lightnvm: pblk: simplify data validity check on GC

When a line is selected for recycling by the garbage collector (GC), the
line state changes and the invalid bitmap is frozen, preventing
invalidations from happening. Throughout the GC, the L2P map is checked
to verify that not data being recycled has been updated. The last check
is done before the new map is being stored on the L2P table. Though
this algorithm works, it requires a number of corner cases to be checked
each time the L2P table is being updated. This complicates readability
and is error prone in case that the recycling algorithm is modified.

Instead, this patch makes the invalid bitmap accessible even when the
line is being recycled. When recycled data is being remapped, it is
enough to check the invalid bitmap for the line before updating the L2P
table.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/lightnvm/pblk-cache.c

@@ -73,12 +73,11 @@ out:
  * On GC the incoming lbas are not necessarily sequential. Also, some of the
  * lbas might not be valid entries, which are marked as empty by the GC thread
  */
-int pblk_write_gc_to_cache(struct pblk *pblk, void *data, u64 *lba_list,
-			   unsigned int nr_entries, unsigned int nr_rec_entries,
-			   struct pblk_line *gc_line, unsigned long flags)
+int pblk_write_gc_to_cache(struct pblk *pblk, struct pblk_gc_rq *gc_rq)
 {
 	struct pblk_w_ctx w_ctx;
 	unsigned int bpos, pos;
+	void *data = gc_rq->data;
 	int i, valid_entries;
 
 	/* Update the write buffer head (mem) with the entries that we can
@@ -86,28 +85,29 @@ int pblk_write_gc_to_cache(struct pblk *pblk, void *data, u64 *lba_list,
 	 * rollback from here on.
 	 */
 retry:
-	if (!pblk_rb_may_write_gc(&pblk->rwb, nr_rec_entries, &bpos)) {
+	if (!pblk_rb_may_write_gc(&pblk->rwb, gc_rq->secs_to_gc, &bpos)) {
 		io_schedule();
 		goto retry;
 	}
 
-	w_ctx.flags = flags;
+	w_ctx.flags = PBLK_IOTYPE_GC;
 	pblk_ppa_set_empty(&w_ctx.ppa);
 
-	for (i = 0, valid_entries = 0; i < nr_entries; i++) {
-		if (lba_list[i] == ADDR_EMPTY)
+	for (i = 0, valid_entries = 0; i < gc_rq->nr_secs; i++) {
+		if (gc_rq->lba_list[i] == ADDR_EMPTY)
 			continue;
 
-		w_ctx.lba = lba_list[i];
+		w_ctx.lba = gc_rq->lba_list[i];
 
 		pos = pblk_rb_wrap_pos(&pblk->rwb, bpos + valid_entries);
-		pblk_rb_write_entry_gc(&pblk->rwb, data, w_ctx, gc_line, pos);
+		pblk_rb_write_entry_gc(&pblk->rwb, data, w_ctx, gc_rq->line,
+						gc_rq->paddr_list[i], pos);
 
 		data += PBLK_EXPOSED_PAGE_SIZE;
 		valid_entries++;
 	}
 
-	WARN_ONCE(nr_rec_entries != valid_entries,
+	WARN_ONCE(gc_rq->secs_to_gc != valid_entries,
 					"pblk: inconsistent GC write\n");
 
 #ifdef CONFIG_NVM_DEBUG

drivers/lightnvm/pblk-core.c

@@ -78,11 +78,7 @@ void __pblk_map_invalidate(struct pblk *pblk, struct pblk_line *line,
 	 * that newer updates are not overwritten.
 	 */
 	spin_lock(&line->lock);
-	if (line->state == PBLK_LINESTATE_GC ||
-					line->state == PBLK_LINESTATE_FREE) {
-		spin_unlock(&line->lock);
-		return;
-	}
+	WARN_ON(line->state == PBLK_LINESTATE_FREE);
 
 	if (test_and_set_bit(paddr, line->invalid_bitmap)) {
 		WARN_ONCE(1, "pblk: double invalidate\n");
@@ -99,8 +95,7 @@ void __pblk_map_invalidate(struct pblk *pblk, struct pblk_line *line,
 		spin_lock(&l_mg->gc_lock);
 		spin_lock(&line->lock);
 		/* Prevent moving a line that has just been chosen for GC */
-		if (line->state == PBLK_LINESTATE_GC ||
-					line->state == PBLK_LINESTATE_FREE) {
+		if (line->state == PBLK_LINESTATE_GC) {
 			spin_unlock(&line->lock);
 			spin_unlock(&l_mg->gc_lock);
 			return;
@@ -1766,6 +1761,7 @@ void pblk_update_map(struct pblk *pblk, sector_t lba, struct ppa_addr ppa)
 
