[SCSI] libsas: improve debug statements

It's difficult to determine which domain_device is triggering error recovery,
so convert messages like:

  sas: ex 5001b4da000e703f phy08:T attached: 5001b4da000e7028
  sas: ex 5001b4da000e703f phy09:T attached: 5001b4da000e7029
  ...
  ata7: sas eh calling libata port error handler
  ata8: sas eh calling libata port error handler

...into:

  sas: ex 5001517e85cfefff phy05:T:9 attached: 5001517e85cfefe5 (stp)
  sas: ex 5001517e3b0af0bf phy11:T:8 attached: 5001517e3b0af0ab (stp)
  ...
  sas: ata7: end_device-21:1: dev error handler
  sas: ata8: end_device-20:0:5: dev error handler

which shows attached link rate, device type, and associates a
domain_device with its ata_port id to correlate messages emitted from
libata-eh.

As Doug notes, we can also take the opportunity to clarify expander phy
routing capabilities.

[dgilbert@interlog.com: clarify table2table with 'U']
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 52 insertions, 22 deletions

diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index 68a80a00f73f..4b2ecd35dc5a 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -166,7 +166,22 @@ static inline void *alloc_smp_resp(int size)
         return kzalloc(size, GFP_KERNEL);
 }
 
-/* ---------- Expander configuration ---------- */
+static char sas_route_char(struct domain_device *dev, struct ex_phy *phy)
+{
+        switch (phy->routing_attr) {
+        case TABLE_ROUTING:
+                if (dev->ex_dev.t2t_supp)
+                        return 'U';
+                else
+                        return 'T';
+        case DIRECT_ROUTING:
+                return 'D';
+        case SUBTRACTIVE_ROUTING:
+                return 'S';
+        default:
+                return '?';
+        }
+}
 
 static void sas_set_ex_phy(struct domain_device *dev, int phy_id,
                            void *disc_resp)
@@ -176,9 +191,10 @@ static void sas_set_ex_phy(struct domain_device *dev, int phy_id,
         struct smp_resp *resp = disc_resp;
         struct discover_resp *dr = &resp->disc;
         struct sas_rphy *rphy = dev->rphy;
-        int rediscover = (phy->phy != NULL);
+        bool new_phy = !phy->phy;
+        char *type;
 
-        if (!rediscover) {
+        if (new_phy) {
                 phy->phy = sas_phy_alloc(&rphy->dev, phy_id);
 
                 /* FIXME: error_handling */
@@ -223,20 +239,41 @@ static void sas_set_ex_phy(struct domain_device *dev, int phy_id,
         phy->phy->maximum_linkrate = dr->pmax_linkrate;
         phy->phy->negotiated_linkrate = phy->linkrate;
 
-        if (!rediscover)
+        if (new_phy)
                 if (sas_phy_add(phy->phy)) {
                         sas_phy_free(phy->phy);
                         return;
                 }
 
-        SAS_DPRINTK("ex %016llx phy%02d:%c attached: %016llx\n",
-                    SAS_ADDR(dev->sas_addr), phy->phy_id,
-                    phy->routing_attr == TABLE_ROUTING ? 'T' :
-                    phy->routing_attr == DIRECT_ROUTING ? 'D' :
-                    phy->routing_attr == SUBTRACTIVE_ROUTING ? 'S' : '?',
-                    SAS_ADDR(phy->attached_sas_addr));
+        switch (phy->attached_dev_type) {
+        case NO_DEVICE:
+                type = "no device";
+                break;
+        case SAS_END_DEV:
+                if (phy->attached_iproto) {
+                        if (phy->attached_tproto)
+                                type = "host+target";
+                        else
+                                type = "host";
+                } else {
+                        if (dr->attached_sata_dev)
+                                type = "stp";
+                        else
+                                type = "ssp";
+                }
+                break;
+        case EDGE_DEV:
+        case FANOUT_DEV:
+                type = "smp";
+                break;
+        default:
+                type = "unknown";
+        }
 
-        return;
+        SAS_DPRINTK("ex %016llx phy%02d:%c:%X attached: %016llx (%s)\n",
+                    SAS_ADDR(dev->sas_addr), phy->phy_id,
+                    sas_route_char(dev, phy), phy->linkrate,
+                    SAS_ADDR(phy->attached_sas_addr), type);
 }
 
 /* check if we have an existing attached ata device on this expander phy */
@@ -1176,32 +1213,25 @@ static void sas_print_parent_topology_bug(struct domain_device *child,
                                                  struct ex_phy *parent_phy,
                                                  struct ex_phy *child_phy)
 {
-        static const char ra_char[] = {
-                [DIRECT_ROUTING] = 'D',
-                [SUBTRACTIVE_ROUTING] = 'S',
-                [TABLE_ROUTING] = 'T',
-        };
         static const char *ex_type[] = {
                 [EDGE_DEV] = "edge",
                 [FANOUT_DEV] = "fanout",
         };
         struct domain_device *parent = child->parent;
 
-        sas_printk("%s ex %016llx (T2T supp:%d) phy 0x%x <--> %s ex %016llx "
-                   "(T2T supp:%d) phy 0x%x has %c:%c routing link!\n",
+        sas_printk("%s ex %016llx phy 0x%x <--> %s ex %016llx "
+                   "phy 0x%x has %c:%c routing link!\n",
 
                    ex_type[parent->dev_type],
                    SAS_ADDR(parent->sas_addr),
-                   parent->ex_dev.t2t_supp,
                    parent_phy->phy_id,
 
                    ex_type[child->dev_type],
                    SAS_ADDR(child->sas_addr),
-                   child->ex_dev.t2t_supp,
                    child_phy->phy_id,
 
-                   ra_char[parent_phy->routing_attr],
-                   ra_char[child_phy->routing_attr]);
+                   sas_route_char(parent, parent_phy),
+                   sas_route_char(child, child_phy));
 }
 
 static int sas_check_eeds(struct domain_device *child,