[SCSI] megaraid_sas: Fix synchronization problem between sysPD IO path and AEN path

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-

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@lsi.com>
Signed-off-by: Sumit Saxena <sumit.saxena@lsi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

2 files changed, 7 insertions, 4 deletions

diff --git a/drivers/scsi/megaraid/megaraid_sas.h b/drivers/scsi/megaraid/megaraid_sas.h
index 0c73ba4bf451..e9e543c58485 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 e62ff020c253..2cf9470dd11b 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -3194,19 +3194,21 @@ 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,