skd: rip out bio path

The skd driver has a selectable rq or bio based queueing model.
For 3.14, we want to turn this into a single blk-mq interface
instead. With the immutable biovecs being merged in 3.13, the
bio model would need patches to even work. So rip it out, with
a conversion pending for blk-mq in the next release.
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/skd_main.c

@@ -354,13 +354,7 @@ struct skd_device {
 
 	u32 timo_slot;
 
-
 	struct work_struct completion_worker;
-
-	struct bio_list bio_queue;
-	int queue_stopped;
-
-	struct list_head flush_list;
 };
 
 #define SKD_FLUSH_JOB   "skd-flush-jobs"
@@ -470,11 +464,6 @@ MODULE_PARM_DESC(skd_dbg_level, "s1120 debug level (0,1,2)");
 module_param(skd_isr_comp_limit, int, 0444);
 MODULE_PARM_DESC(skd_isr_comp_limit, "s1120 isr comp limit (0=none) default=4");
 
-static int skd_bio;
-module_param(skd_bio, int, 0444);
-MODULE_PARM_DESC(skd_bio,
-		 "Register as a bio device instead of block (0, 1) default=0");
-
 /* Major device number dynamically assigned. */
 static u32 skd_major;
 
@@ -512,11 +501,6 @@ static void skd_log_skmsg(struct skd_device *skdev,
 static void skd_log_skreq(struct skd_device *skdev,
 			  struct skd_request_context *skreq, const char *event);
 
-/* FLUSH FUA flag handling. */
-static int skd_flush_cmd_enqueue(struct skd_device *, void *);
-static void *skd_flush_cmd_dequeue(struct skd_device *);
-
-
 /*
  *****************************************************************************
  * READ/WRITE REQUESTS
@@ -524,40 +508,25 @@ static void *skd_flush_cmd_dequeue(struct skd_device *);
  */
 static void skd_stop_queue(struct skd_device *skdev)
 {
-	if (!skd_bio)
 	blk_stop_queue(skdev->queue);
-	else
-		skdev->queue_stopped = 1;
 }
 
 static void skd_unstop_queue(struct skd_device *skdev)
 {
-	if (!skd_bio)
 	queue_flag_clear(QUEUE_FLAG_STOPPED, skdev->queue);
-	else
-		skdev->queue_stopped = 0;
 }
 
 static void skd_start_queue(struct skd_device *skdev)
 {
-	if (!skd_bio) {
 	blk_start_queue(skdev->queue);
-	} else {
-		pr_err("(%s): Starting queue\n", skd_name(skdev));
-		skdev->queue_stopped = 0;
-		skd_request_fn(skdev->queue);
-	}
 }
 
 static int skd_queue_stopped(struct skd_device *skdev)
 {
-	if (!skd_bio)
 	return blk_queue_stopped(skdev->queue);
-	else
-		return skdev->queue_stopped;
 }
 
-static void skd_fail_all_pending_blk(struct skd_device *skdev)
+static void skd_fail_all_pending(struct skd_device *skdev)
 {
 	struct request_queue *q = skdev->queue;
 	struct request *req;
@@ -571,42 +540,6 @@ static void skd_fail_all_pending_blk(struct skd_device *skdev)
 	}
 }
 
-static void skd_fail_all_pending_bio(struct skd_device *skdev)
-{
-	struct bio *bio;
-	int error = -EIO;
-
-	for (;; ) {
-		bio = bio_list_pop(&skdev->bio_queue);
-
-		if (bio == NULL)
-			break;
-
-		bio_endio(bio, error);
-	}
-}
-
-static void skd_fail_all_pending(struct skd_device *skdev)
-{
-	if (!skd_bio)
-		skd_fail_all_pending_blk(skdev);
-	else
-		skd_fail_all_pending_bio(skdev);
-}
-
-static void skd_make_request(struct request_queue *q, struct bio *bio)
-{
-	struct skd_device *skdev = q->queuedata;
-	unsigned long flags;
-
-	spin_lock_irqsave(&skdev->lock, flags);
-
-	bio_list_add(&skdev->bio_queue, bio);
-	skd_request_fn(skdev->queue);
-
-	spin_unlock_irqrestore(&skdev->lock, flags);
-}
-
 static void
 skd_prep_rw_cdb(struct skd_scsi_request *scsi_req,
 		int data_dir, unsigned lba,
@@ -667,18 +600,9 @@ skd_prep_discard_cdb(struct skd_scsi_request *scsi_req,
 	put_unaligned_be64(lba, &buf[8]);
 	put_unaligned_be32(count, &buf[16]);
 
