13bd94003SHeinz Mauelshagen // SPDX-License-Identifier: GPL-2.0-only 21da177e4SLinus Torvalds /* 31da177e4SLinus Torvalds * Copyright (C) 2001 Sistina Software (UK) Limited 41da177e4SLinus Torvalds * 51da177e4SLinus Torvalds * This file is released under the GPL. 61da177e4SLinus Torvalds */ 71da177e4SLinus Torvalds 84cc96131SMike Snitzer #include "dm-core.h" 91da177e4SLinus Torvalds 101da177e4SLinus Torvalds #include <linux/module.h> 111da177e4SLinus Torvalds #include <linux/init.h> 121da177e4SLinus Torvalds #include <linux/kmod.h> 131da177e4SLinus Torvalds #include <linux/bio.h> 14e511c4a3SJane Chu #include <linux/dax.h> 151da177e4SLinus Torvalds 1672d94861SAlasdair G Kergon #define DM_MSG_PREFIX "target" 1772d94861SAlasdair G Kergon 181da177e4SLinus Torvalds static LIST_HEAD(_targets); 191da177e4SLinus Torvalds static DECLARE_RWSEM(_lock); 201da177e4SLinus Torvalds 2145194e4fSCheng Renquan static inline struct target_type *__find_target_type(const char *name) 221da177e4SLinus Torvalds { 2345194e4fSCheng Renquan struct target_type *tt; 241da177e4SLinus Torvalds 2545194e4fSCheng Renquan list_for_each_entry(tt, &_targets, list) 2645194e4fSCheng Renquan if (!strcmp(name, tt->name)) 2745194e4fSCheng Renquan return tt; 281da177e4SLinus Torvalds 291da177e4SLinus Torvalds return NULL; 301da177e4SLinus Torvalds } 311da177e4SLinus Torvalds 3245194e4fSCheng Renquan static struct target_type *get_target_type(const char *name) 331da177e4SLinus Torvalds { 3445194e4fSCheng Renquan struct target_type *tt; 351da177e4SLinus Torvalds 361da177e4SLinus Torvalds down_read(&_lock); 371da177e4SLinus Torvalds 3845194e4fSCheng Renquan tt = __find_target_type(name); 3945194e4fSCheng Renquan if (tt && !try_module_get(tt->module)) 4045194e4fSCheng Renquan tt = NULL; 411da177e4SLinus Torvalds 421da177e4SLinus Torvalds up_read(&_lock); 4345194e4fSCheng Renquan return tt; 441da177e4SLinus Torvalds } 451da177e4SLinus Torvalds 461da177e4SLinus Torvalds static void load_module(const char *name) 471da177e4SLinus Torvalds { 481da177e4SLinus Torvalds request_module("dm-%s", name); 491da177e4SLinus Torvalds } 501da177e4SLinus Torvalds 511da177e4SLinus Torvalds struct target_type *dm_get_target_type(const char *name) 521da177e4SLinus Torvalds { 5345194e4fSCheng Renquan struct target_type *tt = get_target_type(name); 541da177e4SLinus Torvalds 5545194e4fSCheng Renquan if (!tt) { 561da177e4SLinus Torvalds load_module(name); 5745194e4fSCheng Renquan tt = get_target_type(name); 581da177e4SLinus Torvalds } 591da177e4SLinus Torvalds 6045194e4fSCheng Renquan return tt; 611da177e4SLinus Torvalds } 621da177e4SLinus Torvalds 6345194e4fSCheng Renquan void dm_put_target_type(struct target_type *tt) 641da177e4SLinus Torvalds { 651da177e4SLinus Torvalds down_read(&_lock); 6645194e4fSCheng Renquan module_put(tt->module); 671da177e4SLinus Torvalds up_read(&_lock); 681da177e4SLinus Torvalds } 691da177e4SLinus Torvalds 701da177e4SLinus Torvalds int dm_target_iterate(void (*iter_func)(struct target_type *tt, 711da177e4SLinus Torvalds void *param), void *param) 721da177e4SLinus Torvalds { 7345194e4fSCheng Renquan struct target_type *tt; 741da177e4SLinus Torvalds 751da177e4SLinus Torvalds down_read(&_lock); 7645194e4fSCheng Renquan list_for_each_entry(tt, &_targets, list) 