On 10/16/2013 01:34 PM, Sumit.Saxena@xxxxxxx wrote:
> There is syncronization problem between sysPD IO path and AEN path. Driver maintains instance->pd_list[] array, which will get updated(by calling function megasas_get_pd_list[]), whenever any of below events occurs-
Hi Sumit,
- I'm a bit confused here- there are two threads which might access the same array, but the problem is still there
when the second thread accesses the array during the final memcpy, I have expected that you will add some locking,
but maybe I'm missing something.
- now the code zeroes the pd_list even when the
(ret == 0 && (ci->count < (MEGASAS_MAX_PD_CHANNELS * MEGASAS_MAX_DEV_PER_CHANNEL)))
is not true. This is I think new - is that intentional?
Thanks, Tomas
>
>
>
>
>
>
> MR_EVT_PD_INSERTED
> MR_EVT_PD_REMOVED
> MR_EVT_CTRL_HOST_BUS_SCAN_REQUESTED
> MR_EVT_FOREIGN_CFG_IMPORTED
>
> At same time running sysPD IO will be accessing the same array instance->pd_list[], which is getting updated in AEN path, because
> of this IO may not get correct PD info from instance->pd_list[] array.
>
> Signed-off-by: Adam Radford <adam.radford@xxxxxxx>
> Signed-off-by: Sumit Saxena <sumit.saxena@xxxxxxx>
> ---
> diff --git a/drivers/scsi/megaraid/megaraid_sas.h b/drivers/scsi/megaraid/megaraid_sas.h
> index 0c73ba4..e9e543c 100644
> --- a/drivers/scsi/megaraid/megaraid_sas.h
> +++ b/drivers/scsi/megaraid/megaraid_sas.h
> @@ -1531,6 +1531,7 @@ struct megasas_instance {
> struct megasas_register_set __iomem *reg_set;
> u32 *reply_post_host_index_addr[MR_MAX_MSIX_REG_ARRAY];
> struct megasas_pd_list pd_list[MEGASAS_MAX_PD];
> + struct megasas_pd_list local_pd_list[MEGASAS_MAX_PD];
> u8 ld_ids[MEGASAS_MAX_LD_IDS];
> s8 init_id;
>
> diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
> index e62ff02..83ebc75 100644
> --- a/drivers/scsi/megaraid/megaraid_sas_base.c
> +++ b/drivers/scsi/megaraid/megaraid_sas_base.c
> @@ -3194,21 +3194,23 @@ megasas_get_pd_list(struct megasas_instance *instance)
> (le32_to_cpu(ci->count) <
> (MEGASAS_MAX_PD_CHANNELS * MEGASAS_MAX_DEV_PER_CHANNEL))) {
>
> - memset(instance->pd_list, 0,
> + memset(instance->local_pd_list, 0,
> MEGASAS_MAX_PD * sizeof(struct megasas_pd_list));
>
> for (pd_index = 0; pd_index < le32_to_cpu(ci->count); pd_index++) {
>
> - instance->pd_list[le16_to_cpu(pd_addr->deviceId)].tid =
> + instance->local_pd_list[le16_to_cpu(pd_addr->deviceId)].tid =
> le16_to_cpu(pd_addr->deviceId);
> - instance->pd_list[le16_to_cpu(pd_addr->deviceId)].driveType =
> + instance->local_pd_list[le16_to_cpu(pd_addr->deviceId)].driveType =
> pd_addr->scsiDevType;
> - instance->pd_list[le16_to_cpu(pd_addr->deviceId)].driveState =
> + instance->local_pd_list[le16_to_cpu(pd_addr->deviceId)].driveState =
> MR_PD_STATE_SYSTEM;
> pd_addr++;
> }
> }
>
> + memcpy(instance->pd_list, instance->local_pd_list,
> + sizeof(instance->pd_list));
> pci_free_consistent(instance->pdev,
> MEGASAS_MAX_PD * sizeof(struct MR_PD_LIST),
> ci, ci_h);
>
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