Re: [PATCH 4/4] hisi_sas: fix calls to dma_set_mask_and_coherent()

[John Garry <john.garry@huawei.com>]

On 13/02/2019 11:42, Hannes Reinecke wrote:
> The change to use dma_set_mask_and_coherent() incorrectly made a second
> call with the 32 bit DMA mask value when the call with the 64 bit DMA
> mask value succeeded.  This resulted in FC connections failing due
> to corrupted data buffers, and various other SCSI/FCP I/O errors.
>
> Fixes: e4db40e7a1a2 ("scsi: hisi_sas: use dma_set_mask_and_coherent")
> Cc: <stable@vger.kernel.org>
> Suggested-by: Ewan D. Milne <emilne@redhat.com>
> Signed-off-by: Hannes Reinecke <hare@suse.com>
> ---
>  drivers/scsi/hisi_sas/hisi_sas_main.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c
> index eed7fc5b3389..bc17fa0d8375 100644
> --- a/drivers/scsi/hisi_sas/hisi_sas_main.c
> +++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
> @@ -2323,6 +2323,7 @@ static struct Scsi_Host *hisi_sas_shost_alloc(struct platform_device *pdev,
>  	struct Scsi_Host *shost;
>  	struct hisi_hba *hisi_hba;
>  	struct device *dev = &pdev->dev;
> +	int error;
>
>  	shost = scsi_host_alloc(hw->sht, sizeof(*hisi_hba));
>  	if (!shost) {
> @@ -2343,8 +2344,11 @@ static struct Scsi_Host *hisi_sas_shost_alloc(struct platform_device *pdev,
>  	if (hisi_sas_get_fw_info(hisi_hba) < 0)
>  		goto err_out;
>
> -	if (dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64)) &&
> -	    dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32))) {

Aren't we supposed to be fixing hisi_sas_v3_probe()? We have a path for 
platform device probe and a path for pci device probe. You're changing 
the platform device probe, which is currently ok.

I meant to unify all this. Now would be a good time, as it's not a fix. 
Can do it later.

Thanks,
John

> +	error = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
> +	if (error)
> +		error = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
> +
> +	if (error) {
>  		dev_err(dev, "No usable DMA addressing method\n");
>  		goto err_out;
>  	}
>