From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Hunter Subject: [PATCH 3/8] serial: tegra: check the count and read if any from dma Date: Tue, 5 May 2015 15:17:54 +0100 Message-ID: <1430835479-6613-4-git-send-email-jonathanh@nvidia.com> References: <1430835479-6613-1-git-send-email-jonathanh@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <1430835479-6613-1-git-send-email-jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Laxman Dewangan , Greg Kroah-Hartman , Jiri Slaby Cc: linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Shardar Shariff Md , Jon Hunter List-Id: linux-serial@vger.kernel.org From: Shardar Shariff Md It is only necessary to read data from the dma buffer when the count value is non-zero and hence, tegra_uart_copy_rx_to_tty() so only be called when this is the case. Although, this was being tested for in two places, there is a third place where this was not tested. However, instead of adding another if-statement prior to calling tegra_uart_copy_rx_to_tty(), move the test inside the function. Signed-off-by: Shardar Shariff Md [jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org: Re-worked patch to move the check for the count value inside the function tegra_uart_copy_rx_to_tty(). Updated changelog with more commentary.] Signed-off-by: Jon Hunter --- drivers/tty/serial/serial-tegra.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c index 0d9d7ceb1dbb..a53899c47e60 100644 --- a/drivers/tty/serial/serial-tegra.c +++ b/drivers/tty/serial/serial-tegra.c @@ -554,6 +554,10 @@ static void tegra_uart_copy_rx_to_tty(struct tegra_uart_port *tup, { int copied; + /* If count is zero, then there is no data to be copied */ + if (!count) + return; + tup->uport.icount.rx += count; if (!tty) { dev_err(tup->uport.dev, "No tty port\n"); @@ -588,8 +592,7 @@ static void tegra_uart_rx_dma_complete(void *args) set_rts(tup, false); /* If we are here, DMA is stopped */ - if (count) - tegra_uart_copy_rx_to_tty(tup, port, count); + tegra_uart_copy_rx_to_tty(tup, port, count); tegra_uart_handle_rx_pio(tup, port); if (tty) { @@ -626,8 +629,7 @@ static void tegra_uart_handle_rx_dma(struct tegra_uart_port *tup, count = tup->rx_bytes_requested - state.residue; /* If we are here, DMA is stopped */ - if (count) - tegra_uart_copy_rx_to_tty(tup, port, count); + tegra_uart_copy_rx_to_tty(tup, port, count); tegra_uart_handle_rx_pio(tup, port); if (tty) { -- 1.9.1