scsi: virtio_scsi: Remove per-target data because it is no longer used

Commit b5b6e8c8 ("scsi: virtio_scsi: fix IO hang caused by automatic
irq vector affinity") removed all virtio_scsi hostdata users. Since the
SCSI host data is no longer used, also remove the host data itself.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/virtio_scsi.c

@@ -68,33 +68,6 @@ struct virtio_scsi_vq {
 	struct virtqueue *vq;
 };
 
-/*
- * Per-target queue state.
- *
- * This struct holds the data needed by the queue steering policy.  When a
- * target is sent multiple requests, we need to drive them to the same queue so
- * that FIFO processing order is kept.  However, if a target was idle, we can
- * choose a queue arbitrarily.  In this case the queue is chosen according to
- * the current VCPU, so the driver expects the number of request queues to be
- * equal to the number of VCPUs.  This makes it easy and fast to select the
- * queue, and also lets the driver optimize the IRQ affinity for the virtqueues
- * (each virtqueue's affinity is set to the CPU that "owns" the queue).
- *
- * tgt_seq is held to serialize reading and writing req_vq.
- *
- * Decrements of reqs are never concurrent with writes of req_vq: before the
- * decrement reqs will be != 0; after the decrement the virtqueue completion
- * routine will not use the req_vq so it can be changed by a new request.
- * Thus they can happen outside the tgt_seq, provided of course we make reqs
- * an atomic_t.
- */
-struct virtio_scsi_target_state {
-	seqcount_t tgt_seq;
-
-	/* Currently active virtqueue for requests sent to this target. */
-	struct virtio_scsi_vq *req_vq;
-};
-
 /* Driver instance state */
 struct virtio_scsi {
 	struct virtio_device *vdev;
@@ -693,29 +666,6 @@ static int virtscsi_abort(struct scsi_cmnd *sc)
 	return virtscsi_tmf(vscsi, cmd);
 }
 
-static int virtscsi_target_alloc(struct scsi_target *starget)
-{
-	struct Scsi_Host *sh = dev_to_shost(starget->dev.parent);
-	struct virtio_scsi *vscsi = shost_priv(sh);
-
-	struct virtio_scsi_target_state *tgt =
-				kmalloc(sizeof(*tgt), GFP_KERNEL);
-	if (!tgt)
-		return -ENOMEM;
-
-	seqcount_init(&tgt->tgt_seq);
-	tgt->req_vq = &vscsi->req_vqs[0];
-
-	starget->hostdata = tgt;
-	return 0;
-}
-
-static void virtscsi_target_destroy(struct scsi_target *starget)
-{
-	struct virtio_scsi_target_state *tgt = starget->hostdata;
-	kfree(tgt);
-}
-
 static int virtscsi_map_queues(struct Scsi_Host *shost)
 {
 	struct virtio_scsi *vscsi = shost_priv(shost);
@@ -748,8 +698,6 @@ static struct scsi_host_template virtscsi_host_template = {
 
 	.dma_boundary = UINT_MAX,
 	.use_clustering = ENABLE_CLUSTERING,
-	.target_alloc = virtscsi_target_alloc,
-	.target_destroy = virtscsi_target_destroy,
 	.map_queues = virtscsi_map_queues,
 	.track_queue_depth = 1,
 	.force_blk_mq = 1,