 10) * TIME_CHAR(tty);
if (time)
- tty->minimum_to_wake = 1;
+ ldata->minimum_to_wake = 1;
else if (!waitqueue_active(&tty->read_wait) ||
- (tty->minimum_to_wake > minimum))
- tty->minimum_to_wake = minimum;
+ (ldata->minimum_to_wake > minimum))
+ ldata->minimum_to_wake = minimum;
} else {
- timeout = 0;
- if (time) {
- timeout = time;
- time = 0;
- }
- tty->minimum_to_wake = minimum = 1;
+ timeout = (HZ / 10) * TIME_CHAR(tty);
+ ldata->minimum_to_wake = minimum = 1;
}
}
- /*
- * Internal serialization of reads.
- */
- if (file->f_flags & O_NONBLOCK) {
- if (!mutex_trylock(&ldata->atomic_read_lock))
- return -EAGAIN;
- } else {
- if (mutex_lock_interruptible(&ldata->atomic_read_lock))
- return -ERESTARTSYS;
- }
packet = tty->packet;
add_wait_queue(&tty->read_wait, &wait);
@@ -1860,31 +2191,40 @@ do_it_again:
TASK_RUNNING. */
set_current_state(TASK_INTERRUPTIBLE);
- if (((minimum - (b - buf)) < tty->minimum_to_wake) &&
+ if (((minimum - (b - buf)) < ldata->minimum_to_wake) &&
((minimum - (b - buf)) >= 1))
- tty->minimum_to_wake = (minimum - (b - buf));
+ ldata->minimum_to_wake = (minimum - (b - buf));
if (!input_available_p(tty, 0)) {
if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
- retval = -EIO;
- break;
- }
- if (tty_hung_up_p(file))
- break;
- if (!timeout)
- break;
- if (file->f_flags & O_NONBLOCK) {
- retval = -EAGAIN;
- break;
- }
- if (signal_pending(current)) {
- retval = -ERESTARTSYS;
- break;
+ up_read(&tty->termios_rwsem);
+ tty_flush_to_ldisc(tty);
+ down_read(&tty->termios_rwsem);
+ if (!input_available_p(tty, 0)) {
+ retval = -EIO;
+ break;
+ }
+ } else {
+ if (tty_hung_up_p(file))
+ break;
+ if (!timeout)
+ break;
+ if (file->f_flags & O_NONBLOCK) {
+ retval = -EAGAIN;
+ break;
+ }
+ if (signal_pending(current)) {
+ retval = -ERESTARTSYS;
+ break;
+ }
+ n_tty_set_room(tty);
+ up_read(&tty->termios_rwsem);
+
+ timeout = schedule_timeout(timeout);
+
+ down_read(&tty->termios_rwsem);
+ continue;
}
- /* FIXME: does n_tty_set_room need locking ? */
- n_tty_set_room(tty);
- timeout = schedule_timeout(timeout);
- continue;
}
__set_current_state(TASK_RUNNING);
@@ -1899,45 +2239,11 @@ do_it_again:
}
if (ldata->icanon && !L_EXTPROC(tty)) {
- /* N.B. avoid overrun if nr == 0 */
- spin_lock_irqsave(&ldata->read_lock, flags);
- while (nr && ldata->read_cnt) {
- int eol;
-
- eol = test_and_clear_bit(ldata->read_tail,
- ldata->read_flags);
- c = ldata->read_buf[ldata->read_tail];
- ldata->read_tail = ((ldata->read_tail+1) &
- (N_TTY_BUF_SIZE-1));
- ldata->read_cnt--;
- if (eol) {
- /* this test should be redundant:
- * we shouldn't be reading data if
- * canon_data is 0
- */
- if (--ldata->canon_data < 0)
- ldata->canon_data = 0;
- }
- 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(&ldata->read_lock, flags);
- break;
- }
- nr--;
- }
- if (eol) {
- tty_audit_push(tty);
- spin_lock_irqsave(&ldata->read_lock, flags);
- break;
- }
- spin_lock_irqsave(&ldata->read_lock, flags);
- }
- spin_unlock_irqrestore(&ldata->read_lock, flags);
- if (retval)
+ retval = canon_copy_from_read_buf(tty, &b, &nr);
+ if (retval == -EAGAIN) {
+ retval = 0;
+ continue;
+ } else if (retval)
break;
} else {
int uncopied;
@@ -1951,39 +2257,26 @@ do_it_again:
}
}
- /* If there is enough space in the read buffer now, let the
- * low-level driver know. We use n_tty_chars_in_buffer() to
- * check the buffer, as it now knows about canonical mode.
- * Otherwise, if the driver is throttled and the line is
- * longer than TTY_THRESHOLD_UNTHROTTLE in canonical mode,
- * we won't get any more characters.
