* [PATCH 1/1] remove invalid BUG_ON in scsi_transport_fc.c
[not found] ` <4AB3DE99.3080602@sgi.com>
@ 2009-10-09 19:15 ` Michael Reed
2009-10-13 17:15 ` James Smart
0 siblings, 1 reply; 2+ messages in thread
From: Michael Reed @ 2009-10-09 19:15 UTC (permalink / raw)
To: linux-scsi; +Cc: James Smart
I was doing some large lun count testing with 2.6.31 and hit
a BUG_ON() in fc_timeout_deleted_rport(), and it seems like it
should have been just a matter of time before someone did.
It seems invalid to set port_state under lock, then expect it to
remain set after releasing the lock. Another thread called
fc_remote_port_add() when the lock was released, changing the
port_state.
This patch removes the BUG_ON and moves the test of the
port_state to inside the host_lock. It's been running for
several weeks now with no ill effect.
Applies to 2.6.31 and 2.6.32-rc3.
Signed-off-by: Michael Reed <mdr@sgi.com>
--- a/drivers/scsi/scsi_transport_fc.c 2009-09-09 17:13:59.000000000 -0500
+++ b/drivers/scsi/scsi_transport_fc.c 2009-10-02 15:09:00.298487474 -0500
@@ -2384,6 +2384,7 @@ fc_rport_final_delete(struct work_struct
struct Scsi_Host *shost = rport_to_shost(rport);
struct fc_internal *i = to_fc_internal(shost->transportt);
unsigned long flags;
+ int do_callback = 0;
/*
* if a scan is pending, flush the SCSI Host work_q so that
@@ -2422,8 +2423,15 @@ fc_rport_final_delete(struct work_struct
* Avoid this call if we already called it when we preserved the
* rport for the binding.
*/
+ spin_lock_irqsave(shost->host_lock, flags);
if (!(rport->flags & FC_RPORT_DEVLOSS_CALLBK_DONE) &&
- (i->f->dev_loss_tmo_callbk))
+ (i->f->dev_loss_tmo_callbk)) {
+ rport->flags |= FC_RPORT_DEVLOSS_CALLBK_DONE;
+ do_callback = 1;
+ }
+ spin_unlock_irqrestore(shost->host_lock, flags);
+
+ if (do_callback)
i->f->dev_loss_tmo_callbk(rport);
fc_bsg_remove(rport->rqst_q);
@@ -2970,6 +2978,7 @@ fc_timeout_deleted_rport(struct work_str
struct fc_internal *i = to_fc_internal(shost->transportt);
struct fc_host_attrs *fc_host = shost_to_fc_host(shost);
unsigned long flags;
+ int do_callback = 0;
spin_lock_irqsave(shost->host_lock, flags);
@@ -3035,7 +3044,6 @@ fc_timeout_deleted_rport(struct work_str
rport->roles = FC_PORT_ROLE_UNKNOWN;
rport->port_state = FC_PORTSTATE_NOTPRESENT;
rport->flags &= ~FC_RPORT_FAST_FAIL_TIMEDOUT;
- rport->flags |= FC_RPORT_DEVLOSS_CALLBK_DONE;
/*
* Pre-emptively kill I/O rather than waiting for the work queue
@@ -3045,32 +3053,40 @@ fc_timeout_deleted_rport(struct work_str
spin_unlock_irqrestore(shost->host_lock, flags);
fc_terminate_rport_io(rport);
- BUG_ON(rport->port_state != FC_PORTSTATE_NOTPRESENT);
+ spin_lock_irqsave(shost->host_lock, flags);
+
+ if (rport->port_state == FC_PORTSTATE_NOTPRESENT) { /* still missing */
+
+ /* remove the identifiers that aren't used in the consisting binding */
+ switch (fc_host->tgtid_bind_type) {
+ case FC_TGTID_BIND_BY_WWPN:
+ rport->node_name = -1;
+ rport->port_id = -1;
+ break;
+ case FC_TGTID_BIND_BY_WWNN:
+ rport->port_name = -1;
+ rport->port_id = -1;
+ break;
+ case FC_TGTID_BIND_BY_ID:
+ rport->node_name = -1;
+ rport->port_name = -1;
+ break;
+ case FC_TGTID_BIND_NONE: /* to keep compiler happy */
+ break;
+ }
- /* remove the identifiers that aren't used in the consisting binding */
- switch (fc_host->tgtid_bind_type) {
- case FC_TGTID_BIND_BY_WWPN:
- rport->node_name = -1;
- rport->port_id = -1;
- break;
- case FC_TGTID_BIND_BY_WWNN:
- rport->port_name = -1;
- rport->port_id = -1;
- break;
- case FC_TGTID_BIND_BY_ID:
- rport->node_name = -1;
- rport->port_name = -1;
- break;
- case FC_TGTID_BIND_NONE: /* to keep compiler happy */
- break;
+ /*
+ * As this only occurs if the remote port (scsi target)
+ * went away and didn't come back - we'll remove
+ * all attached scsi devices.
+ */
+ rport->flags |= FC_RPORT_DEVLOSS_CALLBK_DONE;
+ fc_queue_work(shost, &rport->stgt_delete_work);
+
+ do_callback = 1;
}
- /*
- * As this only occurs if the remote port (scsi target)
- * went away and didn't come back - we'll remove
- * all attached scsi devices.
- */
- fc_queue_work(shost, &rport->stgt_delete_work);
+ spin_unlock_irqrestore(shost->host_lock, flags);
/*
* Notify the driver that the rport is now dead. The LLDD will
@@ -3078,7 +3094,7 @@ fc_timeout_deleted_rport(struct work_str
*
* Note: we set the CALLBK_DONE flag above to correspond
*/
- if (i->f->dev_loss_tmo_callbk)
+ if (do_callback && i->f->dev_loss_tmo_callbk)
i->f->dev_loss_tmo_callbk(rport);
}
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