linux/drivers/lightnvm/pblk-read.c

530 lines
13 KiB
C

/*
* 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)
{
#ifdef CONFIG_NVM_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,
pblk_addr_to_cacheline(ppa), bio_iter);
}
static void pblk_read_ppalist_rq(struct pblk *pblk, struct nvm_rq *rqd,
unsigned long *read_bitmap)
{
struct bio *bio = rqd->bio;
struct ppa_addr ppas[PBLK_MAX_REQ_ADDRS];
sector_t blba = pblk_get_lba(bio);
int nr_secs = rqd->nr_ppas;
int advanced_bio = 0;
int i, j = 0;
/* logic error: lba out-of-bounds. Ignore read request */
if (blba + nr_secs >= pblk->rl.nr_secs) {
WARN(1, "pblk: read lbas out of bounds\n");
return;
}
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));
continue;
}
/* 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)) {
pblk_lookup_l2p_seq(pblk, &p, lba, 1);
goto retry;
}
WARN_ON(test_and_set_bit(i, read_bitmap));
advanced_bio = 1;
} else {
/* Read from media non-cached sectors */
rqd->ppa_list[j++] = p;
}
if (advanced_bio)
bio_advance(bio, PBLK_EXPOSED_PAGE_SIZE);
}
#ifdef CONFIG_NVM_DEBUG
atomic_long_add(nr_secs, &pblk->inflight_reads);
#endif
}
static int pblk_submit_read_io(struct pblk *pblk, struct nvm_rq *rqd)
{
int err;
rqd->flags = pblk_set_read_mode(pblk);
err = pblk_submit_io(pblk, rqd);
if (err)
return NVM_IO_ERR;
return NVM_IO_OK;
}
static void pblk_end_io_read(struct nvm_rq *rqd)
{
struct pblk *pblk = rqd->private;
struct nvm_tgt_dev *dev = pblk->dev;
struct pblk_r_ctx *r_ctx = nvm_rq_to_pdu(rqd);
struct bio *bio = rqd->bio;
if (rqd->error)
pblk_log_read_err(pblk, rqd);
#ifdef CONFIG_NVM_DEBUG
else
WARN_ONCE(bio->bi_error, "pblk: corrupted read error\n");
#endif
if (rqd->nr_ppas > 1)
nvm_dev_dma_free(dev->parent, rqd->ppa_list, rqd->dma_ppa_list);
bio_put(bio);
if (r_ctx->orig_bio) {
#ifdef CONFIG_NVM_DEBUG
WARN_ONCE(r_ctx->orig_bio->bi_error,
"pblk: corrupted read bio\n");
#endif
bio_endio(r_ctx->orig_bio);
bio_put(r_ctx->orig_bio);
}
#ifdef CONFIG_NVM_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, READ);
}
static int pblk_fill_partial_read_bio(struct pblk *pblk, struct nvm_rq *rqd,
unsigned int bio_init_idx,
unsigned long *read_bitmap)
{
struct bio *new_bio, *bio = rqd->bio;
struct bio_vec src_bv, dst_bv;
void *ppa_ptr = NULL;
void *src_p, *dst_p;
dma_addr_t dma_ppa_list = 0;
int nr_secs = rqd->nr_ppas;
int nr_holes = nr_secs - bitmap_weight(read_bitmap, nr_secs);
int i, ret, hole;
DECLARE_COMPLETION_ONSTACK(wait);
new_bio = bio_alloc(GFP_KERNEL, nr_holes);
if (!new_bio) {
pr_err("pblk: could not alloc read bio\n");
return NVM_IO_ERR;
}
if (pblk_bio_add_pages(pblk, new_bio, GFP_KERNEL, nr_holes))
goto err;
if (nr_holes != new_bio->bi_vcnt) {
pr_err("pblk: malformed bio\n");
goto err;
}
new_bio->bi_iter.bi_sector = 0; /* internal bio */
bio_set_op_attrs(new_bio, REQ_OP_READ, 0);
new_bio->bi_private = &wait;
new_bio->bi_end_io = pblk_end_bio_sync;
rqd->bio = new_bio;
rqd->nr_ppas = nr_holes;
rqd->end_io = NULL;
if (unlikely(nr_secs > 1 && nr_holes == 1)) {
ppa_ptr = rqd->ppa_list;
dma_ppa_list = rqd->dma_ppa_list;
