scsi: libsas: Use dynamic alloced work to avoid sas event lost

Now libsas hotplug work is static, every sas event type has its own
static work, LLDD driver queues the hotplug work into shost->work_q.  If
LLDD driver burst posts lots hotplug events to libsas, the hotplug
events may pending in the workqueue like

shost->work_q
new work[PORTE_BYTES_DMAED] --> |[PHYE_LOSS_OF_SIGNAL][PORTE_BYTES_DMAED] -> processing
                                |<-------wait worker to process-------->|

In this case, a new PORTE_BYTES_DMAED event coming, libsas try to queue
it to shost->work_q, but this work is already pending, so it would be
lost. Finally, libsas delete the related sas port and sas devices, but
LLDD driver expect libsas add the sas port and devices(last sas event).

This patch use dynamic allocated work to avoid this issue.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
CC: John Garry <john.garry@huawei.com>
CC: Johannes Thumshirn <jthumshirn@suse.de>
CC: Ewan Milne <emilne@redhat.com>
CC: Christoph Hellwig <hch@lst.de>
CC: Tomas Henzl <thenzl@redhat.com>
CC: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/libsas/sas_event.c

@@ -29,7 +29,8 @@
 
 int sas_queue_work(struct sas_ha_struct *ha, struct sas_work *sw)
 {
-	int rc = 0;
+	/* it's added to the defer_q when draining so return succeed */
+	int rc = 1;
 
 	if (!test_bit(SAS_HA_REGISTERED, &ha->state))
 		return 0;
@@ -44,19 +45,15 @@ int sas_queue_work(struct sas_ha_struct *ha, struct sas_work *sw)
 	return rc;
 }
 
-static int sas_queue_event(int event, unsigned long *pending,
-			    struct sas_work *work,
+static int sas_queue_event(int event, struct sas_work *work,
 			    struct sas_ha_struct *ha)
 {
-	int rc = 0;
+	unsigned long flags;
+	int rc;
 
-	if (!test_and_set_bit(event, pending)) {
-		unsigned long flags;
-
-		spin_lock_irqsave(&ha->lock, flags);
-		rc = sas_queue_work(ha, work);
-		spin_unlock_irqrestore(&ha->lock, flags);
-	}
+	spin_lock_irqsave(&ha->lock, flags);
+	rc = sas_queue_work(ha, work);
+	spin_unlock_irqrestore(&ha->lock, flags);
 
 	return rc;
 }
@@ -66,6 +63,7 @@ void __sas_drain_work(struct sas_ha_struct *ha)
 {
 	struct workqueue_struct *wq = ha->core.shost->work_q;
 	struct sas_work *sw, *_sw;
+	int ret;
 
 	set_bit(SAS_HA_DRAINING, &ha->state);
 	/* flush submitters */
@@ -78,7 +76,10 @@ void __sas_drain_work(struct sas_ha_struct *ha)
 	clear_bit(SAS_HA_DRAINING, &ha->state);
 	list_for_each_entry_safe(sw, _sw, &ha->defer_q, drain_node) {
 		list_del_init(&sw->drain_node);
-		sas_queue_work(ha, sw);
+		ret = sas_queue_work(ha, sw);
+		if (ret != 1)
+			sas_free_event(to_asd_sas_event(&sw->work));
+
 	}
 	spin_unlock_irq(&ha->lock);
 }
@@ -119,29 +120,68 @@ void sas_enable_revalidation(struct sas_ha_struct *ha)
 		if (!test_and_clear_bit(ev, &d->pending))
 			continue;
 
-		sas_queue_event(ev, &d->pending, &d->disc_work[ev].work, ha);
+		sas_queue_event(ev, &d->disc_work[ev].work, ha);
 	}
 	mutex_unlock(&ha->disco_mutex);
 }
 
+
+static void sas_port_event_worker(struct work_struct *work)
+{
+	struct asd_sas_event *ev = to_asd_sas_event(work);
+
+	sas_port_event_fns[ev->event](work);
+	sas_free_event(ev);
+}
+
+static void sas_phy_event_worker(struct work_struct *work)
+{
+	struct asd_sas_event *ev = to_asd_sas_event(work);
+
+	sas_phy_event_fns[ev->event](work);
+	sas_free_event(ev);
+}
+
 static int sas_notify_port_event(struct asd_sas_phy *phy, enum port_event event)
 {
+	struct asd_sas_event *ev;
 	struct sas_ha_struct *ha = phy->ha;
+	int ret;
 
 	BUG_ON(event >= PORT_NUM_EVENTS);
 
