[SCSI] libsas, libata: fix start of life for a sas ata_port

This changes the ordering of initialization and probing events from:
  1/ allocate rphy in PORTE_BYTES_DMAED, DISCE_REVALIDATE_DOMAIN
  2/ allocate ata_port and schedule port probe in DISCE_PROBE
...to:
  1/ allocate ata_port in PORTE_BYTES_DMAED, DISCE_REVALIDATE_DOMAIN
  2/ allocate rphy in PORTE_BYTES_DMAED, DISCE_REVALIDATE_DOMAIN
  3/ schedule port probe in DISCE_PROBE

This ordering prevents PHYE_SIGNAL_LOSS_EVENTS from sneaking in to
destrory ata devices before they have been fully initialized:

  BUG: unable to handle kernel paging request at 0000000000003b10
  IP: [<ffffffffa0053d7e>] sas_ata_end_eh+0x12/0x5e [libsas]
  ...
  [<ffffffffa004d1af>] sas_unregister_common_dev+0x78/0xc9 [libsas]
  [<ffffffffa004d4d4>] sas_unregister_dev+0x4f/0xad [libsas]
  [<ffffffffa004d5b1>] sas_unregister_domain_devices+0x7f/0xbf [libsas]
  [<ffffffffa004c487>] sas_deform_port+0x61/0x1b8 [libsas]
  [<ffffffffa004bed0>] sas_phye_loss_of_signal+0x29/0x2b [libsas]

...and kills the awkward "sata domain_device briefly existing in the
domain without an ata_port" state.

Reported-by: Michal Kosciowski <michal.kosciowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

3 files changed, 25 insertions, 29 deletions

diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index bc0cecc6ad62..441d88ad99a7 100644
--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -546,11 +546,12 @@ static struct ata_port_info sata_port_info = {
         .port_ops = &sas_sata_ops
 };
 
-int sas_ata_init_host_and_port(struct domain_device *found_dev)
+int sas_ata_init(struct domain_device *found_dev)
 {
         struct sas_ha_struct *ha = found_dev->port->ha;
         struct Scsi_Host *shost = ha->core.shost;
         struct ata_port *ap;
+        int rc;
 
         ata_host_init(&found_dev->sata_dev.ata_host,
                       ha->dev,
@@ -567,8 +568,11 @@ int sas_ata_init_host_and_port(struct domain_device *found_dev)
         ap->private_data = found_dev;
         ap->cbl = ATA_CBL_SATA;
         ap->scsi_host = shost;
-        /* publish initialized ata port */
-        smp_wmb();
+        rc = ata_sas_port_init(ap);
+        if (rc) {
+                ata_sas_port_destroy(ap);
+                return rc;
+        }
         found_dev->sata_dev.ap = ap;
 
         return 0;
@@ -648,18 +652,13 @@ static void sas_get_ata_command_set(struct domain_device *dev)
 void sas_probe_sata(struct asd_sas_port *port)
 {
         struct domain_device *dev, *n;
-        int err;
 
         mutex_lock(&port->ha->disco_mutex);
-        list_for_each_entry_safe(dev, n, &port->disco_list, disco_list_node) {
+        list_for_each_entry(dev, &port->disco_list, disco_list_node) {
                 if (!dev_is_sata(dev))
                         continue;
 
-                err = sas_ata_init_host_and_port(dev);
-                if (err)
-                        sas_fail_probe(dev, __func__, err);
-                else
-                        ata_sas_async_port_init(dev->sata_dev.ap);
+                ata_sas_async_probe(dev->sata_dev.ap);
         }
         mutex_unlock(&port->ha->disco_mutex);
 
@@ -718,18 +717,6 @@ static void async_sas_ata_eh(void *data, async_cookie_t cookie)
         sas_put_device(dev);
 }
 
-static bool sas_ata_dev_eh_valid(struct domain_device *dev)
-{
-        struct ata_port *ap;
-
-        if (!dev_is_sata(dev))
-                return false;
-        ap = dev->sata_dev.ap;
-        /* consume fully initialized ata ports */
-        smp_rmb();
-        return !!ap;
-}
-
 void sas_ata_strategy_handler(struct Scsi_Host *shost)
 {
         struct sas_ha_struct *sas_ha = SHOST_TO_SAS_HA(shost);
@@ -753,7 +740,7 @@ void sas_ata_strategy_handler(struct Scsi_Host *shost)
 
                 spin_lock(&port->dev_list_lock);
                 list_for_each_entry(dev, &port->dev_list, dev_list_node) {
-                        if (!sas_ata_dev_eh_valid(dev))
+                        if (!dev_is_sata(dev))
                                 continue;
                         async_schedule_domain(async_sas_ata_eh, dev, &async);
                 }
diff --git a/drivers/scsi/libsas/sas_discover.c b/drivers/scsi/libsas/sas_discover.c
index 13b5891f9961..629a0865b130 100644
--- a/drivers/scsi/libsas/sas_discover.c
+++ b/drivers/scsi/libsas/sas_discover.c
@@ -72,6 +72,7 @@ static int sas_get_port_device(struct asd_sas_port *port)
         struct asd_sas_phy *phy;
         struct sas_rphy *rphy;
         struct domain_device *dev;
+        int rc = -ENODEV;
 
         dev = sas_alloc_device();
         if (!dev)
@@ -110,9 +111,16 @@ static int sas_get_port_device(struct asd_sas_port *port)
 
         sas_init_dev(dev);
 
+        dev->port = port;
         switch (dev->dev_type) {
-        case SAS_END_DEV:
         case SATA_DEV:
+                rc = sas_ata_init(dev);
+                if (rc) {
+                        rphy = NULL;
+                        break;
+                }
+                /* fall through */
+        case SAS_END_DEV:
                 rphy = sas_end_device_alloc(port->port);
                 break;
         case EDGE_DEV:
@@ -131,7 +139,7 @@ static int sas_get_port_device(struct asd_sas_port *port)
 
         if (!rphy) {
                 sas_put_device(dev);
-                return -ENODEV;
+                return rc;
         }
 
         rphy->identify.phy_identifier = phy->phy->identify.phy_identifier;
@@ -139,7 +147,6 @@ static int sas_get_port_device(struct asd_sas_port *port)
         sas_fill_in_rphy(dev, rphy);
         sas_hash_addr(dev->hashed_sas_addr, dev->sas_addr);
         port->port_dev = dev;
-        dev->port = port;
         dev->linkrate = port->linkrate;
         dev->min_linkrate = port->linkrate;
         dev->max_linkrate = port->linkrate;
diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index c1f91b1c27c3..75247a176c6b 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -790,12 +790,14 @@ static struct domain_device *sas_ex_discover_end_dev(
                 if (res)
                         goto out_free;
 
+                sas_init_dev(child);
+                res = sas_ata_init(child);
+                if (res)
+                        goto out_free;
                 rphy = sas_end_device_alloc(phy->port);
-                if (unlikely(!rphy))
+                if (!rphy)
                         goto out_free;
 
-                sas_init_dev(child);
-
                 child->rphy = rphy;
                 get_device(&rphy->dev);