Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 701 insertions, 0 deletions

diff --git a/drivers/lightnvm/pblk-read.c b/drivers/lightnvm/pblk-read.c
new file mode 100644
index 000000000..5a46d7f93
--- /dev/null
+++ b/drivers/lightnvm/pblk-read.c
@@ -0,0 +1,701 @@
+/*
+ * Copyright (C) 2016 CNEX Labs
+ * Initial release: Javier Gonzalez <javier@cnexlabs.com>
+ *                  Matias Bjorling <matias@cnexlabs.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * pblk-read.c - pblk's read path
+ */
+
+#include "pblk.h"
+
+/*
+ * There is no guarantee that the value read from cache has not been updated and
+ * resides at another location in the cache. We guarantee though that if the
+ * value is read from the cache, it belongs to the mapped lba. In order to
+ * guarantee and order between writes and reads are ordered, a flush must be
+ * issued.
+ */
+static int pblk_read_from_cache(struct pblk *pblk, struct bio *bio,
+				sector_t lba, struct ppa_addr ppa,
+				int bio_iter, bool advanced_bio)
+{
+#ifdef CONFIG_NVM_PBLK_DEBUG
+	/* Callers must ensure that the ppa points to a cache address */
+	BUG_ON(pblk_ppa_empty(ppa));
+	BUG_ON(!pblk_addr_in_cache(ppa));
+#endif
+
+	return pblk_rb_copy_to_bio(&pblk->rwb, bio, lba, ppa,
+						bio_iter, advanced_bio);
+}
+
+static void pblk_read_ppalist_rq(struct pblk *pblk, struct nvm_rq *rqd,
+				 struct bio *bio, sector_t blba,
+				 unsigned long *read_bitmap)
+{
+	struct pblk_sec_meta *meta_list = rqd->meta_list;
+	struct ppa_addr ppas[PBLK_MAX_REQ_ADDRS];
+	int nr_secs = rqd->nr_ppas;
+	bool advanced_bio = false;
+	int i, j = 0;
+
+	pblk_lookup_l2p_seq(pblk, ppas, blba, nr_secs);
+
+	for (i = 0; i < nr_secs; i++) {
+		struct ppa_addr p = ppas[i];
+		sector_t lba = blba + i;
+
+retry:
+		if (pblk_ppa_empty(p)) {
+			WARN_ON(test_and_set_bit(i, read_bitmap));
+			meta_list[i].lba = cpu_to_le64(ADDR_EMPTY);
+
+			if (unlikely(!advanced_bio)) {
+				bio_advance(bio, (i) * PBLK_EXPOSED_PAGE_SIZE);
+				advanced_bio = true;
+			}
+
+			goto next;
+		}
+
+		/* Try to read from write buffer. The address is later checked
+		 * on the write buffer to prevent retrieving overwritten data.
+		 */
+		if (pblk_addr_in_cache(p)) {
+			if (!pblk_read_from_cache(pblk, bio, lba, p, i,
+								advanced_bio)) {
+				pblk_lookup_l2p_seq(pblk, &p, lba, 1);
+				goto retry;
+			}
+			WARN_ON(test_and_set_bit(i, read_bitmap));
+			meta_list[i].lba = cpu_to_le64(lba);
+			advanced_bio = true;
+#ifdef CONFIG_NVM_PBLK_DEBUG
+			atomic_long_inc(&pblk->cache_reads);
+#endif
+		} else {
+			/* Read from media non-cached sectors */
+			rqd->ppa_list[j++] = p;
+		}
+
+next:
+		if (advanced_bio)
+			bio_advance(bio, PBLK_EXPOSED_PAGE_SIZE);
+	}
+
+	if (pblk_io_aligned(pblk, nr_secs))
+		rqd->flags = pblk_set_read_mode(pblk, PBLK_READ_SEQUENTIAL);
+	else
+		rqd->flags = pblk_set_read_mode(pblk, PBLK_READ_RANDOM);
+
+#ifdef CONFIG_NVM_PBLK_DEBUG
+	atomic_long_add(nr_secs, &pblk->inflight_reads);
+#endif
+}
+
+
+static void pblk_read_check_seq(struct pblk *pblk, struct nvm_rq *rqd,
+				sector_t blba)
+{
+	struct pblk_sec_meta *meta_lba_list = rqd->meta_list;
+	int nr_lbas = rqd->nr_ppas;
+	int i;
+
+	for (i = 0; i < nr_lbas; i++) {
+		u64 lba = le64_to_cpu(meta_lba_list[i].lba);
+
+		if (lba == ADDR_EMPTY)
+			continue;
+
+		if (lba != blba + i) {
+#ifdef CONFIG_NVM_PBLK_DEBUG
+			struct ppa_addr *p;
+
+			p = (nr_lbas == 1) ? &rqd->ppa_list[i] : &rqd->ppa_addr;
+			print_ppa(pblk, p, "seq", i);
+#endif
+			pblk_err(pblk, "corrupted read LBA (%llu/%llu)\n",
+							lba, (u64)blba + i);
+			WARN_ON(1);
+		}
+	}
+}
+
+/*
+ * There can be holes in the lba list.
