linux/drivers/md/dm-core.h
Mikulas Patocka aad5b23ebf dm: fix dm_io and dm_target_io flags race condition on Alpha
Early alpha processors cannot write a single byte or short; they read 8
bytes, modify the value in registers and write back 8 bytes.

This could cause race condition in the structure dm_io - if the fields
flags and io_count are modified simultaneously.

Fix this bug by using 32-bit flags if we are on Alpha and if we are
compiling for a processor that doesn't have the byte-word-extension.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: bd4a6dd241 ("dm: reduce size of dm_io and dm_target_io structs")
[snitzer: Jens allowed this change since Mikulas owns a relevant Alpha!]
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2022-04-01 13:19:27 -04:00

304 lines
6.2 KiB
C

/*
* Internal header file _only_ for device mapper core
*
* Copyright (C) 2016 Red Hat, Inc. All rights reserved.
*
* This file is released under the LGPL.
*/
#ifndef DM_CORE_INTERNAL_H
#define DM_CORE_INTERNAL_H
#include <linux/kthread.h>
#include <linux/ktime.h>
#include <linux/blk-mq.h>
#include <linux/blk-crypto-profile.h>
#include <trace/events/block.h>
#include "dm.h"
#include "dm-ima.h"
#define DM_RESERVED_MAX_IOS 1024
struct dm_kobject_holder {
struct kobject kobj;
struct completion completion;
};
/*
* DM core internal structures used directly by dm.c, dm-rq.c and dm-table.c.
* DM targets must _not_ deference a mapped_device or dm_table to directly
* access their members!
*/
struct mapped_device {
struct mutex suspend_lock;
struct mutex table_devices_lock;
struct list_head table_devices;
/*
* The current mapping (struct dm_table *).
* Use dm_get_live_table{_fast} or take suspend_lock for
* dereference.
*/
void __rcu *map;
unsigned long flags;
/* Protect queue and type against concurrent access. */
struct mutex type_lock;
enum dm_queue_mode type;
int numa_node_id;
struct request_queue *queue;
atomic_t holders;
atomic_t open_count;
struct dm_target *immutable_target;
struct target_type *immutable_target_type;
char name[16];
struct gendisk *disk;
struct dax_device *dax_dev;
wait_queue_head_t wait;
unsigned long __percpu *pending_io;
/* forced geometry settings */
struct hd_geometry geometry;
/*
* Processing queue (flush)
*/
struct workqueue_struct *wq;
/*
* A list of ios that arrived while we were suspended.
*/
struct work_struct work;
spinlock_t deferred_lock;
struct bio_list deferred;
void *interface_ptr;
/*
* Event handling.
*/
wait_queue_head_t eventq;
atomic_t event_nr;
atomic_t uevent_seq;
struct list_head uevent_list;
spinlock_t uevent_lock; /* Protect access to uevent_list */
/* for blk-mq request-based DM support */
bool init_tio_pdu:1;
struct blk_mq_tag_set *tag_set;
struct dm_stats stats;
/* the number of internal suspends */
unsigned internal_suspend_count;
int swap_bios;
struct semaphore swap_bios_semaphore;
struct mutex swap_bios_lock;
/*
* io objects are allocated from here.
*/
struct bio_set io_bs;
struct bio_set bs;
/* kobject and completion */
struct dm_kobject_holder kobj_holder;
struct srcu_struct io_barrier;
#ifdef CONFIG_BLK_DEV_ZONED
unsigned int nr_zones;
unsigned int *zwp_offset;
#endif
#ifdef CONFIG_IMA
struct dm_ima_measurements ima;
#endif
};
/*
* Bits for the flags field of struct mapped_device.
*/
#define DMF_BLOCK_IO_FOR_SUSPEND 0
#define DMF_SUSPENDED 1
#define DMF_FROZEN 2
#define DMF_FREEING 3
#define DMF_DELETING 4
#define DMF_NOFLUSH_SUSPENDING 5
