Merge branch 'sh-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[~andy/linux] / drivers / tty / tty_buffer.c

diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 46de2e075dacda019589cc5462a0d60f6eea8d51..6c9b7cd6778a9613542d739358f309a38fa56070 100644 (file)
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -413,10 +413,8 @@ static void flush_to_ldisc(struct work_struct *work)
        spin_lock_irqsave(&tty->buf.lock, flags);
 
        if (!test_and_set_bit(TTY_FLUSHING, &tty->flags)) {
-               struct tty_buffer *head, *tail = tty->buf.tail;
-               int seen_tail = 0;
+               struct tty_buffer *head;
                while ((head = tty->buf.head) != NULL) {
-                       int copied;
                        int count;
                        char *char_buf;
                        unsigned char *flag_buf;
@@ -425,15 +423,6 @@ static void flush_to_ldisc(struct work_struct *work)
                        if (!count) {
                                if (head->next == NULL)
                                        break;
-                               /*
-                                 There's a possibility tty might get new buffer
-                                 added during the unlock window below. We could
-                                 end up spinning in here forever hogging the CPU
-                                 completely. To avoid this let's have a rest each
-                                 time we processed the tail buffer.
-                               */
-                               if (tail == head)
-                                       seen_tail = 1;
                                tty->buf.head = head->next;
                                tty_buffer_free(tty, head);
                                continue;
@@ -443,19 +432,17 @@ 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)
+                               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);
-                       copied = disc->ops->receive_buf(tty, char_buf,
+                       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);
        }