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authorDan Williams <dan.j.williams@intel.com>2011-12-21 21:33:17 -0800
committerJames Bottomley <JBottomley@Parallels.com>2012-02-29 13:01:06 -0600
commitf41a0c441c3fe43e79ebeb75584dbb5bfa83e5cd (patch)
tree5a53adb90ebf31888184a9bff16ccc1869e2e4b3 /drivers/scsi/scsi_transport_sas.c
parent[SCSI] libsas: check for 'gone' expanders in smp_execute_task() (diff)
downloadlinux-dev-f41a0c441c3fe43e79ebeb75584dbb5bfa83e5cd.tar.xz
linux-dev-f41a0c441c3fe43e79ebeb75584dbb5bfa83e5cd.zip
[SCSI] libsas: fix sas_find_local_phy(), take phy references
In the direct-attached case this routine returns the phy on which this device was first discovered. Which is broken if we want to support wide-targets, as this phy reference can become stale even though the port is still active. In the expander-attached case this routine tries to lookup the phy by scanning the attached sas addresses of the parent expander, and BUG_ONs if it can't find it. However since eh and the libsas workqueue run independently we can still be attempting device recovery via eh after libsas has recorded the device as detached. This is even easier to hit now that eh is blocked while device domain rediscovery takes place, and that libata is fed more timed out commands increasing the chances that it will try to recover the ata device. Arrange for dev->phy to always point to a last known good phy, it may be stale after the port is torn down, but it will catch up for wide port reconfigurations, and never be NULL. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Diffstat (limited to '')
-rw-r--r--drivers/scsi/scsi_transport_sas.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c
index ab3bd0b5ffd9..7d69a25d2004 100644
--- a/drivers/scsi/scsi_transport_sas.c
+++ b/drivers/scsi/scsi_transport_sas.c
@@ -1060,6 +1060,29 @@ int scsi_is_sas_port(const struct device *dev)
EXPORT_SYMBOL(scsi_is_sas_port);
/**
+ * sas_port_get_phy - try to take a reference on a port member
+ * @port: port to check
+ */
+struct sas_phy *sas_port_get_phy(struct sas_port *port)
+{
+ struct sas_phy *phy;
+
+ mutex_lock(&port->phy_list_mutex);
+ if (list_empty(&port->phy_list))
+ phy = NULL;
+ else {
+ struct list_head *ent = port->phy_list.next;
+
+ phy = list_entry(ent, typeof(*phy), port_siblings);
+ get_device(&phy->dev);
+ }
+ mutex_unlock(&port->phy_list_mutex);
+
+ return phy;
+}
+EXPORT_SYMBOL(sas_port_get_phy);
+
+/**
* sas_port_add_phy - add another phy to a port to form a wide port
* @port: port to add the phy to
* @phy: phy to add