mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-24 01:41:39 +00:00
![Yufen Yu](/assets/img/avatar_default.png)
After commit396eaf21ee
("blk-mq: improve DM's blk-mq IO merging via blk_insert_cloned_request feedback"), map_request() will requeue the tio when issued clone request return BLK_STS_RESOURCE or BLK_STS_DEV_RESOURCE. Thus, if device driver status is error, a tio may be requeued multiple times until the return value is not DM_MAPIO_REQUEUE. That means type->start_io may be called multiple times, while type->end_io is only called when IO complete. In fact, even without commit396eaf21ee
, setup_clone() failure can also cause tio requeue and associated missed call to type->end_io. The service-time path selector selects path based on in_flight_size, which is increased by st_start_io() and decreased by st_end_io(). Missed calls to st_end_io() can lead to in_flight_size count error and will cause the selector to make the wrong choice. In addition, queue-length path selector will also be affected. To fix the problem, call type->end_io in ->release_clone_rq before tio requeue. map_info is passed to ->release_clone_rq() for map_request() error path that result in requeue. Fixes:396eaf21ee
("blk-mq: improve DM's blk-mq IO merging via blk_insert_cloned_request feedback") Cc: stable@vger.kernl.org Signed-off-by: Yufen Yu <yuyufen@huawei.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
173 lines
3.1 KiB
C
173 lines
3.1 KiB
C
/*
|
|
* Copyright (C) 2001 Sistina Software (UK) Limited
|
|
*
|
|
* This file is released under the GPL.
|
|
*/
|
|
|
|
#include "dm-core.h"
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/init.h>
|
|
#include <linux/kmod.h>
|
|
#include <linux/bio.h>
|
|
|
|
#define DM_MSG_PREFIX "target"
|
|
|
|
static LIST_HEAD(_targets);
|
|
static DECLARE_RWSEM(_lock);
|
|
|
|
static inline struct target_type *__find_target_type(const char *name)
|
|
{
|
|
struct target_type *tt;
|
|
|
|
list_for_each_entry(tt, &_targets, list)
|
|
if (!strcmp(name, tt->name))
|
|
return tt;
|
|
|
|
return NULL;
|
|
}
|
|
|
|
static struct target_type *get_target_type(const char *name)
|
|
{
|
|
struct target_type *tt;
|
|
|
|
down_read(&_lock);
|
|
|
|
tt = __find_target_type(name);
|
|
if (tt && !try_module_get(tt->module))
|
|
tt = NULL;
|
|
|
|
up_read(&_lock);
|
|
return tt;
|
|
}
|
|
|
|
static void load_module(const char *name)
|
|
{
|
|
request_module("dm-%s", name);
|
|
}
|
|
|
|
struct target_type *dm_get_target_type(const char *name)
|
|
{
|
|
struct target_type *tt = get_target_type(name);
|
|
|
|
if (!tt) {
|
|
load_module(name);
|
|
tt = get_target_type(name);
|
|
}
|
|
|
|
return tt;
|
|
}
|
|
|
|
void dm_put_target_type(struct target_type *tt)
|
|
{
|
|
down_read(&_lock);
|
|
module_put(tt->module);
|
|
up_read(&_lock);
|
|
}
|
|
|
|
int dm_target_iterate(void (*iter_func)(struct target_type *tt,
|
|
void *param), void *param)
|
|
{
|
|
struct target_type *tt;
|
|
|
|
down_read(&_lock);
|
|
list_for_each_entry(tt, &_targets, list)
|
|
iter_func(tt, param);
|
|
up_read(&_lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
int dm_register_target(struct target_type *tt)
|
|
{
|
|
int rv = 0;
|
|
|
|
down_write(&_lock);
|
|
if (__find_target_type(tt->name))
|
|
rv = -EEXIST;
|
|
else
|
|
list_add(&tt->list, &_targets);
|
|
|
|
up_write(&_lock);
|
|
return rv;
|
|
}
|
|
|
|
void dm_unregister_target(struct target_type *tt)
|
|
{
|
|
down_write(&_lock);
|
|
if (!__find_target_type(tt->name)) {
|
|
DMCRIT("Unregistering unrecognised target: %s", tt->name);
|
|
BUG();
|
|
}
|
|
|
|
list_del(&tt->list);
|
|
|
|
up_write(&_lock);
|
|
}
|
|
|
|
/*
|
|
* io-err: always fails an io, useful for bringing
|
|
* up LVs that have holes in them.
|
|
*/
|
|
static int io_err_ctr(struct dm_target *tt, unsigned int argc, char **args)
|
|
{
|
|
/*
|
|
* Return error for discards instead of -EOPNOTSUPP
|
|
*/
|
|
tt->num_discard_bios = 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void io_err_dtr(struct dm_target *tt)
|
|
{
|
|
/* empty */
|
|
}
|
|
|
|
static int io_err_map(struct dm_target *tt, struct bio *bio)
|
|
{
|
|
return DM_MAPIO_KILL;
|
|
}
|
|
|
|
static int io_err_clone_and_map_rq(struct dm_target *ti, struct request *rq,
|
|
union map_info *map_context,
|
|
struct request **clone)
|
|
{
|
|
return DM_MAPIO_KILL;
|
|
}
|
|
|
|
static void io_err_release_clone_rq(struct request *clone,
|
|
union map_info *map_context)
|
|
{
|
|
}
|
|
|
|
static long io_err_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
|
|
long nr_pages, void **kaddr, pfn_t *pfn)
|
|
{
|
|
return -EIO;
|
|
}
|
|
|
|
static struct target_type error_target = {
|
|
.name = "error",
|
|
.version = {1, 5, 0},
|
|
.features = DM_TARGET_WILDCARD,
|
|
.ctr = io_err_ctr,
|
|
.dtr = io_err_dtr,
|
|
.map = io_err_map,
|
|
.clone_and_map_rq = io_err_clone_and_map_rq,
|
|
.release_clone_rq = io_err_release_clone_rq,
|
|
.direct_access = io_err_dax_direct_access,
|
|
};
|
|
|
|
int __init dm_target_init(void)
|
|
{
|
|
return dm_register_target(&error_target);
|
|
}
|
|
|
|
void dm_target_exit(void)
|
|
{
|
|
dm_unregister_target(&error_target);
|
|
}
|
|
|
|
EXPORT_SYMBOL(dm_register_target);
|
|
EXPORT_SYMBOL(dm_unregister_target);
|