[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>

8 files changed, 57 insertions, 53 deletions

diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
index 14a6198cb8d2..27c48274e8cb 100644
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -26,12 +26,6 @@ struct Scsi_Host;
 #define SCSI_SENSE_VALID(scmd) \
         (((scmd)->sense_buffer[0] & 0x70) == 0x70)
 
-/*
- * 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
-
 /* hosts.c */
 extern int scsi_init_hosts(void);
 extern void scsi_exit_hosts(void);
diff --git a/drivers/scsi/scsi_proc.c b/drivers/scsi/scsi_proc.c
index 1b5711e714a5..07be62bbaaea 100644
--- a/drivers/scsi/scsi_proc.c
+++ b/drivers/scsi/scsi_proc.c
@@ -31,6 +31,7 @@
 #include <scsi/scsi.h>
 #include <scsi/scsi_device.h>
 #include <scsi/scsi_host.h>
+#include <scsi/scsi_transport.h>
 
 #include "scsi_priv.h"
 #include "scsi_logging.h"
@@ -200,7 +201,10 @@ static int scsi_add_single_device(uint host, uint channel, uint id, uint lun)
         if (IS_ERR(shost))
                 return PTR_ERR(shost);
 
-        error = scsi_scan_host_selected(shost, channel, id, lun, 1);
+        if (shost->transportt->user_scan)
+                error = shost->transportt->user_scan(shost, channel, id, lun);
+        else
+                error = scsi_scan_host_selected(shost, channel, id, lun, 1);
         scsi_host_put(shost);
         return error;
 }
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index edcd80b749c1..752fb5da3de4 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -334,19 +334,6 @@ static struct scsi_target *scsi_alloc_target(struct device *parent,
         struct scsi_target *starget;
         struct scsi_target *found_target;
 
-        /*
-         * Obtain the real parent from the transport. The transport
-         * is allowed to fail (no error) if there is nothing at that
-         * target id.
-         */
-        if (shost->transportt->target_parent) {
-                spin_lock_irqsave(shost->host_lock, flags);
-                parent = shost->transportt->target_parent(shost, channel, id);
-                spin_unlock_irqrestore(shost->host_lock, flags);
-                if (!parent)
-                        return NULL;
-        }
-
         starget = kmalloc(size, GFP_KERNEL);
         if (!starget) {
                 printk(KERN_ERR "%s: allocation failure\n", __FUNCTION__);
@@ -1283,8 +1270,9 @@ struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel,
         struct scsi_device *sdev;
         struct device *parent = &shost->shost_gendev;
         int res;
-        struct scsi_target *starget = scsi_alloc_target(parent, channel, id);
+        struct scsi_target *starget;
 
+        starget = scsi_alloc_target(parent, channel, id);
         if (!starget)
                 return ERR_PTR(-ENOMEM);
 
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;
 }
 
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.
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;
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