// 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 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);
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)
{
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);
bool from_cache;
struct pblk_g_ctx *r_ctx;
struct nvm_rq *rqd;
struct bio *int_bio, *split_bio;
generic_start_io_acct(q, REQ_OP_READ, bio_sectors(bio),
&pblk->disk->part0);
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 = jiffies;
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);
generic_make_request(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)) {
/* 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_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));
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;
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));
ret = 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.bio = bio;
if (pblk_submit_io_sync(pblk, &rqd)) {
ret = -EIO;
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:
pblk_free_rqd_meta(pblk, &rqd);
return ret;
err_free_bio:
bio_put(bio);
err_free_dma:
pblk_free_rqd_meta(pblk, &rqd);
return ret;
}
