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[SCSI] scsi_transport_fc: remove invalid BUG_ON 

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.

Signed-off-by: Michael Reed <mdr@sgi.com>
Acked-by:  James Smart <james.smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
This commit is contained in:
Michael Reed 2009-10-09 14:15:59 -05:00 committed by James Bottomley
parent ad63082626
commit 8798a694da
1 changed files with 42 additions and 26 deletions
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68
drivers/scsi/scsi_transport_fc.c
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@ -2384,6 +2384,7 @@ fc_rport_final_delete(struct work_struct *work)
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 *work)
* 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_struct *work)
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_struct *work)
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_struct *work)
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);
/* 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;
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;
}
/*
* 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_struct *work)
*
* 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);
}