Re: [PATCH 124/190] Revert "spi : spi-topcliff-pch: Fix to handle empty DMA buffers"

[Greg Kroah-Hartman]

On Wed, Apr 21, 2021 at 02:59:59PM +0200, Greg Kroah-Hartman wrote:
> This reverts commit f37d8e67f39e6d3eaf4cc5471e8a3d21209843c6.
> 
> Commits from @umn.edu addresses have been found to be submitted in "bad
> faith" to try to test the kernel community's ability to review "known
> malicious" changes.  The result of these submissions can be found in a
> paper published at the 42nd IEEE Symposium on Security and Privacy
> entitled, "Open Source Insecurity: Stealthily Introducing
> Vulnerabilities via Hypocrite Commits" written by Qiushi Wu (University
> of Minnesota) and Kangjie Lu (University of Minnesota).
> 
> Because of this, all submissions from this group must be reverted from
> the kernel tree and will need to be re-reviewed again to determine if
> they actually are a valid fix.  Until that work is complete, remove this
> change to ensure that no problems are being introduced into the
> codebase.
> 
> Cc: Aditya Pakki <pakki001@xxxxxxx>
> Cc: Mark Brown <broonie@xxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> ---
>  drivers/spi/spi-topcliff-pch.c | 15 ++-------------
>  1 file changed, 2 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/spi/spi-topcliff-pch.c b/drivers/spi/spi-topcliff-pch.c
> index b459e369079f..12d749e9436b 100644
> --- a/drivers/spi/spi-topcliff-pch.c
> +++ b/drivers/spi/spi-topcliff-pch.c
> @@ -1290,27 +1290,18 @@ static void pch_free_dma_buf(struct pch_spi_board_data *board_dat,
>  				  dma->rx_buf_virt, dma->rx_buf_dma);
>  }
>  
> -static int pch_alloc_dma_buf(struct pch_spi_board_data *board_dat,
> +static void pch_alloc_dma_buf(struct pch_spi_board_data *board_dat,
>  			      struct pch_spi_data *data)
>  {
>  	struct pch_spi_dma_ctrl *dma;
> -	int ret;
>  
>  	dma = &data->dma;
> -	ret = 0;
>  	/* Get Consistent memory for Tx DMA */
>  	dma->tx_buf_virt = dma_alloc_coherent(&board_dat->pdev->dev,
>  				PCH_BUF_SIZE, &dma->tx_buf_dma, GFP_KERNEL);
> -	if (!dma->tx_buf_virt)
> -		ret = -ENOMEM;
> -
>  	/* Get Consistent memory for Rx DMA */
>  	dma->rx_buf_virt = dma_alloc_coherent(&board_dat->pdev->dev,
>  				PCH_BUF_SIZE, &dma->rx_buf_dma, GFP_KERNEL);
> -	if (!dma->rx_buf_virt)
> -		ret = -ENOMEM;
> -
> -	return ret;
>  }
>  
>  static int pch_spi_pd_probe(struct platform_device *plat_dev)
> @@ -1387,9 +1378,7 @@ static int pch_spi_pd_probe(struct platform_device *plat_dev)
>  
>  	if (use_dma) {
>  		dev_info(&plat_dev->dev, "Use DMA for data transfers\n");
> -		ret = pch_alloc_dma_buf(board_dat, data);
> -		if (ret)
> -			goto err_spi_register_master;
> +		pch_alloc_dma_buf(board_dat, data);
>  	}
>  
>  	ret = spi_register_master(master);
> -- 
> 2.31.1
> 

THis looks correct, so I'll drop the revert.

thanks,

greg k-h