scsi: lpfc: Cap CMF read bytes to MBPI

BugLink: https://bugs.launchpad.net/bugs/1956982
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>
(cherry picked from commit 05116ef9c4b444f7fdbb56f9e13c2ec941726639)
Signed-off-by: Jeff Lane <jeffrey.lane@canonical.com>
Acked-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>

diff --git a/drivers/scsi/lpfc/lpfc.h b/drivers/scsi/lpfc/lpfc.h
index 4c7bc0a5fcf7fdd20679be145d5a6ac16a733ddd..f1c87a2d0af2572a9c54b14c2e4e85777decb309 100644 (file)
--- a/drivers/scsi/lpfc/lpfc.h
+++ b/drivers/scsi/lpfc/lpfc.h
@@ -1027,7 +1027,7 @@ 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 bbcf5d446cb152c467199479d1b9fb67cecb4bff..171a3783ced260938afdebe588682c8abe3baa7b 100644 (file)
--- a/drivers/scsi/lpfc/lpfc_init.c
+++ b/drivers/scsi/lpfc/lpfc_init.c
@@ -6003,8 +6003,13 @@ 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);
@@ -6087,6 +6092,8 @@ 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.
@@ -6097,6 +6104,8 @@ 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.