From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0148EC433F5 for ; Sun, 13 Feb 2022 18:11:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233939AbiBMSLd (ORCPT ); Sun, 13 Feb 2022 13:11:33 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:58772 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231246AbiBMSLd (ORCPT ); Sun, 13 Feb 2022 13:11:33 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B76E4112; Sun, 13 Feb 2022 10:11:26 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 6BF99B80B59; Sun, 13 Feb 2022 18:11:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 782C4C004E1; Sun, 13 Feb 2022 18:11:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1644775884; bh=RhzS4TyIJobSkSb/B7mFTwIDZOdt7aPYZTOXJ00X+OQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YIK94Vh2eNUoX3KWJCCrg+DT+eXajBH/h2Af20XKZsXlvRybC2/qytKSEM+z+gH0X 1zl5aVq7zJ82cXW1pub+9bdrE3WvOJAPDnuer9eUKHkkVvOtOm88eH9rdNRUw3vLRX x77B0aoOrxG84Qk6pjH/Rgz+SmODQWR8oRvC+Cpau7XTZorAUxi9HgWTq3xE+7+H1+ CKFWYxLHQrkSL7RE4a/BjNH/usyN96XLixPkrE5fRjk611meGhNZrofQpndwhSUlXK y3fUQIOOf/NWHh7GoE0YzVr6G/18UUBuS3mT9lKdI3SC4+Ntij95eo0cQGcARoRe98 Q3e9bE/hUhwQw== Date: Sun, 13 Feb 2022 11:11:19 -0700 From: Nathan Chancellor To: Lh Kuo =?utf-8?B?6YOt5Yqb6LGq?= Cc: Tom Rix , Mark Brown , Li-hao Kuo , "linux-spi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Wells Lu =?utf-8?B?5ZGC6Iqz6aiw?= Subject: Re: [PATCH] spi: Fix warning for Clang build Message-ID: References: <691d52b72f978f562136c587319852f5c65f08fe.1644460444.git.lhjeff911@gmail.com> <99ab624e2af4414bb2a785f64f35bd95@sphcmbx02.sunplus.com.tw> <0b71842ec1b946729e74d73cbd354162@sphcmbx02.sunplus.com.tw> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <0b71842ec1b946729e74d73cbd354162@sphcmbx02.sunplus.com.tw> Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org On Fri, Feb 11, 2022 at 04:59:00AM +0000, Lh Kuo 郭力豪 wrote: > Yes. I think the function can be simplified as follows > > static int sp7021_spi_slave_transfer_one(struct spi_controller *ctlr, struct spi_device *spi, > struct spi_transfer *xfer) > { > struct sp7021_spi_ctlr *pspim = spi_master_get_devdata(ctlr); > struct device *dev = pspim->dev; > int ret; > > mode = SP7021_SPI_IDLE; > if (xfer->tx_buf && xfer->rx_buf) { > dev_dbg(&ctlr->dev, "%s() wrong command\n", __func__); > return -EINVAL; > } else if (xfer->tx_buf) { > xfer->tx_dma = dma_map_single(dev, (void *)xfer->tx_buf, > xfer->len, DMA_TO_DEVICE); > if (dma_mapping_error(dev, xfer->tx_dma)) > return -ENOMEM; > ret = sp7021_spi_slave_tx(spi, xfer); > } else if (xfer->rx_buf) { > xfer->rx_dma = dma_map_single(dev, xfer->rx_buf, xfer->len, > DMA_FROM_DEVICE); > if (dma_mapping_error(dev, xfer->rx_dma)) > return -ENOMEM; > ret = sp7021_spi_slave_rx(spi, xfer); > } > > if (xfer->tx_buf) > dma_unmap_single(dev, xfer->tx_dma, xfer->len, DMA_TO_DEVICE); > if (xfer->rx_buf) > dma_unmap_single(dev, xfer->rx_dma, xfer->len, DMA_FROM_DEVICE); > > spi_finalize_current_transfer(ctlr); > return ret; > } Clang will still warn that ret is uninitialized when the else if branches are not taken. How about something like: static int sp7021_spi_slave_transfer_one(struct spi_controller *ctlr, struct spi_device *spi, struct spi_transfer *xfer) { struct sp7021_spi_ctlr *pspim = spi_master_get_devdata(ctlr); struct device *dev = pspim->dev; int ret; if (xfer->tx_buf && !xfer->rx_buf) { xfer->tx_dma = dma_map_single(dev, (void *)xfer->tx_buf, xfer->len, DMA_TO_DEVICE); if (dma_mapping_error(dev, xfer->tx_dma)) return -ENOMEM; ret = sp7021_spi_slave_tx(spi, xfer); dma_unmap_single(dev, xfer->tx_dma, xfer->len, DMA_TO_DEVICE); } else if (xfer->rx_buf && !xfer->tx_buf) { xfer->rx_dma = dma_map_single(dev, xfer->rx_buf, xfer->len, DMA_FROM_DEVICE); if (dma_mapping_error(dev, xfer->rx_dma)) return -ENOMEM; ret = sp7021_spi_slave_rx(spi, xfer); dma_unmap_single(dev, xfer->rx_dma, xfer->len, DMA_FROM_DEVICE); } else { dev_dbg(&ctlr->dev, "%s() wrong command\n", __func__); return -EINVAL; } spi_finalize_current_transfer(ctlr); return ret; }