be2iscsi: Couple MCC tag and WRB alloc and free

WARN_ON(atomic_read(&mccq->used) >= mccq->len) seen when FW gets into
UE.

MCCQ overflow is happening because driver discards any new request and
frees up the tag. The tag allocation controls the number of MCC WRB
posted.  It is being replenished but WRBs are not hence the WARN_ON.

Allocation and freeing of WRB and tags for MCC is now done in one place.
This helps to achieve proper accounting of WRB indices and MCC tags.

Signed-off-by: Jitendra Bhivare <jitendra.bhivare@broadcom.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 74 insertions, 29 deletions

diff --git a/drivers/scsi/be2iscsi/be_cmds.c b/drivers/scsi/be2iscsi/be_cmds.c
index 728aa133717f..a55eaeea37e7 100644
--- a/drivers/scsi/be2iscsi/be_cmds.c
+++ b/drivers/scsi/be2iscsi/be_cmds.c
@@ -126,8 +126,62 @@ unsigned int alloc_mcc_tag(struct beiscsi_hba *phba)
 	return tag;
 }
 
-void free_mcc_tag(struct be_ctrl_info *ctrl, unsigned int tag)
+struct be_mcc_wrb *alloc_mcc_wrb(struct beiscsi_hba *phba,
+				 unsigned int *ref_tag)
 {
+	struct be_queue_info *mccq = &phba->ctrl.mcc_obj.q;
+	struct be_mcc_wrb *wrb = NULL;
+	unsigned int tag;
+
+	spin_lock_bh(&phba->ctrl.mcc_lock);
+	if (mccq->used == mccq->len) {
+		beiscsi_log(phba, KERN_ERR, BEISCSI_LOG_INIT |
+			    BEISCSI_LOG_CONFIG | BEISCSI_LOG_MBOX,
+			    "BC_%d : MCC queue full: WRB used %u tag avail %u\n",
+			    mccq->used, phba->ctrl.mcc_tag_available);
+		goto alloc_failed;
+	}
+
+	if (!phba->ctrl.mcc_tag_available)
+		goto alloc_failed;
+
+	tag = phba->ctrl.mcc_tag[phba->ctrl.mcc_alloc_index];
+	if (!tag) {
+		beiscsi_log(phba, KERN_ERR, BEISCSI_LOG_INIT |
+			    BEISCSI_LOG_CONFIG | BEISCSI_LOG_MBOX,
+			    "BC_%d : MCC tag 0 allocated: tag avail %u alloc index %u\n",
+			    phba->ctrl.mcc_tag_available,
+			    phba->ctrl.mcc_alloc_index);
+		goto alloc_failed;
+	}
+
+	/* return this tag for further reference */
+	*ref_tag = tag;
+	phba->ctrl.mcc_tag[phba->ctrl.mcc_alloc_index] = 0;
+	phba->ctrl.mcc_tag_status[tag] = 0;
+	phba->ctrl.ptag_state[tag].tag_state = 0;
+	phba->ctrl.mcc_tag_available--;
+	if (phba->ctrl.mcc_alloc_index == (MAX_MCC_CMD - 1))
+		phba->ctrl.mcc_alloc_index = 0;
+	else
+		phba->ctrl.mcc_alloc_index++;
+
+	wrb = queue_head_node(mccq);
+	memset(wrb, 0, sizeof(*wrb));
+	wrb->tag0 = tag;
+	wrb->tag0 |= (mccq->head << MCC_Q_WRB_IDX_SHIFT) & MCC_Q_WRB_IDX_MASK;
+	queue_head_inc(mccq);
+	mccq->used++;
+
+alloc_failed:
+	spin_unlock_bh(&phba->ctrl.mcc_lock);
+	return wrb;
+}
+
+void free_mcc_wrb(struct be_ctrl_info *ctrl, unsigned int tag)
+{
+	struct be_queue_info *mccq = &ctrl->mcc_obj.q;
+
 	spin_lock_bh(&ctrl->mcc_lock);
 	tag = tag & MCC_Q_CMD_TAG_MASK;
 	ctrl->mcc_tag[ctrl->mcc_free_index] = tag;
@@ -136,6 +190,7 @@ void free_mcc_tag(struct be_ctrl_info *ctrl, unsigned int tag)
 	else
 		ctrl->mcc_free_index++;
 	ctrl->mcc_tag_available++;
+	mccq->used--;
 	spin_unlock_bh(&ctrl->mcc_lock);
 }
 
@@ -173,10 +228,8 @@ int beiscsi_mccq_compl_wait(struct beiscsi_hba *phba,
 	struct be_cmd_resp_hdr *mbx_resp_hdr;
 	struct be_queue_info *mccq = &phba->ctrl.mcc_obj.q;
 