+ */
+static void pblk_read_check_rand(struct pblk *pblk, struct nvm_rq *rqd,
+				 u64 *lba_list, int nr_lbas)
+{
+	struct pblk_sec_meta *meta_lba_list = rqd->meta_list;
+	int i, j;
+
+	for (i = 0, j = 0; i < nr_lbas; i++) {
+		u64 lba = lba_list[i];
+		u64 meta_lba;
+
+		if (lba == ADDR_EMPTY)
+			continue;
+
+		meta_lba = le64_to_cpu(meta_lba_list[j].lba);
+
+		if (lba != meta_lba) {
+#ifdef CONFIG_NVM_PBLK_DEBUG
+			struct ppa_addr *p;
+			int nr_ppas = rqd->nr_ppas;
+
+			p = (nr_ppas == 1) ? &rqd->ppa_list[j] : &rqd->ppa_addr;
+			print_ppa(pblk, p, "seq", j);
+#endif
+			pblk_err(pblk, "corrupted read LBA (%llu/%llu)\n",
+								lba, meta_lba);
+			WARN_ON(1);
+		}
+
+		j++;
+	}
+
+	WARN_ONCE(j != rqd->nr_ppas, "pblk: corrupted random request\n");
+}
+
+static void pblk_read_put_rqd_kref(struct pblk *pblk, struct nvm_rq *rqd)
+{
+	struct ppa_addr *ppa_list;
+	int i;
+
+	ppa_list = (rqd->nr_ppas > 1) ? rqd->ppa_list : &rqd->ppa_addr;
+
+	for (i = 0; i < rqd->nr_ppas; i++) {
+		struct ppa_addr ppa = ppa_list[i];
+		struct pblk_line *line;
+
+		line = &pblk->lines[pblk_ppa_to_line(ppa)];
+		kref_put(&line->ref, pblk_line_put_wq);
+	}
+}
+
+static void pblk_end_user_read(struct bio *bio)
+{
+#ifdef CONFIG_NVM_PBLK_DEBUG
+	WARN_ONCE(bio->bi_status, "pblk: corrupted read bio\n");
+#endif
+	bio_endio(bio);
+}
+
+static void __pblk_end_io_read(struct pblk *pblk, struct nvm_rq *rqd,
+			       bool put_line)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct pblk_g_ctx *r_ctx = nvm_rq_to_pdu(rqd);
+	struct bio *int_bio = rqd->bio;
+	unsigned long start_time = r_ctx->start_time;
+
+	generic_end_io_acct(dev->q, REQ_OP_READ, &pblk->disk->part0, start_time);
+
+	if (rqd->error)
+		pblk_log_read_err(pblk, rqd);
+
+	pblk_read_check_seq(pblk, rqd, r_ctx->lba);
+
+	if (int_bio)
+		bio_put(int_bio);
+
+	if (put_line)
+		pblk_read_put_rqd_kref(pblk, rqd);
+
+#ifdef CONFIG_NVM_PBLK_DEBUG
+	atomic_long_add(rqd->nr_ppas, &pblk->sync_reads);
+	atomic_long_sub(rqd->nr_ppas, &pblk->inflight_reads);
+#endif
+
+	pblk_free_rqd(pblk, rqd, PBLK_READ);
+	atomic_dec(&pblk->inflight_io);
+}
+
+static void pblk_end_io_read(struct nvm_rq *rqd)
+{
+	struct pblk *pblk = rqd->private;
+	struct pblk_g_ctx *r_ctx = nvm_rq_to_pdu(rqd);
+	struct bio *bio = (struct bio *)r_ctx->private;
+
+	pblk_end_user_read(bio);
+	__pblk_end_io_read(pblk, rqd, true);
+}
+
+static void pblk_end_partial_read(struct nvm_rq *rqd)
+{
+	struct pblk *pblk = rqd->private;
+	struct pblk_g_ctx *r_ctx = nvm_rq_to_pdu(rqd);
