Re: [PATCH 03/18] Blackfin Serial Driver: fix a bug in dma circle rx buffer handling - v2

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 10 Mar 2009 17:49:29 +0800
sonic zhang <sonic.adi@gmail.com> wrote:

> The rx buffer tail index may increase to UART_XMIT_SIZE, which is not a valid
> index, at the beginning of the Loop. The exit check should happen after this
> index is adjusted properly.
> 
> Reported-by: Qian Zhang <zhangq@sansitech.com>
> Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
> Signed-off-by: Bryan Wu <cooloney@kernel.org>
> ---
>  drivers/serial/bfin_5xx.c |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c
> index 350bfc4..1e027e3 100644
> --- a/drivers/serial/bfin_5xx.c
> +++ b/drivers/serial/bfin_5xx.c
> @@ -402,9 +402,11 @@ 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);

This appears to be identical to the v1 ptch whcih I merged.