[SCSI] lpfc 8.3.11: FCF failover improvements

FCF failover improvements

- Add random FCF failover when there are multiple FCFs available.
- Prevent FCF log messages from being displayed for FC adapters.
- Separate the New FCF and Modified FCF log messages.

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

5 files changed, 77 insertions, 13 deletions

diff --git a/drivers/scsi/lpfc/lpfc_els.c b/drivers/scsi/lpfc/lpfc_els.c
index 5fbdb22c1899..0a337dab211c 100644
--- a/drivers/scsi/lpfc/lpfc_els.c
+++ b/drivers/scsi/lpfc/lpfc_els.c
@@ -893,11 +893,14 @@ lpfc_cmpl_els_flogi(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
 
                 if (!rc) {
                         /* Mark the FCF discovery process done */
-                        lpfc_printf_vlog(vport, KERN_INFO, LOG_FIP | LOG_ELS,
-                                         "2769 FLOGI successful on FCF record: "
-                                         "current_fcf_index:x%x, terminate FCF "
-                                         "round robin failover process\n",
-                                         phba->fcf.current_rec.fcf_indx);
+                        if (phba->hba_flag & HBA_FIP_SUPPORT)
+                                lpfc_printf_vlog(vport, KERN_INFO, LOG_FIP |
+                                                LOG_ELS,
+                                                "2769 FLOGI successful on FCF "
+                                                "record: current_fcf_index:"
+                                                "x%x, terminate FCF round "
+                                                "robin failover process\n",
+                                                phba->fcf.current_rec.fcf_indx);
                         spin_lock_irq(&phba->hbalock);
                         phba->fcf.fcf_flag &= ~FCF_DISCOVERY;
                         spin_unlock_irq(&phba->hbalock);
diff --git a/drivers/scsi/lpfc/lpfc_hbadisc.c b/drivers/scsi/lpfc/lpfc_hbadisc.c
index e1466eec56b7..362730b6dd85 100644
--- a/drivers/scsi/lpfc/lpfc_hbadisc.c
+++ b/drivers/scsi/lpfc/lpfc_hbadisc.c
@@ -1531,7 +1531,37 @@ lpfc_check_pending_fcoe_event(struct lpfc_hba *phba, uint8_t unreg_fcf)
 }
 
 /**
- * lpfc_sli4_fcf_rec_mbox_parse - parse non-embedded fcf record mailbox command
+ * lpfc_sli4_new_fcf_random_select - Randomly select an eligible new fcf record
+ * @phba: pointer to lpfc hba data structure.
+ * @fcf_cnt: number of eligible fcf record seen so far.
+ *
+ * This function makes an running random selection decision on FCF record to
+ * use through a sequence of @fcf_cnt eligible FCF records with equal
+ * probability. To perform integer manunipulation of random numbers with
+ * size unit32_t, the lower 16 bits of the 32-bit random number returned
+ * from random32() are taken as the random random number generated.
+ *
+ * Returns true when outcome is for the newly read FCF record should be
+ * chosen; otherwise, return false when outcome is for keeping the previously
+ * chosen FCF record.
+ **/
+static bool
+lpfc_sli4_new_fcf_random_select(struct lpfc_hba *phba, uint32_t fcf_cnt)
+{
+        uint32_t rand_num;
+
+        /* Get 16-bit uniform random number */
+        rand_num = (0xFFFF & random32());
+
+        /* Decision with probability 1/fcf_cnt */
+        if ((fcf_cnt * rand_num) < 0xFFFF)
+                return true;
+        else
+                return false;
+}
+
+/**
+ * lpfc_mbx_cmpl_read_fcf_record - Completion handler for read_fcf mbox.
  * @phba: pointer to lpfc hba data structure.
  * @mboxq: pointer to mailbox object.
  * @next_fcf_index: pointer to holder of next fcf index.
@@ -1679,6 +1709,8 @@ lpfc_mbx_cmpl_fcf_scan_read_fcf_rec(struct lpfc_hba *phba, LPFC_MBOXQ_t *mboxq)
         uint16_t fcf_index, next_fcf_index;
         struct lpfc_fcf_rec *fcf_rec = NULL;
         uint16_t vlan_id;
+        uint32_t seed;
+        bool select_new_fcf;
         int rc;
 