+	struct pblk_pr_ctx *pr_ctx = r_ctx->private;
+	struct bio *new_bio = rqd->bio;
+	struct bio *bio = pr_ctx->orig_bio;
+	struct bio_vec src_bv, dst_bv;
+	struct pblk_sec_meta *meta_list = rqd->meta_list;
+	int bio_init_idx = pr_ctx->bio_init_idx;
+	unsigned long *read_bitmap = pr_ctx->bitmap;
+	int nr_secs = pr_ctx->orig_nr_secs;
+	int nr_holes = nr_secs - bitmap_weight(read_bitmap, nr_secs);
+	__le64 *lba_list_mem, *lba_list_media;
+	void *src_p, *dst_p;
+	int hole, i;
+
+	if (unlikely(nr_holes == 1)) {
+		struct ppa_addr ppa;
+
+		ppa = rqd->ppa_addr;
+		rqd->ppa_list = pr_ctx->ppa_ptr;
+		rqd->dma_ppa_list = pr_ctx->dma_ppa_list;
+		rqd->ppa_list[0] = ppa;
+	}
+
+	/* Re-use allocated memory for intermediate lbas */
+	lba_list_mem = (((void *)rqd->ppa_list) + pblk_dma_ppa_size);
+	lba_list_media = (((void *)rqd->ppa_list) + 2 * pblk_dma_ppa_size);
+
+	for (i = 0; i < nr_secs; i++) {
+		lba_list_media[i] = meta_list[i].lba;
+		meta_list[i].lba = lba_list_mem[i];
+	}
+
+	/* Fill the holes in the original bio */
+	i = 0;
+	hole = find_first_zero_bit(read_bitmap, nr_secs);
+	do {
+		int line_id = pblk_ppa_to_line(rqd->ppa_list[i]);
+		struct pblk_line *line = &pblk->lines[line_id];
+
+		kref_put(&line->ref, pblk_line_put);
+
+		meta_list[hole].lba = lba_list_media[i];
+
+		src_bv = new_bio->bi_io_vec[i++];
+		dst_bv = bio->bi_io_vec[bio_init_idx + hole];
+
+		src_p = kmap_atomic(src_bv.bv_page);
+		dst_p = kmap_atomic(dst_bv.bv_page);
+
+		memcpy(dst_p + dst_bv.bv_offset,
+			src_p + src_bv.bv_offset,
+			PBLK_EXPOSED_PAGE_SIZE);
+
+		kunmap_atomic(src_p);
+		kunmap_atomic(dst_p);
+
+		mempool_free(src_bv.bv_page, &pblk->page_bio_pool);
+
+		hole = find_next_zero_bit(read_bitmap, nr_secs, hole + 1);
+	} while (hole < nr_secs);
+
+	bio_put(new_bio);
+	kfree(pr_ctx);
+
+	/* restore original request */
+	rqd->bio = NULL;
+	rqd->nr_ppas = nr_secs;
+
+	bio_endio(bio);
+	__pblk_end_io_read(pblk, rqd, false);
+}
+
+static int pblk_setup_partial_read(struct pblk *pblk, struct nvm_rq *rqd,
+			    unsigned int bio_init_idx,
+			    unsigned long *read_bitmap,
+			    int nr_holes)
+{
+	struct pblk_sec_meta *meta_list = rqd->meta_list;
+	struct pblk_g_ctx *r_ctx = nvm_rq_to_pdu(rqd);
+	struct pblk_pr_ctx *pr_ctx;
+	struct bio *new_bio, *bio = r_ctx->private;
+	__le64 *lba_list_mem;
+	int nr_secs = rqd->nr_ppas;
+	int i;
+
+	/* Re-use allocated memory for intermediate lbas */
+	lba_list_mem = (((void *)rqd->ppa_list) + pblk_dma_ppa_size);
+
+	new_bio = bio_alloc(GFP_KERNEL, nr_holes);