-	if (!skd_bio) {
 	req = skreq->req;
 	blk_add_request_payload(req, page, len);
 	req->buffer = buf;
-	} else {
-		skreq->bio->bi_io_vec->bv_page = page;
-		skreq->bio->bi_io_vec->bv_offset = 0;
-		skreq->bio->bi_io_vec->bv_len = len;
-
-		skreq->bio->bi_vcnt = 1;
-		skreq->bio->bi_phys_segments = 1;
-	}
 }
 
 static void skd_request_fn_not_online(struct request_queue *q);
@@ -690,7 +614,6 @@ static void skd_request_fn(struct request_queue *q)
 	struct fit_msg_hdr *fmh = NULL;
 	struct skd_request_context *skreq;
 	struct request *req = NULL;
-	struct bio *bio = NULL;
 	struct skd_scsi_request *scsi_req;
 	struct page *page;
 	unsigned long io_flags;
@@ -732,7 +655,6 @@ static void skd_request_fn(struct request_queue *q)
 
 		flush = fua = 0;
 
-		if (!skd_bio) {
 		req = blk_peek_request(q);
 
 		/* Are there any native requests to start? */
@@ -754,38 +676,6 @@ static void skd_request_fn(struct request_queue *q)
 			 "count=%u(0x%x) dir=%d\n",
 			 skdev->name, __func__, __LINE__,
 			 req, lba, lba, count, count, data_dir);
-		} else {
-			if (!list_empty(&skdev->flush_list)) {
-				/* Process data part of FLUSH request. */
-				bio = (struct bio *)skd_flush_cmd_dequeue(skdev);
-				flush++;
-				pr_debug("%s:%s:%d processing FLUSH request with data.\n",
-					 skdev->name, __func__, __LINE__);
-			} else {
-				/* peek at our bio queue */
-				bio = bio_list_peek(&skdev->bio_queue);
-			}
-
-			/* Are there any native requests to start? */
-			if (bio == NULL)
-				break;
-
-			lba = (u32)bio->bi_sector;
-			count = bio_sectors(bio);
-			data_dir = bio_data_dir(bio);
-			io_flags = bio->bi_rw;
-
-			pr_debug("%s:%s:%d new bio=%p lba=%u(0x%x) "
-				 "count=%u(0x%x) dir=%d\n",
-				 skdev->name, __func__, __LINE__,
-				 bio, lba, lba, count, count, data_dir);
-
-			if (io_flags & REQ_FLUSH)
-				flush++;
-
-			if (io_flags & REQ_FUA)
-				fua++;
-		}
 
 		/* At this point we know there is a request
 		 * (from our bio q or req q depending on the way
@@ -831,23 +721,9 @@ static void skd_request_fn(struct request_queue *q)
 		 * the native request. Note that skd_request_context is
 		 * available but is still at the head of the free list.
 		 */
-		if (!skd_bio) {
 		blk_start_request(req);
 		skreq->req = req;
 		skreq->fitmsg_id = 0;
-		} else {
-			if (unlikely(flush == SKD_FLUSH_DATA_SECOND)) {
-				skreq->bio = bio;
-			} else {
-				skreq->bio = bio_list_pop(&skdev->bio_queue);
-				SKD_ASSERT(skreq->bio == bio);
-				skreq->start_time = jiffies;
-				part_inc_in_flight(&skdev->disk->part0,
-						   bio_data_dir(bio));
-			}
-
-			skreq->fitmsg_id = 0;
-		}
 
 		/* Either a FIT msg is in progress or we have to start one. */
 		if (skmsg == NULL) {
@@ -923,8 +799,7 @@ static void skd_request_fn(struct request_queue *q)
 		if (fua)
 			scsi_req->cdb[1] |= SKD_FUA_NV;
 
-		if ((!skd_bio && !req->bio) ||
-			(skd_bio && flush == SKD_FLUSH_ZERO_SIZE_FIRST))
+		if (!req->bio)
 			goto skip_sg;
 
 		error = skd_preop_sg_list(skdev, skreq);
@@ -1011,8 +886,7 @@ static void skd_request_fn(struct request_queue *q)
 	 * If req is non-NULL it means there is something to do but
 	 * we are out of a resource.
 	 */
-	if (((!skd_bio) && req) ||
-	    ((skd_bio) && bio_list_peek(&skdev->bio_queue)))
+	if (req)
 		skd_stop_queue(skdev);
 }
 
