[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>

2 files changed, 8 insertions, 5 deletions

diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h
index 6cb1e2788d8b..c60b8ff2f5e4 100644
--- a/include/scsi/scsi.h
+++ b/include/scsi/scsi.h
@@ -32,6 +32,12 @@ extern const unsigned char scsi_command_size[8];
 extern const char *const scsi_device_types[MAX_SCSI_DEVICE_CODE];
 
 /*
+ * Special value for scanning to specify scanning or rescanning of all
+ * possible channels, (target) ids, or luns on a given shost.
+ */
+#define SCAN_WILD_CARD  ~0
+
+/*
  *      SCSI opcodes
  */
 
diff --git a/include/scsi/scsi_transport.h b/include/scsi/scsi_transport.h
index f6e0bb484c63..e7b1054adf86 100644
--- a/include/scsi/scsi_transport.h
+++ b/include/scsi/scsi_transport.h
@@ -30,12 +30,9 @@ struct scsi_transport_template {
         struct transport_container device_attrs;
 
         /*
-         * If set, call target_parent prior to allocating a scsi_target,
-         * so we get the appropriate parent for the target. This function
-         * is required for transports like FC and iSCSI that do not put the
-         * scsi_target under scsi_host.
+         * If set, called from sysfs and legacy procfs rescanning code.
          */
-        struct device *(*target_parent)(struct Scsi_Host *, int, uint);
+        int (*user_scan)(struct Scsi_Host *, uint, uint, uint);
 
         /* The size of the specific transport attribute structure (a
          * space of this size will be left at the end of the