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Message-ID: <c4742680984986864719f36e691883815e6b5d55.1439510240.git.calvinowens@fb.com>
Date:	Thu, 13 Aug 2015 18:48:09 -0700
From:	Calvin Owens <calvinowens@...com>
To:	Nagalakshmi Nandigama <nagalakshmi.nandigama@...gotech.com>,
	Praveen Krishnamoorthy <praveen.krishnamoorthy@...gotech.com>,
	Sreekanth Reddy <sreekanth.reddy@...gotech.com>,
	Abhijit Mahajan <abhijit.mahajan@...gotech.com>
CC:	<MPT-FusionLinux.pdl@...gotech.com>, <linux-scsi@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <kernel-team@...com>,
	<calvinowens@...com>, Joe Lawrence <joe.lawrence@...atus.com>,
	Christoph Hellwig <hch@...radead.org>,
	Bart Van Assche <bart.vanassche@...disk.com>
Subject: [PATCH v4 1/2] mpt2sas: Refcount sas_device objects and fix unsafe list usage

These objects can be referenced concurrently throughout the driver, we
need a way to make sure threads can't delete them out from under each
other. This patch adds the refcount, and refactors the code to use it.

Additionally, we cannot iterate over the sas_device_list without
holding the lock, or we risk corrupting random memory if items are
added or deleted as we iterate. This patch refactors _scsih_probe_sas()
to use the sas_device_list in a safe way.

Cc: Christoph Hellwig <hch@...radead.org>
Cc: Bart Van Assche <bart.vanassche@...disk.com>
Cc: Joe Lawrence <joe.lawrence@...atus.com>
Signed-off-by: Calvin Owens <calvinowens@...com>
---
Changes in v4:
	* Fix lack of put() in non-SATA case in _scsih_change_queue_depth()
	* Fix lack of put() in the non-error case in _scsih_check_device()
	* Add missing put() at bottom of _scsih_add_device()
	* Add put for ->hostdata pointer in _scsih_target_destroy() for the
	  get() in _scsih_target_alloc()

Changes in v3:
	* Drop the sas_device_lock while enabling devices, and leave the
	  sas_device object on the list, since it may need to be looked up there
	  while it is being enabled.
	* Drop put() in _scsih_add_device(), because the ->hostdata now keeps a
	  reference (this was an oversight in v2).
	* Be consistent about calling sas_device_put() while holding the
	  sas_device_lock where feasible.
	* Take and assert_spin_locked() on the sas_device_lock from the newly
	  added __get_sdev_from_target(), add wrapper similar to other lookups
	  for callers which do not explicitly take the lock.

Changes in v2:
	* Squished patches 1-3 into this one
	* s/BUG_ON(!spin_is_locked/assert_spin_locked/g
	* Store a pointer to the sas_device object in ->hostdata, to eliminate
	  the need for several lookups on the lists.

 drivers/scsi/mpt2sas/mpt2sas_base.h      |  22 +-
 drivers/scsi/mpt2sas/mpt2sas_scsih.c     | 480 +++++++++++++++++++++----------
 drivers/scsi/mpt2sas/mpt2sas_transport.c |  12 +-
 3 files changed, 360 insertions(+), 154 deletions(-)

diff --git a/drivers/scsi/mpt2sas/mpt2sas_base.h b/drivers/scsi/mpt2sas/mpt2sas_base.h
index caff8d1..78f41ac 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_base.h
+++ b/drivers/scsi/mpt2sas/mpt2sas_base.h
@@ -238,6 +238,7 @@
  * @flags: MPT_TARGET_FLAGS_XXX flags
  * @deleted: target flaged for deletion
  * @tm_busy: target is busy with TM request.
+ * @sdev: The sas_device associated with this target
  */
 struct MPT2SAS_TARGET {
 	struct scsi_target *starget;
@@ -248,6 +249,7 @@ struct MPT2SAS_TARGET {
 	u32	flags;
 	u8	deleted;
 	u8	tm_busy;
+	struct _sas_device *sdev;
 };
 
 
@@ -376,8 +378,24 @@ struct _sas_device {
 	u8	phy;
 	u8	responding;
 	u8	pfa_led_on;
+	struct kref refcount;
 };
 
+static inline void sas_device_get(struct _sas_device *s)
+{
+	kref_get(&s->refcount);
+}
+
+static inline void sas_device_free(struct kref *r)
+{
+	kfree(container_of(r, struct _sas_device, refcount));
+}
+
+static inline void sas_device_put(struct _sas_device *s)
+{
+	kref_put(&s->refcount, sas_device_free);
+}
+
 /**
  * struct _raid_device - raid volume link list
  * @list: sas device list
@@ -1095,7 +1113,9 @@ struct _sas_node *mpt2sas_scsih_expander_find_by_handle(struct MPT2SAS_ADAPTER *
     u16 handle);
 struct _sas_node *mpt2sas_scsih_expander_find_by_sas_address(struct MPT2SAS_ADAPTER
     *ioc, u64 sas_address);
-struct _sas_device *mpt2sas_scsih_sas_device_find_by_sas_address(
+struct _sas_device *mpt2sas_get_sdev_by_addr(
+    struct MPT2SAS_ADAPTER *ioc, u64 sas_address);
+struct _sas_device *__mpt2sas_get_sdev_by_addr(
     struct MPT2SAS_ADAPTER *ioc, u64 sas_address);
 
 void mpt2sas_port_enable_complete(struct MPT2SAS_ADAPTER *ioc);
diff --git a/drivers/scsi/mpt2sas/mpt2sas_scsih.c b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
index 3f26147..5eca3a4 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_scsih.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
@@ -526,8 +526,61 @@ _scsih_determine_boot_device(struct MPT2SAS_ADAPTER *ioc,
 	}
 }
 
