From b1c43f82c5aa265442f82dba31ce985ebb7aa71c Mon Sep 17 00:00:00 2001 From: Felipe Balbi Date: Mon, 21 Mar 2011 12:25:08 +0200 Subject: tty: make receive_buf() return the amout of bytes received it makes it simpler to keep track of the amount of bytes received and simplifies how flush_to_ldisc counts the remaining bytes. It also fixes a bug of lost bytes on n_tty when flushing too many bytes via the USB serial gadget driver. Tested-by: Stefan Bigler Tested-by: Toby Gray Signed-off-by: Felipe Balbi Signed-off-by: Greg Kroah-Hartman --- drivers/tty/n_gsm.c | 6 +++-- drivers/tty/n_hdlc.c | 18 ++++++++------ drivers/tty/n_r3964.c | 10 +++++--- drivers/tty/n_tty.c | 61 +++++++++++----------------------------------- drivers/tty/tty_buffer.c | 15 +++++++----- drivers/tty/vt/selection.c | 3 +-- 6 files changed, 44 insertions(+), 69 deletions(-) (limited to 'drivers/tty') diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c index 47f8cdb207f1..6abc73598847 100644 --- a/drivers/tty/n_gsm.c +++ b/drivers/tty/n_gsm.c @@ -2138,8 +2138,8 @@ static void gsmld_detach_gsm(struct tty_struct *tty, struct gsm_mux *gsm) gsm->tty = NULL; } -static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, - char *fp, int count) +static unsigned int gsmld_receive_buf(struct tty_struct *tty, + const unsigned char *cp, char *fp, int count) { struct gsm_mux *gsm = tty->disc_data; const unsigned char *dp; @@ -2173,6 +2173,8 @@ static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp, } /* FASYNC if needed ? */ /* If clogged call tty_throttle(tty); */ + + return count; } /** diff --git a/drivers/tty/n_hdlc.c b/drivers/tty/n_hdlc.c index cea56033b34c..cac666314aef 100644 --- a/drivers/tty/n_hdlc.c +++ b/drivers/tty/n_hdlc.c @@ -188,8 +188,8 @@ static unsigned int n_hdlc_tty_poll(struct tty_struct *tty, struct file *filp, poll_table *wait); static int n_hdlc_tty_open(struct tty_struct *tty); static void n_hdlc_tty_close(struct tty_struct *tty); -static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *cp, - char *fp, int count); +static unsigned int n_hdlc_tty_receive(struct tty_struct *tty, + const __u8 *cp, char *fp, int count); static void n_hdlc_tty_wakeup(struct tty_struct *tty); #define bset(p,b) ((p)[(b) >> 5] |= (1 << ((b) & 0x1f))) @@ -509,8 +509,8 @@ static void n_hdlc_tty_wakeup(struct tty_struct *tty) * Called by tty low level driver when receive data is available. Data is * interpreted as one HDLC frame. */ -static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data, - char *flags, int count) +static unsigned int n_hdlc_tty_receive(struct tty_struct *tty, + const __u8 *data, char *flags, int count) { register struct n_hdlc *n_hdlc = tty2n_hdlc (tty); register struct n_hdlc_buf *buf; @@ -521,20 +521,20 @@ static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data, /* This can happen if stuff comes in on the backup tty */ if (!n_hdlc || tty != n_hdlc->tty) - return; + return -ENODEV; /* verify line is using HDLC discipline */ if (n_hdlc->magic != HDLC_MAGIC) { printk("%s(%d) line not using HDLC discipline\n", __FILE__,__LINE__); - return; + return -EINVAL; } if ( count>maxframe ) { if (debuglevel >= DEBUG_LEVEL_INFO) printk("%s(%d) rx count>maxframesize, data discarded\n", __FILE__,__LINE__); - return; + return -EINVAL; } /* get a free HDLC buffer */ @@ -550,7 +550,7 @@ static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data, if (debuglevel >= DEBUG_LEVEL_INFO) printk("%s(%d) no more rx buffers, data discarded\n", __FILE__,__LINE__); - return; + return -EINVAL; } /* copy received data to HDLC buffer */ @@ -565,6 +565,8 @@ static void n_hdlc_tty_receive(struct tty_struct *tty, const __u8 *data, if (n_hdlc->tty->fasync != NULL) kill_fasync (&n_hdlc->tty->fasync, SIGIO, POLL_IN); + return count; + } /* end of n_hdlc_tty_receive() */ /** diff --git a/drivers/tty/n_r3964.c b/drivers/tty/n_r3964.c index 5c6c31459a2f..a4bc39c21a43 100644 --- a/drivers/tty/n_r3964.c +++ b/drivers/tty/n_r3964.c @@ -139,8 +139,8 @@ static int r3964_ioctl(struct tty_struct *tty, struct file *file, static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old); static unsigned int r3964_poll(struct tty_struct *tty, struct file *file, struct poll_table_struct *wait); -static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp, - char *fp, int count); +static unsigned int r3964_receive_buf(struct tty_struct *tty, + const unsigned char *cp, char *fp, int count); static struct tty_ldisc_ops tty_ldisc_N_R3964 = { .owner = THIS_MODULE, @@ -1239,8 +1239,8 @@ static unsigned int r3964_poll(struct tty_struct *tty, struct file *file, return result; } -static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp, - char *fp, int count) +static unsigned int r3964_receive_buf(struct tty_struct *tty, + const unsigned char *cp, char *fp, int count) { struct r3964_info *pInfo = tty->disc_data; const unsigned char *p; @@ -1257,6 +1257,8 @@ static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp, } } + + return count; } MODULE_LICENSE("GPL"); diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index 0ad32888091c..95d0a9c2dd13 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -81,38 +81,6 @@ 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) -{ - /* tty->read_cnt is not read locked ? */ - int left = N_TTY_BUF_SIZE - tty->read_cnt - 1; - int old_left; - - /* - * If we are doing input canonicalization, and there are no - * pending newlines, let characters through without limit, so - * that erase characters will be handled. Other excess - * characters will be beeped. - */ - if (left <= 0) - left = tty->icanon && !tty->canon_data; - old_left = tty->receive_room; - tty->receive_room = left; - - /* Did this open up the receive buffer? We may need to flip */ - if (left && !old_left) - schedule_work(&tty->buf.work); -} - static void put_tty_queue_nolock(unsigned char c, struct tty_struct *tty) { if (tty->read_cnt < N_TTY_BUF_SIZE) { @@ -184,7 +152,6 @@ static void reset_buffer_flags(struct tty_struct *tty) tty->canon_head = tty->canon_data = tty->erasing = 0; memset(&tty->read_flags, 0, sizeof tty->read_flags); - n_tty_set_room(tty); check_unthrottle(tty); } @@ -1360,17 +1327,19 @@ static void n_tty_write_wakeup(struct tty_struct *tty) * calls one at a time and in order (or using flush_to_ldisc) */ -static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, - char *fp, int count) +static unsigned int n_tty_receive_buf(struct tty_struct *tty, + const unsigned char *cp, char *fp, int count) { const unsigned char *p; char *f, flags = TTY_NORMAL; int i; char buf[64]; unsigned long cpuflags; + int left; + int ret = 0; if (!tty->read_buf) - return; + return 0; if (tty->real_raw) { spin_lock_irqsave(&tty->read_lock, cpuflags); @@ -1380,6 +1349,7 @@ static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, memcpy(tty->read_buf + tty->read_head, cp, i); tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1); tty->read_cnt += i; + ret += i; cp += i; count -= i; @@ -1389,8 +1359,10 @@ static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, memcpy(tty->read_buf + tty->read_head, cp, i); tty->read_head = (tty->read_head + i) & (N_TTY_BUF_SIZE-1); tty->read_cnt += i; + ret += i; spin_unlock_irqrestore(&tty->read_lock, cpuflags); } else { + ret = count; for (i = count, p = cp, f = fp; i; i--, p++) { if (f) flags = *f++; @@ -1418,8 +1390,6 @@ static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, tty->ops->flush_chars(tty); } - n_tty_set_room(tty); - if ((!tty->icanon && (tty->read_cnt >= tty->minimum_to_wake)) || L_EXTPROC(tty)) { kill_fasync(&tty->fasync, SIGIO, POLL_IN); @@ -1432,8 +1402,12 @@ static void n_tty_receive_buf(struct tty_struct *tty, const unsigned char *cp, * 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) + left = N_TTY_BUF_SIZE - tty->read_cnt - 1; + + if (left < TTY_THRESHOLD_THROTTLE) tty_throttle(tty); + + return ret; } int is_ignored(int sig) @@ -1477,7 +1451,6 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) if (test_bit(TTY_HW_COOK_IN, &tty->flags)) { tty->raw = 1; tty->real_raw = 1; - n_tty_set_room(tty); return; } if (I_ISTRIP(tty) || I_IUCLC(tty) || I_IGNCR(tty) || @@ -1530,7 +1503,6 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old) else tty->real_raw = 0; } - n_tty_set_room(tty); /* The termios change make the tty ready for I/O */ wake_up_interruptible(&tty->write_wait); wake_up_interruptible(&tty->read_wait); @@ -1812,8 +1784,6 @@ do_it_again: retval = -ERESTARTSYS; break; } - /* FIXME: does n_tty_set_room need locking ? */ - n_tty_set_room(tty); timeout = schedule_timeout(timeout); continue; } @@ -1885,10 +1855,8 @@ do_it_again: * 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); + if (n_tty_chars_in_buffer(tty) <= TTY_THRESHOLD_UNTHROTTLE) check_unthrottle(tty); - } if (b - buf >= minimum) break; @@ -1910,7 +1878,6 @@ do_it_again: } else if (test_and_clear_bit(TTY_PUSH, &tty->flags)) goto do_it_again; - n_tty_set_room(tty); return retval; } diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index f1a7918d71aa..46de2e075dac 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -416,6 +416,7 @@ static void flush_to_ldisc(struct work_struct *work) struct tty_buffer *head, *tail = tty->buf.tail; int seen_tail = 0; while ((head = tty->buf.head) != NULL) { + int copied; int count; char *char_buf; unsigned char *flag_buf; @@ -442,17 +443,19 @@ static void flush_to_ldisc(struct work_struct *work) line discipline as we want to empty the queue */ if (test_bit(TTY_FLUSHPENDING, &tty->flags)) break; - if (!tty->receive_room || seen_tail) - break; - if (count > tty->receive_room) - count = tty->receive_room; char_buf = head->char_buf_ptr + head->read; flag_buf = head->flag_buf_ptr + head->read; - head->read += count; spin_unlock_irqrestore(&tty->buf.lock, flags); - disc->ops->receive_buf(tty, char_buf, + copied = disc->ops->receive_buf(tty, char_buf, flag_buf, count); spin_lock_irqsave(&tty->buf.lock, flags); + + head->read += copied; + + if (copied == 0 || seen_tail) { + schedule_work(&tty->buf.work); + break; + } } clear_bit(TTY_FLUSHING, &tty->flags); } diff --git a/drivers/tty/vt/selection.c b/drivers/tty/vt/selection.c index fb864e7fcd13..67b1d0d7c8ac 100644 --- a/drivers/tty/vt/selection.c +++ b/drivers/tty/vt/selection.c @@ -332,8 +332,7 @@ int paste_selection(struct tty_struct *tty) continue; } count = sel_buffer_lth - pasted; - count = min(count, tty->receive_room); - tty->ldisc->ops->receive_buf(tty, sel_buffer + pasted, + count = tty->ldisc->ops->receive_buf(tty, sel_buffer + pasted, NULL, count); pasted += count; } -- cgit v1.2.3