[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, 24 insertions, 18 deletions

diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c
index e950435a11d8..fb6641b42dfa 100644
--- a/drivers/scsi/scsi_transport_sas.c
+++ b/drivers/scsi/scsi_transport_sas.c
@@ -29,6 +29,7 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 
+#include <scsi/scsi.h>
 #include <scsi/scsi_device.h>
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_transport.h>
@@ -62,7 +63,7 @@ struct sas_internal {
 
 struct sas_host_attrs {
         struct list_head rphy_list;
-        spinlock_t lock;
+        struct mutex lock;
         u32 next_target_id;
 };
 #define to_sas_host_attrs(host) ((struct sas_host_attrs *)(host)->shost_data)
@@ -165,7 +166,7 @@ static int sas_host_setup(struct transport_container *tc, struct device *dev,
         struct sas_host_attrs *sas_host = to_sas_host_attrs(shost);
 
         INIT_LIST_HEAD(&sas_host->rphy_list);
-        spin_lock_init(&sas_host->lock);
+        mutex_init(&sas_host->lock);
         sas_host->next_target_id = 0;
         return 0;
 }
@@ -626,7 +627,7 @@ int sas_rphy_add(struct sas_rphy *rphy)
         transport_add_device(&rphy->dev);
         transport_configure_device(&rphy->dev);
 
-        spin_lock(&sas_host->lock);
+        mutex_lock(&sas_host->lock);
         list_add_tail(&rphy->list, &sas_host->rphy_list);
         if (identify->device_type == SAS_END_DEVICE &&
             (identify->target_port_protocols &
@@ -634,7 +635,7 @@ int sas_rphy_add(struct sas_rphy *rphy)
                 rphy->scsi_target_id = sas_host->next_target_id++;
         else
                 rphy->scsi_target_id = -1;
-        spin_unlock(&sas_host->lock);
+        mutex_unlock(&sas_host->lock);
 
         if (rphy->scsi_target_id != -1) {
                 scsi_scan_target(&rphy->dev, parent->number,
@@ -661,9 +662,9 @@ void sas_rphy_free(struct sas_rphy *rphy)
         struct Scsi_Host *shost = dev_to_shost(rphy->dev.parent->parent);
         struct sas_host_attrs *sas_host = to_sas_host_attrs(shost);
 
-        spin_lock(&sas_host->lock);
+        mutex_lock(&sas_host->lock);
         list_del(&rphy->list);
-        spin_unlock(&sas_host->lock);
+        mutex_unlock(&sas_host->lock);
 
         transport_destroy_device(&rphy->dev);
         put_device(rphy->dev.parent);
@@ -703,9 +704,9 @@ sas_rphy_delete(struct sas_rphy *rphy)
         device_del(dev);
         transport_destroy_device(dev);
 
-        spin_lock(&sas_host->lock);
+        mutex_lock(&sas_host->lock);
         list_del(&rphy->list);
-        spin_unlock(&sas_host->lock);
+        mutex_unlock(&sas_host->lock);
 
         parent->rphy = NULL;
 
@@ -731,23 +732,28 @@ EXPORT_SYMBOL(scsi_is_sas_rphy);
  * SCSI scan helper
  */
 
-static struct device *sas_target_parent(struct Scsi_Host *shost,
-                                        int channel, uint id)
+static int sas_user_scan(struct Scsi_Host *shost, uint channel,
+                uint id, uint lun)
 {
         struct sas_host_attrs *sas_host = to_sas_host_attrs(shost);
         struct sas_rphy *rphy;
-        struct device *dev = NULL;
 
-        spin_lock(&sas_host->lock);
+        mutex_lock(&sas_host->lock);
         list_for_each_entry(rphy, &sas_host->rphy_list, list) {
                 struct sas_phy *parent = dev_to_phy(rphy->dev.parent);
-                if (parent->number == channel &&
-                    rphy->scsi_target_id == id)
-                        dev = &rphy->dev;
+
+                if (rphy->scsi_target_id == -1)
+                        continue;
+
+                if ((channel == SCAN_WILD_CARD || channel == parent->number) &&
+                    (id == SCAN_WILD_CARD || id == rphy->scsi_target_id)) {
+                        scsi_scan_target(&rphy->dev, parent->number,
+                                         rphy->scsi_target_id, lun, 1);
+                }
         }
-        spin_unlock(&sas_host->lock);
+        mutex_unlock(&sas_host->lock);
 
-        return dev;
+        return 0;
 }
 
 
@@ -792,7 +798,7 @@ sas_attach_transport(struct sas_function_template *ft)
                 return NULL;
         memset(i, 0, sizeof(struct sas_internal));
 
-        i->t.target_parent = sas_target_parent;
+        i->t.user_scan = sas_user_scan;
 
         i->t.host_attrs.ac.attrs = &i->host_attrs[0];
         i->t.host_attrs.ac.class = &sas_host_class.class;