[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>
diff --git a/drivers/scsi/lpfc/lpfc_hbadisc.c b/drivers/scsi/lpfc/lpfc_hbadisc.c
index e1466ee..362730b 100644
--- a/drivers/scsi/lpfc/lpfc_hbadisc.c
+++ b/drivers/scsi/lpfc/lpfc_hbadisc.c
@@ -1531,7 +1531,37 @@
}
/**
- * 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 @@
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 @@
* 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 @@
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;