+static struct _sas_device *
+__mpt2sas_get_sdev_from_target(struct MPT2SAS_ADAPTER *ioc,
+		struct MPT2SAS_TARGET *tgt_priv)
+{
+	struct _sas_device *ret;
+
+	assert_spin_locked(&ioc->sas_device_lock);
+
+	ret = tgt_priv->sdev;
+	if (ret)
+		sas_device_get(ret);
+
+	return ret;
+}
+
+static struct _sas_device *
+mpt2sas_get_sdev_from_target(struct MPT2SAS_ADAPTER *ioc,
+		struct MPT2SAS_TARGET *tgt_priv)
+{
+	struct _sas_device *ret;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ioc->sas_device_lock, flags);
+	ret = __mpt2sas_get_sdev_from_target(ioc, tgt_priv);
+	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
+
+	return ret;
+}
+
+
+struct _sas_device *
+__mpt2sas_get_sdev_by_addr(struct MPT2SAS_ADAPTER *ioc,
+    u64 sas_address)
+{
+	struct _sas_device *sas_device;
+
+	assert_spin_locked(&ioc->sas_device_lock);
+
+	list_for_each_entry(sas_device, &ioc->sas_device_list, list)
+		if (sas_device->sas_address == sas_address)
+			goto found_device;
+
+	list_for_each_entry(sas_device, &ioc->sas_device_init_list, list)
+		if (sas_device->sas_address == sas_address)
+			goto found_device;
+
+	return NULL;
+
+found_device:
+	sas_device_get(sas_device);
+	return sas_device;
+}
+
 /**
- * mpt2sas_scsih_sas_device_find_by_sas_address - sas device search
+ * mpt2sas_get_sdev_by_addr - sas device search
  * @ioc: per adapter object
  * @sas_address: sas address
  * Context: Calling function should acquire ioc->sas_device_lock
@@ -536,24 +589,44 @@ _scsih_determine_boot_device(struct MPT2SAS_ADAPTER *ioc,
  * object.
  */
 struct _sas_device *
-mpt2sas_scsih_sas_device_find_by_sas_address(struct MPT2SAS_ADAPTER *ioc,
+mpt2sas_get_sdev_by_addr(struct MPT2SAS_ADAPTER *ioc,
     u64 sas_address)
 {
 	struct _sas_device *sas_device;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ioc->sas_device_lock, flags);
+	sas_device = __mpt2sas_get_sdev_by_addr(ioc,
+			sas_address);
+	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
+
+	return sas_device;
+}
+
+static struct _sas_device *
+__mpt2sas_get_sdev_by_handle(struct MPT2SAS_ADAPTER *ioc, u16 handle)
+{
+	struct _sas_device *sas_device;
+
+	assert_spin_locked(&ioc->sas_device_lock);
 
 	list_for_each_entry(sas_device, &ioc->sas_device_list, list)
-		if (sas_device->sas_address == sas_address)
-			return sas_device;
+		if (sas_device->handle == handle)
+			goto found_device;
 
 	list_for_each_entry(sas_device, &ioc->sas_device_init_list, list)
-		if (sas_device->sas_address == sas_address)
-			return sas_device;
+		if (sas_device->handle == handle)
+			goto found_device;
 
 	return NULL;
+
+found_device:
+	sas_device_get(sas_device);
+	return sas_device;
 }
 
 /**
- * _scsih_sas_device_find_by_handle - sas device search
+ * mpt2sas_get_sdev_by_handle - sas device search
  * @ioc: per adapter object
  * @handle: sas device handle (assigned by firmware)
  * Context: Calling function should acquire ioc->sas_device_lock
@@ -562,19 +635,16 @@ mpt2sas_scsih_sas_device_find_by_sas_address(struct MPT2SAS_ADAPTER *ioc,
  * object.
  */
 static struct _sas_device *
-_scsih_sas_device_find_by_handle(struct MPT2SAS_ADAPTER *ioc, u16 handle)
+mpt2sas_get_sdev_by_handle(struct MPT2SAS_ADAPTER *ioc, u16 handle)
 {
 	struct _sas_device *sas_device;
+	unsigned long flags;
 
-	list_for_each_entry(sas_device, &ioc->sas_device_list, list)
-		if (sas_device->handle == handle)
-			return sas_device;
-
-	list_for_each_entry(sas_device, &ioc->sas_device_init_list, list)
-		if (sas_device->handle == handle)
-			return sas_device;
+	spin_lock_irqsave(&ioc->sas_device_lock, flags);
+	sas_device = __mpt2sas_get_sdev_by_handle(ioc, handle);
+	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 
-	return NULL;
+	return sas_device;
 }
 
 /**
@@ -583,7 +653,7 @@ _scsih_sas_device_find_by_handle(struct MPT2SAS_ADAPTER *ioc, u16 handle)
  * @sas_device: the sas_device object
  * Context: This function will acquire ioc->sas_device_lock.
  *
- * Removing object and freeing associated memory from the ioc->sas_device_list.
+ * If sas_device is on the list, remove it and decrement its reference count.
  */
 static void
 _scsih_sas_device_remove(struct MPT2SAS_ADAPTER *ioc,
@@ -594,9 +664,15 @@ _scsih_sas_device_remove(struct MPT2SAS_ADAPTER *ioc,
 	if (!sas_device)
 		return;
 
+	/*
+	 * The lock serializes access to the list, but we still need to verify
+	 * that nobody removed the entry while we were waiting on the lock.
+	 */
 	spin_lock_irqsave(&ioc->sas_device_lock, flags);
-	list_del(&sas_device->list);
-	kfree(sas_device);
+	if (!list_empty(&sas_device->list)) {
+		list_del_init(&sas_device->list);
+		sas_device_put(sas_device);
+	}
 	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 }
 
@@ -620,6 +696,7 @@ _scsih_sas_device_add(struct MPT2SAS_ADAPTER *ioc,
 	    sas_device->handle, (unsigned long long)sas_device->sas_address));
 
 	spin_lock_irqsave(&ioc->sas_device_lock, flags);
+	sas_device_get(sas_device);
 	list_add_tail(&sas_device->list, &ioc->sas_device_list);
 	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 
@@ -659,6 +736,7 @@ _scsih_sas_device_init_add(struct MPT2SAS_ADAPTER *ioc,
 	    sas_device->handle, (unsigned long long)sas_device->sas_address));
 