 void pblk_update_map_cache(struct pblk *pblk, sector_t lba, struct ppa_addr ppa)
 {
+
 #ifdef CONFIG_NVM_DEBUG
 	/* Callers must ensure that the ppa points to a cache address */
 	BUG_ON(!pblk_addr_in_cache(ppa));
@@ -1776,9 +1772,9 @@ void pblk_update_map_cache(struct pblk *pblk, sector_t lba, struct ppa_addr ppa)
 }
 
 int pblk_update_map_gc(struct pblk *pblk, sector_t lba, struct ppa_addr ppa_new,
-		       struct pblk_line *gc_line)
+		       struct pblk_line *gc_line, u64 paddr_gc)
 {
-	struct ppa_addr ppa_l2p;
+	struct ppa_addr ppa_l2p, ppa_gc;
 	int ret = 1;
 
 #ifdef CONFIG_NVM_DEBUG
@@ -1795,10 +1791,13 @@ int pblk_update_map_gc(struct pblk *pblk, sector_t lba, struct ppa_addr ppa_new,
 
 	spin_lock(&pblk->trans_lock);
 	ppa_l2p = pblk_trans_map_get(pblk, lba);
+	ppa_gc = addr_to_gen_ppa(pblk, paddr_gc, gc_line->id);
 
-	/* Prevent updated entries to be overwritten by GC */
-	if (pblk_addr_in_cache(ppa_l2p) || pblk_ppa_empty(ppa_l2p) ||
-				pblk_tgt_ppa_to_line(ppa_l2p) != gc_line->id) {
+	if (!pblk_ppa_comp(ppa_l2p, ppa_gc)) {
+		spin_lock(&gc_line->lock);
+		WARN(!test_bit(paddr_gc, gc_line->invalid_bitmap),
+						"pblk: corrupted GC update");
+		spin_unlock(&gc_line->lock);
 
 		ret = 0;
 		goto out;
@@ -1870,15 +1869,13 @@ void pblk_lookup_l2p_seq(struct pblk *pblk, struct ppa_addr *ppas,
 void pblk_lookup_l2p_rand(struct pblk *pblk, struct ppa_addr *ppas,
 			  u64 *lba_list, int nr_secs)
 {
-	sector_t lba;
+	u64 lba;
 	int i;
 
 	spin_lock(&pblk->trans_lock);
 	for (i = 0; i < nr_secs; i++) {
 		lba = lba_list[i];
-		if (lba == ADDR_EMPTY) {
-			ppas[i].ppa = ADDR_EMPTY;
-		} else {
+		if (lba != ADDR_EMPTY) {
 			/* logic error: lba out-of-bounds. Ignore update */
 			if (!(lba < pblk->rl.nr_secs)) {
 				WARN(1, "pblk: corrupted L2P map request\n");

drivers/lightnvm/pblk-gc.c

@@ -20,7 +20,8 @@
 
 static void pblk_gc_free_gc_rq(struct pblk_gc_rq *gc_rq)
 {
-	vfree(gc_rq->data);
+	if (gc_rq->data)
+		vfree(gc_rq->data);
 	kfree(gc_rq);
 }
 
@@ -41,10 +42,7 @@ static int pblk_gc_write(struct pblk *pblk)
 	spin_unlock(&gc->w_lock);
 
 	list_for_each_entry_safe(gc_rq, tgc_rq, &w_list, list) {
-		pblk_write_gc_to_cache(pblk, gc_rq->data, gc_rq->lba_list,
-				gc_rq->nr_secs, gc_rq->secs_to_gc,
-				gc_rq->line, PBLK_IOTYPE_GC);
-
+		pblk_write_gc_to_cache(pblk, gc_rq);
 		list_del(&gc_rq->list);
 		kref_put(&gc_rq->line->ref, pblk_line_put);
 		pblk_gc_free_gc_rq(gc_rq);
@@ -69,27 +67,23 @@ static int pblk_gc_move_valid_secs(struct pblk *pblk, struct pblk_gc_rq *gc_rq)
 	struct pblk_gc *gc = &pblk->gc;
 	struct pblk_line *line = gc_rq->line;
 	void *data;
-	unsigned int secs_to_gc;
 	int ret = 0;
 
 	data = vmalloc(gc_rq->nr_secs * geo->sec_size);
 	if (!data) {
 		ret = -ENOMEM;
-		goto out;
+		goto fail;
 	}
 
