Re: [PATCH 05/12] hisi_sas: use dma_set_mask_and_coherent

[John Garry]

On 18/10/2018 14:10, Christoph Hellwig wrote:
The driver currently uses pci_set_dma_mask despite otherwise using
the generic DMA API.  Switch it over to the better generic DMA API.
Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 drivers/scsi/hisi_sas/hisi_sas_v3_hw.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c 
b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
index bd4ce38b98d2..73bf45e52a0a 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
@@ -2201,14 +2201,11 @@ hisi_sas_v3_probe(struct pci_dev *pdev, const struct 
pci_device_id *id)
        if (rc)
                goto err_out_disable_device;

-       if ((pci_set_dma_mask(pdev, DMA_BIT_MASK(64)) != 0) ||
-           (pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(64)) != 0)) {
-               if ((pci_set_dma_mask(pdev, DMA_BIT_MASK(32)) != 0) ||
-                  (pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32)) != 0)) {
-                       dev_err(dev, "No usable DMA addressing method\n");
-                       rc = -EIO;
-                       goto err_out_regions;
-               }
+       if (dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64)) ||
+           dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32))) {
+               dev_err(dev, "No usable DMA addressing method\n");
+               rc = -EIO;
+               goto err_out_regions;
        }


We already do the same thing as your change for the platform driver 
probe, here:
static struct Scsi_Host *hisi_sas_shost_alloc(struct platform_device 
*pdev, ...)
{
    struct resource *res;
    struct Scsi_Host *shost;
    struct hisi_hba *hisi_hba;
    struct device *dev = &pdev->dev;
...

    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))) {
        dev_err(dev, "No usable DMA addressing method\n");
        goto err_out;
    }

...
}

So I could make a common helper function in the driver to factor this 
out, but prob not worth it. Having said that, I think lots of drivers 
have this same pattern...

Acked-by: John Garry <john.ga...@huawei.com>

        shost = hisi_sas_shost_alloc_pci(pdev);