[15/30] lpfc: Fix mailbox hang on adapter init

Commit Message

James Smart March 12, 2019, 11:30 p.m. UTC

The adapter initialization sequence enables interrupts,  initializes
the adapter link_state to LINK_DOWN, then issues commands to
initialize the adapter. The interrupt handler on the adapter validates
the link_state (has to be at least LINK_DOWN) and if invalid, will
discard the interrupting event.

In most cases, there is not a command completion, thus an interrupt
until the initialization commands have been sent which is post the
setting of state to LINK_DOWN.  However, in cases of firmware reset,
the reset will modify the link_state to an invalid value (indicating
a reset of the adapter) and there occasionally are cases where the
adapter will generate an asynchronous event which shares the eq/cq
used for mailbox commands. In the failure case, an interrupt is
generated immediately after enabling them due to the async event.
As link_state is invalid, the eq is list and the CQ not serviced.
At this point link_state is initialized and the mailbox command sent.
As the CQ has not been serviced, it is not armed, so no interrupt
event is generated when the mailbox command completes.

Modify the initialization sequence so that interrupts are enabled
after link_state is properly initialized, which avoids the race
condition with the async event.

Signed-off-by: Dick Kennedy <[e-mail]>
Signed-off-by: James Smart <[e-mail]>
---
 drivers/scsi/lpfc/lpfc_sli.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

Patch

diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c
index 5d216d54fa31..0963f81f2a3f 100644
--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -7660,12 +7660,6 @@  lpfc_sli4_hba_setup(struct lpfc_hba *phba)
 		phba->cfg_xri_rebalancing = 0;
 	}
 
-	/* Arm the CQs and then EQs on device */
-	lpfc_sli4_arm_cqeq_intr(phba);
-
-	/* Indicate device interrupt mode */
-	phba->sli4_hba.intr_enable = 1;
-
 	/* Allow asynchronous mailbox command to go through */
 	spin_lock_irq(&phba->hbalock);
 	phba->sli.sli_flag &= ~LPFC_SLI_ASYNC_MBX_BLK;
@@ -7734,6 +7728,12 @@  lpfc_sli4_hba_setup(struct lpfc_hba *phba)
 		phba->trunk_link.link3.state = LPFC_LINK_DOWN;
 	spin_unlock_irq(&phba->hbalock);
 
+	/* Arm the CQs and then EQs on device */
+	lpfc_sli4_arm_cqeq_intr(phba);
+
+	/* Indicate device interrupt mode */
+	phba->sli4_hba.intr_enable = 1;
+
 	if (!(phba->hba_flag & HBA_FCOE_MODE) &&
 	    (phba->hba_flag & LINK_DISABLED)) {
 		lpfc_printf_log(phba, KERN_ERR, LOG_INIT | LOG_SLI,