rqd->ppa_addr = rqd->ppa_list[0];
}
ret = pblk_submit_read_io(pblk, rqd);
if (ret) {
bio_put(rqd->bio);
pr_err("pblk: read IO submission failed\n");
goto err;
}
if (!wait_for_completion_io_timeout(&wait,
msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
pr_err("pblk: partial read I/O timed out\n");
}
if (rqd->error) {
atomic_long_inc(&pblk->read_failed);
#ifdef CONFIG_NVM_DEBUG
pblk_print_failed_rqd(pblk, rqd, rqd->error);
#endif
}
if (unlikely(nr_secs > 1 && nr_holes == 1)) {
rqd->ppa_list = ppa_ptr;
rqd->dma_ppa_list = dma_ppa_list;
}
/* Fill the holes in the original bio */
i = 0;
hole = find_first_zero_bit(read_bitmap, nr_secs);
do {
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_pool);
hole = find_next_zero_bit(read_bitmap, nr_secs, hole + 1);
} while (hole < nr_secs);
bio_put(new_bio);
/* Complete the original bio and associated request */
rqd->bio = bio;
rqd->nr_ppas = nr_secs;
rqd->private = pblk;
bio_endio(bio);
pblk_end_io_read(rqd);
return NVM_IO_OK;
err:
/* Free allocated pages in new bio */
pblk_bio_free_pages(pblk, bio, 0, new_bio->bi_vcnt);
rqd->private = pblk;
pblk_end_io_read(rqd);
return NVM_IO_ERR;
}
static void pblk_read_rq(struct pblk *pblk, struct nvm_rq *rqd,
unsigned long *read_bitmap)
{
struct bio *bio = rqd->bio;
struct ppa_addr ppa;
sector_t lba = pblk_get_lba(bio);
/* logic error: lba out-of-bounds. Ignore read request */
if (lba >= pblk->rl.nr_secs) {
WARN(1, "pblk: read lba out of bounds\n");
return;
}
pblk_lookup_l2p_seq(pblk, &ppa, lba, 1);
#ifdef CONFIG_NVM_DEBUG
atomic_long_inc(&pblk->inflight_reads);
#endif
retry:
if (pblk_ppa_empty(ppa)) {
WARN_ON(test_and_set_bit(0, read_bitmap));
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)) {
pblk_lookup_l2p_seq(pblk, &ppa, lba, 1);
goto retry;
}
WARN_ON(test_and_set_bit(0, read_bitmap));
} else {
rqd->ppa_addr = ppa;
}
}
int pblk_submit_read(struct pblk *pblk, struct bio *bio)
{
struct nvm_tgt_dev *dev = pblk->dev;
unsigned int nr_secs = pblk_get_secs(bio);
struct nvm_rq *rqd;
unsigned long read_bitmap; /* Max 64 ppas per request */
unsigned int bio_init_idx;
int ret = NVM_IO_ERR;
if (nr_secs > PBLK_MAX_REQ_ADDRS)
return NVM_IO_ERR;
bitmap_zero(&read_bitmap, nr_secs);
rqd = pblk_alloc_rqd(pblk, READ);
if (IS_ERR(rqd)) {
pr_err_ratelimited("pblk: not able to alloc rqd");
return NVM_IO_ERR;
}
rqd->opcode = NVM_OP_PREAD;
rqd->bio = bio;
rqd->nr_ppas = nr_secs;
rqd->private = pblk;
rqd->end_io = pblk_end_io_read;
/* 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);
if (nr_secs > 1) {
rqd->ppa_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
&rqd->dma_ppa_list);
if (!rqd->ppa_list) {
pr_err("pblk: not able to allocate ppa list\n");
goto fail_rqd_free;
}
pblk_read_ppalist_rq(pblk, rqd, &read_bitmap);
} else {
pblk_read_rq(pblk, rqd, &read_bitmap);
}
bio_get(bio);
if (bitmap_full(&read_bitmap, nr_secs)) {
bio_endio(bio);
pblk_end_io_read(rqd);
return NVM_IO_OK;
}
/* All sectors are to be read from the device */
if (bitmap_empty(&read_bitmap, rqd->nr_ppas)) {