@@ -1045,7 +919,7 @@ static void skd_end_request_blk(struct skd_device *skdev,
 	__blk_end_request_all(skreq->req, error);
 }
 
-static int skd_preop_sg_list_blk(struct skd_device *skdev,
+static int skd_preop_sg_list(struct skd_device *skdev,
 				 struct skd_request_context *skreq)
 {
 	struct request *req = skreq->req;
@@ -1108,7 +982,7 @@ static int skd_preop_sg_list_blk(struct skd_device *skdev,
 	return 0;
 }
 
-static void skd_postop_sg_list_blk(struct skd_device *skdev,
+static void skd_postop_sg_list(struct skd_device *skdev,
 				   struct skd_request_context *skreq)
 {
 	int writing = skreq->sg_data_dir == SKD_DATA_DIR_HOST_TO_CARD;
@@ -1124,184 +998,10 @@ static void skd_postop_sg_list_blk(struct skd_device *skdev,
 	pci_unmap_sg(skdev->pdev, &skreq->sg[0], skreq->n_sg, pci_dir);
 }
 
-static void skd_end_request_bio(struct skd_device *skdev,
-				struct skd_request_context *skreq, int error)
-{
-	struct bio *bio = skreq->bio;
-	int rw = bio_data_dir(bio);
-	unsigned long io_flags = bio->bi_rw;
-
-	if ((io_flags & REQ_DISCARD) &&
-		(skreq->discard_page == 1)) {
-		pr_debug("%s:%s:%d biomode: skd_end_request: freeing DISCARD page.\n",
-			 skdev->name, __func__, __LINE__);
-		free_page((unsigned long)page_address(bio->bi_io_vec->bv_page));
-	}
-
-	if (unlikely(error)) {
-		u32 lba = (u32)skreq->bio->bi_sector;
-		u32 count = bio_sectors(skreq->bio);
-		char *cmd = (rw == WRITE) ? "write" : "read";
-		pr_err("(%s): Error cmd=%s sect=%u count=%u id=0x%x\n",
-		       skd_name(skdev), cmd, lba, count, skreq->id);
-	}
-	{
-		int cpu = part_stat_lock();
-
-		if (likely(!error)) {
-			part_stat_inc(cpu, &skdev->disk->part0, ios[rw]);
-			part_stat_add(cpu, &skdev->disk->part0, sectors[rw],
-				      bio_sectors(bio));
-		}
-		part_stat_add(cpu, &skdev->disk->part0, ticks[rw],
-			      jiffies - skreq->start_time);
-		part_dec_in_flight(&skdev->disk->part0, rw);
-		part_stat_unlock();
-	}
-
-	pr_debug("%s:%s:%d id=0x%x error=%d\n",
-		 skdev->name, __func__, __LINE__, skreq->id, error);
-
-	bio_endio(skreq->bio, error);
-}
-
-static int skd_preop_sg_list_bio(struct skd_device *skdev,
-				 struct skd_request_context *skreq)
-{
-	struct bio *bio = skreq->bio;
-	int writing = skreq->sg_data_dir == SKD_DATA_DIR_HOST_TO_CARD;
-	int pci_dir = writing ? PCI_DMA_TODEVICE : PCI_DMA_FROMDEVICE;
-	int n_sg;
-	int i;
-	struct bio_vec *vec;
-	struct fit_sg_descriptor *sgd;
-	u64 dma_addr;
-	u32 count;
-	int errs = 0;
-	unsigned int io_flags = 0;
-	io_flags |= bio->bi_rw;
-
-	skreq->sg_byte_count = 0;
-	n_sg = skreq->n_sg = skreq->bio->bi_vcnt;
-
-	if (n_sg <= 0)
-		return -EINVAL;
-
-	if (n_sg > skdev->sgs_per_request) {
-		pr_err("(%s): sg overflow n=%d\n",
-		       skd_name(skdev), n_sg);
-		skreq->n_sg = 0;
-		return -EIO;
-	}
-
-	for (i = 0; i < skreq->n_sg; i++) {
-		vec = bio_iovec_idx(bio, i);
-		dma_addr = pci_map_page(skdev->pdev,
-					vec->bv_page,
-					vec->bv_offset, vec->bv_len, pci_dir);
-		count = vec->bv_len;
-