+
+	if (pblk_bio_add_pages(pblk, new_bio, GFP_KERNEL, nr_holes))
+		goto fail_bio_put;
+
+	if (nr_holes != new_bio->bi_vcnt) {
+		WARN_ONCE(1, "pblk: malformed bio\n");
+		goto fail_free_pages;
+	}
+
+	pr_ctx = kmalloc(sizeof(struct pblk_pr_ctx), GFP_KERNEL);
+	if (!pr_ctx)
+		goto fail_free_pages;
+
+	for (i = 0; i < nr_secs; i++)
+		lba_list_mem[i] = meta_list[i].lba;
+
+	new_bio->bi_iter.bi_sector = 0; /* internal bio */
+	bio_set_op_attrs(new_bio, REQ_OP_READ, 0);
+
+	rqd->bio = new_bio;
+	rqd->nr_ppas = nr_holes;
+	rqd->flags = pblk_set_read_mode(pblk, PBLK_READ_RANDOM);
+
+	pr_ctx->ppa_ptr = NULL;
+	pr_ctx->orig_bio = bio;
+	bitmap_copy(pr_ctx->bitmap, read_bitmap, NVM_MAX_VLBA);
+	pr_ctx->bio_init_idx = bio_init_idx;
+	pr_ctx->orig_nr_secs = nr_secs;
+	r_ctx->private = pr_ctx;
+
+	if (unlikely(nr_holes == 1)) {
+		pr_ctx->ppa_ptr = rqd->ppa_list;
+		pr_ctx->dma_ppa_list = rqd->dma_ppa_list;
+		rqd->ppa_addr = rqd->ppa_list[0];
+	}
+	return 0;
+
+fail_free_pages:
+	pblk_bio_free_pages(pblk, new_bio, 0, new_bio->bi_vcnt);
+fail_bio_put:
+	bio_put(new_bio);
+
+	return -ENOMEM;
+}
+
+static int pblk_partial_read_bio(struct pblk *pblk, struct nvm_rq *rqd,
+				 unsigned int bio_init_idx,
+				 unsigned long *read_bitmap, int nr_secs)
+{
+	int nr_holes;
+	int ret;
+
+	nr_holes = nr_secs - bitmap_weight(read_bitmap, nr_secs);
+
+	if (pblk_setup_partial_read(pblk, rqd, bio_init_idx, read_bitmap,
+				    nr_holes))
+		return NVM_IO_ERR;
+
+	rqd->end_io = pblk_end_partial_read;
+
+	ret = pblk_submit_io(pblk, rqd);
+	if (ret) {
+		bio_put(rqd->bio);
+		pblk_err(pblk, "partial read IO submission failed\n");
+		goto err;
+	}
+
+	return NVM_IO_OK;
+
+err:
+	pblk_err(pblk, "failed to perform partial read\n");
+
+	/* Free allocated pages in new bio */
+	pblk_bio_free_pages(pblk, rqd->bio, 0, rqd->bio->bi_vcnt);
+	__pblk_end_io_read(pblk, rqd, false);
+	return NVM_IO_ERR;
+}
+
+static void pblk_read_rq(struct pblk *pblk, struct nvm_rq *rqd, struct bio *bio,
+			 sector_t lba, unsigned long *read_bitmap)
+{
+	struct pblk_sec_meta *meta_list = rqd->meta_list;
+	struct ppa_addr ppa;
+
+	pblk_lookup_l2p_seq(pblk, &ppa, lba, 1);
+
+#ifdef CONFIG_NVM_PBLK_DEBUG
+	atomic_long_inc(&pblk->inflight_reads);
+#endif
+
+retry:
+	if (pblk_ppa_empty(ppa)) {
+		WARN_ON(test_and_set_bit(0, read_bitmap));
+		meta_list[0].lba = cpu_to_le64(ADDR_EMPTY);
+		return;
+	}
+
+	/* Try to read from write buffer. The address is later checked on the
+	 * write buffer to prevent retrieving overwritten data.
