[SCSI] remove target parent limitiation

When James Smart fixed the issue of the userspace scan atributes
crashing the system with the FC transport class he added a patch to
let the transport class check if the parent is valid for a given
transport class.

When adding support for the integrated raid of fusion sas devices
we ran into a problem with that, as it didn't allow adding virtual
raid volumes without the transport class knowing about it.

So this patch adds a user_scan attribute instead, that takes over from
scsi_scan_host_selected if the transport class sets it and thus lets
the transport class control the user-initiated scanning.  As this
plugs the hole about user-initiated scanning the target_parent hook
goes away and we rely on callers of the scanning routines to do
something sensible.

For SAS this meant I had to switch from a spinlock to a mutex to
synchronize the topology linked lists, in FC they were completely
unsynchronized which seems wrong.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 14 insertions, 8 deletions

diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
index 625f4a664d06..f2c9acf11bd0 100644
--- a/drivers/scsi/scsi_transport_fc.c
+++ b/drivers/scsi/scsi_transport_fc.c
@@ -1093,17 +1093,23 @@ static int fc_rport_match(struct attribute_container *cont,
 /*
  * Must be called with shost->host_lock held
  */
-static struct device *fc_target_parent(struct Scsi_Host *shost,
-					int channel, uint id)
+static int fc_user_scan(struct Scsi_Host *shost, uint channel,
+		uint id, uint lun)
 {
 	struct fc_rport *rport;
 
-	list_for_each_entry(rport, &fc_host_rports(shost), peers)
-		if ((rport->channel == channel) &&
-		    (rport->scsi_target_id == id))
-			return &rport->dev;
+	list_for_each_entry(rport, &fc_host_rports(shost), peers) {
+		if (rport->scsi_target_id == -1)
+			continue;
 
-	return NULL;
+		if ((channel == SCAN_WILD_CARD || channel == rport->channel) &&
+		    (id == SCAN_WILD_CARD || id == rport->scsi_target_id)) {
+			scsi_scan_target(&rport->dev, rport->channel,
+					 rport->scsi_target_id, lun, 1);
+		}
+	}
+
+	return 0;
 }
 
 struct scsi_transport_template *
@@ -1142,7 +1148,7 @@ fc_attach_transport(struct fc_function_template *ft)
 	/* Transport uses the shost workq for scsi scanning */
 	i->t.create_work_queue = 1;
 
-	i->t.target_parent = fc_target_parent;
+	i->t.user_scan = fc_user_scan;
 	
 	/*
 	 * Setup SCSI Target Attributes.