-	/* Read from GC victim block */
-	if (pblk_submit_read_gc(pblk, gc_rq->lba_list, data, gc_rq->nr_secs,
-							&secs_to_gc, line)) {
-		ret = -EFAULT;
-		goto free_data;
-	}
+	gc_rq->data = data;
 
-	if (!secs_to_gc)
-		goto free_rq;
+	/* Read from GC victim block */
+	ret = pblk_submit_read_gc(pblk, gc_rq);
+	if (ret)
+		goto fail;
 
-	gc_rq->data = data;
-	gc_rq->secs_to_gc = secs_to_gc;
+	if (!gc_rq->secs_to_gc)
+		goto fail;
 
 retry:
 	spin_lock(&gc->w_lock);
@@ -107,11 +101,8 @@ retry:
 
 	return 0;
 
-free_rq:
-	kfree(gc_rq);
-free_data:
-	vfree(data);
-out:
+fail:
+	pblk_gc_free_gc_rq(gc_rq);
 	kref_put(&line->ref, pblk_line_put);
 	return ret;
 }
@@ -167,14 +158,21 @@ static void pblk_gc_line_prepare_ws(struct work_struct *work)
 	struct pblk_line_ws *gc_rq_ws;
 	struct pblk_gc_rq *gc_rq;
 	__le64 *lba_list;
+	unsigned long *invalid_bitmap;
 	int sec_left, nr_secs, bit;
 	int ret;
 
+	invalid_bitmap = kmalloc(lm->sec_bitmap_len, GFP_KERNEL);
+	if (!invalid_bitmap) {
+		pr_err("pblk: could not allocate GC invalid bitmap\n");
+		goto fail_free_ws;
+	}
+
 	emeta_buf = pblk_malloc(lm->emeta_len[0], l_mg->emeta_alloc_type,
 								GFP_KERNEL);
 	if (!emeta_buf) {
 		pr_err("pblk: cannot use GC emeta\n");
-		return;
+		goto fail_free_bitmap;
 	}
 
 	ret = pblk_line_read_emeta(pblk, line, emeta_buf);
@@ -193,7 +191,11 @@ static void pblk_gc_line_prepare_ws(struct work_struct *work)
 		goto fail_free_emeta;
 	}
 
+	spin_lock(&line->lock);
+	bitmap_copy(invalid_bitmap, line->invalid_bitmap, lm->sec_per_line);
 	sec_left = pblk_line_vsc(line);
+	spin_unlock(&line->lock);
+
 	if (sec_left < 0) {
 		pr_err("pblk: corrupted GC line (%d)\n", line->id);
 		goto fail_free_emeta;
@@ -207,11 +209,12 @@ next_rq:
 
 	nr_secs = 0;
 	do {
-		bit = find_next_zero_bit(line->invalid_bitmap, lm->sec_per_line,
+		bit = find_next_zero_bit(invalid_bitmap, lm->sec_per_line,
 								bit + 1);
 		if (bit > line->emeta_ssec)
 			break;
 
+		gc_rq->paddr_list[nr_secs] = bit;
 		gc_rq->lba_list[nr_secs++] = le64_to_cpu(lba_list[bit]);
 	} while (nr_secs < pblk->max_write_pgs);
 
@@ -244,6 +247,7 @@ next_rq:
 out:
 	pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
 	kfree(line_ws);
+	kfree(invalid_bitmap);
 
 	kref_put(&line->ref, pblk_line_put);
 	atomic_dec(&gc->inflight_gc);
@@ -254,9 +258,13 @@ fail_free_gc_rq:
 	kfree(gc_rq);
 fail_free_emeta:
 	pblk_mfree(emeta_buf, l_mg->emeta_alloc_type);
+fail_free_bitmap:
+	kfree(invalid_bitmap);
+fail_free_ws:
+	kfree(line_ws);
+
 	pblk_put_line_back(pblk, line);
 	kref_put(&line->ref, pblk_line_put);
-	kfree(line_ws);
 	atomic_dec(&gc->inflight_gc);
 
 	pr_err("pblk: Failed to GC line %d\n", line->id);