 	spin_lock_irqsave(&ioc->sas_device_lock, flags);
+	sas_device_get(sas_device);
 	list_add_tail(&sas_device->list, &ioc->sas_device_init_list);
 	_scsih_determine_boot_device(ioc, sas_device, 0);
 	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
@@ -1208,12 +1286,15 @@ _scsih_change_queue_depth(struct scsi_device *sdev, int qdepth)
 		goto not_sata;
 	if ((sas_target_priv_data->flags & MPT_TARGET_FLAGS_VOLUME))
 		goto not_sata;
+
 	spin_lock_irqsave(&ioc->sas_device_lock, flags);
-	sas_device = mpt2sas_scsih_sas_device_find_by_sas_address(ioc,
-	   sas_device_priv_data->sas_target->sas_address);
-	if (sas_device && sas_device->device_info &
-	    MPI2_SAS_DEVICE_INFO_SATA_DEVICE)
-		max_depth = MPT2SAS_SATA_QUEUE_DEPTH;
+	sas_device = __mpt2sas_get_sdev_from_target(ioc, sas_target_priv_data);
+	if (sas_device) {
+		if (sas_device->device_info & MPI2_SAS_DEVICE_INFO_SATA_DEVICE)
+			max_depth = MPT2SAS_SATA_QUEUE_DEPTH;
+
+		sas_device_put(sas_device);
+	}
 	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 
  not_sata:
@@ -1271,18 +1352,20 @@ _scsih_target_alloc(struct scsi_target *starget)
 	/* sas/sata devices */
 	spin_lock_irqsave(&ioc->sas_device_lock, flags);
 	rphy = dev_to_rphy(starget->dev.parent);
-	sas_device = mpt2sas_scsih_sas_device_find_by_sas_address(ioc,
+	sas_device = __mpt2sas_get_sdev_by_addr(ioc,
 	   rphy->identify.sas_address);
 
 	if (sas_device) {
 		sas_target_priv_data->handle = sas_device->handle;
 		sas_target_priv_data->sas_address = sas_device->sas_address;
+		sas_target_priv_data->sdev = sas_device;
 		sas_device->starget = starget;
 		sas_device->id = starget->id;
 		sas_device->channel = starget->channel;
 		if (test_bit(sas_device->handle, ioc->pd_handles))
 			sas_target_priv_data->flags |=
 			    MPT_TARGET_FLAGS_RAID_COMPONENT;
+
 	}
 	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 
@@ -1324,13 +1407,21 @@ _scsih_target_destroy(struct scsi_target *starget)
 
 	spin_lock_irqsave(&ioc->sas_device_lock, flags);
 	rphy = dev_to_rphy(starget->dev.parent);
-	sas_device = mpt2sas_scsih_sas_device_find_by_sas_address(ioc,
-	   rphy->identify.sas_address);
+	sas_device = __mpt2sas_get_sdev_from_target(ioc, sas_target_priv_data);
 	if (sas_device && (sas_device->starget == starget) &&
 	    (sas_device->id == starget->id) &&
 	    (sas_device->channel == starget->channel))
 		sas_device->starget = NULL;
 
+	if (sas_device) {
+		/*
+		 * Corresponding get() is in _scsih_target_alloc()
+		 */
+		sas_target_priv_data->sdev = NULL;
+		sas_device_put(sas_device);
+
+		sas_device_put(sas_device);
+	}
 	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 
  out:
@@ -1386,7 +1477,7 @@ _scsih_slave_alloc(struct scsi_device *sdev)
 
 	if (!(sas_target_priv_data->flags & MPT_TARGET_FLAGS_VOLUME)) {
 		spin_lock_irqsave(&ioc->sas_device_lock, flags);
-		sas_device = mpt2sas_scsih_sas_device_find_by_sas_address(ioc,
+		sas_device = __mpt2sas_get_sdev_by_addr(ioc,
 				sas_target_priv_data->sas_address);
 		if (sas_device && (sas_device->starget == NULL)) {
 			sdev_printk(KERN_INFO, sdev,
@@ -1394,6 +1485,10 @@ _scsih_slave_alloc(struct scsi_device *sdev)
 			     __func__, __LINE__);
 			sas_device->starget = starget;
 		}
+
+		if (sas_device)
+			sas_device_put(sas_device);
+
 		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 	}
 
@@ -1428,10 +1523,13 @@ _scsih_slave_destroy(struct scsi_device *sdev)
 
 	if (!(sas_target_priv_data->flags & MPT_TARGET_FLAGS_VOLUME)) {
 		spin_lock_irqsave(&ioc->sas_device_lock, flags);
-		sas_device = mpt2sas_scsih_sas_device_find_by_sas_address(ioc,
-		   sas_target_priv_data->sas_address);
+		sas_device = __mpt2sas_get_sdev_from_target(ioc,
+				sas_target_priv_data);
 		if (sas_device && !sas_target_priv_data->num_luns)
 			sas_device->starget = NULL;
+
+		if (sas_device)
+			sas_device_put(sas_device);
 		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 	}
 
@@ -2078,7 +2176,7 @@ _scsih_slave_configure(struct scsi_device *sdev)
 	}
 
 	spin_lock_irqsave(&ioc->sas_device_lock, flags);
-	sas_device = mpt2sas_scsih_sas_device_find_by_sas_address(ioc,
+	sas_device = __mpt2sas_get_sdev_by_addr(ioc,
 	   sas_device_priv_data->sas_target->sas_address);
 	if (!sas_device) {
 		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
@@ -2112,17 +2210,18 @@ _scsih_slave_configure(struct scsi_device *sdev)
 	    (unsigned long long) sas_device->enclosure_logical_id,
 	    sas_device->slot);
 
+	sas_device_put(sas_device);
 	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 	if (!ssp_target)
 		_scsih_display_sata_capabilities(ioc, handle, sdev);
 
-
 	_scsih_change_queue_depth(sdev, qdepth);
 
 	if (ssp_target) {
 		sas_read_port_mode_page(sdev);
 		_scsih_enable_tlr(ioc, sdev);
 	}
+
 	return 0;
 }
 
@@ -2509,8 +2608,7 @@ _scsih_tm_display_info(struct MPT2SAS_ADAPTER *ioc, struct scsi_cmnd *scmd)
 		    device_str, (unsigned long long)priv_target->sas_address);
 	} else {
 		spin_lock_irqsave(&ioc->sas_device_lock, flags);
-		sas_device = mpt2sas_scsih_sas_device_find_by_sas_address(ioc,
-		    priv_target->sas_address);
+		sas_device = __mpt2sas_get_sdev_from_target(ioc, priv_target);
 		if (sas_device) {
 			if (priv_target->flags &
 			    MPT_TARGET_FLAGS_RAID_COMPONENT) {
@@ -2529,6 +2627,8 @@ _scsih_tm_display_info(struct MPT2SAS_ADAPTER *ioc, struct scsi_cmnd *scmd)
 			    "enclosure_logical_id(0x%016llx), slot(%d)\n",
 			   (unsigned long long)sas_device->enclosure_logical_id,
 			    sas_device->slot);
+
+			sas_device_put(sas_device);
 		}
 		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 	}
@@ -2604,12 +2704,12 @@ _scsih_dev_reset(struct scsi_cmnd *scmd)
 {
 	struct MPT2SAS_ADAPTER *ioc = shost_priv(scmd->device->host);
 	struct MPT2SAS_DEVICE *sas_device_priv_data;
-	struct _sas_device *sas_device;
-	unsigned long flags;
+	struct _sas_device *sas_device = NULL;
 	u16	handle;
 	int r;
 
