From: Brian King <brk...@linux.vnet.ibm.com>
This fixes an issue hitting the BUG_ON in ibmvfc_do_work. When
going through a host action of IBMVFC_HOST_ACTION_RESET,
we change the action to IBMVFC_HOST_ACTION_TGT_DEL,
then drop the host lock, and reset the CRQ, which changes
the host state to IBMVFC_NO_CRQ. If, prior to setting the
host state to IBMVFC_NO_CRQ, ibmvfc_init_host is called,
it can then end up changing the host action to IBMVFC_HOST_ACTION_INIT.
If we then change the host state to IBMVFC_NO_CRQ, we will then
hit the BUG_ON. This patch makes a couple of changes to avoid this.
It leaves the host action to be IBMVFC_HOST_ACTION_RESET
or IBMVFC_HOST_ACTION_REENABLE until after we drop the host
lock and reset or reenable the CRQ. It also hardens the
host state machine to ensure we cannot leave the reset / reenable
state until we've finished processing the reset or reenable.
Fixes: 73ee5d867287 ("[SCSI] ibmvfc: Fix soft lockup on resume")
Signed-off-by: Brian King <brk...@linux.vnet.ibm.com>
[tyreld: added fixes tag]
Signed-off-by: Tyrel Datwyler <tyr...@linux.ibm.com>
---
drivers/scsi/ibmvscsi/ibmvfc.c | 53 ++++++++++++++++++++++------------
1 file changed, 34 insertions(+), 19 deletions(-)
diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index 61831f2fdb30..f813608d74cc 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc.c
@@ -603,8 +603,17 @@ static void ibmvfc_set_host_action(struct ibmvfc_host
*vhost,
if (vhost->action == IBMVFC_HOST_ACTION_ALLOC_TGTS)
vhost->action = action;
break;
+ case IBMVFC_HOST_ACTION_REENABLE:
+ case IBMVFC_HOST_ACTION_RESET:
+ vhost->action = action;
+ break;
case IBMVFC_HOST_ACTION_INIT:
case IBMVFC_HOST_ACTION_TGT_DEL:
+ case IBMVFC_HOST_ACTION_LOGO:
+ case IBMVFC_HOST_ACTION_QUERY_TGTS:
+ case IBMVFC_HOST_ACTION_TGT_DEL_FAILED:
+ case IBMVFC_HOST_ACTION_NONE:
+ default:
switch (vhost->action) {
case IBMVFC_HOST_ACTION_RESET:
case IBMVFC_HOST_ACTION_REENABLE:
@@ -614,15 +623,6 @@ static void ibmvfc_set_host_action(struct ibmvfc_host
*vhost,
break;
}
break;
- case IBMVFC_HOST_ACTION_LOGO:
- case IBMVFC_HOST_ACTION_QUERY_TGTS:
- case IBMVFC_HOST_ACTION_TGT_DEL_FAILED:
- case IBMVFC_HOST_ACTION_NONE:
- case IBMVFC_HOST_ACTION_RESET:
- case IBMVFC_HOST_ACTION_REENABLE:
- default:
- vhost->action = action;
- break;
}
}
@@ -5373,30 +5373,45 @@ static void ibmvfc_do_work(struct ibmvfc_host *vhost)
case IBMVFC_HOST_ACTION_INIT_WAIT:
break;
case IBMVFC_HOST_ACTION_RESET:
- vhost->action = IBMVFC_HOST_ACTION_TGT_DEL;
list_splice_init(&vhost->purge, &purge);
spin_unlock_irqrestore(vhost->host->host_lock, flags);
ibmvfc_complete_purge(&purge);
rc = ibmvfc_reset_crq(vhost);
+
spin_lock_irqsave(vhost->host->host_lock, flags);
- if (rc == H_CLOSED)
+ if (!rc || rc == H_CLOSED)
vio_enable_interrupts(to_vio_dev(vhost->dev));
- if (rc || (rc = ibmvfc_send_crq_init(vhost)) ||
- (rc = vio_enable_interrupts(to_vio_dev(vhost->dev)))) {
- ibmvfc_link_down(vhost, IBMVFC_LINK_DEAD);
- dev_err(vhost->dev, "Error after reset (rc=%d)\n", rc);
+ if (vhost->action == IBMVFC_HOST_ACTION_RESET) {
+ /* The only action we could have changed to would have
been reenable,
+ in which case, we skip the rest of this path and wait
until
+ we've done the re-enable before sending the crq init */
+
+ vhost->action = IBMVFC_HOST_ACTION_TGT_DEL;
+
+ if (rc || (rc = ibmvfc_send_crq_init(vhost)) ||
+ (rc =
vio_enable_interrupts(to_vio_dev(vhost->dev)))) {
+ ibmvfc_link_down(vhost, IBMVFC_LINK_DEAD);
+ dev_err(vhost->dev, "Error after reset
(rc=%d)\n", rc);
+ }
}
break;
case IBMVFC_HOST_ACTION_REENABLE:
- vhost->action = IBMVFC_HOST_ACTION_TGT_DEL;
list_splice_init(&vhost->purge, &purge);
spin_unlock_irqrestore(vhost->host->host_lock, flags);
ibmvfc_complete_purge(&purge);
rc = ibmvfc_reenable_crq_queue(vhost);
+
spin_lock_irqsave(vhost->host->host_lock, flags);
- if (rc || (rc = ibmvfc_send_crq_init(vhost))) {
- ibmvfc_link_down(vhost, IBMVFC_LINK_DEAD);
- dev_err(vhost->dev, "Error after enable (rc=%d)\n", rc);
+ if (vhost->action == IBMVFC_HOST_ACTION_REENABLE) {
+ /* The only action we could have changed to would have
been reset,
+ in which case, we skip the rest of this path and wait
until
+ we've done the reset before sending the crq init */
+
+ vhost->action = IBMVFC_HOST_ACTION_TGT_DEL;
+ if (rc || (rc = ibmvfc_send_crq_init(vhost))) {
+ ibmvfc_link_down(vhost, IBMVFC_LINK_DEAD);
+ dev_err(vhost->dev, "Error after enable
(rc=%d)\n", rc);
+ }
}
break;
case IBMVFC_HOST_ACTION_LOGO:
--
2.27.0
