Re: [PATCH 7/8] hisi_sas: fix calls to dma_set_mask_and_coherent()

[John Garry]

On 18/02/2019 07:34, Hannes Reinecke wrote:

Hi Hannes,
Thanks for this. I have some comments, below.

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.

And the second call to dma_set_mask_and_coherent() is not done if first 
fails, and we just bail out.

This resulted in FC connections failing due
to corrupted data buffers, and various other SCSI/FCP I/O errors.


Not relevant.

Fixes: e4db40e7a1a2 ("scsi: hisi_sas: use dma_set_mask_and_coherent")
Cc: <sta...@vger.kernel.org>

e4db40e7a1a2 only went into 5.0, so I don't know which stable kernel 
we're trying to fix. I am assuming that we can get this fix into 5.0.

Suggested-by: Ewan D. Milne <emi...@redhat.com>
Signed-off-by: Hannes Reinecke <h...@suse.com>
---
 drivers/scsi/hisi_sas/hisi_sas_main.c  | 8 ++++++--
 drivers/scsi/hisi_sas/hisi_sas_v3_hw.c | 8 +++++---
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c 
b/drivers/scsi/hisi_sas/hisi_sas_main.c
index 923296653ed7..13ca5a0bdf6b 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_main.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
@@ -2484,6 +2484,7 @@ 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) {
@@ -2504,8 +2505,11 @@ 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))) {
+       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;


This code was ok as is, so we're not really fixing anything. And 
certainly not fixing e4db40e7a1a2, so I am unsure if this should be 
included.

        }
diff --git a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c 
b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
index 00738d0673fe..79390f235c7e 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c
@@ -2742,10 +2742,12 @@ hisi_sas_v3_probe(struct pci_dev *pdev, const struct 
pci_device_id *id)
        if (rc)
                goto err_out_disable_device;

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