megaraid_sas: Fix for IO failing post OCR in SRIOV environment

BugLink: http://bugs.launchpad.net/bugs/1544679

Driver assumes that VFs always have peers present whenever they have
same LD IDs. But this is not the case.  This patch handles the above
mentioned by explicitly checking for a peer before making HA/non-HA path
decision.
Signed-off-by: Uday Lingala <uday.lingala@avagotech.com>
Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
(cherry picked from linux-next commit 07d6c5aa4d4128cadb7ff0557576f70085f2cae1)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

drivers/scsi/megaraid/megaraid_sas.h

@@ -393,6 +393,7 @@ enum MR_EVT_ARGS {
 
 
 #define SGE_BUFFER_SIZE	4096
+#define MEGASAS_CLUSTER_ID_SIZE	16
 /*
  * define constants for device list query options
  */
@@ -1227,7 +1228,8 @@ struct megasas_ctrl_info {
 	*/
 	struct {
 #if defined(__BIG_ENDIAN_BITFIELD)
-		u32     reserved:26;
+		u32     reserved:25;
+		u32     passive:1;
 		u32     premiumFeatureMismatch:1;
 		u32     ctrlPropIncompatible:1;
 		u32     fwVersionMismatch:1;
@@ -1241,11 +1243,12 @@ struct megasas_ctrl_info {
 		u32     fwVersionMismatch:1;
 		u32     ctrlPropIncompatible:1;
 		u32     premiumFeatureMismatch:1;
-		u32     reserved:26;
+		u32     passive:1;
+		u32     reserved:25;
 #endif
 	} cluster;
 
-	char clusterId[16];                     /*7D4h */
+	char clusterId[MEGASAS_CLUSTER_ID_SIZE]; /*0x7D4 */
 	struct {
 		u8  maxVFsSupported;            /*0x7E4*/
 		u8  numVFsEnabled;              /*0x7E5*/
@@ -2126,7 +2129,9 @@ struct megasas_instance {
 	char skip_heartbeat_timer_del;
 	u8 requestorId;
 	char PlasmaFW111;
-	char mpio;
+	char clusterId[MEGASAS_CLUSTER_ID_SIZE];
+	u8 peerIsPresent;
+	u8 passive;
 	u16 throttlequeuedepth;
 	u8 mask_interrupts;
 	u16 max_chain_frame_sz;

drivers/scsi/megaraid/megaraid_sas_base.c

@@ -1943,7 +1943,7 @@ void megaraid_sas_kill_hba(struct megasas_instance *instance)
 		writel(MFI_STOP_ADP, &instance->reg_set->doorbell);
 		/* Flush */
 		readl(&instance->reg_set->doorbell);
-		if (instance->mpio && instance->requestorId)
+		if (instance->requestorId && instance->peerIsPresent)
 			memset(instance->ld_ids, 0xff, MEGASAS_MAX_LD_IDS);
 	} else {
 		writel(MFI_STOP_ADP,
@@ -5182,7 +5182,9 @@ static int megasas_init_fw(struct megasas_instance *instance)
 
 	tmp_sectors = min_t(u32, max_sectors_1, max_sectors_2);
 
-	instance->mpio = ctrl_info->adapterOperations2.mpio;
+	instance->peerIsPresent = ctrl_info->cluster.peerIsPresent;
+	instance->passive = ctrl_info->cluster.passive;
+	memcpy(instance->clusterId, ctrl_info->clusterId, sizeof(instance->clusterId));
 	instance->UnevenSpanSupport =
 		ctrl_info->adapterOperations2.supportUnevenSpans;
 	if (instance->UnevenSpanSupport) {

drivers/scsi/megaraid/megaraid_sas_fusion.c

@@ -3325,27 +3325,37 @@ int megasas_reset_target_fusion(struct scsi_cmnd *scmd)
 	return ret;
 }
 
+/*SRIOV get other instance in cluster if any*/
+struct megasas_instance *megasas_get_peer_instance(struct megasas_instance *instance)
+{
+	int i;
+
+	for (i = 0; i < MAX_MGMT_ADAPTERS; i++) {
+		if (megasas_mgmt_info.instance[i] &&
+			(megasas_mgmt_info.instance[i] != instance) &&
+			 megasas_mgmt_info.instance[i]->requestorId &&
+			 megasas_mgmt_info.instance[i]->peerIsPresent &&
+			(memcmp((megasas_mgmt_info.instance[i]->clusterId),
+			instance->clusterId, MEGASAS_CLUSTER_ID_SIZE) == 0))
+			return megasas_mgmt_info.instance[i];
+	}
+	return NULL;
+}
+
 /* Check for a second path that is currently UP */
 int megasas_check_mpio_paths(struct megasas_instance *instance,
 	struct scsi_cmnd *scmd)
 {
-	int i, j, retval = (DID_RESET << 16);
-
-	if (instance->mpio && instance->requestorId) {
-		for (i = 0 ; i < MAX_MGMT_ADAPTERS ; i++)
-			for (j = 0 ; j < MAX_LOGICAL_DRIVES; j++)
-				if (megasas_mgmt_info.instance[i] &&
-				    (megasas_mgmt_info.instance[i] != instance) &&
-				    megasas_mgmt_info.instance[i]->mpio &&
-				    megasas_mgmt_info.instance[i]->requestorId
-				    &&
-				    (megasas_mgmt_info.instance[i]->ld_ids[j]
-				     == scmd->device->id)) {
-					    retval = (DID_NO_CONNECT << 16);
-					    goto out;
-				}
+	struct megasas_instance *peer_instance = NULL;
+	int retval = (DID_RESET << 16);
+
+	if (instance->peerIsPresent) {
+		peer_instance = megasas_get_peer_instance(instance);
+		if ((peer_instance) &&
+			(atomic_read(&peer_instance->adprecovery) ==
+			MEGASAS_HBA_OPERATIONAL))
+			retval = (DID_NO_CONNECT << 16);
 	}
-out:
 	return retval;
 }