scsi: lpfc: Fix soft lockup in lpfc worker thread during LIP testing

Orabug: 27631736

During link bounce testing in a point-to-point topology, the host may
enter a soft lockup on the lpfc_worker thread:

    Call Trace:
     lpfc_work_done+0x1f3/0x1390 [lpfc]
     lpfc_do_work+0x16f/0x180 [lpfc]
     kthread+0xc7/0xe0
     ret_from_fork+0x3f/0x70

The driver was simultaneously setting a combination of flags that caused
lpfc_do_work()to effectively spin between slow path work and new event
data, causing the lockup.

Ensure in the typical wq completions, that new event data flags are set
if the slow path flag is running. The slow path will eventually
reschedule the wq handling.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
(cherry picked from commit 161df4f09987ae2e9f0f97f0b38eee298b4a39ff)
Signed-off-by: Dick dkennedy <dick.kennedy@broadcom.com>
Signed-off-by: Dan Duval <dan.duval@oracle.com>
Reviewed-by: Jack Vogel <jack.vogel@oracle.com>

diff --git a/drivers/scsi/lpfc/lpfc_hbadisc.c b/drivers/scsi/lpfc/lpfc_hbadisc.c
index eb541a5c477445ac9c2a400f996f5e1459b4b013..7cc9141ee53a31293225b6007e8301b0b645ef12 100644 (file)
--- a/drivers/scsi/lpfc/lpfc_hbadisc.c
+++ b/drivers/scsi/lpfc/lpfc_hbadisc.c
@@ -691,8 +691,9 @@ lpfc_work_done(struct lpfc_hba *phba)
            (phba->hba_flag & HBA_SP_QUEUE_EVT)) {
                if (pring->flag & LPFC_STOP_IOCB_EVENT) {
                        pring->flag |= LPFC_DEFERRED_RING_EVENT;
-                       /* Set the lpfc data pending flag */
-                       set_bit(LPFC_DATA_READY, &phba->data_flags);
+                       /* Preserve legacy behavior. */
+                       if (!(phba->hba_flag & HBA_SP_QUEUE_EVT))
+                               set_bit(LPFC_DATA_READY, &phba->data_flags);
                } else {
                        if (phba->link_state >= LPFC_LINK_UP ||
                            phba->link_flag & LS_MDS_LOOPBACK) {