diff options
Diffstat (limited to 'drivers/tty/n_tty.c')
| -rw-r--r-- | drivers/tty/n_tty.c | 1414 |
1 files changed, 845 insertions, 569 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index 4bf0fc0843d7..c9a9ddd1d0bc 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -50,6 +50,7 @@ #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 */ @@ -74,37 +75,81 @@ #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; + 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; - 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; - raw_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) { @@ -114,33 +159,18 @@ 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 - * - * Updates tty->receive_room to reflect the currently available space - * in the input buffer, and re-schedules the flip buffer work if space - * just became available. - * - * Locks: Concurrent update is protected with read_lock - */ - -static int 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; - unsigned long flags; - - raw_spin_lock_irqsave(&ldata->read_lock, flags); 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 @@ -149,19 +179,31 @@ static int 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; - raw_spin_unlock_irqrestore(&ldata->read_lock, flags); - - return left && !old_left; + 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 (set_room(tty)) { + if (unlikely(ldata->no_room) && receive_room(tty)) { + ldata->no_room = 0; + WARN_RATELIMIT(tty->port->itty == NULL, "scheduling with invalid itty\n"); /* see if ldisc has been killed - if so, this means that @@ -170,17 +212,93 @@ static void n_tty_set_room(struct tty_struct *tty) */ WARN_RATELIMIT(test_bit(TTY_LDISC_HALTED, &tty->flags), "scheduling buffer work for halted ldisc\n"); - schedule_work(&tty->port->buf.work); + 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) +{ + 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; +} + +/** + * 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 + */ + +static void n_tty_write_wakeup(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++; + 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; + /* + * 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); + 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); } /** @@ -188,21 +306,19 @@ static void put_tty_queue_nolock(unsigned char c, struct n_tty_data *ldata) * @c: character * @ldata: n_tty data * - * 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 + * Add a character to the tty read_buf queue. + * + * 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 put_tty_queue(unsigned char c, struct n_tty_data *ldata) +static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata) { - unsigned long flags; - /* - * The problem of stomping on the buffers ends here. - * Why didn't anyone see this one coming? --AJK - */ - raw_spin_lock_irqsave(&ldata->read_lock, flags); - put_tty_queue_nolock(c, ldata); - raw_spin_unlock_irqrestore(&ldata->read_lock, flags); + *read_buf_addr(ldata, ldata->read_head++) = c; } /** @@ -212,22 +328,17 @@ static void put_tty_queue(unsigned char c, struct n_tty_data *ldata) * 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 n_tty_data *ldata) { - unsigned long flags; + ldata->read_head = ldata->canon_head = ldata->read_tail = 0; + ldata->echo_head = ldata->echo_tail = ldata->echo_commit = 0; + ldata->line_start = 0; - raw_spin_lock_irqsave(&ldata->read_lock, flags); - ldata->read_head = ldata->read_tail = ldata->read_cnt = 0; - raw_spin_unlock_irqrestore(&ldata->read_lock, flags); - - mutex_lock(&ldata->echo_lock); - ldata->echo_pos = ldata->echo_cnt = ldata->echo_overrun = 0; - mutex_unlock(&ldata->echo_lock); - - ldata->canon_head = ldata->canon_data = ldata->erasing = 0; + ldata->erasing = 0; bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); } @@ -251,16 +362,21 @@ static void n_tty_packet_mode_flush(struct tty_struct *tty) * buffer flushed (eg at hangup) or when the N_TTY line discipline * internally has to clean the pending queue (for example some signals). * - * Locking: ctrl_lock, read_lock. + * Holds termios_rwsem to exclude producer/consumer while + * buffer indices are reset. + * + * Locking: ctrl_lock, exclusive termios_rwsem */ static void n_tty_flush_buffer(struct tty_struct *tty) { + down_write(&tty->termios_rwsem); reset_buffer_flags(tty->disc_data); n_tty_set_room(tty); if (tty->link) n_tty_packet_mode_flush(tty); + up_write(&tty->termios_rwsem); } /** @@ -270,24 +386,18 @@ 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; - raw_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); - } - raw_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; } @@ -532,33 +642,23 @@ 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; - - mutex_lock(&ldata->output_lock); - mutex_lock(&ldata->echo_lock); - space = tty_write_room(tty); + old_space = 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; /* @@ -566,18 +666,13 @@ 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 @@ -603,21 +698,18 @@ 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: @@ -629,8 +721,7 @@ 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: @@ -651,8 +742,7 @@ 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) @@ -669,80 +759,92 @@ 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) == 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; + 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 (!L_ECHO(tty) || ldata->echo_commit == ldata->echo_tail) + return; + + mutex_lock(&ldata->output_lock); + 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); } +static void flush_echoes(struct tty_struct *tty) +{ + struct n_tty_data *ldata = tty->disc_data; + + if (!L_ECHO(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; } /** @@ -750,16 +852,12 @@ 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); } /** @@ -768,16 +866,12 @@ 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); } /** @@ -793,15 +887,11 @@ 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); @@ -813,8 +903,6 @@ 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); } /** @@ -826,20 +914,16 @@ 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); } /** @@ -852,16 +936,12 @@ 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); @@ -870,8 +950,6 @@ 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); } /** @@ -896,17 +974,22 @@ 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; @@ -917,19 +1000,11 @@ static void eraser(unsigned char c, struct tty_struct *tty) kill_type = WERASE; else { if (!L_ECHO(tty)) { - raw_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; - raw_spin_unlock_irqrestore(&ldata->read_lock, flags); return; } if (!L_ECHOK(tty) || !L_ECHOKE(tty) || !L_ECHOE(tty)) { - raw_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; - raw_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. */ @@ -941,14 +1016,13 @@ 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 */ @@ -962,11 +1036,8 @@ 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); - raw_spin_lock_irqsave(&ldata->read_lock, flags); + cnt = ldata->read_head - head; ldata->read_head = head; - ldata->read_cnt -= cnt; - raw_spin_unlock_irqrestore(&ldata->read_lock, flags); if (L_ECHO(tty)) { if (L_ECHOPRT(tty)) { if (!ldata->erasing) { @@ -976,9 +1047,8 @@ 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)) { @@ -986,7 +1056,7 @@ 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 @@ -996,8 +1066,8 @@ 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; @@ -1040,7 +1110,7 @@ static void eraser(unsigned char c, struct tty_struct *tty) * Locking: ctrl_lock */ -static inline void isig(int sig, struct tty_struct *tty) +static void isig(int sig, struct tty_struct *tty) { struct pid *tty_pgrp = tty_get_pgrp(tty); if (tty_pgrp) { @@ -1056,10 +1126,14 @@ static inline void isig(int sig, struct tty_struct *tty) * 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; @@ -1068,8 +1142,11 @@ static inline void n_tty_receive_break(struct tty_struct *tty) if (I_BRKINT(tty)) { 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; } @@ -1094,7 +1171,7 @@ 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]; @@ -1116,10 +1193,13 @@ 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; @@ -1136,6 +1216,26 @@ static inline void n_tty_receive_parity_error(struct tty_struct *tty, 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); + } + isig(signal, tty); + return; +} + /** * n_tty_receive_char - perform processing * @tty: terminal device @@ -1144,117 +1244,54 @@ 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; + commit_echoes(tty); + 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: - 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); - } - isig(signal, tty); - 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)) @@ -1264,8 +1301,8 @@ 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; @@ -1274,42 +1311,32 @@ 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; } @@ -1317,11 +1344,6 @@ send_signal: (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?!? */ @@ -1330,7 +1352,7 @@ 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 @@ -1340,26 +1362,17 @@ send_signal: put_tty_queue(c, ldata); handle_newline: - raw_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++; - raw_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') @@ -1370,29 +1383,123 @@ handle_newline: echo_set_canon_col(ldata); echo_char(c, tty); } - process_echoes(tty); + commit_echoes(tty); } if (parmrk) 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; + int parmrk; -/** - * 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 = (c == (unsigned char) '\377' && I_PARMRK(tty)) ? 1 : 0; + if (parmrk) + put_tty_queue(c, ldata); + put_tty_queue(c, ldata); +} -static void n_tty_write_wakeup(struct tty_struct *tty) +static inline 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 inline 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); } /** @@ -1406,86 +1513,220 @@ 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) { - 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; - raw_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); } - set_room(tty); - - if ((!ldata->icanon && (ldata->read_cnt >= ldata->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); } +} + +static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count) +{ + int room, n; + + down_read(&tty->termios_rwsem); - /* - * 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) { - tty_set_flow_change(tty, TTY_THROTTLE_SAFE); - if (tty->receive_room >= TTY_THRESHOLD_THROTTLE) + room = receive_room(tty); + n = min(count, room); + if (!n) break; - if (!tty_throttle_safe(tty)) + __receive_buf(tty, cp, fp, n); + cp += n; + if (fp) + fp += n; + count -= n; + } + + tty->receive_room = room; + n_tty_check_throttle(tty); + up_read(&tty->termios_rwsem); +} + +static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp, + char *fp, int count) +{ + 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 (!room) + ldata->no_room = 1; break; + } + __receive_buf(tty, cp, fp, n); + cp += n; + if (fp) + fp += n; + count -= n; + rcvd += n; } - __tty_set_flow_change(tty, 0); + + tty->receive_room = room; + n_tty_check_throttle(tty); + up_read(&tty->termios_rwsem); + + return rcvd; } int is_ignored(int sig) @@ -1505,7 +1746,7 @@ 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) @@ -1517,12 +1758,13 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) canon_change = (old->c_lflag ^ tty->termios.c_lflag) & ICANON; if (canon_change) { bitmap_zero(ldata->read_flags, N_TTY_BUF_SIZE); + ldata->line_start = 0; ldata->canon_head = ldata->read_tail; - ldata->canon_data = 0; ldata->erasing = 0; + ldata->lnext = 0; } - if (canon_change && !L_ICANON(tty) && ldata->read_cnt) + if (canon_change && !L_ICANON(tty) && read_cnt(ldata)) wake_up_interruptible(&tty->read_wait); ldata->icanon = (L_ICANON(tty) != 0); @@ -1531,41 +1773,38 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) 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 { @@ -1608,9 +1847,7 @@ static void n_tty_close(struct tty_struct *tty) if (tty->link) n_tty_packet_mode_flush(tty); - kfree(ldata->read_buf); - kfree(ldata->echo_buf); - kfree(ldata); + vfree(ldata); tty->disc_data = NULL; } @@ -1628,26 +1865,23 @@ 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); - raw_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->disc_data); ldata->column = 0; + 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); @@ -1655,10 +1889,6 @@ static int n_tty_open(struct tty_struct *tty) tty_unthrottle(tty); return 0; -err_free_bufs: - kfree(ldata->read_buf); - kfree(ldata->echo_buf); - kfree(ldata); err: return -ENOMEM; } @@ -1667,11 +1897,10 @@ static inline int input_available_p(struct tty_struct *tty, int amt) { struct n_tty_data *ldata = tty->disc_data; - tty_flush_to_ldisc(tty); if (ldata->icanon && !L_EXTPROC(tty)) { - if (ldata->canon_data) + if (ldata->canon_head != ldata->read_tail) return 1; - } else if (ldata->read_cnt >= (amt ? amt : 1)) + } else if (read_cnt(ldata) >= (amt ? amt : 1)) return 1; return 0; @@ -1692,6 +1921,9 @@ 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, @@ -1702,34 +1934,114 @@ 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; - raw_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); - raw_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); - raw_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; - raw_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. + * + * 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 = (found + eol + size) & (N_TTY_BUF_SIZE - 1); + c = n; + + if (found && 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_clear_bit(); + ldata->read_tail += c; + + if (found) { + ldata->line_start = ldata->read_tail; + tty_audit_push(tty); + } + return eof_push ? -EAGAIN : 0; +} + extern ssize_t redirected_tty_write(struct file *, const char __user *, size_t, loff_t *); @@ -1787,6 +2099,10 @@ 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, @@ -1798,16 +2114,27 @@ 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) { @@ -1825,16 +2152,6 @@ do_it_again: } } - /* - * 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); @@ -1883,7 +2200,11 @@ do_it_again: break; } n_tty_set_room(tty); + up_read(&tty->termios_rwsem); + timeout = schedule_timeout(timeout); + + down_read(&tty->termios_rwsem); continue; } __set_current_state(TASK_RUNNING); @@ -1899,45 +2220,11 @@ do_it_again: } if (ldata->icanon && !L_EXTPROC(tty)) { - /* N.B. avoid overrun if nr == 0 */ - raw_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; - } - raw_spin_unlock_irqrestore(&ldata->read_lock, flags); - - if (!eol || (c != __DISABLED_CHAR)) { - if (tty_put_user(tty, c, b++)) { - retval = -EFAULT; - b--; - raw_spin_lock_irqsave(&ldata->read_lock, flags); - break; - } - nr--; - } - if (eol) { - tty_audit_push(tty); - raw_spin_lock_irqsave(&ldata->read_lock, flags); - break; - } - raw_spin_lock_irqsave(&ldata->read_lock, flags); - } - raw_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; @@ -1951,24 +2238,7 @@ 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. - */ - while (1) { - tty_set_flow_change(tty, TTY_UNTHROTTLE_SAFE); - if (n_tty_chars_in_buffer(tty) > TTY_THRESHOLD_UNTHROTTLE) - break; - if (!tty->count) - break; - n_tty_set_room(tty); - if (!tty_unthrottle_safe(tty)) - break; - } - __tty_set_flow_change(tty, 0); + n_tty_check_unthrottle(tty); if (b - buf >= minimum) break; @@ -1982,15 +2252,11 @@ do_it_again: ldata->minimum_to_wake = minimum; __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); + up_read(&tty->termios_rwsem); return retval; } @@ -2031,6 +2297,8 @@ 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); @@ -2084,13 +2352,18 @@ 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; } @@ -2139,19 +2412,19 @@ 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; } @@ -2166,10 +2439,12 @@ 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); @@ -2203,6 +2478,7 @@ struct tty_ldisc_ops tty_ldisc_N_TTY = { .receive_buf = n_tty_receive_buf, .write_wakeup = n_tty_write_wakeup, .fasync = n_tty_fasync, + .receive_buf2 = n_tty_receive_buf2, }; /** |