Re: [PATCH] scsi: myrs: check return value of dma_alloc_coherent() instead of using dma_mapping_error()

[Alexey Khoroshilov <khoroshilov@ispras.ru>]

On 16.11.2022 12:41, Peter Kosyh wrote:
> dma_alloc_coherent() may leave third parameter uninitialized. So
> it is not safe to use dma_mapping_error() without checking return
> value of dma_alloc_coherent().
> 
> Check the return value of dma_alloc_coherent() to detect
> an error.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Signed-off-by: Peter Kosyh <pkosyh@yandex.ru>
> ---
>  drivers/scsi/myrs.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/myrs.c b/drivers/scsi/myrs.c
> index 7eb8c39da366..1811c1a6385b 100644
> --- a/drivers/scsi/myrs.c
> +++ b/drivers/scsi/myrs.c
> @@ -498,14 +498,14 @@ static bool myrs_enable_mmio_mbox(struct myrs_hba *cs,
>  	/* Temporary dma mapping, used only in the scope of this function */
>  	mbox = dma_alloc_coherent(&pdev->dev, sizeof(union myrs_cmd_mbox),
>  				  &mbox_addr, GFP_KERNEL);
> -	if (dma_mapping_error(&pdev->dev, mbox_addr))
> +	if (!mbox)
>  		return false;
>  
>  	/* These are the base addresses for the command memory mailbox array */
>  	cs->cmd_mbox_size = MYRS_MAX_CMD_MBOX * sizeof(union myrs_cmd_mbox);
>  	cmd_mbox = dma_alloc_coherent(&pdev->dev, cs->cmd_mbox_size,
>  				      &cs->cmd_mbox_addr, GFP_KERNEL);
> -	if (dma_mapping_error(&pdev->dev, cs->cmd_mbox_addr)) {
> +	if (!cmd_mbox) {
>  		dev_err(&pdev->dev, "Failed to map command mailbox\n");
>  		goto out_free;
>  	}
> 

Reviewed-by: Alexey Khoroshilov <khoroshilov@ispras.ru>

Also you may want to add
Fixes: 77266186397c ("scsi: myrs: Add Mylex RAID controller (SCSI
interface)")

--
Alexey