1 files changed, 474 insertions, 0 deletions

diff --git a/drivers/lightnvm/pblk-read.c b/drivers/lightnvm/pblk-read.c
new file mode 100644
index 000000000..c28537a48
--- /dev/null
+++ b/drivers/lightnvm/pblk-read.c
@@ -0,0 +1,474 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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)
+{
+#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);
+}
+
+static int pblk_read_ppalist_rq(struct pblk *pblk, struct nvm_rq *rqd,
+				 struct bio *bio, sector_t blba,
+				 bool *from_cache)
+{
+	void *meta_list = rqd->meta_list;
+	int nr_secs, i;
+
+retry:
+	nr_secs = pblk_lookup_l2p_seq(pblk, rqd->ppa_list, blba, rqd->nr_ppas,
+					from_cache);
+
+	if (!*from_cache)
+		goto end;
+
+	for (i = 0; i < nr_secs; i++) {
+		struct pblk_sec_meta *meta = pblk_get_meta(pblk, meta_list, i);
+		sector_t lba = blba + i;
+
+		if (pblk_ppa_empty(rqd->ppa_list[i])) {
+			__le64 addr_empty = cpu_to_le64(ADDR_EMPTY);
+
+			meta->lba = addr_empty;
+		} else if (pblk_addr_in_cache(rqd->ppa_list[i])) {
+			/*
+			 * Try to read from write buffer. The address is later
+			 * checked on the write buffer to prevent retrieving
+			 * overwritten data.
+			 */
+			if (!pblk_read_from_cache(pblk, bio, lba,
+							rqd->ppa_list[i])) {
+				if (i == 0) {
+					/*
+					 * We didn't call with bio_advance()
+					 * yet, so we can just retry.
+					 */
+					goto retry;
+				} else {
+					/*
+					 * We already call bio_advance()
+					 * so we cannot retry and we need
+					 * to quit that function in order
+					 * to allow caller to handle the bio
+					 * splitting in the current sector
+					 * position.
+					 */
+					nr_secs = i;
+					goto end;
+				}
+			}
+			meta->lba = cpu_to_le64(lba);
+#ifdef CONFIG_NVM_PBLK_DEBUG
+			atomic_long_inc(&pblk->cache_reads);
+#endif
+		}
+		bio_advance(bio, PBLK_EXPOSED_PAGE_SIZE);
+	}
+
+end:
+	if (pblk_io_aligned(pblk, nr_secs))
+		rqd->is_seq = 1;
+
+#ifdef CONFIG_NVM_PBLK_DEBUG
+	atomic_long_add(nr_secs, &pblk->inflight_reads);
+#endif
+
+	return nr_secs;
+}
+
+
+static void pblk_read_check_seq(struct pblk *pblk, struct nvm_rq *rqd,
+				sector_t blba)
+{
+	void *meta_list = rqd->meta_list;
+	int nr_lbas = rqd->nr_ppas;
+	int i;
+
+	if (!pblk_is_oob_meta_supported(pblk))
+		return;
+
+	for (i = 0; i < nr_lbas; i++) {
+		struct pblk_sec_meta *meta = pblk_get_meta(pblk, meta_list, i);
+		u64 lba = le64_to_cpu(meta->lba);
+
+		if (lba == ADDR_EMPTY)
+			continue;
+
+		if (lba != blba + i) {
+#ifdef CONFIG_NVM_PBLK_DEBUG
+			struct ppa_addr *ppa_list = nvm_rq_to_ppa_list(rqd);
+
+			print_ppa(pblk, &ppa_list[i], "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)
+{
+	void *meta_lba_list = rqd->meta_list;
+	int i, j;
+
+	if (!pblk_is_oob_meta_supported(pblk))
+		return;
+
+	for (i = 0, j = 0; i < nr_lbas; i++) {
+		struct pblk_sec_meta *meta = pblk_get_meta(pblk,
+							   meta_lba_list, j);
+		u64 lba = lba_list[i];
+		u64 meta_lba;
+
+		if (lba == ADDR_EMPTY)
+			continue;
+
+		meta_lba = le64_to_cpu(meta->lba);
+
+		if (lba != meta_lba) {
+#ifdef CONFIG_NVM_PBLK_DEBUG
+			struct ppa_addr *ppa_list = nvm_rq_to_ppa_list(rqd);
+
+			print_ppa(pblk, &ppa_list[j], "rnd", j);
+#endif
+			pblk_err(pblk, "corrupted read LBA (%llu/%llu)\n",
+							meta_lba, lba);
+			WARN_ON(1);
+		}
+
+		j++;
+	}
+
+	WARN_ONCE(j != rqd->nr_ppas, "pblk: corrupted random request\n");
+}
+
+static void pblk_end_user_read(struct bio *bio, int error)
+{
+	if (error && error != NVM_RSP_WARN_HIGHECC)
+		bio_io_error(bio);
+	else
+		bio_endio(bio);
+}
+
+static void __pblk_end_io_read(struct pblk *pblk, struct nvm_rq *rqd,
+			       bool put_line)
+{
+	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;
+
+	bio_end_io_acct(int_bio, start_time);
+
+	if (rqd->error)
+		pblk_log_read_err(pblk, rqd);
+
+	pblk_read_check_seq(pblk, rqd, r_ctx->lba);
+	bio_put(int_bio);
+
+	if (put_line)
+		pblk_rq_to_line_put(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, rqd->error);
+	__pblk_end_io_read(pblk, rqd, true);
+}
+
