[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, 19 insertions, 14 deletions

diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c
index ce232803f43..010845fd2b8 100644
--- a/drivers/scsi/scsi_transport_sas.c
+++ b/drivers/scsi/scsi_transport_sas.c
@@ -1299,7 +1299,7 @@ EXPORT_SYMBOL(sas_rphy_add);
  * Note:
  *   This function must only be called on a remote
  *   PHY that has not sucessfully been added using
- *   sas_rphy_add().
+ *   sas_rphy_add() (or has been sas_rphy_remove()'d)
  */
 void sas_rphy_free(struct sas_rphy *rphy)
 {
@@ -1318,18 +1318,30 @@ void sas_rphy_free(struct sas_rphy *rphy)
 EXPORT_SYMBOL(sas_rphy_free);
 
 /**
- * sas_rphy_delete  --  remove SAS remote PHY
- * @rphy:	SAS remote PHY to remove
+ * sas_rphy_delete  --  remove and free SAS remote PHY
+ * @rphy:	SAS remote PHY to remove and free
  *
- * Removes the specified SAS remote PHY.
+ * Removes the specified SAS remote PHY and frees it.
  */
 void
 sas_rphy_delete(struct sas_rphy *rphy)
 {
+	sas_rphy_remove(rphy);
+	sas_rphy_free(rphy);
+}
+EXPORT_SYMBOL(sas_rphy_delete);
+
+/**
+ * sas_rphy_remove  --  remove SAS remote PHY
+ * @rphy:	SAS remote phy to remove
+ *
+ * Removes the specified SAS remote PHY.
+ */
+void
+sas_rphy_remove(struct sas_rphy *rphy)
+{
 	struct device *dev = &rphy->dev;
 	struct sas_port *parent = dev_to_sas_port(dev->parent);
-	struct Scsi_Host *shost = dev_to_shost(parent->dev.parent);
-	struct sas_host_attrs *sas_host = to_sas_host_attrs(shost);
 
 	switch (rphy->identify.device_type) {
 	case SAS_END_DEVICE:
@@ -1345,17 +1357,10 @@ sas_rphy_delete(struct sas_rphy *rphy)
 
 	transport_remove_device(dev);
 	device_del(dev);
-	transport_destroy_device(dev);
-
-	mutex_lock(&sas_host->lock);
-	list_del(&rphy->list);
-	mutex_unlock(&sas_host->lock);
 
 	parent->rphy = NULL;
-
-	put_device(dev);
 }
-EXPORT_SYMBOL(sas_rphy_delete);
+EXPORT_SYMBOL(sas_rphy_remove);
 
 /**
  * scsi_is_sas_rphy  --  check if a struct device represents a SAS remote PHY