 	struct scsi_target *starget = scmd->device->sdev_target;
+	struct MPT2SAS_TARGET *target_priv_data = starget->hostdata;
 
 	starget_printk(KERN_INFO, starget, "attempting device reset! "
 	    "scmd(%p)\n", scmd);
@@ -2629,12 +2729,10 @@ _scsih_dev_reset(struct scsi_cmnd *scmd)
 	handle = 0;
 	if (sas_device_priv_data->sas_target->flags &
 	    MPT_TARGET_FLAGS_RAID_COMPONENT) {
-		spin_lock_irqsave(&ioc->sas_device_lock, flags);
-		sas_device = _scsih_sas_device_find_by_handle(ioc,
-		   sas_device_priv_data->sas_target->handle);
+		sas_device = mpt2sas_get_sdev_from_target(ioc,
+				target_priv_data);
 		if (sas_device)
 			handle = sas_device->volume_handle;
-		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 	} else
 		handle = sas_device_priv_data->sas_target->handle;
 
@@ -2651,6 +2749,10 @@ _scsih_dev_reset(struct scsi_cmnd *scmd)
  out:
 	sdev_printk(KERN_INFO, scmd->device, "device reset: %s scmd(%p)\n",
 	    ((r == SUCCESS) ? "SUCCESS" : "FAILED"), scmd);
+
+	if (sas_device)
+		sas_device_put(sas_device);
+
 	return r;
 }
 
@@ -2665,11 +2767,11 @@ _scsih_target_reset(struct scsi_cmnd *scmd)
 {
 	struct MPT2SAS_ADAPTER *ioc = shost_priv(scmd->device->host);
 	struct MPT2SAS_DEVICE *sas_device_priv_data;
-	struct _sas_device *sas_device;
-	unsigned long flags;
+	struct _sas_device *sas_device = NULL;
 	u16	handle;
 	int r;
 	struct scsi_target *starget = scmd->device->sdev_target;
+	struct MPT2SAS_TARGET *target_priv_data = starget->hostdata;
 
 	starget_printk(KERN_INFO, starget, "attempting target reset! "
 	    "scmd(%p)\n", scmd);
@@ -2689,12 +2791,10 @@ _scsih_target_reset(struct scsi_cmnd *scmd)
 	handle = 0;
 	if (sas_device_priv_data->sas_target->flags &
 	    MPT_TARGET_FLAGS_RAID_COMPONENT) {
-		spin_lock_irqsave(&ioc->sas_device_lock, flags);
-		sas_device = _scsih_sas_device_find_by_handle(ioc,
-		   sas_device_priv_data->sas_target->handle);
+		sas_device = mpt2sas_get_sdev_from_target(ioc,
+				target_priv_data);
 		if (sas_device)
 			handle = sas_device->volume_handle;
-		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 	} else
 		handle = sas_device_priv_data->sas_target->handle;
 
@@ -2711,6 +2811,10 @@ _scsih_target_reset(struct scsi_cmnd *scmd)
  out:
 	starget_printk(KERN_INFO, starget, "target reset: %s scmd(%p)\n",
 	    ((r == SUCCESS) ? "SUCCESS" : "FAILED"), scmd);
+
+	if (sas_device)
+		sas_device_put(sas_device);
+
 	return r;
 }
 
@@ -3002,15 +3106,15 @@ _scsih_block_io_to_children_attached_to_ex(struct MPT2SAS_ADAPTER *ioc,
 
 	list_for_each_entry(mpt2sas_port,
 	   &sas_expander->sas_port_list, port_list) {
-		if (mpt2sas_port->remote_identify.device_type ==
-		    SAS_END_DEVICE) {
+		if (mpt2sas_port->remote_identify.device_type == SAS_END_DEVICE) {
 			spin_lock_irqsave(&ioc->sas_device_lock, flags);
-			sas_device =
-			    mpt2sas_scsih_sas_device_find_by_sas_address(ioc,
-			   mpt2sas_port->remote_identify.sas_address);
-			if (sas_device)
+			sas_device = __mpt2sas_get_sdev_by_addr(ioc,
+					mpt2sas_port->remote_identify.sas_address);
+			if (sas_device) {
 				set_bit(sas_device->handle,
-				    ioc->blocking_handles);
+						ioc->blocking_handles);
+				sas_device_put(sas_device);
+			}
 			spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 		}
 	}
@@ -3080,7 +3184,7 @@ _scsih_tm_tr_send(struct MPT2SAS_ADAPTER *ioc, u16 handle)
 {
 	Mpi2SCSITaskManagementRequest_t *mpi_request;
 	u16 smid;
-	struct _sas_device *sas_device;
+	struct _sas_device *sas_device = NULL;
 	struct MPT2SAS_TARGET *sas_target_priv_data = NULL;
 	u64 sas_address = 0;
 	unsigned long flags;
@@ -3110,7 +3214,7 @@ _scsih_tm_tr_send(struct MPT2SAS_ADAPTER *ioc, u16 handle)
 		return;
 
 	spin_lock_irqsave(&ioc->sas_device_lock, flags);
-	sas_device = _scsih_sas_device_find_by_handle(ioc, handle);
+	sas_device = __mpt2sas_get_sdev_by_handle(ioc, handle);
 	if (sas_device && sas_device->starget &&
 	     sas_device->starget->hostdata) {
 		sas_target_priv_data = sas_device->starget->hostdata;
@@ -3131,14 +3235,14 @@ _scsih_tm_tr_send(struct MPT2SAS_ADAPTER *ioc, u16 handle)
 	if (!smid) {
 		delayed_tr = kzalloc(sizeof(*delayed_tr), GFP_ATOMIC);
 		if (!delayed_tr)
-			return;
+			goto out;
 		INIT_LIST_HEAD(&delayed_tr->list);
 		delayed_tr->handle = handle;
 		list_add_tail(&delayed_tr->list, &ioc->delayed_tr_list);
 		dewtprintk(ioc, printk(MPT2SAS_INFO_FMT
 		    "DELAYED:tr:handle(0x%04x), (open)\n",
 		    ioc->name, handle));
-		return;
+		goto out;
 	}
 
 	dewtprintk(ioc, printk(MPT2SAS_INFO_FMT "tr_send:handle(0x%04x), "
@@ -3150,6 +3254,9 @@ _scsih_tm_tr_send(struct MPT2SAS_ADAPTER *ioc, u16 handle)
 	mpi_request->DevHandle = cpu_to_le16(handle);
 	mpi_request->TaskType = MPI2_SCSITASKMGMT_TASKTYPE_TARGET_RESET;
 	mpt2sas_base_put_smid_hi_priority(ioc, smid);
+out:
+	if (sas_device)
+		sas_device_put(sas_device);
 }
 