drivers/lightnvm/pblk-rb.c

@@ -325,8 +325,8 @@ void pblk_rb_write_entry_user(struct pblk_rb *rb, void *data,
 }
 
 void pblk_rb_write_entry_gc(struct pblk_rb *rb, void *data,
-			    struct pblk_w_ctx w_ctx, struct pblk_line *gc_line,
-			    unsigned int ring_pos)
+			    struct pblk_w_ctx w_ctx, struct pblk_line *line,
+			    u64 paddr, unsigned int ring_pos)
 {
 	struct pblk *pblk = container_of(rb, struct pblk, rwb);
 	struct pblk_rb_entry *entry;
@@ -341,7 +341,7 @@ void pblk_rb_write_entry_gc(struct pblk_rb *rb, void *data,
 
 	__pblk_rb_write_entry(rb, data, w_ctx, entry);
 
-	if (!pblk_update_map_gc(pblk, w_ctx.lba, entry->cacheline, gc_line))
+	if (!pblk_update_map_gc(pblk, w_ctx.lba, entry->cacheline, line, paddr))
 		entry->w_ctx.lba = ADDR_EMPTY;
 
 	flags = w_ctx.flags | PBLK_WRITTEN_DATA;

drivers/lightnvm/pblk-read.c

@@ -388,34 +388,40 @@ fail_rqd_free:
 
 static int read_ppalist_rq_gc(struct pblk *pblk, struct nvm_rq *rqd,
 			      struct pblk_line *line, u64 *lba_list,
-			      unsigned int nr_secs)
+			      u64 *paddr_list_gc, unsigned int nr_secs)
 {
-	struct ppa_addr ppas[PBLK_MAX_REQ_ADDRS];
+	struct ppa_addr ppa_list_l2p[PBLK_MAX_REQ_ADDRS];
+	struct ppa_addr ppa_gc;
 	int valid_secs = 0;
 	int i;
 
-	pblk_lookup_l2p_rand(pblk, ppas, lba_list, nr_secs);
+	pblk_lookup_l2p_rand(pblk, ppa_list_l2p, lba_list, nr_secs);
 
 	for (i = 0; i < nr_secs; i++) {
-		if (pblk_addr_in_cache(ppas[i]) || ppas[i].g.blk != line->id ||
-						pblk_ppa_empty(ppas[i])) {
-			lba_list[i] = ADDR_EMPTY;
+		if (lba_list[i] == ADDR_EMPTY)
+			continue;
+
+		ppa_gc = addr_to_gen_ppa(pblk, paddr_list_gc[i], line->id);
+		if (!pblk_ppa_comp(ppa_list_l2p[i], ppa_gc)) {
+			paddr_list_gc[i] = lba_list[i] = ADDR_EMPTY;
 			continue;
 		}
 
-		rqd->ppa_list[valid_secs++] = ppas[i];
+		rqd->ppa_list[valid_secs++] = ppa_list_l2p[i];
 	}
 
 #ifdef CONFIG_NVM_DEBUG
 	atomic_long_add(valid_secs, &pblk->inflight_reads);
 #endif
+
 	return valid_secs;
 }
 
 static int read_rq_gc(struct pblk *pblk, struct nvm_rq *rqd,
-		      struct pblk_line *line, sector_t lba)
+		      struct pblk_line *line, sector_t lba,
+		      u64 paddr_gc)
 {
-	struct ppa_addr ppa;
+	struct ppa_addr ppa_l2p, ppa_gc;
 	int valid_secs = 0;
 
 	if (lba == ADDR_EMPTY)
@@ -428,15 +434,14 @@ static int read_rq_gc(struct pblk *pblk, struct nvm_rq *rqd,
 	}
 
 	spin_lock(&pblk->trans_lock);
-	ppa = pblk_trans_map_get(pblk, lba);
+	ppa_l2p = pblk_trans_map_get(pblk, lba);
 	spin_unlock(&pblk->trans_lock);
 
-	/* Ignore updated values until the moment */
-	if (pblk_addr_in_cache(ppa) || ppa.g.blk != line->id ||
-							pblk_ppa_empty(ppa))
+	ppa_gc = addr_to_gen_ppa(pblk, paddr_gc, line->id);
+	if (!pblk_ppa_comp(ppa_l2p, ppa_gc))
 		goto out;
 