         /* If there is pending FCoE event restart FCF table scan */
@@ -1809,9 +1841,21 @@ lpfc_mbx_cmpl_fcf_scan_read_fcf_rec(struct lpfc_hba *phba, LPFC_MBOXQ_t *mboxq)
                  * than the driver FCF record, use the new record.
                  */
                 if (new_fcf_record->fip_priority < fcf_rec->priority) {
-                        /* Choose this FCF record */
+                        /* Choose the new FCF record with lower priority */
                         __lpfc_update_fcf_record(phba, fcf_rec, new_fcf_record,
                                         addr_mode, vlan_id, 0);
+                        /* Reset running random FCF selection count */
+                        phba->fcf.eligible_fcf_cnt = 1;
+                } else if (new_fcf_record->fip_priority == fcf_rec->priority) {
+                        /* Update running random FCF selection count */
+                        phba->fcf.eligible_fcf_cnt++;
+                        select_new_fcf = lpfc_sli4_new_fcf_random_select(phba,
+                                                phba->fcf.eligible_fcf_cnt);
+                        if (select_new_fcf)
+                                /* Choose the new FCF by random selection */
+                                __lpfc_update_fcf_record(phba, fcf_rec,
+                                                         new_fcf_record,
+                                                         addr_mode, vlan_id, 0);
                 }
                 spin_unlock_irq(&phba->hbalock);
                 goto read_next_fcf;
@@ -1825,6 +1869,11 @@ lpfc_mbx_cmpl_fcf_scan_read_fcf_rec(struct lpfc_hba *phba, LPFC_MBOXQ_t *mboxq)
                                          addr_mode, vlan_id, (boot_flag ?
                                          BOOT_ENABLE : 0));
                 phba->fcf.fcf_flag |= FCF_AVAILABLE;
+                /* Setup initial running random FCF selection count */
+                phba->fcf.eligible_fcf_cnt = 1;
+                /* Seeding the random number generator for random selection */
+                seed = (uint32_t)(0xFFFFFFFF & jiffies);
+                srandom32(seed);
         }
         spin_unlock_irq(&phba->hbalock);
         goto read_next_fcf;
diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
index 774663e8e1fe..25ee8cc6ab7a 100644
--- a/drivers/scsi/lpfc/lpfc_init.c
+++ b/drivers/scsi/lpfc/lpfc_init.c
@@ -3304,11 +3304,20 @@ lpfc_sli4_async_fcoe_evt(struct lpfc_hba *phba,
         switch (event_type) {
         case LPFC_FCOE_EVENT_TYPE_NEW_FCF:
         case LPFC_FCOE_EVENT_TYPE_FCF_PARAM_MOD:
-                lpfc_printf_log(phba, KERN_ERR, LOG_FIP | LOG_DISCOVERY,
-                        "2546 New FCF found/FCF parameter modified event: "
-                        "evt_tag:x%x, fcf_index:x%x\n",
-                        acqe_fcoe->event_tag, acqe_fcoe->index);
-
+                if (event_type == LPFC_FCOE_EVENT_TYPE_NEW_FCF)
+                        lpfc_printf_log(phba, KERN_ERR, LOG_FIP |
+                                        LOG_DISCOVERY,
+                                        "2546 New FCF found event: "
+                                        "evt_tag:x%x, fcf_index:x%x\n",
+                                        acqe_fcoe->event_tag,
+                                        acqe_fcoe->index);
+                else
+                        lpfc_printf_log(phba, KERN_WARNING, LOG_FIP |
+                                        LOG_DISCOVERY,
+                                        "2788 FCF parameter modified event: "
+                                        "evt_tag:x%x, fcf_index:x%x\n",
+                                        acqe_fcoe->event_tag,
+                                        acqe_fcoe->index);
                 spin_lock_irq(&phba->hbalock);
                 if ((phba->fcf.fcf_flag & FCF_SCAN_DONE) ||
                     (phba->hba_flag & FCF_DISC_INPROGRESS)) {
diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c
index 049fb9a17b3f..2eff81d366f9 100644
--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -12040,9 +12040,11 @@ lpfc_sli4_fcf_scan_read_fcf_rec(struct lpfc_hba *phba, uint16_t fcf_index)
                 phba->hba_flag |= FCF_DISC_INPROGRESS;
                 spin_unlock_irq(&phba->hbalock);
                 /* Reset FCF round robin index bmask for new scan */
-                if (fcf_index == LPFC_FCOE_FCF_GET_FIRST)
+                if (fcf_index == LPFC_FCOE_FCF_GET_FIRST) {
                         memset(phba->fcf.fcf_rr_bmask, 0,
                                sizeof(*phba->fcf.fcf_rr_bmask));
+                        phba->fcf.eligible_fcf_cnt = 0;
+                }
                 error = 0;
         }
 fail_fcf_scan:
diff --git a/drivers/scsi/lpfc/lpfc_sli4.h b/drivers/scsi/lpfc/lpfc_sli4.h
index 4a35e7b9bc5b..5b6cb9742c58 100644
--- a/drivers/scsi/lpfc/lpfc_sli4.h
+++ b/drivers/scsi/lpfc/lpfc_sli4.h
@@ -162,6 +162,7 @@ struct lpfc_fcf {
 #define FCF_REDISC_FOV  0x200 /* Post FCF rediscovery fast failover */
         uint32_t addr_mode;
         uint16_t fcf_rr_init_indx;
+        uint32_t eligible_fcf_cnt;
         struct lpfc_fcf_rec current_rec;
         struct lpfc_fcf_rec failover_rec;
         struct timer_list redisc_wait;