-		if (count == 0 || count > 64u * 1024u || (count & 3) != 0
-		    || (dma_addr & 3) != 0) {
-			pr_err(
-			       "(%s): Bad sg ix=%d count=%d addr=0x%llx\n",
-			       skd_name(skdev), i, count, dma_addr);
-			errs++;
-		}
-
-		sgd = &skreq->sksg_list[i];
-
-		sgd->control = FIT_SGD_CONTROL_NOT_LAST;
-		sgd->byte_count = vec->bv_len;
-		skreq->sg_byte_count += vec->bv_len;
-		sgd->host_side_addr = dma_addr;
-		sgd->dev_side_addr = 0; /* not used */
-	}
-
-	skreq->sksg_list[n_sg - 1].next_desc_ptr = 0LL;
-	skreq->sksg_list[n_sg - 1].control = FIT_SGD_CONTROL_LAST;
-
-
-	 if (!(io_flags & REQ_DISCARD)) {
-		count = bio_sectors(bio) << 9u;
-		if (count != skreq->sg_byte_count) {
-			pr_err("(%s): mismatch count sg=%d req=%d\n",
-			       skd_name(skdev), skreq->sg_byte_count, count);
-			errs++;
-		}
-	}
-
-	if (unlikely(skdev->dbg_level > 1)) {
-		pr_debug("%s:%s:%d skreq=%x sksg_list=%p sksg_dma=%llx\n",
-			 skdev->name, __func__, __LINE__,
-			 skreq->id, skreq->sksg_list, skreq->sksg_dma_address);
-		for (i = 0; i < n_sg; i++) {
-			struct fit_sg_descriptor *sgd = &skreq->sksg_list[i];
-			pr_debug("%s:%s:%d   sg[%d] count=%u ctrl=0x%x "
-				 "addr=0x%llx next=0x%llx\n",
-				 skdev->name, __func__, __LINE__,
-				 i, sgd->byte_count, sgd->control,
-				 sgd->host_side_addr, sgd->next_desc_ptr);
-		}
-	}
-
-	if (errs != 0) {
-		skd_postop_sg_list(skdev, skreq);
-		skreq->n_sg = 0;
-		return -EIO;
-	}
-
-	return 0;
-}
-
-static int skd_preop_sg_list(struct skd_device *skdev,
-			     struct skd_request_context *skreq)
-{
-	if (!skd_bio)
-		return skd_preop_sg_list_blk(skdev, skreq);
-	else
-		return skd_preop_sg_list_bio(skdev, skreq);
-}
-
-static void skd_postop_sg_list_bio(struct skd_device *skdev,
-				   struct skd_request_context *skreq)
-{
-	int writing = skreq->sg_data_dir == SKD_DATA_DIR_HOST_TO_CARD;
-	int pci_dir = writing ? PCI_DMA_TODEVICE : PCI_DMA_FROMDEVICE;
-	int i;
-	struct fit_sg_descriptor *sgd;
-
-	/*
-	 * restore the next ptr for next IO request so we
-	 * don't have to set it every time.
-	 */
-	skreq->sksg_list[skreq->n_sg - 1].next_desc_ptr =
-		skreq->sksg_dma_address +
-		((skreq->n_sg) * sizeof(struct fit_sg_descriptor));
-
-	for (i = 0; i < skreq->n_sg; i++) {
-		sgd = &skreq->sksg_list[i];
-		pci_unmap_page(skdev->pdev, sgd->host_side_addr,
-			       sgd->byte_count, pci_dir);
-	}
-}
-
-static void skd_postop_sg_list(struct skd_device *skdev,
-			       struct skd_request_context *skreq)
-{
-	if (!skd_bio)
-		skd_postop_sg_list_blk(skdev, skreq);
-	else
-		skd_postop_sg_list_bio(skdev, skreq);
-}
-
 static void skd_end_request(struct skd_device *skdev,
 			    struct skd_request_context *skreq, int error)
 {
-	if (likely(!skd_bio))
 	skd_end_request_blk(skdev, skreq, error);
-	else
-		skd_end_request_bio(skdev, skreq, error);
 }
 
 static void skd_request_fn_not_online(struct request_queue *q)
@@ -2754,14 +2454,11 @@ static void skd_resolve_req_exception(struct skd_device *skdev,
 		break;
 
