From: James Smart <jsmart2021@gmail.com>

Date: Fri, 3 Dec 2021 16:26:42 -0800

Subject: scsi: lpfc: Cap CMF read bytes to MBPI

Patch-mainline: Queued in subsystem maintainer repository

Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi.git

Git-commit: 05116ef9c4b444f7fdbb56f9e13c2ec941726639

References: bsc1192145

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>

Acked-by: Daniel Wagner <dwagner@suse.de>

---

 drivers/scsi/lpfc/lpfc.h      |    2 +-

 drivers/scsi/lpfc/lpfc_init.c |   11 ++++++++++-

 2 files changed, 11 insertions(+), 2 deletions(-)

--- a/drivers/scsi/lpfc/lpfc.h

+++ b/drivers/scsi/lpfc/lpfc.h

@@ -937,7 +937,7 @@ 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 */

--- a/drivers/scsi/lpfc/lpfc_init.c

+++ b/drivers/scsi/lpfc/lpfc_init.c

@@ -5909,8 +5909,13 @@ 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);

@@ -5993,6 +5998,8 @@ 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.

@@ -6003,6 +6010,8 @@ 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.