+	 */
+	if (pblk_addr_in_cache(ppa)) {
+		if (!pblk_read_from_cache(pblk, bio, lba, ppa, 0, 1)) {
+			pblk_lookup_l2p_seq(pblk, &ppa, lba, 1);
+			goto retry;
+		}
+
+		WARN_ON(test_and_set_bit(0, read_bitmap));
+		meta_list[0].lba = cpu_to_le64(lba);
+
+#ifdef CONFIG_NVM_PBLK_DEBUG
+		atomic_long_inc(&pblk->cache_reads);
+#endif
+	} else {
+		rqd->ppa_addr = ppa;
+	}
+
+	rqd->flags = pblk_set_read_mode(pblk, PBLK_READ_RANDOM);
+}
+
+int pblk_submit_read(struct pblk *pblk, struct bio *bio)
+{
+	struct nvm_tgt_dev *dev = pblk->dev;
+	struct request_queue *q = dev->q;
+	sector_t blba = pblk_get_lba(bio);
+	unsigned int nr_secs = pblk_get_secs(bio);
+	struct pblk_g_ctx *r_ctx;
+	struct nvm_rq *rqd;
+	unsigned int bio_init_idx;
+	DECLARE_BITMAP(read_bitmap, NVM_MAX_VLBA);
+	int ret = NVM_IO_ERR;
+
+	/* logic error: lba out-of-bounds. Ignore read request */
+	if (blba >= pblk->rl.nr_secs || nr_secs > PBLK_MAX_REQ_ADDRS) {
+		WARN(1, "pblk: read lba out of bounds (lba:%llu, nr:%d)\n",
+					(unsigned long long)blba, nr_secs);
+		return NVM_IO_ERR;
+	}
+
+	generic_start_io_acct(q, REQ_OP_READ, bio_sectors(bio),
+			      &pblk->disk->part0);
+
+	bitmap_zero(read_bitmap, nr_secs);
+
+	rqd = pblk_alloc_rqd(pblk, PBLK_READ);
+
+	rqd->opcode = NVM_OP_PREAD;
+	rqd->nr_ppas = nr_secs;
+	rqd->bio = NULL; /* cloned bio if needed */
+	rqd->private = pblk;
+	rqd->end_io = pblk_end_io_read;
+
+	r_ctx = nvm_rq_to_pdu(rqd);
+	r_ctx->start_time = jiffies;
+	r_ctx->lba = blba;
+	r_ctx->private = bio; /* original bio */
+
+	/* Save the index for this bio's start. This is needed in case
+	 * we need to fill a partial read.
+	 */
+	bio_init_idx = pblk_get_bi_idx(bio);
+
+	rqd->meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
+							&rqd->dma_meta_list);
+	if (!rqd->meta_list) {
+		pblk_err(pblk, "not able to allocate ppa list\n");
+		goto fail_rqd_free;
+	}
+
+	if (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;
+
+		pblk_read_ppalist_rq(pblk, rqd, bio, blba, read_bitmap);
+	} else {
+		pblk_read_rq(pblk, rqd, bio, blba, read_bitmap);
+	}
+
+	if (bitmap_full(read_bitmap, nr_secs)) {
+		atomic_inc(&pblk->inflight_io);
+		__pblk_end_io_read(pblk, rqd, false);
+		return NVM_IO_DONE;
+	}
+
+	/* All sectors are to be read from the device */
+	if (bitmap_empty(read_bitmap, rqd->nr_ppas)) {
+		struct bio *int_bio = NULL;
+
+		/* Clone read bio to deal with read errors internally */
+		int_bio = bio_clone_fast(bio, GFP_KERNEL, &pblk_bio_set);
+		if (!int_bio) {
+			pblk_err(pblk, "could not clone read bio\n");
+			goto fail_end_io;
+		}
+
+		rqd->bio = int_bio;
+
+		if (pblk_submit_io(pblk, rqd)) {
+			pblk_err(pblk, "read IO submission failed\n");
+			ret = NVM_IO_ERR;
+			goto fail_end_io;
+		}
+
+		return NVM_IO_OK;
+	}
+
+	/* The read bio request could be partially filled by the write buffer,
+	 * but there are some holes that need to be read from the drive.