 	case SKD_CHECK_STATUS_REQUEUE_REQUEST:
-		if (!skd_bio) {
-			if ((unsigned long) ++skreq->req->special <
-			    SKD_MAX_RETRIES) {
+		if ((unsigned long) ++skreq->req->special < SKD_MAX_RETRIES) {
 			skd_log_skreq(skdev, skreq, "retry");
 			skd_requeue_request(skdev, skreq);
 			break;
 		}
-		}
 	/* fall through to report error */
 
 	case SKD_CHECK_STATUS_REPORT_ERROR:
@@ -2774,12 +2471,7 @@ static void skd_resolve_req_exception(struct skd_device *skdev,
 static void skd_requeue_request(struct skd_device *skdev,
 				struct skd_request_context *skreq)
 {
-	if (!skd_bio) {
 	blk_requeue_request(skdev->queue, skreq->req);
-	} else {
-		bio_list_add_head(&skdev->bio_queue, skreq->bio);
-		skreq->bio = NULL;
-	}
 }
 
 
@@ -2840,11 +2532,7 @@ static void skd_release_skreq(struct skd_device *skdev,
 	/*
 	 * Reset backpointer
 	 */
-	if (likely(!skd_bio))
 	skreq->req = NULL;
-	else
-		skreq->bio = NULL;
-
 
 	/*
 	 * Reclaim the skd_request_context
@@ -3084,8 +2772,6 @@ static int skd_isr_completion_posted(struct skd_device *skdev,
 	u32 cmp_bytes = 0;
 	int rc = 0;
 	int processed = 0;
-	int ret;
-
 
 	for (;; ) {
 		SKD_ASSERT(skdev->skcomp_ix < SKD_N_COMPLETION_ENTRY);
@@ -3180,8 +2866,7 @@ static int skd_isr_completion_posted(struct skd_device *skdev,
 		if (skreq->n_sg > 0)
 			skd_postop_sg_list(skdev, skreq);
 
-		if (((!skd_bio) && !skreq->req) ||
-		    ((skd_bio) && !skreq->bio)) {
+		if (!skreq->req) {
 			pr_debug("%s:%s:%d NULL backptr skdreq %p, "
 				 "req=0x%x req_id=0x%x\n",
 				 skdev->name, __func__, __LINE__,
@@ -3191,31 +2876,11 @@ static int skd_isr_completion_posted(struct skd_device *skdev,
 			 * Capture the outcome and post it back to the
 			 * native request.
 			 */
-			if (likely(cmp_status == SAM_STAT_GOOD)) {
-				if (unlikely(skreq->flush_cmd)) {
-					if (skd_bio) {
-						/* if empty size bio, we are all done */
-						if (bio_sectors(skreq->bio) == 0) {
+			if (likely(cmp_status == SAM_STAT_GOOD))
 				skd_end_request(skdev, skreq, 0);
-						} else {
-							ret = skd_flush_cmd_enqueue(skdev, (void *)skreq->bio);
-							if (ret != 0) {
-								pr_err("Failed to enqueue flush bio with Data. Err=%d.\n", ret);
-								skd_end_request(skdev, skreq, ret);
-							} else {
-								((*enqueued)++);
-							}
-						}
-					} else {
-						skd_end_request(skdev, skreq, 0);
-					}
-				} else {
-					skd_end_request(skdev, skreq, 0);
-				}
-			} else {
+			else
 				skd_resolve_req_exception(skdev, skreq);
 		}
-		}
 
 		/*
 		 * Release the skreq, its FIT msg (if one), timeout slot,
@@ -3645,29 +3310,20 @@ static void skd_recover_requests(struct skd_device *skdev, int requeue)
 			skd_log_skreq(skdev, skreq, "recover");
 
 			SKD_ASSERT((skreq->id & SKD_ID_INCR) != 0);
-			if (!skd_bio)
 			SKD_ASSERT(skreq->req != NULL);
-			else
-				SKD_ASSERT(skreq->bio != NULL);
 
 			/* Release DMA resources for the request. */
 			if (skreq->n_sg > 0)
 				skd_postop_sg_list(skdev, skreq);
 
-			if (!skd_bio) {
 			if (requeue &&
 			    (unsigned long) ++skreq->req->special <
 			    SKD_MAX_RETRIES)
 				skd_requeue_request(skdev, skreq);
 			else
 				skd_end_request(skdev, skreq, -EIO);
-			} else
-				skd_end_request(skdev, skreq, -EIO);
 