+static void pblk_read_rq(struct pblk *pblk, struct nvm_rq *rqd, struct bio *bio,
+			 sector_t lba, bool *from_cache)
+{
+	struct pblk_sec_meta *meta = pblk_get_meta(pblk, rqd->meta_list, 0);
+	struct ppa_addr ppa;
+
+	pblk_lookup_l2p_seq(pblk, &ppa, lba, 1, from_cache);
+
+#ifdef CONFIG_NVM_PBLK_DEBUG
+	atomic_long_inc(&pblk->inflight_reads);
+#endif
+
+retry:
+	if (pblk_ppa_empty(ppa)) {
+		__le64 addr_empty = cpu_to_le64(ADDR_EMPTY);
+
+		meta->lba = 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)) {
+			pblk_lookup_l2p_seq(pblk, &ppa, lba, 1, from_cache);
+			goto retry;
+		}
+
+		meta->lba = cpu_to_le64(lba);
+
+#ifdef CONFIG_NVM_PBLK_DEBUG
+		atomic_long_inc(&pblk->cache_reads);
+#endif
+	} else {
+		rqd->ppa_addr = ppa;
+	}
+}
+
+void pblk_submit_read(struct pblk *pblk, struct bio *bio)
+{
+	sector_t blba = pblk_get_lba(bio);
+	unsigned int nr_secs = pblk_get_secs(bio);
+	bool from_cache;
+	struct pblk_g_ctx *r_ctx;
+	struct nvm_rq *rqd;
+	struct bio *int_bio, *split_bio;
+	unsigned long start_time;
+
+	start_time = bio_start_io_acct(bio);
+
+	rqd = pblk_alloc_rqd(pblk, PBLK_READ);
+
+	rqd->opcode = NVM_OP_PREAD;
+	rqd->nr_ppas = nr_secs;
+	rqd->private = pblk;
+	rqd->end_io = pblk_end_io_read;
+
+	r_ctx = nvm_rq_to_pdu(rqd);
+	r_ctx->start_time = start_time;
+	r_ctx->lba = blba;
+
+	if (pblk_alloc_rqd_meta(pblk, rqd)) {
+		bio_io_error(bio);
+		pblk_free_rqd(pblk, rqd, PBLK_READ);
+		return;
+	}
+
+	/* Clone read bio to deal internally with:
+	 * -read errors when reading from drive
+	 * -bio_advance() calls during cache reads
+	 */
+	int_bio = bio_clone_fast(bio, GFP_KERNEL, &pblk_bio_set);
+
+	if (nr_secs > 1)
+		nr_secs = pblk_read_ppalist_rq(pblk, rqd, int_bio, blba,
+						&from_cache);
+	else
+		pblk_read_rq(pblk, rqd, int_bio, blba, &from_cache);
+
+split_retry:
+	r_ctx->private = bio; /* original bio */
+	rqd->bio = int_bio; /* internal bio */
+
+	if (from_cache && nr_secs == rqd->nr_ppas) {
+		/* All data was read from cache, we can complete the IO. */
+		pblk_end_user_read(bio, 0);
+		atomic_inc(&pblk->inflight_io);
+		__pblk_end_io_read(pblk, rqd, false);
+	} else if (nr_secs != rqd->nr_ppas) {
+		/* 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. In order to handle this, we will use block layer
+		 * mechanism to split this request in to smaller ones and make
+		 * a chain of it.
+		 */
+		split_bio = bio_split(bio, nr_secs * NR_PHY_IN_LOG, GFP_KERNEL,
+					&pblk_bio_set);
+		bio_chain(split_bio, bio);
+		submit_bio_noacct(bio);
+
+		/* New bio contains first N sectors of the previous one, so
+		 * we can continue to use existing rqd, but we need to shrink
+		 * the number of PPAs in it. New bio is also guaranteed that
+		 * it contains only either data from cache or from drive, newer
+		 * mix of them.
+		 */
+		bio = split_bio;
+		rqd->nr_ppas = nr_secs;
+		if (rqd->nr_ppas == 1)
+			rqd->ppa_addr = rqd->ppa_list[0];
+
+		/* Recreate int_bio - existing might have some needed internal
+		 * fields modified already.
+		 */
+		bio_put(int_bio);
+		int_bio = bio_clone_fast(bio, GFP_KERNEL, &pblk_bio_set);
+		goto split_retry;
+	} else if (pblk_submit_io(pblk, rqd, NULL)) {
+		/* Submitting IO to drive failed, let's report an error */
+		rqd->error = -ENODEV;
+		pblk_end_io_read(rqd);
+	}
+}
+
+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[NVM_MAX_VLBA];
+	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->capacity) {
+		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_rq rqd;
+	int ret = NVM_IO_OK;
+
+	memset(&rqd, 0, sizeof(struct nvm_rq));
+
+	ret = pblk_alloc_rqd_meta(pblk, &rqd);
+	if (ret)
+		return ret;
+
+	if (gc_rq->nr_secs > 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 {
+		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;
+
+	rqd.opcode = NVM_OP_PREAD;
+	rqd.nr_ppas = gc_rq->secs_to_gc;
+
+	if (pblk_submit_io_sync(pblk, &rqd, gc_rq->data)) {
+		ret = -EIO;
+		goto err_free_dma;
+	}
+
+	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:
+	pblk_free_rqd_meta(pblk, &rqd);
+	return ret;
+
+err_free_dma:
+	pblk_free_rqd_meta(pblk, &rqd);
+	return ret;
+}