Merge commit 'v3.0-rc3' into perf/core

Merge reason: add the latest fixes.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 20 deletions

diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 46de2e075dac..6c9b7cd6778a 100644
--- 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);
 	}