On Fri, 2019-01-11 at 09:40 -0800, Himanshu Madhani wrote:
> From: Ming Lei <ming.lei@xxxxxxxxxx>
>
> When SCSI-MQ is enabled, in some case system would present
> nr_possible_cpus() which is greater than requested vectors
> by the driver. This results into driver being able to get
> larger number of MSI-X vectors than actual online CPUs.
> Driver then uses pci_alloc_irq_vectors_affinity() to assign
> 1:1 mapping and affinity for each MSI-x vector to CPUs. When
> the command is submitted using MSI-x vector, assigned to
> offline CPU, it results in an ABTS and system hang. This hang
> is result of a driver not being able to process interrupt on a
> vector assigned to an Off-line CPUs
>
> This patch fixes this issue by setting irq_offset value for the
> blk_mq_pci_map_queues() to use only those CPUs which has CPU mask
> affinity assigned and are online. By using the irq_offset value,
> driver will allow online cpumask to decide which vectors are used
> in blk_mq_pci_map_queues().
>
> Fixes: 5601236b6f794 ("scsi: qla2xxx: Add Block Multi Queue functionality.")
> Cc: <stable@xxxxxxxxxxxxxxx> #4.19
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
> Reviewed-by: Himanshu Madhani <hmadhani@xxxxxxxxxxx>
> Tested-by: Himanshu Madhani <hmadhani@xxxxxxxxxxx>
> Signed-off-by: Himanshu Madhani <hmadhani@xxxxxxxxxxx>
> ---
> Hi Martin,
>
> With SCSI-MQ set as default starting 4.19, we found regression where systems with lower
> online CPUs but higer possible CPUs in a system resulted in the driver assigning MSIx
> vectors to offline CPU causing system hang.
>
> Please apply this patch to 5.0/fixes branch at your earliest convenience for inclusion
> in 5.0-rc3.
>
> Thanks,
> Himanshu
> ---
> drivers/scsi/qla2xxx/qla_def.h | 2 ++
> drivers/scsi/qla2xxx/qla_isr.c | 1 +
> drivers/scsi/qla2xxx/qla_os.c | 2 +-
> 3 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
> index 26b93c563f92..d1fc4958222a 100644
> --- a/drivers/scsi/qla2xxx/qla_def.h
> +++ b/drivers/scsi/qla2xxx/qla_def.h
> @@ -4394,6 +4394,8 @@ typedef struct scsi_qla_host {
> uint16_t n2n_id;
> struct list_head gpnid_list;
> struct fab_scan scan;
> +
> + unsigned int irq_offset;
> } scsi_qla_host_t;
>
> struct qla27xx_image_status {
> diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
> index 30d3090842f8..8507c43b918c 100644
> --- a/drivers/scsi/qla2xxx/qla_isr.c
> +++ b/drivers/scsi/qla2xxx/qla_isr.c
> @@ -3446,6 +3446,7 @@ qla24xx_enable_msix(struct qla_hw_data *ha, struct rsp_que *rsp)
> "Adjusted Max no of queues pairs: %d.\n", ha->max_qpairs);
> }
> }
> + vha->irq_offset = desc.pre_vectors;
> ha->msix_entries = kcalloc(ha->msix_count,
> sizeof(struct qla_msix_entry),
> GFP_KERNEL);
> diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
> index ea69dafc9774..c6ef83d0d99b 100644
> --- a/drivers/scsi/qla2xxx/qla_os.c
> +++ b/drivers/scsi/qla2xxx/qla_os.c
> @@ -6939,7 +6939,7 @@ static int qla2xxx_map_queues(struct Scsi_Host *shost)
> if (USER_CTRL_IRQ(vha->hw))
> rc = blk_mq_map_queues(qmap);
> else
> - rc = blk_mq_pci_map_queues(qmap, vha->hw->pdev, 0);
> + rc = blk_mq_pci_map_queues(qmap, vha->hw->pdev, vha->irq_offset);
> return rc;
> }
>
I have such a machine, SCSI-MQ doesn't work with its 8Gb adapter without this.
Reviewed-by: Ewan D. Milne <emilne@xxxxxxxxxx>