-	return sas_queue_event(event, &phy->port_events_pending,
-			       &phy->port_events[event].work, ha);
+	ev = sas_alloc_event(phy);
+	if (!ev)
+		return -ENOMEM;
+
+	INIT_SAS_EVENT(ev, sas_port_event_worker, phy, event);
+
+	ret = sas_queue_event(event, &ev->work, ha);
+	if (ret != 1)
+		sas_free_event(ev);
+
+	return ret;
 }
 
 int sas_notify_phy_event(struct asd_sas_phy *phy, enum phy_event event)
 {
+	struct asd_sas_event *ev;
 	struct sas_ha_struct *ha = phy->ha;
+	int ret;
 
 	BUG_ON(event >= PHY_NUM_EVENTS);
 
-	return sas_queue_event(event, &phy->phy_events_pending,
-			       &phy->phy_events[event].work, ha);
+	ev = sas_alloc_event(phy);
+	if (!ev)
+		return -ENOMEM;
+
+	INIT_SAS_EVENT(ev, sas_phy_event_worker, phy, event);
+
+	ret = sas_queue_event(event, &ev->work, ha);
+	if (ret != 1)
+		sas_free_event(ev);
+
+	return ret;
 }
 
 int sas_init_events(struct sas_ha_struct *sas_ha)

drivers/scsi/libsas/sas_init.c

@@ -39,6 +39,7 @@
 #include "../scsi_sas_internal.h"
 
 static struct kmem_cache *sas_task_cache;
+static struct kmem_cache *sas_event_cache;
 
 struct sas_task *sas_alloc_task(gfp_t flags)
 {
@@ -364,8 +365,6 @@ void sas_prep_resume_ha(struct sas_ha_struct *ha)
 		struct asd_sas_phy *phy = ha->sas_phy[i];
 
 		memset(phy->attached_sas_addr, 0, SAS_ADDR_SIZE);
-		phy->port_events_pending = 0;
-		phy->phy_events_pending = 0;
 		phy->frame_rcvd_size = 0;
 	}
 }
@@ -555,20 +554,42 @@ sas_domain_attach_transport(struct sas_domain_function_template *dft)
 }
 EXPORT_SYMBOL_GPL(sas_domain_attach_transport);
 
+
+struct asd_sas_event *sas_alloc_event(struct asd_sas_phy *phy)
+{
+	gfp_t flags = in_interrupt() ? GFP_ATOMIC : GFP_KERNEL;
+
+	return kmem_cache_zalloc(sas_event_cache, flags);
+}
+
+void sas_free_event(struct asd_sas_event *event)
+{
+	kmem_cache_free(sas_event_cache, event);
+}
+
 /* ---------- SAS Class register/unregister ---------- */
 
 static int __init sas_class_init(void)
 {
 	sas_task_cache = KMEM_CACHE(sas_task, SLAB_HWCACHE_ALIGN);
 	if (!sas_task_cache)
-		return -ENOMEM;
+		goto out;
+
+	sas_event_cache = KMEM_CACHE(asd_sas_event, SLAB_HWCACHE_ALIGN);
+	if (!sas_event_cache)
+		goto free_task_kmem;
 
 	return 0;
+free_task_kmem:
+	kmem_cache_destroy(sas_task_cache);
+out:
+	return -ENOMEM;
 }
 
 static void __exit sas_class_exit(void)
 {
 	kmem_cache_destroy(sas_task_cache);
+	kmem_cache_destroy(sas_event_cache);
 }
 
 MODULE_AUTHOR("Luben Tuikov <luben_tuikov@adaptec.com>");

drivers/scsi/libsas/sas_internal.h

@@ -61,6 +61,9 @@ int sas_show_oob_mode(enum sas_oob_mode oob_mode, char *buf);
 int  sas_register_phys(struct sas_ha_struct *sas_ha);
 void sas_unregister_phys(struct sas_ha_struct *sas_ha);
 
+struct asd_sas_event *sas_alloc_event(struct asd_sas_phy *phy);
+void sas_free_event(struct asd_sas_event *event);
+
 int  sas_register_ports(struct sas_ha_struct *sas_ha);
 void sas_unregister_ports(struct sas_ha_struct *sas_ha);
 
@@ -99,6 +102,9 @@ void sas_hae_reset(struct work_struct *work);
 
 void sas_free_device(struct kref *kref);
 
