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authorJames Smart <james.smart@emulex.com>2010-03-15 11:24:56 -0400
committerJames Bottomley <James.Bottomley@suse.de>2010-04-11 09:23:47 -0500
commit999d813f227435c35b44362ee82211a1458844fc (patch)
treeba5c1ab8169b8156a59b6484cd032ce3b873dfa8 /drivers/scsi/lpfc/lpfc_hbadisc.c
parent65c054f235fda2d545ecd2a7948906a3cf0c1f39 (diff)
downloadblackbird-op-linux-999d813f227435c35b44362ee82211a1458844fc.tar.gz
blackbird-op-linux-999d813f227435c35b44362ee82211a1458844fc.zip
[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>
Diffstat (limited to 'drivers/scsi/lpfc/lpfc_hbadisc.c')
-rw-r--r--drivers/scsi/lpfc/lpfc_hbadisc.c53
1 files changed, 51 insertions, 2 deletions
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;
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