#define DMF_DEFERRED_REMOVE 6
#define DMF_SUSPENDED_INTERNALLY 7
#define DMF_POST_SUSPENDING 8
#define DMF_EMULATE_ZONE_APPEND 9
void disable_discard(struct mapped_device *md);
void disable_write_zeroes(struct mapped_device *md);
static inline sector_t dm_get_size(struct mapped_device *md)
{
return get_capacity(md->disk);
}
static inline struct dm_stats *dm_get_stats(struct mapped_device *md)
{
return &md->stats;
}
static inline bool dm_emulate_zone_append(struct mapped_device *md)
{
if (blk_queue_is_zoned(md->queue))
return test_bit(DMF_EMULATE_ZONE_APPEND, &md->flags);
return false;
}
#define DM_TABLE_MAX_DEPTH 16
struct dm_table {
struct mapped_device *md;
enum dm_queue_mode type;
/* btree table */
unsigned int depth;
unsigned int counts[DM_TABLE_MAX_DEPTH]; /* in nodes */
sector_t *index[DM_TABLE_MAX_DEPTH];
unsigned int num_targets;
unsigned int num_allocated;
sector_t *highs;
struct dm_target *targets;
struct target_type *immutable_target_type;
bool integrity_supported:1;
bool singleton:1;
unsigned integrity_added:1;
/*
* Indicates the rw permissions for the new logical
* device. This should be a combination of FMODE_READ
* and FMODE_WRITE.
*/
fmode_t mode;
/* a list of devices used by this table */
struct list_head devices;
/* events get handed up using this callback */
void (*event_fn)(void *);
void *event_context;
struct dm_md_mempools *mempools;
#ifdef CONFIG_BLK_INLINE_ENCRYPTION
struct blk_crypto_profile *crypto_profile;
#endif
};
/*
* One of these is allocated per clone bio.
*/
#define DM_TIO_MAGIC 28714
struct dm_target_io {
unsigned short magic;
blk_short_t flags;
unsigned int target_bio_nr;
struct dm_io *io;
struct dm_target *ti;
unsigned int *len_ptr;
sector_t old_sector;
struct bio clone;
};
/*
* dm_target_io flags
*/
enum {
DM_TIO_INSIDE_DM_IO,
DM_TIO_IS_DUPLICATE_BIO
};
static inline bool dm_tio_flagged(struct dm_target_io *tio, unsigned int bit)
{
return (tio->flags & (1U << bit)) != 0;
}
static inline void dm_tio_set_flag(struct dm_target_io *tio, unsigned int bit)
{
tio->flags |= (1U << bit);
}
/*
* One of these is allocated per original bio.
* It contains the first clone used for that original.
*/
#define DM_IO_MAGIC 19577
struct dm_io {
unsigned short magic;
blk_short_t flags;
atomic_t io_count;
struct mapped_device *md;
struct bio *orig_bio;
blk_status_t status;
spinlock_t lock;
unsigned long start_time;
void *data;
struct hlist_node node;
struct task_struct *map_task;
struct dm_stats_aux stats_aux;
/* last member of dm_target_io is 'struct bio' */
struct dm_target_io tio;
};
/*
* dm_io flags
*/
enum {
DM_IO_START_ACCT,
DM_IO_ACCOUNTED
};
static inline bool dm_io_flagged(struct dm_io *io, unsigned int bit)
{
return (io->flags & (1U << bit)) != 0;
}
static inline void dm_io_set_flag(struct dm_io *io, unsigned int bit)
{
io->flags |= (1U << bit);
}
static inline void dm_io_inc_pending(struct dm_io *io)
{
atomic_inc(&io->io_count);
}
void dm_io_dec_pending(struct dm_io *io, blk_status_t error);
static inline struct completion *dm_get_completion_from_kobject(struct kobject *kobj)
{
return &container_of(kobj, struct dm_kobject_holder, kobj)->completion;
}
unsigned __dm_get_module_param(unsigned *module_param, unsigned def, unsigned max);
static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen)
{
return !maxlen || strlen(result) + 1 >= maxlen;
}
extern atomic_t dm_global_event_nr;
extern wait_queue_head_t dm_global_eventq;
void dm_issue_global_event(void);
#endif