linux-stable/drivers/md/dm-stripe.c
Christoph Hellwig 7ac5360cd4 dax: remove the copy_from_iter and copy_to_iter methods
These methods indirect the actual DAX read/write path.  In the end pmem
uses magic flush and mc safe variants and fuse and dcssblk use plain ones
while device mapper picks redirects to the underlying device.

Add set_dax_nocache() and set_dax_nomc() APIs to control which copy
routines are used to remove indirect call from the read/write fast path
as well as a lot of boilerplate code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Vivek Goyal <vgoyal@redhat.com> [virtiofs]
Link: https://lore.kernel.org/r/20211215084508.435401-5-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-12-18 08:04:53 -08:00

490 lines
11 KiB
C

/*
* Copyright (C) 2001-2003 Sistina Software (UK) Limited.
*
* This file is released under the GPL.
*/
#include "dm.h"
#include <linux/device-mapper.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/bio.h>
#include <linux/dax.h>
#include <linux/slab.h>
#include <linux/log2.h>
#define DM_MSG_PREFIX "striped"
#define DM_IO_ERROR_THRESHOLD 15
struct stripe {
struct dm_dev *dev;
sector_t physical_start;
atomic_t error_count;
};
struct stripe_c {
uint32_t stripes;
int stripes_shift;
/* The size of this target / num. stripes */
sector_t stripe_width;
uint32_t chunk_size;
int chunk_size_shift;
/* Needed for handling events */
struct dm_target *ti;
/* Work struct used for triggering events*/
struct work_struct trigger_event;
struct stripe stripe[];
};
/*
* An event is triggered whenever a drive
* drops out of a stripe volume.
*/
static void trigger_event(struct work_struct *work)
{
struct stripe_c *sc = container_of(work, struct stripe_c,
trigger_event);
dm_table_event(sc->ti->table);
}
/*
* Parse a single <dev> <sector> pair
*/
static int get_stripe(struct dm_target *ti, struct stripe_c *sc,
unsigned int stripe, char **argv)
{
unsigned long long start;
char dummy;
int ret;
if (sscanf(argv[1], "%llu%c", &start, &dummy) != 1)
return -EINVAL;
ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
&sc->stripe[stripe].dev);
if (ret)
return ret;
sc->stripe[stripe].physical_start = start;
return 0;
}
/*
* Construct a striped mapping.
* <number of stripes> <chunk size> [<dev_path> <offset>]+
*/
static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
struct stripe_c *sc;
sector_t width, tmp_len;
uint32_t stripes;
uint32_t chunk_size;
int r;
unsigned int i;
if (argc < 2) {
ti->error = "Not enough arguments";
return -EINVAL;
}
if (kstrtouint(argv[0], 10, &stripes) || !stripes) {
ti->error = "Invalid stripe count";
return -EINVAL;
}
if (kstrtouint(argv[1], 10, &chunk_size) || !chunk_size) {
ti->error = "Invalid chunk_size";
return -EINVAL;
}
width = ti->len;
if (sector_div(width, stripes)) {
ti->error = "Target length not divisible by "
"number of stripes";
return -EINVAL;
}
tmp_len = width;
if (sector_div(tmp_len, chunk_size)) {
ti->error = "Target length not divisible by "
"chunk size";
return -EINVAL;
}
/*
* Do we have enough arguments for that many stripes ?
*/
if (argc != (2 + 2 * stripes)) {
ti->error = "Not enough destinations "
"specified";
return -EINVAL;
}
sc = kmalloc(struct_size(sc, stripe, stripes), GFP_KERNEL);
if (!sc) {
ti->error = "Memory allocation for striped context "
"failed";
return -ENOMEM;
}
INIT_WORK(&sc->trigger_event, trigger_event);
/* Set pointer to dm target; used in trigger_event */
sc->ti = ti;
sc->stripes = stripes;
sc->stripe_width = width;
if (stripes & (stripes - 1))
sc->stripes_shift = -1;
else
sc->stripes_shift = __ffs(stripes);
r = dm_set_target_max_io_len(ti, chunk_size);
if (r) {
kfree(sc);
return r;
}
ti->num_flush_bios = stripes;
ti->num_discard_bios = stripes;
ti->num_secure_erase_bios = stripes;
ti->num_write_same_bios = stripes;
ti->num_write_zeroes_bios = stripes;
sc->chunk_size = chunk_size;
if (chunk_size & (chunk_size - 1))
sc->chunk_size_shift = -1;
else
sc->chunk_size_shift = __ffs(chunk_size);
/*
* Get the stripe destinations.