- */
- if (n_tty_chars_in_buffer(tty) <= TTY_THRESHOLD_UNTHROTTLE) {
- n_tty_set_room(tty);
- check_unthrottle(tty);
- }
+ n_tty_check_unthrottle(tty);
if (b - buf >= minimum)
break;
if (time)
timeout = time;
}
- mutex_unlock(&ldata->atomic_read_lock);
- remove_wait_queue(&tty->read_wait, &wait);
+ n_tty_set_room(tty);
+ up_read(&tty->termios_rwsem);
+ remove_wait_queue(&tty->read_wait, &wait);
if (!waitqueue_active(&tty->read_wait))
- tty->minimum_to_wake = minimum;
+ ldata->minimum_to_wake = minimum;
+
+ mutex_unlock(&ldata->atomic_read_lock);
__set_current_state(TASK_RUNNING);
- size = b - buf;
- if (size) {
- retval = size;
- if (nr)
- clear_bit(TTY_PUSH, &tty->flags);
- } else if (test_and_clear_bit(TTY_PUSH, &tty->flags))
- goto do_it_again;
+ if (b - buf)
+ retval = b - buf;
- n_tty_set_room(tty);
return retval;
}
@@ -2024,6 +2317,8 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
return retval;
}
+ down_read(&tty->termios_rwsem);
+
/* Write out any echoed characters that are still pending */
process_echoes(tty);
@@ -2038,7 +2333,7 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
retval = -EIO;
break;
}
- if (O_OPOST(tty) && !(test_bit(TTY_HW_COOK_OUT, &tty->flags))) {
+ if (O_OPOST(tty)) {
while (nr > 0) {
ssize_t num = process_output_block(tty, b, nr);
if (num < 0) {
@@ -2059,8 +2354,12 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
if (tty->ops->flush_chars)
tty->ops->flush_chars(tty);
} else {
+ struct n_tty_data *ldata = tty->disc_data;
+
while (nr > 0) {
+ mutex_lock(&ldata->output_lock);
c = tty->ops->write(tty, b, nr);
+ mutex_unlock(&ldata->output_lock);
if (c < 0) {
retval = c;
goto break_out;
@@ -2077,13 +2376,18 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
retval = -EAGAIN;
break;
}
+ up_read(&tty->termios_rwsem);
+
schedule();
+
+ down_read(&tty->termios_rwsem);
}
break_out:
__set_current_state(TASK_RUNNING);
remove_wait_queue(&tty->write_wait, &wait);
if (b - buf != nr && tty->fasync)
set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+ up_read(&tty->termios_rwsem);
return (b - buf) ? b - buf : retval;
}
@@ -2104,11 +2408,12 @@ break_out:
static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
poll_table *wait)
{
+ struct n_tty_data *ldata = tty->disc_data;
unsigned int mask = 0;
poll_wait(file, &tty->read_wait, wait);
poll_wait(file, &tty->write_wait, wait);
- if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty)))
+ if (input_available_p(tty, 1))
mask |= POLLIN | POLLRDNORM;
if (tty->packet && tty->link->ctrl_status)
mask |= POLLPRI | POLLIN | POLLRDNORM;
@@ -2118,9 +2423,9 @@ static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
mask |= POLLHUP;
if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) {
if (MIN_CHAR(tty) && !TIME_CHAR(tty))
- tty->minimum_to_wake = MIN_CHAR(tty);
+ ldata->minimum_to_wake = MIN_CHAR(tty);
else
- tty->minimum_to_wake = 1;
+ ldata->minimum_to_wake = 1;
}
if (tty->ops->write && !tty_is_writelocked(tty) &&
tty_chars_in_buffer(tty) < WAKEUP_CHARS &&
@@ -2131,19 +2436,19 @@ static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
static unsigned long inq_canon(struct n_tty_data *ldata)
{
- int nr, head, tail;
+ size_t nr, head, tail;
- if (!ldata->canon_data)
+ if (ldata->canon_head == ldata->read_tail)
return 0;
head = ldata->canon_head;
tail = ldata->read_tail;
- nr = (head - tail) & (N_TTY_BUF_SIZE-1);
+ nr = head - tail;
/* Skip EOF-chars.. */
while (head != tail) {
- if (test_bit(tail, ldata->read_flags) &&
- ldata->read_buf[tail] == __DISABLED_CHAR)
+ if (test_bit(tail & (N_TTY_BUF_SIZE - 1), ldata->read_flags) &&
+ read_buf(ldata, tail) == __DISABLED_CHAR)
nr--;
- tail = (tail+1) & (N_TTY_BUF_SIZE-1);
+ tail++;
}
return nr;
}
@@ -2158,16 +2463,30 @@ static int n_tty_ioctl(struct tty_struct *tty, struct file *file,
case TIOCOUTQ:
return put_user(tty_chars_in_buffer(tty), (int __user *) arg);
case TIOCINQ:
- /* FIXME: Locking */
- retval = ldata->read_cnt;
+ down_write(&tty->termios_rwsem);
if (L_ICANON(tty))
retval = inq_canon(ldata);
+ else
+ retval = read_cnt(ldata);
+ up_write(&tty->termios_rwsem);
return put_user(retval, (unsigned int __user *) arg);
default:
return n_tty_ioctl_helper(tty, file, cmd, arg);
}
}
+static void n_tty_fasync(struct tty_struct *tty, int on)
+{
+ struct n_tty_data *ldata = tty->disc_data;
+
+ if (!waitqueue_active(&tty->read_wait)) {
+ if (on)
+ ldata->minimum_to_wake = 1;
+ else if (!tty->fasync)
+ ldata->minimum_to_wake = N_TTY_BUF_SIZE;
+ }
+}
+
struct tty_ldisc_ops tty_ldisc_N_TTY = {
.magic = TTY_LDISC_MAGIC,
.name = "n_tty",
@@ -2181,14 +2500,16 @@ struct tty_ldisc_ops tty_ldisc_N_TTY = {
.set_termios = n_tty_set_termios,
.poll = n_tty_poll,
.receive_buf = n_tty_receive_buf,
- .write_wakeup = n_tty_write_wakeup
+ .write_wakeup = n_tty_write_wakeup,
+ .fasync = n_tty_fasync,
+ .receive_buf2 = n_tty_receive_buf2,
};
/**
* n_tty_inherit_ops - inherit N_TTY methods
* @ops: struct tty_ldisc_ops where to save N_TTY methods
*
- * Used by a generic struct tty_ldisc_ops to easily inherit N_TTY
+ * Enables a 'subclass' line discipline to 'inherit' N_TTY
* methods.
*/
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-09 12:09:03 +0000