struct bio *int_bio = NULL;
struct pblk_r_ctx *r_ctx = nvm_rq_to_pdu(rqd);
/* Clone read bio to deal with read errors internally */
int_bio = bio_clone_bioset(bio, GFP_KERNEL, fs_bio_set);
if (!int_bio) {
pr_err("pblk: could not clone read bio\n");
return NVM_IO_ERR;
}
rqd->bio = int_bio;
r_ctx->orig_bio = bio;
ret = pblk_submit_read_io(pblk, rqd);
if (ret) {
pr_err("pblk: read IO submission failed\n");
if (int_bio)
bio_put(int_bio);
return ret;
}
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_fill_partial_read_bio(pblk, rqd, bio_init_idx, &read_bitmap);
if (ret) {
pr_err("pblk: failed to perform partial read\n");
return ret;
}
return NVM_IO_OK;
fail_rqd_free:
pblk_free_rqd(pblk, rqd, READ);
return ret;
}
static int read_ppalist_rq_gc(struct pblk *pblk, struct nvm_rq *rqd,
struct pblk_line *line, u64 *lba_list,
unsigned int nr_secs)
{
struct ppa_addr ppas[PBLK_MAX_REQ_ADDRS];
int valid_secs = 0;
int i;
pblk_lookup_l2p_rand(pblk, ppas, 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;
continue;
}
rqd->ppa_list[valid_secs++] = ppas[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 ppa_addr ppa;
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 = 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))
goto out;
rqd->ppa_addr = ppa;
valid_secs = 1;
#ifdef CONFIG_NVM_DEBUG
atomic_long_inc(&pblk->inflight_reads);
#endif
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)
{
struct nvm_tgt_dev *dev = pblk->dev;
struct nvm_geo *geo = &dev->geo;
struct request_queue *q = dev->q;
struct bio *bio;
struct nvm_rq rqd;
int ret, data_len;
DECLARE_COMPLETION_ONSTACK(wait);
memset(&rqd, 0, sizeof(struct nvm_rq));
if (nr_secs > 1) {
rqd.ppa_list = nvm_dev_dma_alloc(dev->parent, GFP_KERNEL,
&rqd.dma_ppa_list);
if (!rqd.ppa_list)
return NVM_IO_ERR;
*secs_to_gc = read_ppalist_rq_gc(pblk, &rqd, line, lba_list,
nr_secs);
if (*secs_to_gc == 1) {
struct ppa_addr ppa;
ppa = rqd.ppa_list[0];
nvm_dev_dma_free(dev->parent, rqd.ppa_list,
rqd.dma_ppa_list);
rqd.ppa_addr = ppa;
}
} else {
*secs_to_gc = read_rq_gc(pblk, &rqd, line, lba_list[0]);
}
if (!(*secs_to_gc))
goto out;
data_len = (*secs_to_gc) * geo->sec_size;
bio = bio_map_kern(q, data, data_len, GFP_KERNEL);
if (IS_ERR(bio)) {
pr_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.end_io = pblk_end_io_sync;
rqd.private = &wait;
rqd.nr_ppas = *secs_to_gc;
rqd.bio = bio;
ret = pblk_submit_read_io(pblk, &rqd);
if (ret) {
bio_endio(bio);
pr_err("pblk: GC read request failed\n");
goto err_free_dma;
}
if (!wait_for_completion_io_timeout(&wait,
msecs_to_jiffies(PBLK_COMMAND_TIMEOUT_MS))) {
pr_err("pblk: GC read I/O timed out\n");
}
if (rqd.error) {
atomic_long_inc(&pblk->read_failed_gc);
#ifdef CONFIG_NVM_DEBUG
pblk_print_failed_rqd(pblk, &rqd, rqd.error);
#endif
}
#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);
#endif
out:
if (rqd.nr_ppas > 1)
nvm_dev_dma_free(dev->parent, rqd.ppa_list, rqd.dma_ppa_list);
return NVM_IO_OK;
err_free_dma:
if (rqd.nr_ppas > 1)
nvm_dev_dma_free(dev->parent, rqd.ppa_list, rqd.dma_ppa_list);
return NVM_IO_ERR;
}