*/
for (i = 0; i < stripes; i++) {
argv += 2;
r = get_stripe(ti, sc, i, argv);
if (r < 0) {
ti->error = "Couldn't parse stripe destination";
while (i--)
dm_put_device(ti, sc->stripe[i].dev);
kfree(sc);
return r;
}
atomic_set(&(sc->stripe[i].error_count), 0);
}
ti->private = sc;
return 0;
}
static void stripe_dtr(struct dm_target *ti)
{
unsigned int i;
struct stripe_c *sc = (struct stripe_c *) ti->private;
for (i = 0; i < sc->stripes; i++)
dm_put_device(ti, sc->stripe[i].dev);
flush_work(&sc->trigger_event);
kfree(sc);
}
static void stripe_map_sector(struct stripe_c *sc, sector_t sector,
uint32_t *stripe, sector_t *result)
{
sector_t chunk = dm_target_offset(sc->ti, sector);
sector_t chunk_offset;
if (sc->chunk_size_shift < 0)
chunk_offset = sector_div(chunk, sc->chunk_size);
else {
chunk_offset = chunk & (sc->chunk_size - 1);
chunk >>= sc->chunk_size_shift;
}
if (sc->stripes_shift < 0)
*stripe = sector_div(chunk, sc->stripes);
else {
*stripe = chunk & (sc->stripes - 1);
chunk >>= sc->stripes_shift;
}
if (sc->chunk_size_shift < 0)
chunk *= sc->chunk_size;
else
chunk <<= sc->chunk_size_shift;
*result = chunk + chunk_offset;
}
static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector,
uint32_t target_stripe, sector_t *result)
{
uint32_t stripe;
stripe_map_sector(sc, sector, &stripe, result);
if (stripe == target_stripe)
return;
/* round down */
sector = *result;
if (sc->chunk_size_shift < 0)
*result -= sector_div(sector, sc->chunk_size);
else
*result = sector & ~(sector_t)(sc->chunk_size - 1);
if (target_stripe < stripe)
*result += sc->chunk_size; /* next chunk */
}
static int stripe_map_range(struct stripe_c *sc, struct bio *bio,
uint32_t target_stripe)
{
sector_t begin, end;
stripe_map_range_sector(sc, bio->bi_iter.bi_sector,
target_stripe, &begin);
stripe_map_range_sector(sc, bio_end_sector(bio),
target_stripe, &end);
if (begin < end) {
bio_set_dev(bio, sc->stripe[target_stripe].dev->bdev);
bio->bi_iter.bi_sector = begin +
sc->stripe[target_stripe].physical_start;
bio->bi_iter.bi_size = to_bytes(end - begin);
return DM_MAPIO_REMAPPED;
} else {
/* The range doesn't map to the target stripe */
bio_endio(bio);
return DM_MAPIO_SUBMITTED;
}
}
static int stripe_map(struct dm_target *ti, struct bio *bio)
{
struct stripe_c *sc = ti->private;
uint32_t stripe;
unsigned target_bio_nr;
if (bio->bi_opf & REQ_PREFLUSH) {
target_bio_nr = dm_bio_get_target_bio_nr(bio);
BUG_ON(target_bio_nr >= sc->stripes);
bio_set_dev(bio, sc->stripe[target_bio_nr].dev->bdev);
return DM_MAPIO_REMAPPED;
}
if (unlikely(bio_op(bio) == REQ_OP_DISCARD) ||
unlikely(bio_op(bio) == REQ_OP_SECURE_ERASE) ||
unlikely(bio_op(bio) == REQ_OP_WRITE_ZEROES) ||
unlikely(bio_op(bio) == REQ_OP_WRITE_SAME)) {
target_bio_nr = dm_bio_get_target_bio_nr(bio);
BUG_ON(target_bio_nr >= sc->stripes);
return stripe_map_range(sc, bio, target_bio_nr);
}
stripe_map_sector(sc, bio->bi_iter.bi_sector,
&stripe, &bio->bi_iter.bi_sector);
bio->bi_iter.bi_sector += sc->stripe[stripe].physical_start;
bio_set_dev(bio, sc->stripe[stripe].dev->bdev);
return DM_MAPIO_REMAPPED;
}
#if IS_ENABLED(CONFIG_FS_DAX)
static struct dax_device *stripe_dax_pgoff(struct dm_target *ti, pgoff_t *pgoff)
{
struct stripe_c *sc = ti->private;
struct block_device *bdev;
sector_t dev_sector;
uint32_t stripe;
stripe_map_sector(sc, *pgoff * PAGE_SECTORS, &stripe, &dev_sector);
dev_sector += sc->stripe[stripe].physical_start;
bdev = sc->stripe[stripe].dev->bdev;
*pgoff = (get_start_sect(bdev) + dev_sector) >> PAGE_SECTORS_SHIFT;
return sc->stripe[stripe].dev->dax_dev;
}
static long stripe_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
long nr_pages, void **kaddr, pfn_t *pfn)
{
struct dax_device *dax_dev = stripe_dax_pgoff(ti, &pgoff);
return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
}
static int stripe_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,
size_t nr_pages)
{
struct dax_device *dax_dev = stripe_dax_pgoff(ti, &pgoff);
return dax_zero_page_range(dax_dev, pgoff, nr_pages);
}
#else
#define stripe_dax_direct_access NULL
#define stripe_dax_zero_page_range NULL
#endif
/*
* Stripe status:
*
* INFO
* #stripes [stripe_name <stripe_name>] [group word count]
* [error count 'A|D' <error count 'A|D'>]
*
* TABLE
* #stripes [stripe chunk size]
* [stripe_name physical_start <stripe_name physical_start>]
*
*/
static void stripe_status(struct dm_target *ti, status_type_t type,
unsigned status_flags, char *result, unsigned maxlen)
{
struct stripe_c *sc = (struct stripe_c *) ti->private;
unsigned int sz = 0;
unsigned int i;
switch (type) {
case STATUSTYPE_INFO:
DMEMIT("%d ", sc->stripes);
for (i = 0; i < sc->stripes; i++) {
DMEMIT("%s ", sc->stripe[i].dev->name);
}
DMEMIT("1 ");
for (i = 0; i < sc->stripes; i++) {
DMEMIT("%c", atomic_read(&(sc->stripe[i].error_count)) ?
