diff --git a/sys/dev/isci/isci.c b/sys/dev/isci/isci.c
index 6a1b4a8d57cc..4d2f4bdf035e 100644
--- a/sys/dev/isci/isci.c
+++ b/sys/dev/isci/isci.c
@@ -185,6 +185,7 @@ isci_detach(device_t device)
 	for (i = 0; i < isci->controller_count; i++) {
 		struct ISCI_CONTROLLER *controller = &isci->controllers[i];
 		SCI_STATUS status;
+		void *unmap_buffer;
 
 		if (controller->scif_controller_handle != NULL) {
 			scic_controller_disable_interrupts(
@@ -218,6 +219,13 @@ isci_detach(device_t device)
 
 		if (controller->remote_device_memory != NULL)
 			free(controller->remote_device_memory, M_ISCI);
+
+		while (1) {
+			sci_pool_get(controller->unmap_buffer_pool, unmap_buffer);
+			if (unmap_buffer == NULL)
+				break;
+			contigfree(unmap_buffer, PAGE_SIZE, M_ISCI);
+		}
 	}
 
 	/* The SCIF controllers have been stopped, so we can now
diff --git a/sys/dev/isci/isci.h b/sys/dev/isci/isci.h
index cdba7de1806b..48236b9dca99 100644
--- a/sys/dev/isci/isci.h
+++ b/sys/dev/isci/isci.h
@@ -175,6 +175,7 @@ struct ISCI_CONTROLLER
 	SCI_POOL_CREATE(remote_device_pool, struct ISCI_REMOTE_DEVICE *, SCI_MAX_REMOTE_DEVICES);
 	SCI_POOL_CREATE(request_pool, struct ISCI_REQUEST *, SCI_MAX_IO_REQUESTS);
 	SCI_POOL_CREATE(timer_pool, struct ISCI_TIMER *, SCI_MAX_TIMERS);
+	SCI_POOL_CREATE(unmap_buffer_pool, void *, SCI_MAX_REMOTE_DEVICES);
 };
 
 struct ISCI_REQUEST
diff --git a/sys/dev/isci/isci_controller.c b/sys/dev/isci/isci_controller.c
index 49785cbfd158..1255201fe835 100644
--- a/sys/dev/isci/isci_controller.c
+++ b/sys/dev/isci/isci_controller.c
@@ -145,6 +145,14 @@ void scif_cb_controller_stop_complete(SCI_CONTROLLER_HANDLE_T controller,
 	isci_controller->is_started = FALSE;
 }
 
+static void
+isci_single_map(void *arg, bus_dma_segment_t *seg, int nseg, int error)
+{
+	SCI_PHYSICAL_ADDRESS *phys_addr = arg;
+
+	*phys_addr = seg[0].ds_addr;
+}
+
 /**
  * @brief This method will be invoked to allocate memory dynamically.
  *
@@ -159,7 +167,29 @@ void scif_cb_controller_stop_complete(SCI_CONTROLLER_HANDLE_T controller,
 void scif_cb_controller_allocate_memory(SCI_CONTROLLER_HANDLE_T controller,
     SCI_PHYSICAL_MEMORY_DESCRIPTOR_T *mde)
 {
+	struct ISCI_CONTROLLER *isci_controller = (struct ISCI_CONTROLLER *)
+	    sci_object_get_association(controller);
 
+	/*
+	 * Note this routine is only used for buffers needed to translate
+	 * SCSI UNMAP commands to ATA DSM commands for SATA disks.
+	 *
+	 * We first try to pull a buffer from the controller's pool, and only
+	 * call contigmalloc if one isn't there.
+	 */
+	if (!sci_pool_empty(isci_controller->unmap_buffer_pool)) {
+		sci_pool_get(isci_controller->unmap_buffer_pool,
+		    mde->virtual_address);
+	} else
+		mde->virtual_address = contigmalloc(PAGE_SIZE,
+		    M_ISCI, M_NOWAIT, 0, BUS_SPACE_MAXADDR,
+		    mde->constant_memory_alignment, 0);
+
+	if (mde->virtual_address != NULL)
+		bus_dmamap_load(isci_controller->buffer_dma_tag,
+		    NULL, mde->virtual_address, PAGE_SIZE,
+		    isci_single_map, &mde->physical_address,
+		    BUS_DMA_NOWAIT);
 }
 
 /**
@@ -176,7 +206,16 @@ void scif_cb_controller_allocate_memory(SCI_CONTROLLER_HANDLE_T controller,
 void scif_cb_controller_free_memory(SCI_CONTROLLER_HANDLE_T controller,
     SCI_PHYSICAL_MEMORY_DESCRIPTOR_T * mde)
 {
+	struct ISCI_CONTROLLER *isci_controller = (struct ISCI_CONTROLLER *)
+	    sci_object_get_association(controller);
 
