[SCSI] lpfc 8.3.25: Add FCF priority failover functionality

This patch implements a new FCF failover policy for the lpfc driver. It
allows the driver to choose which FCF to failover to based on the FCF
priority. This patch also introduces a new sysfs parameter
(fcf_failover_policy) to allow the user to choose which FCF failover policy
to use.

Signed-off-by: Alex Iannicelli <alex.iannicelli@emulex.com>
Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 128 insertions, 3 deletions

diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c
index 247c24f..8b799f0 100644
--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -14635,6 +14635,92 @@ fail_fcf_read:
 }
 
 /**
+ * lpfc_check_next_fcf_pri
+ * phba pointer to the lpfc_hba struct for this port.
+ * This routine is called from the lpfc_sli4_fcf_rr_next_index_get
+ * routine when the rr_bmask is empty. The FCF indecies are put into the
+ * rr_bmask based on their priority level. Starting from the highest priority
+ * to the lowest. The most likely FCF candidate will be in the highest
+ * priority group. When this routine is called it searches the fcf_pri list for
+ * next lowest priority group and repopulates the rr_bmask with only those
+ * fcf_indexes.
+ * returns:
+ * 1=success 0=failure
+ **/
+int
+lpfc_check_next_fcf_pri_level(struct lpfc_hba *phba)
+{
+	uint16_t next_fcf_pri;
+	uint16_t last_index;
+	struct lpfc_fcf_pri *fcf_pri;
+	int rc;
+	int ret = 0;
+
+	last_index = find_first_bit(phba->fcf.fcf_rr_bmask,
+			LPFC_SLI4_FCF_TBL_INDX_MAX);
+	lpfc_printf_log(phba, KERN_INFO, LOG_FIP,
+			"3060 Last IDX %d\n", last_index);
+	if (list_empty(&phba->fcf.fcf_pri_list)) {
+		lpfc_printf_log(phba, KERN_ERR, LOG_FIP,
+			"3061 Last IDX %d\n", last_index);
+		return 0; /* Empty rr list */
+	}
+	next_fcf_pri = 0;
+	/*
+	 * Clear the rr_bmask and set all of the bits that are at this
+	 * priority.
+	 */
+	memset(phba->fcf.fcf_rr_bmask, 0,
+			sizeof(*phba->fcf.fcf_rr_bmask));
+	spin_lock_irq(&phba->hbalock);
+	list_for_each_entry(fcf_pri, &phba->fcf.fcf_pri_list, list) {
+		if (fcf_pri->fcf_rec.flag & LPFC_FCF_FLOGI_FAILED)
+			continue;
+		/*
+		 * the 1st priority that has not FLOGI failed
+		 * will be the highest.
+		 */
+		if (!next_fcf_pri)
+			next_fcf_pri = fcf_pri->fcf_rec.priority;
+		spin_unlock_irq(&phba->hbalock);
+		if (fcf_pri->fcf_rec.priority == next_fcf_pri) {
+			rc = lpfc_sli4_fcf_rr_index_set(phba,
+						fcf_pri->fcf_rec.fcf_index);
+			if (rc)
+				return 0;
+		}
+		spin_lock_irq(&phba->hbalock);
+	}
+	/*
+	 * if next_fcf_pri was not set above and the list is not empty then
+	 * we have failed flogis on all of them. So reset flogi failed
+	 * and start at the begining.
+	 */
+	if (!next_fcf_pri && !list_empty(&phba->fcf.fcf_pri_list)) {
+		list_for_each_entry(fcf_pri, &phba->fcf.fcf_pri_list, list) {
+			fcf_pri->fcf_rec.flag &= ~LPFC_FCF_FLOGI_FAILED;
+			/*
+			 * the 1st priority that has not FLOGI failed
+			 * will be the highest.
+			 */
+			if (!next_fcf_pri)
+				next_fcf_pri = fcf_pri->fcf_rec.priority;
+			spin_unlock_irq(&phba->hbalock);
+			if (fcf_pri->fcf_rec.priority == next_fcf_pri) {
+				rc = lpfc_sli4_fcf_rr_index_set(phba,
+						fcf_pri->fcf_rec.fcf_index);
+				if (rc)
+					return 0;
+			}
+			spin_lock_irq(&phba->hbalock);
+		}
+	} else
+		ret = 1;
+	spin_unlock_irq(&phba->hbalock);
+
+	return ret;
+}
+/**
  * lpfc_sli4_fcf_rr_next_index_get - Get next eligible fcf record index
  * @phba: pointer to lpfc hba data structure.
  *
@@ -14650,6 +14736,7 @@ lpfc_sli4_fcf_rr_next_index_get(struct lpfc_hba *phba)
 	uint16_t next_fcf_index;
 