'D' : 'A');
}
break;
case STATUSTYPE_TABLE:
DMEMIT("%d %llu", sc->stripes,
(unsigned long long)sc->chunk_size);
for (i = 0; i < sc->stripes; i++)
DMEMIT(" %s %llu", sc->stripe[i].dev->name,
(unsigned long long)sc->stripe[i].physical_start);
break;
case STATUSTYPE_IMA:
DMEMIT_TARGET_NAME_VERSION(ti->type);
DMEMIT(",stripes=%d,chunk_size=%llu", sc->stripes,
(unsigned long long)sc->chunk_size);
for (i = 0; i < sc->stripes; i++) {
DMEMIT(",stripe_%d_device_name=%s", i, sc->stripe[i].dev->name);
DMEMIT(",stripe_%d_physical_start=%llu", i,
(unsigned long long)sc->stripe[i].physical_start);
DMEMIT(",stripe_%d_status=%c", i,
atomic_read(&(sc->stripe[i].error_count)) ? 'D' : 'A');
}
DMEMIT(";");
break;
}
}
static int stripe_end_io(struct dm_target *ti, struct bio *bio,
blk_status_t *error)
{
unsigned i;
char major_minor[16];
struct stripe_c *sc = ti->private;
if (!*error)
return DM_ENDIO_DONE; /* I/O complete */
if (bio->bi_opf & REQ_RAHEAD)
return DM_ENDIO_DONE;
if (*error == BLK_STS_NOTSUPP)
return DM_ENDIO_DONE;
memset(major_minor, 0, sizeof(major_minor));
sprintf(major_minor, "%d:%d", MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)));
/*
* Test to see which stripe drive triggered the event
* and increment error count for all stripes on that device.
* If the error count for a given device exceeds the threshold
* value we will no longer trigger any further events.
*/
for (i = 0; i < sc->stripes; i++)
if (!strcmp(sc->stripe[i].dev->name, major_minor)) {
atomic_inc(&(sc->stripe[i].error_count));
if (atomic_read(&(sc->stripe[i].error_count)) <
DM_IO_ERROR_THRESHOLD)
schedule_work(&sc->trigger_event);
}
return DM_ENDIO_DONE;
}
static int stripe_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn, void *data)
{
struct stripe_c *sc = ti->private;
int ret = 0;
unsigned i = 0;
do {
ret = fn(ti, sc->stripe[i].dev,
sc->stripe[i].physical_start,
sc->stripe_width, data);
} while (!ret && ++i < sc->stripes);
return ret;
}
static void stripe_io_hints(struct dm_target *ti,
struct queue_limits *limits)
{
struct stripe_c *sc = ti->private;
unsigned chunk_size = sc->chunk_size << SECTOR_SHIFT;
blk_limits_io_min(limits, chunk_size);
blk_limits_io_opt(limits, chunk_size * sc->stripes);
}
static struct target_type stripe_target = {
.name = "striped",
.version = {1, 6, 0},
.features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT,
.module = THIS_MODULE,
.ctr = stripe_ctr,
.dtr = stripe_dtr,
.map = stripe_map,
.end_io = stripe_end_io,
.status = stripe_status,
.iterate_devices = stripe_iterate_devices,
.io_hints = stripe_io_hints,
.direct_access = stripe_dax_direct_access,
.dax_zero_page_range = stripe_dax_zero_page_range,
};
int __init dm_stripe_init(void)
{
int r;
r = dm_register_target(&stripe_target);
if (r < 0)
DMWARN("target registration failed");
return r;
}
void dm_stripe_exit(void)
{
dm_unregister_target(&stripe_target);
}