[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>

1 files changed, 20 insertions, 15 deletions

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 7832b1ad232..22226350cd0 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3839,18 +3839,25 @@ void ata_sas_port_stop(struct ata_port *ap)
 }
 EXPORT_SYMBOL_GPL(ata_sas_port_stop);
 
-int ata_sas_async_port_init(struct ata_port *ap)
+/**
+ * ata_sas_async_probe - simply schedule probing and return
+ * @ap: Port to probe
+ *
+ * For batch scheduling of probe for sas attached ata devices, assumes
+ * the port has already been through ata_sas_port_init()
+ */
+void ata_sas_async_probe(struct ata_port *ap)
 {
-	int rc = ap->ops->port_start(ap);
-
-	if (!rc) {
-		ap->print_id = atomic_inc_return(&ata_print_id);
-		__ata_port_probe(ap);
-	}
+	__ata_port_probe(ap);
+}
+EXPORT_SYMBOL_GPL(ata_sas_async_probe);
 
-	return rc;
+int ata_sas_sync_probe(struct ata_port *ap)
+{
+	return ata_port_probe(ap);
 }
-EXPORT_SYMBOL_GPL(ata_sas_async_port_init);
+EXPORT_SYMBOL_GPL(ata_sas_sync_probe);
+
 
 /**
  *	ata_sas_port_init - Initialize a SATA device
@@ -3867,12 +3874,10 @@ int ata_sas_port_init(struct ata_port *ap)
 {
 	int rc = ap->ops->port_start(ap);
 
-	if (!rc) {
-		ap->print_id = atomic_inc_return(&ata_print_id);
-		rc = ata_port_probe(ap);
-	}
-
-	return rc;
+	if (rc)
+		return rc;
+	ap->print_id = atomic_inc_return(&ata_print_id);
+	return 0;
 }
 EXPORT_SYMBOL_GPL(ata_sas_port_init);