+extern const work_func_t sas_phy_event_fns[PHY_NUM_EVENTS];
+extern const work_func_t sas_port_event_fns[PORT_NUM_EVENTS];
+
 #ifdef CONFIG_SCSI_SAS_HOST_SMP
 extern void sas_smp_host_handler(struct bsg_job *job, struct Scsi_Host *shost);
 #else

drivers/scsi/libsas/sas_phy.c

@@ -35,7 +35,6 @@ static void sas_phye_loss_of_signal(struct work_struct *work)
 	struct asd_sas_event *ev = to_asd_sas_event(work);
 	struct asd_sas_phy *phy = ev->phy;
 
-	clear_bit(PHYE_LOSS_OF_SIGNAL, &phy->phy_events_pending);
 	phy->error = 0;
 	sas_deform_port(phy, 1);
 }
@@ -45,7 +44,6 @@ static void sas_phye_oob_done(struct work_struct *work)
 	struct asd_sas_event *ev = to_asd_sas_event(work);
 	struct asd_sas_phy *phy = ev->phy;
 
-	clear_bit(PHYE_OOB_DONE, &phy->phy_events_pending);
 	phy->error = 0;
 }
 
@@ -58,8 +56,6 @@ static void sas_phye_oob_error(struct work_struct *work)
 	struct sas_internal *i =
 		to_sas_internal(sas_ha->core.shost->transportt);
 
-	clear_bit(PHYE_OOB_ERROR, &phy->phy_events_pending);
-
 	sas_deform_port(phy, 1);
 
 	if (!port && phy->enabled && i->dft->lldd_control_phy) {
@@ -88,8 +84,6 @@ static void sas_phye_spinup_hold(struct work_struct *work)
 	struct sas_internal *i =
 		to_sas_internal(sas_ha->core.shost->transportt);
 
-	clear_bit(PHYE_SPINUP_HOLD, &phy->phy_events_pending);
-
 	phy->error = 0;
 	i->dft->lldd_control_phy(phy, PHY_FUNC_RELEASE_SPINUP_HOLD, NULL);
 }
@@ -99,8 +93,6 @@ static void sas_phye_resume_timeout(struct work_struct *work)
 	struct asd_sas_event *ev = to_asd_sas_event(work);
 	struct asd_sas_phy *phy = ev->phy;
 
-	clear_bit(PHYE_RESUME_TIMEOUT, &phy->phy_events_pending);
-
 	/* phew, lldd got the phy back in the nick of time */
 	if (!phy->suspended) {
 		dev_info(&phy->phy->dev, "resume timeout cancelled\n");
@@ -119,39 +111,12 @@ int sas_register_phys(struct sas_ha_struct *sas_ha)
 {
 	int i;
 
-	static const work_func_t sas_phy_event_fns[PHY_NUM_EVENTS] = {
-		[PHYE_LOSS_OF_SIGNAL] = sas_phye_loss_of_signal,
-		[PHYE_OOB_DONE] = sas_phye_oob_done,
-		[PHYE_OOB_ERROR] = sas_phye_oob_error,
-		[PHYE_SPINUP_HOLD] = sas_phye_spinup_hold,
-		[PHYE_RESUME_TIMEOUT] = sas_phye_resume_timeout,
-
-	};
-
-	static const work_func_t sas_port_event_fns[PORT_NUM_EVENTS] = {
-		[PORTE_BYTES_DMAED] = sas_porte_bytes_dmaed,
-		[PORTE_BROADCAST_RCVD] = sas_porte_broadcast_rcvd,
-		[PORTE_LINK_RESET_ERR] = sas_porte_link_reset_err,
-		[PORTE_TIMER_EVENT] = sas_porte_timer_event,
-		[PORTE_HARD_RESET] = sas_porte_hard_reset,
-	};
-
 	/* Now register the phys. */
 	for (i = 0; i < sas_ha->num_phys; i++) {
-		int k;
 		struct asd_sas_phy *phy = sas_ha->sas_phy[i];
 
 		phy->error = 0;
 		INIT_LIST_HEAD(&phy->port_phy_el);
-		for (k = 0; k < PORT_NUM_EVENTS; k++) {
-			INIT_SAS_WORK(&phy->port_events[k].work, sas_port_event_fns[k]);
-			phy->port_events[k].phy = phy;
-		}
-
-		for (k = 0; k < PHY_NUM_EVENTS; k++) {
-			INIT_SAS_WORK(&phy->phy_events[k].work, sas_phy_event_fns[k]);
-			phy->phy_events[k].phy = phy;
-		}
 
 		phy->port = NULL;
 		phy->ha = sas_ha;
@@ -179,3 +144,12 @@ int sas_register_phys(struct sas_ha_struct *sas_ha)
 
