[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>

3 files changed, 69 insertions, 2 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 *);