Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752696AbcCVQXj (ORCPT ); Tue, 22 Mar 2016 12:23:39 -0400 Received: from mail-vk0-f42.google.com ([209.85.213.42]:34733 "EHLO mail-vk0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750860AbcCVQX2 (ORCPT ); Tue, 22 Mar 2016 12:23:28 -0400 MIME-Version: 1.0 In-Reply-To: <1458646574-12830-1-git-send-email-shawn.lin@rock-chips.com> References: <1458646574-12830-1-git-send-email-shawn.lin@rock-chips.com> Date: Tue, 22 Mar 2016 09:23:27 -0700 X-Google-Sender-Auth: N0aeuQObrmUTOMzN7XP0_2ixrDI Message-ID: Subject: Re: [PATCH] spi: rockchip: fix warning of static check From: Doug Anderson To: Shawn Lin Cc: Mark Brown , "linux-kernel@vger.kernel.org" , linux-spi@vger.kernel.org, Dan Carpenter Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2372 Lines: 63 Hi, On Tue, Mar 22, 2016 at 4:36 AM, Shawn Lin wrote: > Let's improve the check with -EPROBE_DEFER, otherwise > we may pass on null pointer to PTR_ERR. That causes the > static checker warning: passing zero to 'PTR_ERR'. > > Reported-by: Dan Carpenter > Cc: Doug Anderson > Cc: Dan Carpenter > Signed-off-by: Shawn Lin > --- > > drivers/spi/spi-rockchip.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c > index bfeb0d4..2cb36d9 100644 > --- a/drivers/spi/spi-rockchip.c > +++ b/drivers/spi/spi-rockchip.c > @@ -726,20 +726,24 @@ static int rockchip_spi_probe(struct platform_device *pdev) > rs->dma_tx.ch = dma_request_slave_channel(rs->dev, "tx"); Please change from: dma_request_slave_channel() to: dma_request_chan() The first will never return -EPROBE_DEFER. The second will. > if (IS_ERR_OR_NULL(rs->dma_tx.ch)) { Once you've changed to dma_request_chan(), change IS_ERR_OR_NULL() to just IS_ERR(). dma_request_chan() never returns NULL. > /* Check tx to see if we need defer probing driver */ > - if (PTR_ERR(rs->dma_tx.ch) == -EPROBE_DEFER) { > + if (rs->dma_tx.ch == ERR_PTR(-EPROBE_DEFER)) { Once you've changed to use dma_request_chan(), no need to change this line. Leave it as it was. > ret = -EPROBE_DEFER; > goto err_get_fifo_len; > } > dev_warn(rs->dev, "Failed to request TX DMA channel\n"); > + rs->dma_tx.ch = NULL; > } > > rs->dma_rx.ch = dma_request_slave_channel(rs->dev, "rx"); > - if (!rs->dma_rx.ch) { > - if (rs->dma_tx.ch) { > + if (IS_ERR_OR_NULL(rs->dma_rx.ch)) { > + if (rs->dma_tx.ch == ERR_PTR(-EPROBE_DEFER)) { > dma_release_channel(rs->dma_tx.ch); > rs->dma_tx.ch = NULL; > + ret = -EPROBE_DEFER; > + goto err_get_fifo_len; > } > dev_warn(rs->dev, "Failed to request RX DMA channel\n"); > + rs->dma_rx.ch = NULL; Same comments apply to the rx path.