Messages in this thread | | | Date | Sun, 13 Feb 2022 11:11:19 -0700 | From | Nathan Chancellor <> | Subject | Re: [PATCH] spi: Fix warning for Clang build |
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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; }
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