[SCSI] libsas: execute transport link resets with libata-eh via host workqueue

Link resets leave ata affiliations intact, so arrange for libsas to make
an effort to avoid dropping the device due to a slow-to-recover link.
Towards this end carry out reset in the host workqueue so that it can
check for ata devices and kick the reset request to libata.  Hard
resets, in contrast, bypass libata since they are meant for associating
an ata device with another initiator in the domain (tears down
affiliations).

Need to add a new transport_sas_phy_reset() since the current
sas_phy_reset() is a utility function to libsas lldds.  They are not
prepared for it to loop back into eh.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index a9b282038000c921eca51f7484866d890dec5d54..c61316e9d2f7fe0aa45cf542093be2fd811eec05 100644 (file)
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -863,6 +863,7 @@ void ata_port_wait_eh(struct ata_port *ap)
                goto retry;
        }
 }
+EXPORT_SYMBOL_GPL(ata_port_wait_eh);
 
 static int ata_eh_nr_in_flight(struct ata_port *ap)
 {

diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 814486d35c4445b31eadf175c3a06ebceef68bce..1fab235ee51653e322cfc741085c9e9bfbf8ffd8 100644 (file)
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -151,7 +151,6 @@ extern void ata_eh_acquire(struct ata_port *ap);
 extern void ata_eh_release(struct ata_port *ap);
 extern enum blk_eh_timer_return ata_scsi_timed_out(struct scsi_cmnd *cmd);
 extern void ata_scsi_error(struct Scsi_Host *host);
-extern void ata_port_wait_eh(struct ata_port *ap);
 extern void ata_eh_fastdrain_timerfn(unsigned long arg);
 extern void ata_qc_schedule_eh(struct ata_queued_cmd *qc);
 extern void ata_dev_disable(struct ata_device *dev);

diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
index 48cadf88c39901fe505c6d4ec710efffc6ac44a6..03930a04a679e88679dc037b055027410a4dca63 100644 (file)
--- a/drivers/scsi/libsas/sas_ata.c
+++ b/drivers/scsi/libsas/sas_ata.c
@@ -698,3 +698,14 @@ void sas_ata_schedule_reset(struct domain_device *dev)
        ata_port_schedule_eh(ap);
        spin_unlock_irqrestore(ap->lock, flags);
 }
+
+void sas_ata_wait_eh(struct domain_device *dev)
+{
+       struct ata_port *ap;
+
+       if (!dev_is_sata(dev))
+               return;
+
+       ap = dev->sata_dev.ap;
+       ata_port_wait_eh(ap);
+}

diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index f4894b0f537b4b8489e28d80d280b85eddd73618..d3c1a29b8a2aaba4b5cad835890554f97b4f136e 100644 (file)
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -228,7 +228,7 @@ static void sas_set_ex_phy(struct domain_device *dev, int phy_id,
 }
 
 /* check if we have an existing attached ata device on this expander phy */
-static struct domain_device *sas_ex_to_ata(struct domain_device *ex_dev, int phy_id)
+struct domain_device *sas_ex_to_ata(struct domain_device *ex_dev, int phy_id)
 {
        struct ex_phy *ex_phy = &ex_dev->ex_dev.ex_phy[phy_id];
        struct domain_device *dev;

diff --git a/drivers/scsi/libsas/sas_init.c b/drivers/scsi/libsas/sas_init.c
index cb65adf4ab16790f5b8a8377cbcee1e8d26e31e1..a15fb861daba4ac1975add39c9891739761fb938 100644 (file)
--- a/drivers/scsi/libsas/sas_init.c
+++ b/drivers/scsi/libsas/sas_init.c
@@ -28,6 +28,7 @@
 #include <linux/init.h>
 #include <linux/device.h>
 #include <linux/spinlock.h>
+#include <scsi/sas_ata.h>
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_device.h>
 #include <scsi/scsi_transport.h>
@@ -195,6 +196,59 @@ static int sas_get_linkerrors(struct sas_phy *phy)
        return sas_smp_get_phy_events(phy);
 }
 
