| Date | Tue, 30 Mar 2010 15:41:32 -0700 | From | Greg KH <> | Subject | [058/156] SCSI: scsi_transport_fc: Fix synchronization issue while deleting vport |
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2.6.33-stable review patch. If anyone has any objections, please let us know.
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From: Gal Rosen <galr@storwize.com>
commit 0d9dc7c8b9b7fa0f53647423b41056ee1beed735 upstream.
The issue occur while deleting 60 virtual ports through the sys interface /sys/class/fc_vports/vport-X/vport_delete. It happen while in a mistake each request sent twice for the same vport. This interface is asynchronous, entering the delete request into a work queue, allowing more than one request to enter to the delete work queue. The result is a NULL pointer. The first request already delete the vport, while the second request got a pointer to the vport before the device destroyed. Re-create vport later cause system freeze.
Solution: Check vport flags before entering the request to the work queue.
[jejb: fixed int<->long problem on spinlock flags variable] Signed-off-by: Gal Rosen <galr@storwize.com> Acked-by: James Smart <james.smart@emulex.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- drivers/scsi/scsi_transport_fc.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-)
--- a/drivers/scsi/scsi_transport_fc.c +++ b/drivers/scsi/scsi_transport_fc.c @@ -1216,6 +1216,15 @@ store_fc_vport_delete(struct device *dev { struct fc_vport *vport = transport_class_to_vport(dev); struct Scsi_Host *shost = vport_to_shost(vport); + unsigned long flags; + + spin_lock_irqsave(shost->host_lock, flags); + if (vport->flags & (FC_VPORT_DEL | FC_VPORT_CREATING)) { + spin_unlock_irqrestore(shost->host_lock, flags); + return -EBUSY; + } + vport->flags |= FC_VPORT_DELETING; + spin_unlock_irqrestore(shost->host_lock, flags); fc_queue_work(shost, &vport->vport_delete_work); return count; @@ -1805,6 +1814,9 @@ store_fc_host_vport_delete(struct device list_for_each_entry(vport, &fc_host->vports, peers) { if ((vport->channel == 0) && (vport->port_name == wwpn) && (vport->node_name == wwnn)) { + if (vport->flags & (FC_VPORT_DEL | FC_VPORT_CREATING)) + break; + vport->flags |= FC_VPORT_DELETING; match = 1; break; } @@ -3354,18 +3366,6 @@ fc_vport_terminate(struct fc_vport *vpor unsigned long flags; int stat; - spin_lock_irqsave(shost->host_lock, flags); - if (vport->flags & FC_VPORT_CREATING) { - spin_unlock_irqrestore(shost->host_lock, flags); - return -EBUSY; - } - if (vport->flags & (FC_VPORT_DEL)) { - spin_unlock_irqrestore(shost->host_lock, flags); - return -EALREADY; - } - vport->flags |= FC_VPORT_DELETING; - spin_unlock_irqrestore(shost->host_lock, flags); - if (i->f->vport_delete) stat = i->f->vport_delete(vport); else
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