[SCSI] libsas: Clean up discovery failure handler code

sas_rphy_delete does two things: it removes the sas_rphy from the transport
layer and frees the sas_rphy.  This can be broken down into two functions,
sas_rphy_remove and sas_rphy_free; sas_rphy_remove is of interest to
sas_discover_root_expander because it calls functions that require
sas_rphy_add as a prerequisite and can fail (namely sas_discover_expander).
In that case, sas_discover_root_expander needs to be able to undo the effects
of sas_rphy_add yet leave the job of freeing the sas_rphy to the caller of
sas_discover_root_expander.

This patch also removes some unnecessary code from sas_discover_end_dev
to eliminate an unnecessary cycle of sas_notify_lldd_gone/found for SAS
devices, thus eliminating a sas_rphy_remove call (and fixing a race condition
where a SCSI target scan can come in between the gone and found call).
It also moves the sas_rphy_free calls into sas_discover_domain and
sas_ex_discover_end_dev to complement the sas_rphy_allocation via
sas_get_port_device.

This patch does not change the semantics of sas_rphy_delete.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 3 insertions, 5 deletions

diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index 0dfd97e7e96..d9b9a008d36 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -667,6 +667,8 @@ static struct domain_device *sas_ex_discover_end_dev(
 	return child;
 
  out_list_del:
+	sas_rphy_free(child->rphy);
+	child->rphy = NULL;
 	list_del(&child->dev_list_node);
  out_free:
 	sas_port_delete(phy->port);
@@ -1444,12 +1446,8 @@ int sas_discover_root_expander(struct domain_device *dev)
 	return res;
 
 out_err2:
-	sas_rphy_delete(dev->rphy);
-	dev->rphy = NULL;
-	return res;
+	sas_rphy_remove(dev->rphy);
 out_err:
-	sas_rphy_free(dev->rphy);
-	dev->rphy = NULL;
 	return res;
 }