 
@@ -4068,7 +4175,6 @@ _scsih_scsi_ioc_info(struct MPT2SAS_ADAPTER *ioc, struct scsi_cmnd *scmd,
 	char *desc_scsi_state = ioc->tmp_string;
 	u32 log_info = le32_to_cpu(mpi_reply->IOCLogInfo);
 	struct _sas_device *sas_device = NULL;
-	unsigned long flags;
 	struct scsi_target *starget = scmd->device->sdev_target;
 	struct MPT2SAS_TARGET *priv_target = starget->hostdata;
 	char *device_str = NULL;
@@ -4200,9 +4306,7 @@ _scsih_scsi_ioc_info(struct MPT2SAS_ADAPTER *ioc, struct scsi_cmnd *scmd,
 		printk(MPT2SAS_WARN_FMT "\t%s wwid(0x%016llx)\n", ioc->name,
 		    device_str, (unsigned long long)priv_target->sas_address);
 	} else {
-		spin_lock_irqsave(&ioc->sas_device_lock, flags);
-		sas_device = mpt2sas_scsih_sas_device_find_by_sas_address(ioc,
-		    priv_target->sas_address);
+		sas_device = mpt2sas_get_sdev_from_target(ioc, priv_target);
 		if (sas_device) {
 			printk(MPT2SAS_WARN_FMT "\tsas_address(0x%016llx), "
 			    "phy(%d)\n", ioc->name, sas_device->sas_address,
@@ -4211,8 +4315,9 @@ _scsih_scsi_ioc_info(struct MPT2SAS_ADAPTER *ioc, struct scsi_cmnd *scmd,
 			    "\tenclosure_logical_id(0x%016llx), slot(%d)\n",
 			    ioc->name, sas_device->enclosure_logical_id,
 			    sas_device->slot);
+
+			sas_device_put(sas_device);
 		}
-		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 	}
 
 	printk(MPT2SAS_WARN_FMT "\thandle(0x%04x), ioc_status(%s)(0x%04x), "
@@ -4259,7 +4364,7 @@ _scsih_turn_on_pfa_led(struct MPT2SAS_ADAPTER *ioc, u16 handle)
 	Mpi2SepRequest_t mpi_request;
 	struct _sas_device *sas_device;
 
-	sas_device = _scsih_sas_device_find_by_handle(ioc, handle);
+	sas_device = mpt2sas_get_sdev_by_handle(ioc, handle);
 	if (!sas_device)
 		return;
 
@@ -4274,7 +4379,7 @@ _scsih_turn_on_pfa_led(struct MPT2SAS_ADAPTER *ioc, u16 handle)
 	    &mpi_request)) != 0) {
 		printk(MPT2SAS_ERR_FMT "failure at %s:%d/%s()!\n", ioc->name,
 		__FILE__, __LINE__, __func__);
-		return;
+		goto out;
 	}
 	sas_device->pfa_led_on = 1;
 
@@ -4284,8 +4389,10 @@ _scsih_turn_on_pfa_led(struct MPT2SAS_ADAPTER *ioc, u16 handle)
 		 "enclosure_processor: ioc_status (0x%04x), loginfo(0x%08x)\n",
 		 ioc->name, le16_to_cpu(mpi_reply.IOCStatus),
 		 le32_to_cpu(mpi_reply.IOCLogInfo)));
-		return;
+		goto out;
 	}
+out:
+	sas_device_put(sas_device);
 }
 
 /**
@@ -4370,19 +4477,17 @@ _scsih_smart_predicted_fault(struct MPT2SAS_ADAPTER *ioc, u16 handle)
 
 	/* only handle non-raid devices */
 	spin_lock_irqsave(&ioc->sas_device_lock, flags);
-	sas_device = _scsih_sas_device_find_by_handle(ioc, handle);
+	sas_device = __mpt2sas_get_sdev_by_handle(ioc, handle);
 	if (!sas_device) {
-		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
-		return;
+		goto out_unlock;
 	}
 	starget = sas_device->starget;
 	sas_target_priv_data = starget->hostdata;
 
 	if ((sas_target_priv_data->flags & MPT_TARGET_FLAGS_RAID_COMPONENT) ||
-	   ((sas_target_priv_data->flags & MPT_TARGET_FLAGS_VOLUME))) {
-		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
-		return;
-	}
+	   ((sas_target_priv_data->flags & MPT_TARGET_FLAGS_VOLUME)))
+		goto out_unlock;
+
 	starget_printk(KERN_WARNING, starget, "predicted fault\n");
 	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 
@@ -4396,7 +4501,7 @@ _scsih_smart_predicted_fault(struct MPT2SAS_ADAPTER *ioc, u16 handle)
 	if (!event_reply) {
 		printk(MPT2SAS_ERR_FMT "failure at %s:%d/%s()!\n",
 		    ioc->name, __FILE__, __LINE__, __func__);
-		return;
+		goto out;
 	}
 
 	event_reply->Function = MPI2_FUNCTION_EVENT_NOTIFICATION;
@@ -4413,6 +4518,14 @@ _scsih_smart_predicted_fault(struct MPT2SAS_ADAPTER *ioc, u16 handle)
 	event_data->SASAddress = cpu_to_le64(sas_target_priv_data->sas_address);
 	mpt2sas_ctl_add_to_event_log(ioc, event_reply);
 	kfree(event_reply);
+out:
+	if (sas_device)
+		sas_device_put(sas_device);
+	return;
+
+out_unlock:
+	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
+	goto out;
 }
 
