isci: kill device_sequence

Now that we have upleveled device reassignment protection to the
isci_remote_device reference count we no longer need this level of
self-defense.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/scsi/isci/host.h

@@ -187,15 +187,6 @@ struct scic_sds_controller {
 	/* sequence number per tci */
 	u8 io_request_sequence[SCI_MAX_IO_REQUESTS];
 
-	/**
-	 * This field in the array of sequence values for the RNi.  These are used
-	 * to control io request build to io request start operations.  The sequence
-	 * value is recorded into an io request when it is built and is checked on
-	 * the io request start operation to make sure that there was not a device
-	 * hot plug between the build and start operation.
-	 */
-	u8 remote_device_sequence[SCI_MAX_REMOTE_DEVICES];
-
 	/**
 	 * This field is a pointer to the memory allocated by the driver for the task
 	 * context table.  This data is shared between the hardware and software.

drivers/scsi/isci/remote_device.c

@@ -887,8 +887,6 @@ static void scic_sds_remote_device_ready_state_enter(struct sci_base_state_machi
 	struct isci_remote_device *idev = sci_dev_to_idev(sci_dev);
 	struct domain_device *dev = idev->domain_dev;
 
-	scic->remote_device_sequence[sci_dev->rnc.remote_node_index]++;
-
 	if (dev->dev_type == SATA_DEV || (dev->tproto & SAS_PROTOCOL_SATA)) {
 		sci_change_state(&sci_dev->sm, SCI_STP_DEV_IDLE);
 	} else if (dev_is_expander(dev)) {

drivers/scsi/isci/remote_device.h

@@ -410,17 +410,6 @@ static inline bool dev_is_expander(struct domain_device *dev)
 #define scic_sds_remote_device_get_port(sci_dev) \
 	((sci_dev)->owning_port)
 
-/**
- * scic_sds_remote_device_get_sequence() -
- *
- * This macro returns the remote device sequence value
- */
-#define scic_sds_remote_device_get_sequence(sci_dev) \
-	(\
-		scic_sds_remote_device_get_controller(sci_dev)-> \
-		remote_device_sequence[(sci_dev)->rnc.remote_node_index] \
-	)
-
 /**
  * scic_sds_remote_device_get_controller_peg() -
  *

drivers/scsi/isci/request.c

@@ -753,10 +753,6 @@ enum sci_status scic_sds_request_start(struct scic_sds_request *sci_req)
 	struct scu_task_context *task_context;
 	enum sci_base_request_states state;
 
-	if (sci_req->device_sequence !=
-	    scic_sds_remote_device_get_sequence(sci_req->target_device))
-		return SCI_FAILURE;
-
 	state = sci_req->sm.current_state_id;
 	if (state != SCI_REQ_CONSTRUCTED) {
 		dev_warn(scic_to_dev(scic),
@@ -3112,7 +3108,6 @@ scic_sds_general_request_construct(struct scic_sds_controller *scic,
 	sci_req->target_device = sci_dev;
 	sci_req->protocol = SCIC_NO_PROTOCOL;
 	sci_req->saved_rx_frame_index = SCU_INVALID_FRAME_INDEX;
-	sci_req->device_sequence = scic_sds_remote_device_get_sequence(sci_dev);
 
 	sci_req->sci_status   = SCI_SUCCESS;
 	sci_req->scu_status   = 0;

drivers/scsi/isci/request.h

@@ -231,14 +231,6 @@ struct scic_sds_request {
 	 */
 	u32 saved_rx_frame_index;
 
-	/*
-	 * This field in the recorded device sequence for the io request.
-	 * This is recorded during the build operation and is compared in the
-	 * start operation.  If the sequence is different then there was a
-	 * change of devices from the build to start operations.
-	 */
-	u8 device_sequence;
-
 	union {
 		struct {
 			union {
@@ -262,7 +254,6 @@ struct scic_sds_request {
 			struct dev_to_host_fis rsp;
 		} stp;
 	};
-
 };
 
 static inline struct scic_sds_request *to_sci_req(struct scic_sds_stp_request *stp_req)