scsi: lpfc: Cap CMF read bytes to MBPI

Ensure read bytes data does not go over MBPI for CMF timer intervals that
are purposely shortened.

Link: https://lore.kernel.org/r/20211204002644.116455-8-jsmart2021@gmail.com
Co-developed-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/lpfc/lpfc.h b/drivers/scsi/lpfc/lpfc.h
index 49abbf1..3faadcf 100644 (file)
--- a/drivers/scsi/lpfc/lpfc.h
+++ b/drivers/scsi/lpfc/lpfc.h
@@ -1028,7 +1028,7 @@ struct lpfc_hba {
                                         */
 #define HBA_PCI_ERR            0x80000 /* The PCI slot is offline */
 #define HBA_FLOGI_ISSUED       0x100000 /* FLOGI was issued */
-#define HBA_CGN_RSVD1          0x200000 /* Reserved CGN flag */
+#define HBA_SHORT_CMF          0x200000 /* shorter CMF timer routine */
 #define HBA_CGN_DAY_WRAP       0x400000 /* HBA Congestion info day wraps */
 #define HBA_DEFER_FLOGI                0x800000 /* Defer FLOGI till read_sparm cmpl */
 #define HBA_SETUP              0x1000000 /* Signifies HBA setup is completed */

diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
index 132f2e6..2fe7d9d 100644 (file)
--- a/drivers/scsi/lpfc/lpfc_init.c
+++ b/drivers/scsi/lpfc/lpfc_init.c
@@ -6004,8 +6004,13 @@ lpfc_cmf_timer(struct hrtimer *timer)
                if (ms && ms < LPFC_CMF_INTERVAL) {
                        cnt = div_u64(total, ms); /* bytes per ms */
                        cnt *= LPFC_CMF_INTERVAL; /* what total should be */
-                       if (cnt > mbpi)
+
+                       /* If the timeout is scheduled to be shorter,
+                        * this value may skew the data, so cap it at mbpi.
+                        */
+                       if ((phba->hba_flag & HBA_SHORT_CMF) && cnt > mbpi)
                                cnt = mbpi;
+
                        extra = cnt - total;
                }
                lpfc_issue_cmf_sync_wqe(phba, LPFC_CMF_INTERVAL, total + extra);
@@ -6088,6 +6093,8 @@ lpfc_cmf_timer(struct hrtimer *timer)
        /* Each minute save Fabric and Driver congestion information */
        lpfc_cgn_save_evt_cnt(phba);
 
+       phba->hba_flag &= ~HBA_SHORT_CMF;
+
        /* Since we need to call lpfc_cgn_save_evt_cnt every minute, on the
         * minute, adjust our next timer interval, if needed, to ensure a
         * 1 minute granularity when we get the next timer interrupt.
@@ -6098,6 +6105,8 @@ lpfc_cmf_timer(struct hrtimer *timer)
                                                  jiffies);
                if (timer_interval <= 0)
                        timer_interval = LPFC_CMF_INTERVAL;
+               else
+                       phba->hba_flag |= HBA_SHORT_CMF;
 
                /* If we adjust timer_interval, max_bytes_per_interval
                 * needs to be adjusted as well.