 	/* Search start from next bit of currently registered FCF index */
+next_priority:
 	next_fcf_index = (phba->fcf.current_rec.fcf_indx + 1) %
 					LPFC_SLI4_FCF_TBL_INDX_MAX;
 	next_fcf_index = find_next_bit(phba->fcf.fcf_rr_bmask,
@@ -14657,17 +14744,46 @@ lpfc_sli4_fcf_rr_next_index_get(struct lpfc_hba *phba)
 				       next_fcf_index);
 
 	/* Wrap around condition on phba->fcf.fcf_rr_bmask */
-	if (next_fcf_index >= LPFC_SLI4_FCF_TBL_INDX_MAX)
+	if (next_fcf_index >= LPFC_SLI4_FCF_TBL_INDX_MAX) {
+		/*
+		 * If we have wrapped then we need to clear the bits that
+		 * have been tested so that we can detect when we should
+		 * change the priority level.
+		 */
 		next_fcf_index = find_next_bit(phba->fcf.fcf_rr_bmask,
 					       LPFC_SLI4_FCF_TBL_INDX_MAX, 0);
+	}
+
 
 	/* Check roundrobin failover list empty condition */
-	if (next_fcf_index >= LPFC_SLI4_FCF_TBL_INDX_MAX) {
+	if (next_fcf_index >= LPFC_SLI4_FCF_TBL_INDX_MAX ||
+		next_fcf_index == phba->fcf.current_rec.fcf_indx) {
+		/*
+		 * If next fcf index is not found check if there are lower
+		 * Priority level fcf's in the fcf_priority list.
+		 * Set up the rr_bmask with all of the avaiable fcf bits
+		 * at that level and continue the selection process.
+		 */
+		if (lpfc_check_next_fcf_pri_level(phba))
+			goto next_priority;
 		lpfc_printf_log(phba, KERN_WARNING, LOG_FIP,
 				"2844 No roundrobin failover FCF available\n");
-		return LPFC_FCOE_FCF_NEXT_NONE;
+		if (next_fcf_index >= LPFC_SLI4_FCF_TBL_INDX_MAX)
+			return LPFC_FCOE_FCF_NEXT_NONE;
+		else {
+			lpfc_printf_log(phba, KERN_WARNING, LOG_FIP,
+				"3063 Only FCF available idx %d, flag %x\n",
+				next_fcf_index,
+			phba->fcf.fcf_pri[next_fcf_index].fcf_rec.flag);
+			return next_fcf_index;
+		}
 	}
 
+	if (next_fcf_index < LPFC_SLI4_FCF_TBL_INDX_MAX &&
+		phba->fcf.fcf_pri[next_fcf_index].fcf_rec.flag &
+		LPFC_FCF_FLOGI_FAILED)
+		goto next_priority;
+
 	lpfc_printf_log(phba, KERN_INFO, LOG_FIP,
 			"2845 Get next roundrobin failover FCF (x%x)\n",
 			next_fcf_index);
@@ -14719,6 +14835,7 @@ lpfc_sli4_fcf_rr_index_set(struct lpfc_hba *phba, uint16_t fcf_index)
 void
 lpfc_sli4_fcf_rr_index_clear(struct lpfc_hba *phba, uint16_t fcf_index)
 {
+	struct lpfc_fcf_pri *fcf_pri;
 	if (fcf_index >= LPFC_SLI4_FCF_TBL_INDX_MAX) {
 		lpfc_printf_log(phba, KERN_ERR, LOG_FIP,
 				"2762 FCF (x%x) reached driver's book "
@@ -14727,6 +14844,14 @@ lpfc_sli4_fcf_rr_index_clear(struct lpfc_hba *phba, uint16_t fcf_index)
 		return;
 	}
 	/* Clear the eligible FCF record index bmask */
+	spin_lock_irq(&phba->hbalock);
+	list_for_each_entry(fcf_pri, &phba->fcf.fcf_pri_list, list) {
+		if (fcf_pri->fcf_rec.fcf_index == fcf_index) {
+			list_del_init(&fcf_pri->list);
+			break;
+		}
+	}
+	spin_unlock_irq(&phba->hbalock);
 	clear_bit(fcf_index, phba->fcf.fcf_rr_bmask);
 
 	lpfc_printf_log(phba, KERN_INFO, LOG_FIP,