From 76cb841cb886eef6b3bee341a2266c76578724ad Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 6 May 2024 03:02:30 +0200 Subject: Adding upstream version 4.19.249. Signed-off-by: Daniel Baumann --- drivers/md/dm-target.c | 173 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 173 insertions(+) create mode 100644 drivers/md/dm-target.c (limited to 'drivers/md/dm-target.c') diff --git a/drivers/md/dm-target.c b/drivers/md/dm-target.c new file mode 100644 index 000000000..64dd0b34f --- /dev/null +++ b/drivers/md/dm-target.c @@ -0,0 +1,173 @@ +/* + * Copyright (C) 2001 Sistina Software (UK) Limited + * + * This file is released under the GPL. + */ + +#include "dm-core.h" + +#include +#include +#include +#include + +#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); -- cgit v1.2.3