-	rqd->ppa_addr = ppa;
+	rqd->ppa_addr = ppa_l2p;
 	valid_secs = 1;
 
 #ifdef CONFIG_NVM_DEBUG
@@ -447,15 +452,14 @@ out:
 	return valid_secs;
 }
 
-int pblk_submit_read_gc(struct pblk *pblk, u64 *lba_list, void *data,
-			unsigned int nr_secs, unsigned int *secs_to_gc,
-			struct pblk_line *line)
+int pblk_submit_read_gc(struct pblk *pblk, struct pblk_gc_rq *gc_rq)
 {
 	struct nvm_tgt_dev *dev = pblk->dev;
 	struct nvm_geo *geo = &dev->geo;
 	struct bio *bio;
 	struct nvm_rq rqd;
-	int ret, data_len;
+	int data_len;
+	int ret = NVM_IO_OK;
 	DECLARE_COMPLETION_ONSTACK(wait);
 
 	memset(&rqd, 0, sizeof(struct nvm_rq));
@@ -463,25 +467,29 @@ int pblk_submit_read_gc(struct pblk *pblk, u64 *lba_list, void *data,
 	rqd.meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
 							&rqd.dma_meta_list);
 	if (!rqd.meta_list)
-		return NVM_IO_ERR;
+		return -ENOMEM;
 
-	if (nr_secs > 1) {
+	if (gc_rq->nr_secs > 1) {
 		rqd.ppa_list = rqd.meta_list + pblk_dma_meta_size;
 		rqd.dma_ppa_list = rqd.dma_meta_list + pblk_dma_meta_size;
 
-		*secs_to_gc = read_ppalist_rq_gc(pblk, &rqd, line, lba_list,
-								nr_secs);
-		if (*secs_to_gc == 1)
+		gc_rq->secs_to_gc = read_ppalist_rq_gc(pblk, &rqd, gc_rq->line,
+							gc_rq->lba_list,
+							gc_rq->paddr_list,
+							gc_rq->nr_secs);
+		if (gc_rq->secs_to_gc == 1)
 			rqd.ppa_addr = rqd.ppa_list[0];
 	} else {
-		*secs_to_gc = read_rq_gc(pblk, &rqd, line, lba_list[0]);
+		gc_rq->secs_to_gc = read_rq_gc(pblk, &rqd, gc_rq->line,
+							gc_rq->lba_list[0],
+							gc_rq->paddr_list[0]);
 	}
 
-	if (!(*secs_to_gc))
+	if (!(gc_rq->secs_to_gc))
 		goto out;
 
-	data_len = (*secs_to_gc) * geo->sec_size;
-	bio = pblk_bio_map_addr(pblk, data, *secs_to_gc, data_len,
+	data_len = (gc_rq->secs_to_gc) * geo->sec_size;
+	bio = pblk_bio_map_addr(pblk, gc_rq->data, gc_rq->secs_to_gc, data_len,
 						PBLK_VMALLOC_META, GFP_KERNEL);
 	if (IS_ERR(bio)) {
 		pr_err("pblk: could not allocate GC bio (%lu)\n", PTR_ERR(bio));
@@ -494,13 +502,12 @@ int pblk_submit_read_gc(struct pblk *pblk, u64 *lba_list, void *data,
 	rqd.opcode = NVM_OP_PREAD;
 	rqd.end_io = pblk_end_io_sync;
 	rqd.private = &wait;
-	rqd.nr_ppas = *secs_to_gc;
+	rqd.nr_ppas = gc_rq->secs_to_gc;
 	rqd.flags = pblk_set_read_mode(pblk, PBLK_READ_RANDOM);
 	rqd.bio = bio;
 
-	ret = pblk_submit_read_io(pblk, &rqd);
-	if (ret) {
-		bio_endio(bio);
+	if (pblk_submit_read_io(pblk, &rqd)) {
+		ret = -EIO;
 		pr_err("pblk: GC read request failed\n");
 		goto err_free_bio;
 	}
@@ -519,19 +526,19 @@ int pblk_submit_read_gc(struct pblk *pblk, u64 *lba_list, void *data,
 	}
 
