scsi: lpfc: Coordinate adapter error handling with offline handling

The driver periodically checks for adapter error in a background thread. If
the thread detects an error, the adapter will be reset including the
deletion and reallocation of workqueues on the adapter.  Simultaneously,
there may be a user-space request to offline the adapter which may try to
do many of the same steps, in parallel, on a different thread. As memory
was deallocated while unexpected, the parallel offline request hit a bad
pointer.

Add coordination between the two threads.  The error recovery thread has
precedence. So, when an error is detected, a flag is set on the adapter to
indicate the error thread is terminating the adapter. But, before doing
that work, it will look for a flag that is set by the offline flow, and if
set, will wait for it to complete before then processing the error handling
path.  Similarly, in the offline thread, it first checks for whether the
error thread is resetting the adapter, and if so, will then wait for the
error thread to finish. Only after it has finished, will it set its flag
and offline the adapter.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/drivers/scsi/lpfc/lpfc_attr.c b/drivers/scsi/lpfc/lpfc_attr.c
index 5d6c874c44e7..61745f590916 100644
--- a/drivers/scsi/lpfc/lpfc_attr.c
+++ b/drivers/scsi/lpfc/lpfc_attr.c
@@ -1204,6 +1204,20 @@ lpfc_do_offline(struct lpfc_hba *phba, uint32_t type)
 
 	psli = &phba->sli;
 
+	/*
+	 * If freeing the queues have already started, don't access them.
+	 * Otherwise set FREE_WAIT to indicate that queues are being used
+	 * to hold the freeing process until we finish.
+	 */
+	spin_lock_irq(&phba->hbalock);
+	if (!(psli->sli_flag & LPFC_QUEUE_FREE_INIT)) {
+		psli->sli_flag |= LPFC_QUEUE_FREE_WAIT;
+	} else {
+		spin_unlock_irq(&phba->hbalock);
+		goto skip_wait;
+	}
+	spin_unlock_irq(&phba->hbalock);
+
 	/* Wait a little for things to settle down, but not
 	 * long enough for dev loss timeout to expire.
 	 */
@@ -1225,6 +1239,11 @@ lpfc_do_offline(struct lpfc_hba *phba, uint32_t type)
 		}
 	}
 out:
+	spin_lock_irq(&phba->hbalock);
+	psli->sli_flag &= ~LPFC_QUEUE_FREE_WAIT;
+	spin_unlock_irq(&phba->hbalock);
+
+skip_wait:
 	init_completion(&online_compl);
 	rc = lpfc_workq_post_event(phba, &status, &online_compl, type);
 	if (rc == 0)