-			if (!skd_bio)
 			skreq->req = NULL;
-			else
-				skreq->bio = NULL;
 
 			skreq->state = SKD_REQ_STATE_IDLE;
 			skreq->id += SKD_ID_INCR;
@@ -4580,16 +4236,11 @@ static struct skd_device *skd_construct(struct pci_dev *pdev)
 	skdev->sgs_per_request = skd_sgs_per_request;
 	skdev->dbg_level = skd_dbg_level;
 
-	if (skd_bio)
-		bio_list_init(&skdev->bio_queue);
-
-
 	atomic_set(&skdev->device_count, 0);
 
 	spin_lock_init(&skdev->lock);
 
 	INIT_WORK(&skdev->completion_worker, skd_completion_worker);
-	INIT_LIST_HEAD(&skdev->flush_list);
 
 	pr_debug("%s:%s:%d skcomp\n", skdev->name, __func__, __LINE__);
 	rc = skd_cons_skcomp(skdev);
@@ -4941,13 +4592,7 @@ static int skd_cons_disk(struct skd_device *skdev)
 	disk->fops = &skd_blockdev_ops;
 	disk->private_data = skdev;
 
-	if (!skd_bio) {
 	q = blk_init_queue(skd_request_fn, &skdev->lock);
-	} else {
-		q = blk_alloc_queue(GFP_KERNEL);
-		q->queue_flags = QUEUE_FLAG_IO_STAT | QUEUE_FLAG_STACKABLE;
-	}
-
 	if (!q) {
 		rc = -ENOMEM;
 		goto err_out;
@@ -4957,11 +4602,6 @@ static int skd_cons_disk(struct skd_device *skdev)
 	disk->queue = q;
 	q->queuedata = skdev;
 
-	if (skd_bio) {
-		q->queue_lock = &skdev->lock;
-		blk_queue_make_request(q, skd_make_request);
-	}
-
 	blk_queue_flush(q, REQ_FLUSH | REQ_FUA);
 	blk_queue_max_segments(q, skdev->sgs_per_request);
 	blk_queue_max_hw_sectors(q, SKD_N_MAX_SECTORS);
@@ -5794,7 +5434,6 @@ static void skd_log_skreq(struct skd_device *skdev,
 		 skdev->name, __func__, __LINE__,
 		 skreq->timeout_stamp, skreq->sg_data_dir, skreq->n_sg);
 
-	if (!skd_bio) {
 	if (skreq->req != NULL) {
 		struct request *req = skreq->req;
 		u32 lba = (u32)blk_rq_pos(req);
@@ -5808,21 +5447,6 @@ static void skd_log_skreq(struct skd_device *skdev,
 	} else
 		pr_debug("%s:%s:%d req=NULL\n",
 			 skdev->name, __func__, __LINE__);
-	} else {
-		if (skreq->bio != NULL) {
-			struct bio *bio = skreq->bio;
-			u32 lba = (u32)bio->bi_sector;
-			u32 count = bio_sectors(bio);
-
-			pr_debug("%s:%s:%d "
-				 "bio=%p lba=%u(0x%x) count=%u(0x%x) dir=%d\n",
-				 skdev->name, __func__, __LINE__,
-				 bio, lba, lba, count, count,
-				 (int)bio_data_dir(bio));
-		} else
-			pr_debug("%s:%s:%d req=NULL\n",
-				 skdev->name, __func__, __LINE__);
-	}
 }
 
 /*
@@ -5918,34 +5542,5 @@ static void __exit skd_exit(void)
 	kmem_cache_destroy(skd_flush_slab);
 }
 
-static int
-skd_flush_cmd_enqueue(struct skd_device *skdev, void *cmd)
-{
-	struct skd_flush_cmd *item;
-
-	item = kmem_cache_zalloc(skd_flush_slab, GFP_ATOMIC);
-	if (!item) {
-		pr_err("skd_flush_cmd_enqueue: Failed to allocated item.\n");
-		return -ENOMEM;
-	}
-
-	item->cmd = cmd;
-	list_add_tail(&item->flist, &skdev->flush_list);
-	return 0;
-}
-
-static void *
-skd_flush_cmd_dequeue(struct skd_device *skdev)
-{
-	void *cmd;
-	struct skd_flush_cmd *item;
-
-	item = list_entry(skdev->flush_list.next, struct skd_flush_cmd, flist);
-	list_del_init(&item->flist);
-	cmd = item->cmd;
-	kmem_cache_free(skd_flush_slab, item);
-	return cmd;
-}
-
 module_init(skd_init);
 module_exit(skd_exit);