-	if (beiscsi_error(phba)) {
-		free_mcc_tag(&phba->ctrl, tag);
+	if (beiscsi_error(phba))
 		return -EPERM;
-	}
 
 	/* wait for the mccq completion */
 	rc = wait_event_interruptible_timeout(
@@ -259,7 +312,7 @@ int beiscsi_mccq_compl_wait(struct beiscsi_hba *phba,
 		}
 	}
 
-	free_mcc_tag(&phba->ctrl, tag);
+	free_mcc_wrb(&phba->ctrl, tag);
 	return rc;
 }
 
@@ -479,7 +532,7 @@ int beiscsi_process_mcc_compl(struct be_ctrl_info *ctrl,
 		if (tag_mem->size)
 			pci_free_consistent(ctrl->pdev, tag_mem->size,
 					tag_mem->va, tag_mem->dma);
-		free_mcc_tag(ctrl, tag);
+		free_mcc_wrb(ctrl, tag);
 		return 0;
 	}
 
@@ -519,15 +572,24 @@ int be_mcc_compl_poll(struct beiscsi_hba *phba, unsigned int tag)
 	struct be_ctrl_info *ctrl = &phba->ctrl;
 	int i;
 
+	if (!test_bit(MCC_TAG_STATE_RUNNING,
+		      &ctrl->ptag_state[tag].tag_state)) {
+		beiscsi_log(phba, KERN_ERR,
+			    BEISCSI_LOG_CONFIG | BEISCSI_LOG_MBOX,
+			    "BC_%d: tag %u state not running\n", tag);
+		return 0;
+	}
 	for (i = 0; i < mcc_timeout; i++) {
 		if (beiscsi_error(phba))
 			return -EIO;
 
 		beiscsi_process_mcc_cq(phba);
-
+		/* after polling, wrb and tag need to be released */
 		if (!test_bit(MCC_TAG_STATE_RUNNING,
-			      &ctrl->ptag_state[tag].tag_state))
+			      &ctrl->ptag_state[tag].tag_state)) {
+			free_mcc_wrb(ctrl, tag);
 			break;
+		}
 		udelay(100);
 	}
 
@@ -717,21 +779,6 @@ struct be_mcc_wrb *wrb_from_mbox(struct be_dma_mem *mbox_mem)
 	return &((struct be_mcc_mailbox *)(mbox_mem->va))->wrb;
 }
 
-struct be_mcc_wrb *wrb_from_mccq(struct beiscsi_hba *phba)
-{
-	struct be_queue_info *mccq = &phba->ctrl.mcc_obj.q;
-	struct be_mcc_wrb *wrb;
-
-	WARN_ON(atomic_read(&mccq->used) >= mccq->len);
-	wrb = queue_head_node(mccq);
-	memset(wrb, 0, sizeof(*wrb));
-	wrb->tag0 = (mccq->head << MCC_Q_WRB_IDX_SHIFT) & MCC_Q_WRB_IDX_MASK;
-	queue_head_inc(mccq);
-	atomic_inc(&mccq->used);
-	return wrb;
-}
-
-
 int beiscsi_cmd_eq_create(struct be_ctrl_info *ctrl,
 			  struct be_queue_info *eq, int eq_delay)
 {
@@ -1328,22 +1375,20 @@ int beiscsi_cmd_reset_function(struct beiscsi_hba  *phba)
 int be_cmd_set_vlan(struct beiscsi_hba *phba,
 		     uint16_t vlan_tag)
 {
-	unsigned int tag = 0;
+	unsigned int tag;
 	struct be_mcc_wrb *wrb;
 	struct be_cmd_set_vlan_req *req;
 	struct be_ctrl_info *ctrl = &phba->ctrl;
 
 	if (mutex_lock_interruptible(&ctrl->mbox_lock))
 		return 0;
-	tag = alloc_mcc_tag(phba);
-	if (!tag) {
+	wrb = alloc_mcc_wrb(phba, &tag);
+	if (!wrb) {
 		mutex_unlock(&ctrl->mbox_lock);
-		return tag;
+		return 0;
 	}
 
-	wrb = wrb_from_mccq(phba);
 	req = embedded_payload(wrb);
-	wrb->tag0 |= tag;
 	be_wrb_hdr_prepare(wrb, sizeof(*wrb), true, 0);
 	be_cmd_hdr_prepare(&req->hdr, CMD_SUBSYSTEM_ISCSI,
 			   OPCODE_COMMON_ISCSI_NTWK_SET_VLAN,