 #ifdef CONFIG_NVM_DEBUG
-	atomic_long_add(*secs_to_gc, &pblk->sync_reads);
-	atomic_long_add(*secs_to_gc, &pblk->recov_gc_reads);
-	atomic_long_sub(*secs_to_gc, &pblk->inflight_reads);
+	atomic_long_add(gc_rq->secs_to_gc, &pblk->sync_reads);
+	atomic_long_add(gc_rq->secs_to_gc, &pblk->recov_gc_reads);
+	atomic_long_sub(gc_rq->secs_to_gc, &pblk->inflight_reads);
 #endif
 
 	bio_put(bio);
 out:
 	nvm_dev_dma_free(dev->parent, rqd.meta_list, rqd.dma_meta_list);
-	return NVM_IO_OK;
+	return ret;
 
 err_free_bio:
 	bio_put(bio);
 err_free_dma:
 	nvm_dev_dma_free(dev->parent, rqd.meta_list, rqd.dma_meta_list);
-	return NVM_IO_ERR;
+	return ret;
 }

drivers/lightnvm/pblk.h

@@ -206,6 +206,7 @@ struct pblk_lun {
 struct pblk_gc_rq {
 	struct pblk_line *line;
 	void *data;
+	u64 paddr_list[PBLK_MAX_REQ_ADDRS];
 	u64 lba_list[PBLK_MAX_REQ_ADDRS];
 	int nr_secs;
 	int secs_to_gc;
@@ -658,8 +659,8 @@ int pblk_rb_may_write_gc(struct pblk_rb *rb, unsigned int nr_entries,
 void pblk_rb_write_entry_user(struct pblk_rb *rb, void *data,
 			      struct pblk_w_ctx w_ctx, unsigned int pos);
 void pblk_rb_write_entry_gc(struct pblk_rb *rb, void *data,
-			    struct pblk_w_ctx w_ctx, struct pblk_line *gc_line,
-			    unsigned int pos);
+			    struct pblk_w_ctx w_ctx, struct pblk_line *line,
+			    u64 paddr, unsigned int pos);
 struct pblk_w_ctx *pblk_rb_w_ctx(struct pblk_rb *rb, unsigned int pos);
 void pblk_rb_flush(struct pblk_rb *rb);
 
@@ -761,7 +762,7 @@ void pblk_update_map_cache(struct pblk *pblk, sector_t lba,
 void pblk_update_map_dev(struct pblk *pblk, sector_t lba,
 			 struct ppa_addr ppa, struct ppa_addr entry_line);
 int pblk_update_map_gc(struct pblk *pblk, sector_t lba, struct ppa_addr ppa,
-		       struct pblk_line *gc_line);
+		       struct pblk_line *gc_line, u64 paddr);
 void pblk_lookup_l2p_rand(struct pblk *pblk, struct ppa_addr *ppas,
 			  u64 *lba_list, int nr_secs);
 void pblk_lookup_l2p_seq(struct pblk *pblk, struct ppa_addr *ppas,
@@ -772,9 +773,7 @@ void pblk_lookup_l2p_seq(struct pblk *pblk, struct ppa_addr *ppas,
  */
 int pblk_write_to_cache(struct pblk *pblk, struct bio *bio,
 			unsigned long flags);
-int pblk_write_gc_to_cache(struct pblk *pblk, void *data, u64 *lba_list,
-			   unsigned int nr_entries, unsigned int nr_rec_entries,
-			   struct pblk_line *gc_line, unsigned long flags);
+int pblk_write_gc_to_cache(struct pblk *pblk, struct pblk_gc_rq *gc_rq);
 
 /*
  * pblk map
@@ -798,9 +797,7 @@ void pblk_write_should_kick(struct pblk *pblk);
  */
 extern struct bio_set *pblk_bio_set;
 int pblk_submit_read(struct pblk *pblk, struct bio *bio);
-int pblk_submit_read_gc(struct pblk *pblk, u64 *lba_list, void *data,
-			unsigned int nr_secs, unsigned int *secs_to_gc,
-			struct pblk_line *line);
+int pblk_submit_read_gc(struct pblk *pblk, struct pblk_gc_rq *gc_rq);
 /*
  * pblk recovery
  */
@@ -893,13 +890,7 @@ static inline void *emeta_to_vsc(struct pblk *pblk, struct line_emeta *emeta)
 
 static inline int pblk_line_vsc(struct pblk_line *line)
 {
-	int vsc;
-
-	spin_lock(&line->lock);
-	vsc = le32_to_cpu(*line->vsc);
-	spin_unlock(&line->lock);
-
-	return vsc;
+	return le32_to_cpu(*line->vsc);
 }
 
 #define NVM_MEM_PAGE_WRITE (8)