From 8c4210e3362e1cd44bd10c857dc5f69c0bf434da Mon Sep 17 00:00:00 2001
From: Sonic Zhang <sonic.zhang@analog.com>
Date: Mon, 6 Apr 2009 17:32:42 +0100
Subject: [PATCH] Fix DMA rx ring buffer handling

Reported-by: Qian Zhang <zhangq@sansitech.com>
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 drivers/serial/bfin_5xx.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c
index d7b271656a2..12b11da40b4 100644
--- a/drivers/serial/bfin_5xx.c
+++ b/drivers/serial/bfin_5xx.c
@@ -401,9 +401,11 @@ static void bfin_serial_dma_rx_chars(struct bfin_serial_port *uart)
 	else
 		flg = TTY_NORMAL;
 
-	for (i = uart->rx_dma_buf.tail; i != uart->rx_dma_buf.head; i++) {
+	for (i = uart->rx_dma_buf.tail; ; i++) {
 		if (i >= UART_XMIT_SIZE)
 			i = 0;
+		if (i == uart->rx_dma_buf.head)
+			break;
 		if (!uart_handle_sysrq_char(&uart->port, uart->rx_dma_buf.buf[i]))
 			uart_insert_char(&uart->port, status, OE,
 				uart->rx_dma_buf.buf[i], flg);
-- 
2.41.0