[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, 4 insertions, 1 deletions

diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 2cb962751a7e..a77b32deaf8f 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -106,7 +106,10 @@ static int scsi_scan(struct Scsi_Host *shost, const char *str)
 		return -EINVAL;
 	if (check_set(&lun, s3))
 		return -EINVAL;
-	res = scsi_scan_host_selected(shost, channel, id, lun, 1);
+	if (shost->transportt->user_scan)
+		res = shost->transportt->user_scan(shost, channel, id, lun);
+	else
+		res = scsi_scan_host_selected(shost, channel, id, lun, 1);
 	return res;
 }