+/**
+ * transport_sas_phy_reset - reset a phy and permit libata to manage the link
+ *
+ * phy reset request via sysfs in host workqueue context so we know we
+ * can block on eh and safely traverse the domain_device topology
+ */
+static int transport_sas_phy_reset(struct sas_phy *phy, int hard_reset)
+{
+       int ret;
+       enum phy_func reset_type;
+
+       if (hard_reset)
+               reset_type = PHY_FUNC_HARD_RESET;
+       else
+               reset_type = PHY_FUNC_LINK_RESET;
+
+       if (scsi_is_sas_phy_local(phy)) {
+               struct Scsi_Host *shost = dev_to_shost(phy->dev.parent);
+               struct sas_ha_struct *sas_ha = SHOST_TO_SAS_HA(shost);
+               struct asd_sas_phy *asd_phy = sas_ha->sas_phy[phy->number];
+               struct sas_internal *i =
+                       to_sas_internal(sas_ha->core.shost->transportt);
+               struct domain_device *dev = NULL;
+
+               if (asd_phy->port)
+                       dev = asd_phy->port->port_dev;
+
+               /* validate that dev has been probed */
+               if (dev)
+                       dev = sas_find_dev_by_rphy(dev->rphy);
+
+               if (dev && dev_is_sata(dev) && !hard_reset) {
+                       sas_ata_schedule_reset(dev);
+                       sas_ata_wait_eh(dev);
+                       ret = 0;
+               } else
+                       ret = i->dft->lldd_control_phy(asd_phy, reset_type, NULL);
+       } else {
+               struct sas_rphy *rphy = dev_to_rphy(phy->dev.parent);
+               struct domain_device *ddev = sas_find_dev_by_rphy(rphy);
+               struct domain_device *ata_dev = sas_ex_to_ata(ddev, phy->number);
+
+               if (ata_dev && !hard_reset) {
+                       sas_ata_schedule_reset(ata_dev);
+                       sas_ata_wait_eh(ata_dev);
+                       ret = 0;
+               } else
+                       ret = sas_smp_phy_control(ddev, phy->number, reset_type, NULL);
+       }
+
+       return ret;
+}
+
 int sas_phy_enable(struct sas_phy *phy, int enable)
 {
        int ret;
@@ -300,7 +354,7 @@ static void phy_reset_work(struct work_struct *work)
 {
        struct sas_phy_data *d = container_of(work, typeof(*d), reset_work);
 
-       d->reset_result = sas_phy_reset(d->phy, d->hard_reset);
+       d->reset_result = transport_sas_phy_reset(d->phy, d->hard_reset);
 }
 
 static int sas_phy_setup(struct sas_phy *phy)

diff --git a/drivers/scsi/libsas/sas_internal.h b/drivers/scsi/libsas/sas_internal.h
index 9ba65e0c6f91226f55a228ffb64f213f194cbdc3..ae9698d9d857906112a2781a0c66d0de0c034ab7 100644 (file)
--- a/drivers/scsi/libsas/sas_internal.h
+++ b/drivers/scsi/libsas/sas_internal.h
@@ -85,6 +85,7 @@ int sas_smp_phy_control(struct domain_device *dev, int phy_id,
 int sas_smp_get_phy_events(struct sas_phy *phy);
 
 struct domain_device *sas_find_dev_by_rphy(struct sas_rphy *rphy);
+struct domain_device *sas_ex_to_ata(struct domain_device *ex_dev, int phy_id);
 
 void sas_hae_reset(struct work_struct *work);
 

diff --git a/include/linux/libata.h b/include/linux/libata.h
index cafc09a64fe43636cbc1cf9f16366eb5c3e9ef06..aa4270477563f04c7cd13a705287d5047c062fde 100644 (file)
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -1147,6 +1147,7 @@ static inline int ata_acpi_cbl_80wire(struct ata_port *ap,
  * EH - drivers/ata/libata-eh.c
  */
 extern void ata_port_schedule_eh(struct ata_port *ap);
+extern void ata_port_wait_eh(struct ata_port *ap);
 extern int ata_link_abort(struct ata_link *link);
 extern int ata_port_abort(struct ata_port *ap);
 extern int ata_port_freeze(struct ata_port *ap);

diff --git a/include/scsi/sas_ata.h b/include/scsi/sas_ata.h
index c0bcd30eec560a7d6b104378e85c865f3667c9a3..da3f377273877cefc15a9aff661b8596acef2a80 100644 (file)
--- a/include/scsi/sas_ata.h
+++ b/include/scsi/sas_ata.h
@@ -45,6 +45,7 @@ int sas_ata_eh(struct Scsi_Host *shost, struct list_head *work_q,
               struct list_head *done_q);
 void sas_probe_sata(struct work_struct *work);
 void sas_ata_schedule_reset(struct domain_device *dev);
+void sas_ata_wait_eh(struct domain_device *dev);
 #else
 
 
@@ -79,6 +80,9 @@ static inline void sas_ata_schedule_reset(struct domain_device *dev)
 {
 }
 
+static inline void sas_ata_wait_eh(struct domain_device *dev)
+{
+}
 #endif
 
 #endif /* _SAS_ATA_H_ */