>From previous patch we have below changes in v2 -
1. Updated change log. Provided more detail in change log.
2. Agreed to remove module parameter. If we remove module parameter, we
can ask customer to disable WCE on drive to get similar impact.
3. Always Send SYNCHRONIZE_CACHE for JBOD (non Raid) Device to Firmware.
Current megaraid_sas driver returns SYNCHRONIZE_CACHE(related to Drive
Cache) command back to SCSI layer without sending it down to firmware as
firmware supposed to take care of flushing disk cache for all drives
belongs to Virtual Disk at the time of system reboot/shutdown.
We evaluate and understood that for Raid Volume, why driver should not
send SYNC_CACHE command to the Firmware.
There may be a some reason in past, but now it looks to be not required and
we have fixed this issue as part of this patch.
Commit- " 02b01e0 [SCSI] megaraid_sas: return sync cache call with success"
added the code in driver to return SYNCHRONIZE_CACHE without sending it to
firmware back in 2007. Earlier MR was mainly for Virtual Disk,
so same code continue for JBOD as well whenever JBOD support was added and it
introduced bug that
SYNCHRONIZE_CACHE is not passed to FW for JBOD (non Raid disk).
But our recent analysis indicates that, From Day-1 MR Firmware always
expect Driver to forward SYNCHRONIZE_CACHE for JBOD (non Raid disk) to the
Firmware.
We have fixed this as part of this patch.
- Additional background -
There are some instance of MegaRaid FW (E.a Gen2 and Gen2.5 FW) set WCE bit
for Virtual Disk but firmware does not reply correct status for SYNCH_CACHE.
It is very difficult to find out which Device ID and firmware has capability
to manage SYNC_CACHE, so we managed to figure out which are the new firmware
(canHandleSyncCache is set in scratch pad register at 0xB4) and use that
interface for correct behavior as explained above.
E.g Liberator/Thunderbolt MegaRaid FW returns SYNC_CACHE as Unsupported
command (this is a firmware bug) and eventually command will be failed to SML.
This will cause File system to go Read-only.
- New behavior described -
IF application requests SYNCH_CACHE
IF 'JBOD'
Driver sends SYNCH_CACHE command to the FW
FW sends SYNCH_CACHE to drive
FW obtains status from drive and returns same status back to
driver
ELSEIF 'VirtualDisk'
IF any FW which supports new API bit called canHandleSyncCache
Driver sends SYNCH_CACHE command to the FW
FW does not send SYNCH_CACHE to drives
FW returns SUCCESS
ELSE
Driver does not send SYNCH_CACHE command to the
FW.
Driver return SUCCESS for that command.
ENDIF
ENDIF
ENDIF
CC: [email protected]
Signed-off-by: Kashyap Desai <[email protected]>
Signed-off-by: Sumit Saxena <[email protected]>
---
drivers/scsi/megaraid/megaraid_sas.h | 3 +++
drivers/scsi/megaraid/megaraid_sas_base.c | 10 ++--------
drivers/scsi/megaraid/megaraid_sas_fusion.c | 5 +++++
3 files changed, 10 insertions(+), 8 deletions(-)
diff --git a/drivers/scsi/megaraid/megaraid_sas.h
b/drivers/scsi/megaraid/megaraid_sas.h
index ca86c88..43fd14f 100644
--- a/drivers/scsi/megaraid/megaraid_sas.h
+++ b/drivers/scsi/megaraid/megaraid_sas.h
@@ -1429,6 +1429,8 @@ enum FW_BOOT_CONTEXT {
#define MR_MAX_REPLY_QUEUES_EXT_OFFSET_SHIFT 14
#define MR_MAX_MSIX_REG_ARRAY 16
#define MR_RDPQ_MODE_OFFSET 0X00800000
+#define MR_CAN_HANDLE_SYNC_CACHE_OFFSET 0X01000000
+
/*
* register set for both 1068 and 1078 controllers
* structure extended for 1078 registers
@@ -2140,6 +2142,7 @@ struct megasas_instance {
u8 is_imr;
u8 is_rdpq;
bool dev_handle;
+ bool fw_sync_cache_support;
};
struct MR_LD_VF_MAP {
u32 size;
diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c
b/drivers/scsi/megaraid/megaraid_sas_base.c
index 3236632..f7a2ab1 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -1700,16 +1700,10 @@ inline int megasas_cmd_type(struct scsi_cmnd *cmd)
goto out_done;
}
- switch (scmd->cmnd[0]) {
- case SYNCHRONIZE_CACHE:
- /*
- * FW takes care of flush cache on its own
- * No need to send it down
- */
+ if (MEGASAS_IS_LOGICAL(scmd) && (scmd->cmnd[0] == SYNCHRONIZE_CACHE) &&
+ (!instance->fw_sync_cache_support)) {
scmd->result = DID_OK << 16;
goto out_done;
- default:
- break;
}
return instance->instancet->build_and_issue_cmd(instance, scmd);
diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.c
b/drivers/scsi/megaraid/megaraid_sas_fusion.c
index 2159f6a..2e61306 100644
--- a/drivers/scsi/megaraid/megaraid_sas_fusion.c
+++ b/drivers/scsi/megaraid/megaraid_sas_fusion.c
@@ -748,6 +748,11 @@ static int megasas_create_sg_sense_fusion(struct
megasas_instance *instance)
goto fail_fw_init;
}
+ instance->fw_sync_cache_support = (scratch_pad_2 &
+ MR_CAN_HANDLE_SYNC_CACHE_OFFSET) ? 1 : 0;
+ dev_info(&instance->pdev->dev, "FW supports sync cache\t: %s\n",
+ instance->fw_sync_cache_support ? "Yes" : "No");
+
IOCInitMessage =
dma_alloc_coherent(&instance->pdev->dev,
sizeof(struct MPI2_IOC_INIT_REQUEST),
--
1.8.3.1
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