 /**
@@ -5148,14 +5261,13 @@ _scsih_check_device(struct MPT2SAS_ADAPTER *ioc, u16 handle)
 
 	spin_lock_irqsave(&ioc->sas_device_lock, flags);
 	sas_address = le64_to_cpu(sas_device_pg0.SASAddress);
-	sas_device = mpt2sas_scsih_sas_device_find_by_sas_address(ioc,
+	sas_device = __mpt2sas_get_sdev_by_addr(ioc,
 	    sas_address);
 
 	if (!sas_device) {
 		printk(MPT2SAS_ERR_FMT "device is not present "
 		    "handle(0x%04x), no sas_device!!!\n", ioc->name, handle);
-		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
-		return;
+		goto out_unlock;
 	}
 
 	if (unlikely(sas_device->handle != handle)) {
@@ -5172,19 +5284,24 @@ _scsih_check_device(struct MPT2SAS_ADAPTER *ioc, u16 handle)
 	    MPI2_SAS_DEVICE0_FLAGS_DEVICE_PRESENT)) {
 		printk(MPT2SAS_ERR_FMT "device is not present "
 		    "handle(0x%04x), flags!!!\n", ioc->name, handle);
-		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
-		return;
+		goto out_unlock;
 	}
 
 	/* check if there were any issues with discovery */
 	if (_scsih_check_access_status(ioc, sas_address, handle,
-	    sas_device_pg0.AccessStatus)) {
-		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
-		return;
-	}
+	    sas_device_pg0.AccessStatus))
+		goto out_unlock;
+
 	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 	_scsih_ublock_io_device(ioc, sas_address);
+	if (sas_device)
+		sas_device_put(sas_device);
+	return;
 
+out_unlock:
+	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
+	if (sas_device)
+		sas_device_put(sas_device);
 }
 
 /**
@@ -5208,7 +5325,6 @@ _scsih_add_device(struct MPT2SAS_ADAPTER *ioc, u16 handle, u8 phy_num, u8 is_pd)
 	u32 ioc_status;
 	__le64 sas_address;
 	u32 device_info;
-	unsigned long flags;
 
 	if ((mpt2sas_config_get_sas_device_pg0(ioc, &mpi_reply, &sas_device_pg0,
 	    MPI2_SAS_DEVICE_PGAD_FORM_HANDLE, handle))) {
@@ -5250,14 +5366,13 @@ _scsih_add_device(struct MPT2SAS_ADAPTER *ioc, u16 handle, u8 phy_num, u8 is_pd)
 		return -1;
 	}
 
-
-	spin_lock_irqsave(&ioc->sas_device_lock, flags);
-	sas_device = mpt2sas_scsih_sas_device_find_by_sas_address(ioc,
+	sas_device = mpt2sas_get_sdev_by_addr(ioc,
 	    sas_address);
-	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 
-	if (sas_device)
+	if (sas_device) {
+		sas_device_put(sas_device);
 		return 0;
+	}
 
 	sas_device = kzalloc(sizeof(struct _sas_device),
 	    GFP_KERNEL);
@@ -5267,6 +5382,7 @@ _scsih_add_device(struct MPT2SAS_ADAPTER *ioc, u16 handle, u8 phy_num, u8 is_pd)
 		return -1;
 	}
 
+	kref_init(&sas_device->refcount);
 	sas_device->handle = handle;
 	if (_scsih_get_sas_address(ioc, le16_to_cpu
 		(sas_device_pg0.ParentDevHandle),
@@ -5296,6 +5412,7 @@ _scsih_add_device(struct MPT2SAS_ADAPTER *ioc, u16 handle, u8 phy_num, u8 is_pd)
 	else
 		_scsih_sas_device_add(ioc, sas_device);
 
+	sas_device_put(sas_device);
 	return 0;
 }
 
@@ -5344,7 +5461,6 @@ _scsih_remove_device(struct MPT2SAS_ADAPTER *ioc,
 	    "handle(0x%04x), sas_addr(0x%016llx)\n", ioc->name, __func__,
 	    sas_device->handle, (unsigned long long)
 	    sas_device->sas_address));
-	kfree(sas_device);
 }
 /**
  * _scsih_device_remove_by_handle - removing device object by handle
@@ -5363,12 +5479,17 @@ _scsih_device_remove_by_handle(struct MPT2SAS_ADAPTER *ioc, u16 handle)
 		return;
 
 	spin_lock_irqsave(&ioc->sas_device_lock, flags);
-	sas_device = _scsih_sas_device_find_by_handle(ioc, handle);
-	if (sas_device)
-		list_del(&sas_device->list);
+	sas_device = __mpt2sas_get_sdev_by_handle(ioc, handle);
+	if (sas_device) {
+		list_del_init(&sas_device->list);
+		sas_device_put(sas_device);
+	}
 	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
-	if (sas_device)
+
+	if (sas_device) {
 		_scsih_remove_device(ioc, sas_device);
+		sas_device_put(sas_device);
+	}
 }
 
 /**
@@ -5389,13 +5510,17 @@ mpt2sas_device_remove_by_sas_address(struct MPT2SAS_ADAPTER *ioc,
 		return;
 
 	spin_lock_irqsave(&ioc->sas_device_lock, flags);
-	sas_device = mpt2sas_scsih_sas_device_find_by_sas_address(ioc,
-	    sas_address);
-	if (sas_device)
-		list_del(&sas_device->list);
+	sas_device = __mpt2sas_get_sdev_by_addr(ioc, sas_address);
+	if (sas_device) {
+		list_del_init(&sas_device->list);
+		sas_device_put(sas_device);
+	}
 	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
-	if (sas_device)
+
+	if (sas_device) {
 		_scsih_remove_device(ioc, sas_device);
+		sas_device_put(sas_device);
+	}
 }
 #ifdef CONFIG_SCSI_MPT2SAS_LOGGING
 /**
@@ -5716,26 +5841,28 @@ _scsih_sas_device_status_change_event(struct MPT2SAS_ADAPTER *ioc,
 
 	spin_lock_irqsave(&ioc->sas_device_lock, flags);
 	sas_address = le64_to_cpu(event_data->SASAddress);
-	sas_device = mpt2sas_scsih_sas_device_find_by_sas_address(ioc,
+	sas_device = __mpt2sas_get_sdev_by_addr(ioc,
 	    sas_address);
 
-	if (!sas_device || !sas_device->starget) {
-		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
-		return;
-	}
+	if (!sas_device || !sas_device->starget)
+		goto out;
 
 	target_priv_data = sas_device->starget->hostdata;
-	if (!target_priv_data) {
-		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
-		return;
-	}
+	if (!target_priv_data)
+		goto out;
 
 	if (event_data->ReasonCode ==
 	    MPI2_EVENT_SAS_DEV_STAT_RC_INTERNAL_DEVICE_RESET)
 		target_priv_data->tm_busy = 1;
 	else
 		target_priv_data->tm_busy = 0;
+
+out:
+	if (sas_device)
+		sas_device_put(sas_device);
+
 	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
+
 }
 