+	/*
+	 * Put the buffer back into the controller's buffer pool, rather
+	 * than invoking configfree.  This helps reduce chance we won't
+	 * have buffers available when system is under memory pressure.
+	 */ 
+	sci_pool_put(isci_controller->unmap_buffer_pool,
+	    mde->virtual_address);
 }
 
 void isci_controller_construct(struct ISCI_CONTROLLER *controller,
@@ -228,6 +267,8 @@ void isci_controller_construct(struct ISCI_CONTROLLER *controller,
 	for ( int i = 0; i < SCI_MAX_TIMERS; i++ ) {
 		sci_pool_put(controller->timer_pool, timer++);
 	}
+
+	sci_pool_initialize(controller->unmap_buffer_pool);
 }
 
 SCI_STATUS isci_controller_initialize(struct ISCI_CONTROLLER *controller)
diff --git a/sys/dev/isci/scil/sati_unmap.c b/sys/dev/isci/scil/sati_unmap.c
index cc8327b3bc25..4cd6e9c41952 100644
--- a/sys/dev/isci/scil/sati_unmap.c
+++ b/sys/dev/isci/scil/sati_unmap.c
@@ -335,8 +335,8 @@ SATI_STATUS sati_unmap_initial_processing(
       sati_scsi_sense_data_construct(
          sequence,
          scsi_io,
-         SCSI_STATUS_CHECK_CONDITION,
-         SCSI_SENSE_ABORTED_COMMAND,
+         SCSI_STATUS_BUSY,
+         SCSI_SENSE_NO_SENSE,
          SCSI_ASC_NO_ADDITIONAL_SENSE,
          SCSI_ASCQ_NO_ADDITIONAL_SENSE
       );
diff --git a/sys/dev/isci/scil/scif_sas_sati_binding.h b/sys/dev/isci/scil/scif_sas_sati_binding.h
index 99c94333a78b..329efd7794f9 100644
--- a/sys/dev/isci/scil/scif_sas_sati_binding.h
+++ b/sys/dev/isci/scil/scif_sas_sati_binding.h
@@ -183,22 +183,16 @@ extern "C" {
 {                                                                 \
    SCIF_SAS_REQUEST_T* fw_request = (SCIF_SAS_REQUEST_T*)scsi_io; \
    SCI_PHYSICAL_MEMORY_DESCRIPTOR_T mde;                          \
-   SCI_PHYSICAL_ADDRESS phys_addr;                                \
    mde.virtual_address = NULL;                                    \
-   sci_cb_make_physical_address(mde.physical_address, 0, 0);      \
    sci_base_mde_construct(                                        \
       &mde, 4, length, SCI_MDE_ATTRIBUTE_PHYSICALLY_CONTIGUOUS    \
    );                                                             \
    scif_cb_controller_allocate_memory(                            \
       fw_request->device->domain->controller, &mde                \
    );                                                             \
-   scic_cb_io_request_get_physical_address(fw_request->device->domain->controller, \
-                                           NULL,                  \
-                                           mde.virtual_address,   \
-                                           &phys_addr);           \
    *(virt_address)       = mde.virtual_address;                      \
-   *(phys_address_low)   = sci_cb_physical_address_lower(phys_addr); \
-   *(phys_address_high)  = sci_cb_physical_address_upper(phys_addr); \
+   *(phys_address_low)   = sci_cb_physical_address_lower(mde.physical_address); \
+   *(phys_address_high)  = sci_cb_physical_address_upper(mde.physical_address); \
 }
 
 #define sati_cb_free_dma_buffer(scsi_io, virt_address)         \
@@ -206,7 +200,6 @@ extern "C" {
    SCIF_SAS_REQUEST_T* fw_request = (SCIF_SAS_REQUEST_T*)scsi_io; \
    SCI_PHYSICAL_MEMORY_DESCRIPTOR_T mde;                          \
    mde.virtual_address = virt_address;                         \
-   sci_cb_make_physical_address(mde.physical_address, 0, 0);      \
    sci_base_mde_construct(                                        \
       &mde, 4, 0, SCI_MDE_ATTRIBUTE_PHYSICALLY_CONTIGUOUS         \
    );                                                             \
diff --git a/sys/dev/isci/scil/scif_sas_stp_io_request.c b/sys/dev/isci/scil/scif_sas_stp_io_request.c
index 36910bd70962..cca50c64f969 100644
--- a/sys/dev/isci/scil/scif_sas_stp_io_request.c
+++ b/sys/dev/isci/scil/scif_sas_stp_io_request.c
@@ -171,6 +171,8 @@ SCI_STATUS scif_sas_stp_io_request_constructed_complete_handler(
          );
    }
 
+   sati_sequence_terminate(&fw_io->parent.stp.sequence, fw_io, fw_io);
+
    return SCI_SUCCESS;
 }
 /**