 	return 0;
 }
+
+const work_func_t sas_phy_event_fns[PHY_NUM_EVENTS] = {
+	[PHYE_LOSS_OF_SIGNAL] = sas_phye_loss_of_signal,
+	[PHYE_OOB_DONE] = sas_phye_oob_done,
+	[PHYE_OOB_ERROR] = sas_phye_oob_error,
+	[PHYE_SPINUP_HOLD] = sas_phye_spinup_hold,
+	[PHYE_RESUME_TIMEOUT] = sas_phye_resume_timeout,
+
+};

drivers/scsi/libsas/sas_port.c

@@ -261,8 +261,6 @@ void sas_porte_bytes_dmaed(struct work_struct *work)
 	struct asd_sas_event *ev = to_asd_sas_event(work);
 	struct asd_sas_phy *phy = ev->phy;
 
-	clear_bit(PORTE_BYTES_DMAED, &phy->port_events_pending);
-
 	sas_form_port(phy);
 }
 
@@ -273,8 +271,6 @@ void sas_porte_broadcast_rcvd(struct work_struct *work)
 	unsigned long flags;
 	u32 prim;
 
-	clear_bit(PORTE_BROADCAST_RCVD, &phy->port_events_pending);
-
 	spin_lock_irqsave(&phy->sas_prim_lock, flags);
 	prim = phy->sas_prim;
 	spin_unlock_irqrestore(&phy->sas_prim_lock, flags);
@@ -288,8 +284,6 @@ void sas_porte_link_reset_err(struct work_struct *work)
 	struct asd_sas_event *ev = to_asd_sas_event(work);
 	struct asd_sas_phy *phy = ev->phy;
 
-	clear_bit(PORTE_LINK_RESET_ERR, &phy->port_events_pending);
-
 	sas_deform_port(phy, 1);
 }
 
@@ -298,8 +292,6 @@ void sas_porte_timer_event(struct work_struct *work)
 	struct asd_sas_event *ev = to_asd_sas_event(work);
 	struct asd_sas_phy *phy = ev->phy;
 
-	clear_bit(PORTE_TIMER_EVENT, &phy->port_events_pending);
-
 	sas_deform_port(phy, 1);
 }
 
@@ -308,8 +300,6 @@ void sas_porte_hard_reset(struct work_struct *work)
 	struct asd_sas_event *ev = to_asd_sas_event(work);
 	struct asd_sas_phy *phy = ev->phy;
 
-	clear_bit(PORTE_HARD_RESET, &phy->port_events_pending);
-
 	sas_deform_port(phy, 1);
 }
 
@@ -353,3 +343,11 @@ void sas_unregister_ports(struct sas_ha_struct *sas_ha)
 			sas_deform_port(sas_ha->sas_phy[i], 0);
 
 }
+
+const work_func_t sas_port_event_fns[PORT_NUM_EVENTS] = {
+	[PORTE_BYTES_DMAED] = sas_porte_bytes_dmaed,
+	[PORTE_BROADCAST_RCVD] = sas_porte_broadcast_rcvd,
+	[PORTE_LINK_RESET_ERR] = sas_porte_link_reset_err,
+	[PORTE_TIMER_EVENT] = sas_porte_timer_event,
+	[PORTE_HARD_RESET] = sas_porte_hard_reset,
+};

include/scsi/libsas.h

@@ -292,6 +292,7 @@ struct asd_sas_port {
 struct asd_sas_event {
 	struct sas_work work;
 	struct asd_sas_phy *phy;
+	int event;
 };
 
 static inline struct asd_sas_event *to_asd_sas_event(struct work_struct *work)
@@ -301,17 +302,21 @@ static inline struct asd_sas_event *to_asd_sas_event(struct work_struct *work)
 	return ev;
 }
 
+static inline void INIT_SAS_EVENT(struct asd_sas_event *ev,
+		void (*fn)(struct work_struct *),
+		struct asd_sas_phy *phy, int event)
+{
+	INIT_SAS_WORK(&ev->work, fn);
+	ev->phy = phy;
+	ev->event = event;
+}
+
+
 /* The phy pretty much is controlled by the LLDD.
  * The class only reads those fields.
  */
 struct asd_sas_phy {
 /* private: */
-	struct asd_sas_event   port_events[PORT_NUM_EVENTS];
-	struct asd_sas_event   phy_events[PHY_NUM_EVENTS];
-
-	unsigned long port_events_pending;
-	unsigned long phy_events_pending;
-
 	int error;
 	int suspended;