+	 */
+	ret = pblk_partial_read_bio(pblk, rqd, bio_init_idx, read_bitmap,
+				    nr_secs);
+	if (ret)
+		goto fail_meta_free;
+
+	return NVM_IO_OK;
+
+fail_meta_free:
+	nvm_dev_dma_free(dev->parent, rqd->meta_list, rqd->dma_meta_list);
+fail_rqd_free:
+	pblk_free_rqd(pblk, rqd, PBLK_READ);
+	return ret;
+fail_end_io:
+	__pblk_end_io_read(pblk, rqd, false);
+	return ret;
+}
+
+static int read_ppalist_rq_gc(struct pblk *pblk, struct nvm_rq *rqd,
+			      struct pblk_line *line, u64 *lba_list,
+			      u64 *paddr_list_gc, unsigned int nr_secs)
+{
+	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, ppa_list_l2p, lba_list, nr_secs);
+
+	for (i = 0; i < nr_secs; i++) {
+		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++] = ppa_list_l2p[i];
+	}
+
+#ifdef CONFIG_NVM_PBLK_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,
+		      u64 paddr_gc)
+{
+	struct ppa_addr ppa_l2p, ppa_gc;
+	int valid_secs = 0;
+
+	if (lba == ADDR_EMPTY)
+		goto out;
+
+	/* logic error: lba out-of-bounds */
+	if (lba >= pblk->rl.nr_secs) {
+		WARN(1, "pblk: read lba out of bounds\n");
+		goto out;
+	}
+
+	spin_lock(&pblk->trans_lock);
+	ppa_l2p = pblk_trans_map_get(pblk, lba);
+	spin_unlock(&pblk->trans_lock);
+
+	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_l2p;
+	valid_secs = 1;
+
+#ifdef CONFIG_NVM_PBLK_DEBUG
+	atomic_long_inc(&pblk->inflight_reads);
+#endif
+
+out:
+	return valid_secs;
+}
+
+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 data_len;
+	int ret = NVM_IO_OK;
+
+	memset(&rqd, 0, sizeof(struct nvm_rq));
+
+	rqd.meta_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
+							&rqd.dma_meta_list);
+	if (!rqd.meta_list)
+		return -ENOMEM;
+
+	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;
+
+		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 {
+		gc_rq->secs_to_gc = read_rq_gc(pblk, &rqd, gc_rq->line,
+							gc_rq->lba_list[0],
+							gc_rq->paddr_list[0]);
+	}
+
+	if (!(gc_rq->secs_to_gc))
+		goto out;
+
+	data_len = (gc_rq->secs_to_gc) * geo->csecs;
+	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)) {
+		pblk_err(pblk, "could not allocate GC bio (%lu)\n",
+				PTR_ERR(bio));
+		goto err_free_dma;
+	}
+
+	bio->bi_iter.bi_sector = 0; /* internal bio */
+	bio_set_op_attrs(bio, REQ_OP_READ, 0);
+
+	rqd.opcode = NVM_OP_PREAD;
+	rqd.nr_ppas = gc_rq->secs_to_gc;
+	rqd.flags = pblk_set_read_mode(pblk, PBLK_READ_RANDOM);
+	rqd.bio = bio;
+
+	if (pblk_submit_io_sync(pblk, &rqd)) {
+		ret = -EIO;
+		pblk_err(pblk, "GC read request failed\n");
+		goto err_free_bio;
+	}
+
+	pblk_read_check_rand(pblk, &rqd, gc_rq->lba_list, gc_rq->nr_secs);
+
+	atomic_dec(&pblk->inflight_io);
+
+	if (rqd.error) {
+		atomic_long_inc(&pblk->read_failed_gc);
+#ifdef CONFIG_NVM_PBLK_DEBUG
+		pblk_print_failed_rqd(pblk, &rqd, rqd.error);
+#endif
+	}
+
+#ifdef CONFIG_NVM_PBLK_DEBUG
+	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
+
+out:
+	nvm_dev_dma_free(dev->parent, rqd.meta_list, rqd.dma_meta_list);
+	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 ret;
+}