[SCSI] libsas: perform sas-transport resets in shost->workq context

Extend the sas transport class to allow transport users to attach extra
data to a sas_phy (->hostdata).  Use this area in libsas to move resets
to workq context in preparation for scheduling ata device resets through
libata-eh.

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

5 files changed, 90 insertions, 4 deletions

diff --git a/drivers/scsi/libsas/sas_event.c b/drivers/scsi/libsas/sas_event.c
index 933d757499b5..dbfaceeea0f7 100644
--- a/drivers/scsi/libsas/sas_event.c
+++ b/drivers/scsi/libsas/sas_event.c
@@ -27,7 +27,7 @@
 #include "sas_internal.h"
 #include "sas_dump.h"
 
-static void sas_queue_work(struct sas_ha_struct *ha, struct work_struct *work)
+void sas_queue_work(struct sas_ha_struct *ha, struct work_struct *work)
 {
         if (!test_bit(SAS_HA_REGISTERED, &ha->state))
                 return;
diff --git a/drivers/scsi/libsas/sas_init.c b/drivers/scsi/libsas/sas_init.c
index e17fe35af30c..cb65adf4ab16 100644
--- a/drivers/scsi/libsas/sas_init.c
+++ b/drivers/scsi/libsas/sas_init.c
@@ -290,9 +290,66 @@ int sas_set_phy_speed(struct sas_phy *phy,
         return ret;
 }
 
+static void sas_phy_release(struct sas_phy *phy)
+{
+        kfree(phy->hostdata);
+        phy->hostdata = NULL;
+}
+
+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);
+}
+
+static int sas_phy_setup(struct sas_phy *phy)
+{
+        struct sas_phy_data *d = kzalloc(sizeof(*d), GFP_KERNEL);
+
+        if (!d)
+                return -ENOMEM;
+
+        mutex_init(&d->event_lock);
+        INIT_WORK(&d->reset_work, phy_reset_work);
+        d->phy = phy;
+        phy->hostdata = d;
+
+        return 0;
+}
+
+static int queue_phy_reset(struct sas_phy *phy, int hard_reset)
+{
+        struct Scsi_Host *shost = dev_to_shost(phy->dev.parent);
+        struct sas_ha_struct *ha = SHOST_TO_SAS_HA(shost);
+        struct sas_phy_data *d = phy->hostdata;
+        int rc;
+
+        if (!d)
+                return -ENOMEM;
+
+        /* libsas workqueue coordinates ata-eh reset with discovery */
+        mutex_lock(&d->event_lock);
+        d->reset_result = 0;
+        d->hard_reset = hard_reset;
+
+        spin_lock_irq(&ha->state_lock);
+        sas_queue_work(ha, &d->reset_work);
+        spin_unlock_irq(&ha->state_lock);
+
+        rc = sas_drain_work(ha);
+        if (rc == 0)
+                rc = d->reset_result;
+        mutex_unlock(&d->event_lock);
+
+        return rc;
+}
+
 static struct sas_function_template sft = {
         .phy_enable = sas_phy_enable,
-        .phy_reset = sas_phy_reset,
+        .phy_reset = queue_phy_reset,
+        .phy_setup = sas_phy_setup,
+        .phy_release = sas_phy_release,
         .set_phy_speed = sas_set_phy_speed,
         .get_linkerrors = sas_get_linkerrors,
         .smp_handler = sas_smp_handler,
diff --git a/drivers/scsi/libsas/sas_internal.h b/drivers/scsi/libsas/sas_internal.h
index 662ffcba99d2..9ba65e0c6f91 100644
--- a/drivers/scsi/libsas/sas_internal.h
+++ b/drivers/scsi/libsas/sas_internal.h
@@ -38,6 +38,15 @@
 #define TO_SAS_TASK(_scsi_cmd)  ((void *)(_scsi_cmd)->host_scribble)
 #define ASSIGN_SAS_TASK(_sc, _t) do { (_sc)->host_scribble = (void *) _t; } while (0)
 
+struct sas_phy_data {
+        /* let reset be performed in sas_queue_work() context */
+        struct sas_phy *phy;
+        struct mutex event_lock;
+        int hard_reset;
+        int reset_result;
+        struct work_struct reset_work;
+};
+
 void sas_scsi_recover_host(struct Scsi_Host *shost);
 
 int sas_show_class(enum sas_class class, char *buf);
@@ -66,6 +75,7 @@ void sas_porte_broadcast_rcvd(struct work_struct *work);
 void sas_porte_link_reset_err(struct work_struct *work);
 void sas_porte_timer_event(struct work_struct *work);
 void sas_porte_hard_reset(struct work_struct *work);
+void sas_queue_work(struct sas_ha_struct *ha, struct work_struct *work);
 
 int sas_notify_lldd_dev_found(struct domain_device *);
 void sas_notify_lldd_dev_gone(struct domain_device *);
diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c
index 9421bae8af1a..ab3bd0b5ffd9 100644
--- a/drivers/scsi/scsi_transport_sas.c
+++ b/drivers/scsi/scsi_transport_sas.c
@@ -652,9 +652,21 @@ sas_phy_linkerror_attr(running_disparity_error_count);
 sas_phy_linkerror_attr(loss_of_dword_sync_count);
 sas_phy_linkerror_attr(phy_reset_problem_count);
 
+static int sas_phy_setup(struct transport_container *tc, struct device *dev,
+                         struct device *cdev)
+{
+        struct sas_phy *phy = dev_to_phy(dev);
+        struct Scsi_Host *shost = dev_to_shost(phy->dev.parent);
+        struct sas_internal *i = to_sas_internal(shost->transportt);
+
+        if (i->f->phy_setup)
+                i->f->phy_setup(phy);
+
+        return 0;
+}
 
 static DECLARE_TRANSPORT_CLASS(sas_phy_class,
-                "sas_phy", NULL, NULL, NULL);
+                "sas_phy", sas_phy_setup, NULL, NULL);
 
 static int sas_phy_match(struct attribute_container *cont, struct device *dev)
 {
@@ -678,7 +690,11 @@ static int sas_phy_match(struct attribute_container *cont, struct device *dev)
 static void sas_phy_release(struct device *dev)
 {
         struct sas_phy *phy = dev_to_phy(dev);
+        struct Scsi_Host *shost = dev_to_shost(phy->dev.parent);
+        struct sas_internal *i = to_sas_internal(shost->transportt);
 
+        if (i->f->phy_release)
+                i->f->phy_release(phy);
         put_device(dev->parent);
         kfree(phy);
 }
diff --git a/include/scsi/scsi_transport_sas.h b/include/scsi/scsi_transport_sas.h
index 6d14daac7589..42817facaeda 100644
--- a/include/scsi/scsi_transport_sas.h
+++ b/include/scsi/scsi_transport_sas.h
@@ -75,7 +75,8 @@ struct sas_phy {
         /* for the list of phys belonging to a port */
         struct list_head        port_siblings;
 
-        struct work_struct      reset_work;
+        /* available to the lldd */
+        void                    *hostdata;
 };
 
 #define dev_to_phy(d) \
@@ -169,6 +170,8 @@ struct sas_function_template {
         int (*get_bay_identifier)(struct sas_rphy *);
         int (*phy_reset)(struct sas_phy *, int);
         int (*phy_enable)(struct sas_phy *, int);
+        int (*phy_setup)(struct sas_phy *);
+        void (*phy_release)(struct sas_phy *);
         int (*set_phy_speed)(struct sas_phy *, struct sas_phy_linkrates *);
         int (*smp_handler)(struct Scsi_Host *, struct sas_rphy *, struct request *);
 };