 #ifdef CONFIG_SCSI_MPT2SAS_LOGGING
@@ -6123,7 +6250,7 @@ _scsih_sas_pd_expose(struct MPT2SAS_ADAPTER *ioc,
 	u16 handle = le16_to_cpu(element->PhysDiskDevHandle);
 
 	spin_lock_irqsave(&ioc->sas_device_lock, flags);
-	sas_device = _scsih_sas_device_find_by_handle(ioc, handle);
+	sas_device = __mpt2sas_get_sdev_by_handle(ioc, handle);
 	if (sas_device) {
 		sas_device->volume_handle = 0;
 		sas_device->volume_wwid = 0;
@@ -6142,6 +6269,8 @@ _scsih_sas_pd_expose(struct MPT2SAS_ADAPTER *ioc,
 	/* exposing raid component */
 	if (starget)
 		starget_for_each_device(starget, NULL, _scsih_reprobe_lun);
+
+	sas_device_put(sas_device);
 }
 
 /**
@@ -6170,7 +6299,7 @@ _scsih_sas_pd_hide(struct MPT2SAS_ADAPTER *ioc,
 		    &volume_wwid);
 
 	spin_lock_irqsave(&ioc->sas_device_lock, flags);
-	sas_device = _scsih_sas_device_find_by_handle(ioc, handle);
+	sas_device = __mpt2sas_get_sdev_by_handle(ioc, handle);
 	if (sas_device) {
 		set_bit(handle, ioc->pd_handles);
 		if (sas_device->starget && sas_device->starget->hostdata) {
@@ -6189,6 +6318,8 @@ _scsih_sas_pd_hide(struct MPT2SAS_ADAPTER *ioc,
 	/* hiding raid component */
 	if (starget)
 		starget_for_each_device(starget, (void *)1, _scsih_reprobe_lun);
+
+	sas_device_put(sas_device);
 }
 
 /**
@@ -6221,7 +6352,6 @@ _scsih_sas_pd_add(struct MPT2SAS_ADAPTER *ioc,
     Mpi2EventIrConfigElement_t *element)
 {
 	struct _sas_device *sas_device;
-	unsigned long flags;
 	u16 handle = le16_to_cpu(element->PhysDiskDevHandle);
 	Mpi2ConfigReply_t mpi_reply;
 	Mpi2SasDevicePage0_t sas_device_pg0;
@@ -6231,11 +6361,11 @@ _scsih_sas_pd_add(struct MPT2SAS_ADAPTER *ioc,
 
 	set_bit(handle, ioc->pd_handles);
 
-	spin_lock_irqsave(&ioc->sas_device_lock, flags);
-	sas_device = _scsih_sas_device_find_by_handle(ioc, handle);
-	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
-	if (sas_device)
+	sas_device = mpt2sas_get_sdev_by_handle(ioc, handle);
+	if (sas_device) {
+		sas_device_put(sas_device);
 		return;
+	}
 
 	if ((mpt2sas_config_get_sas_device_pg0(ioc, &mpi_reply, &sas_device_pg0,
 	    MPI2_SAS_DEVICE_PGAD_FORM_HANDLE, handle))) {
@@ -6509,7 +6639,6 @@ _scsih_sas_ir_physical_disk_event(struct MPT2SAS_ADAPTER *ioc,
 	u16 handle, parent_handle;
 	u32 state;
 	struct _sas_device *sas_device;
-	unsigned long flags;
 	Mpi2ConfigReply_t mpi_reply;
 	Mpi2SasDevicePage0_t sas_device_pg0;
 	u32 ioc_status;
@@ -6542,12 +6671,11 @@ _scsih_sas_ir_physical_disk_event(struct MPT2SAS_ADAPTER *ioc,
 		if (!ioc->is_warpdrive)
 			set_bit(handle, ioc->pd_handles);
 
-		spin_lock_irqsave(&ioc->sas_device_lock, flags);
-		sas_device = _scsih_sas_device_find_by_handle(ioc, handle);
-		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
-
-		if (sas_device)
+		sas_device = mpt2sas_get_sdev_by_handle(ioc, handle);
+		if (sas_device) {
+			sas_device_put(sas_device);
 			return;
+		}
 
 		if ((mpt2sas_config_get_sas_device_pg0(ioc, &mpi_reply,
 		    &sas_device_pg0, MPI2_SAS_DEVICE_PGAD_FORM_HANDLE,
@@ -7015,6 +7143,7 @@ _scsih_remove_unresponding_sas_devices(struct MPT2SAS_ADAPTER *ioc)
 	struct _raid_device *raid_device, *raid_device_next;
 	struct list_head tmp_list;
 	unsigned long flags;
+	LIST_HEAD(head);
 
 	printk(MPT2SAS_INFO_FMT "removing unresponding devices: start\n",
 	    ioc->name);
@@ -7022,14 +7151,29 @@ _scsih_remove_unresponding_sas_devices(struct MPT2SAS_ADAPTER *ioc)
 	/* removing unresponding end devices */
 	printk(MPT2SAS_INFO_FMT "removing unresponding devices: end-devices\n",
 	    ioc->name);
+
+	/*
+	 * Iterate, pulling off devices marked as non-responding. We become the
+	 * owner for the reference the list had on any object we prune.
+	 */
+	spin_lock_irqsave(&ioc->sas_device_lock, flags);
 	list_for_each_entry_safe(sas_device, sas_device_next,
-	    &ioc->sas_device_list, list) {
+			&ioc->sas_device_list, list) {
 		if (!sas_device->responding)
-			mpt2sas_device_remove_by_sas_address(ioc,
-				sas_device->sas_address);
+			list_move_tail(&sas_device->list, &head);
 		else
 			sas_device->responding = 0;
 	}
+	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
+
+	/*
+	 * Now, uninitialize and remove the unresponding devices we pruned.
+	 */
+	list_for_each_entry_safe(sas_device, sas_device_next, &head, list) {
+		_scsih_remove_device(ioc, sas_device);
+		list_del_init(&sas_device->list);
+		sas_device_put(sas_device);
+	}
 
 	/* removing unresponding volumes */
 	if (ioc->ir_firmware) {
@@ -7179,11 +7323,11 @@ _scsih_scan_for_devices_after_reset(struct MPT2SAS_ADAPTER *ioc)
 		}
 		phys_disk_num = pd_pg0.PhysDiskNum;
 		handle = le16_to_cpu(pd_pg0.DevHandle);
-		spin_lock_irqsave(&ioc->sas_device_lock, flags);
-		sas_device = _scsih_sas_device_find_by_handle(ioc, handle);
-		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
-		if (sas_device)
+		sas_device = mpt2sas_get_sdev_by_handle(ioc, handle);
+		if (sas_device) {
+			sas_device_put(sas_device);
 			continue;
+		}
 		if (mpt2sas_config_get_sas_device_pg0(ioc, &mpi_reply,
 		    &sas_device_pg0, MPI2_SAS_DEVICE_PGAD_FORM_HANDLE,
 		    handle) != 0)
@@ -7302,12 +7446,12 @@ _scsih_scan_for_devices_after_reset(struct MPT2SAS_ADAPTER *ioc)
 		if (!(_scsih_is_end_device(
 		    le32_to_cpu(sas_device_pg0.DeviceInfo))))
 			continue;
-		spin_lock_irqsave(&ioc->sas_device_lock, flags);
-		sas_device = mpt2sas_scsih_sas_device_find_by_sas_address(ioc,
+		sas_device = mpt2sas_get_sdev_by_addr(ioc,
 		    le64_to_cpu(sas_device_pg0.SASAddress));
-		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
-		if (sas_device)
+		if (sas_device) {
+			sas_device_put(sas_device);
 			continue;
+		}
 		parent_handle = le16_to_cpu(sas_device_pg0.ParentDevHandle);
 		if (!_scsih_get_sas_address(ioc, parent_handle, &sas_address)) {
 			printk(MPT2SAS_INFO_FMT "\tBEFORE adding end device: "
@@ -7966,6 +8110,48 @@ _scsih_probe_raid(struct MPT2SAS_ADAPTER *ioc)
 	}
 }
 
+static struct _sas_device *get_next_sas_device(struct MPT2SAS_ADAPTER *ioc)
+{
+	struct _sas_device *sas_device = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ioc->sas_device_lock, flags);
+	if (!list_empty(&ioc->sas_device_init_list)) {
+		sas_device = list_first_entry(&ioc->sas_device_init_list,
+				struct _sas_device, list);
+		sas_device_get(sas_device);
+	}
+	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
+
+	return sas_device;
+}
+
+static void sas_device_make_active(struct MPT2SAS_ADAPTER *ioc,
+		struct _sas_device *sas_device)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&ioc->sas_device_lock, flags);
+
+	/*
+	 * Since we dropped the lock during the call to port_add(), we need to
+	 * be careful here that somebody else didn't move or delete this item
+	 * while we were busy with other things.
+	 *
+	 * If it was on the list, we need a put() for the reference the list
+	 * had. Either way, we need a get() for the destination list.
+	 */
+	if (!list_empty(&sas_device->list)) {
+		list_del_init(&sas_device->list);
+		sas_device_put(sas_device);
+	}
+
+	sas_device_get(sas_device);
+	list_add_tail(&sas_device->list, &ioc->sas_device_list);
+
+	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
+}
+
 /**
  * _scsih_probe_sas - reporting sas devices to sas transport
  * @ioc: per adapter object
@@ -7975,34 +8161,30 @@ _scsih_probe_raid(struct MPT2SAS_ADAPTER *ioc)
 static void
 _scsih_probe_sas(struct MPT2SAS_ADAPTER *ioc)
 {
-	struct _sas_device *sas_device, *next;
-	unsigned long flags;
-
-	/* SAS Device List */
-	list_for_each_entry_safe(sas_device, next, &ioc->sas_device_init_list,
-	    list) {
+	struct _sas_device *sas_device;
 
-		if (ioc->hide_drives)
-			continue;
+	if (ioc->hide_drives)
+		return;
 
+	while ((sas_device = get_next_sas_device(ioc))) {
 		if (!mpt2sas_transport_port_add(ioc, sas_device->handle,
-		    sas_device->sas_address_parent)) {
-			list_del(&sas_device->list);
-			kfree(sas_device);
+				sas_device->sas_address_parent)) {
+			_scsih_sas_device_remove(ioc, sas_device);
+			sas_device_put(sas_device);
 			continue;
 		} else if (!sas_device->starget) {
 			if (!ioc->is_driver_loading) {
 				mpt2sas_transport_port_remove(ioc,
-					sas_device->sas_address,
-					sas_device->sas_address_parent);
-				list_del(&sas_device->list);
-				kfree(sas_device);
+						sas_device->sas_address,
+						sas_device->sas_address_parent);
+				_scsih_sas_device_remove(ioc, sas_device);
+				sas_device_put(sas_device);
 				continue;
 			}
 		}
-		spin_lock_irqsave(&ioc->sas_device_lock, flags);
-		list_move_tail(&sas_device->list, &ioc->sas_device_list);
-		spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
+
+		sas_device_make_active(ioc, sas_device);
+		sas_device_put(sas_device);
 	}
 }
 
diff --git a/drivers/scsi/mpt2sas/mpt2sas_transport.c b/drivers/scsi/mpt2sas/mpt2sas_transport.c
index ff2500a..af86800 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_transport.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_transport.c
@@ -1323,15 +1323,17 @@ _transport_get_enclosure_identifier(struct sas_rphy *rphy, u64 *identifier)
 	int rc;
 
 	spin_lock_irqsave(&ioc->sas_device_lock, flags);
-	sas_device = mpt2sas_scsih_sas_device_find_by_sas_address(ioc,
+	sas_device = __mpt2sas_get_sdev_by_addr(ioc,
 	    rphy->identify.sas_address);
 	if (sas_device) {
 		*identifier = sas_device->enclosure_logical_id;
 		rc = 0;
+		sas_device_put(sas_device);
 	} else {
 		*identifier = 0;
 		rc = -ENXIO;
 	}
+
 	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 	return rc;
 }
@@ -1351,12 +1353,14 @@ _transport_get_bay_identifier(struct sas_rphy *rphy)
 	int rc;
 
 	spin_lock_irqsave(&ioc->sas_device_lock, flags);
-	sas_device = mpt2sas_scsih_sas_device_find_by_sas_address(ioc,
+	sas_device = __mpt2sas_get_sdev_by_addr(ioc,
 	    rphy->identify.sas_address);
-	if (sas_device)
+	if (sas_device) {
 		rc = sas_device->slot;
-	else
+		sas_device_put(sas_device);
+	} else {
 		rc = -ENXIO;
+	}
 	spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
 	return rc;
 }
-- 
2.5.0

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