7745194e4fSCheng Renquan iter_func(tt, param); 781da177e4SLinus Torvalds up_read(&_lock); 791da177e4SLinus Torvalds 801da177e4SLinus Torvalds return 0; 811da177e4SLinus Torvalds } 821da177e4SLinus Torvalds 8345194e4fSCheng Renquan int dm_register_target(struct target_type *tt) 841da177e4SLinus Torvalds { 851da177e4SLinus Torvalds int rv = 0; 861da177e4SLinus Torvalds 871da177e4SLinus Torvalds down_write(&_lock); 88b362c733SYangtao Li if (__find_target_type(tt->name)) { 89b362c733SYangtao Li DMERR("%s: '%s' target already registered", 90b362c733SYangtao Li __func__, tt->name); 911da177e4SLinus Torvalds rv = -EEXIST; 92b362c733SYangtao Li } else { 9345194e4fSCheng Renquan list_add(&tt->list, &_targets); 94b362c733SYangtao Li } 951da177e4SLinus Torvalds up_write(&_lock); 96b362c733SYangtao Li 971da177e4SLinus Torvalds return rv; 981da177e4SLinus Torvalds } 99aa07f9d8SHeinz Mauelshagen EXPORT_SYMBOL(dm_register_target); 1001da177e4SLinus Torvalds 10145194e4fSCheng Renquan void dm_unregister_target(struct target_type *tt) 1021da177e4SLinus Torvalds { 1031da177e4SLinus Torvalds down_write(&_lock); 10445194e4fSCheng Renquan if (!__find_target_type(tt->name)) { 10545194e4fSCheng Renquan DMCRIT("Unregistering unrecognised target: %s", tt->name); 10610d3bd09SMikulas Patocka BUG(); 1071da177e4SLinus Torvalds } 1081da177e4SLinus Torvalds 10945194e4fSCheng Renquan list_del(&tt->list); 1101da177e4SLinus Torvalds 1111da177e4SLinus Torvalds up_write(&_lock); 1121da177e4SLinus Torvalds } 113aa07f9d8SHeinz Mauelshagen EXPORT_SYMBOL(dm_unregister_target); 1141da177e4SLinus Torvalds 1151da177e4SLinus Torvalds /* 1161da177e4SLinus Torvalds * io-err: always fails an io, useful for bringing 1171da177e4SLinus Torvalds * up LVs that have holes in them. 1181da177e4SLinus Torvalds */ 119*a9511043SDamien Le Moal struct io_err_c { 120*a9511043SDamien Le Moal struct dm_dev *dev; 121*a9511043SDamien Le Moal sector_t start; 122*a9511043SDamien Le Moal }; 123*a9511043SDamien Le Moal 124*a9511043SDamien Le Moal static int io_err_get_args(struct dm_target *tt, unsigned int argc, char **args) 125*a9511043SDamien Le Moal { 126*a9511043SDamien Le Moal unsigned long long start; 127*a9511043SDamien Le Moal struct io_err_c *ioec; 128*a9511043SDamien Le Moal char dummy; 129*a9511043SDamien Le Moal int ret; 130*a9511043SDamien Le Moal 131*a9511043SDamien Le Moal ioec = kmalloc(sizeof(*ioec), GFP_KERNEL); 132*a9511043SDamien Le Moal if (!ioec) { 133*a9511043SDamien Le Moal tt->error = "Cannot allocate io_err context"; 134*a9511043SDamien Le Moal return -ENOMEM; 135*a9511043SDamien Le Moal } 136*a9511043SDamien Le Moal 137*a9511043SDamien Le Moal ret = -EINVAL; 138*a9511043SDamien Le Moal if (sscanf(args[1], "%llu%c", &start, &dummy) != 1 || 139*a9511043SDamien Le Moal start != (sector_t)start) { 140*a9511043SDamien Le Moal tt->error = "Invalid device sector"; 141*a9511043SDamien Le Moal goto bad; 142*a9511043SDamien Le Moal } 143*a9511043SDamien Le Moal ioec->start = start; 144*a9511043SDamien Le Moal 145*a9511043SDamien Le Moal ret = dm_get_device(tt, args[0], dm_table_get_mode(tt->table), &ioec->dev); 146*a9511043SDamien Le Moal if (ret) { 147*a9511043SDamien Le Moal tt->error = "Device lookup failed"; 148*a9511043SDamien Le Moal goto bad; 149*a9511043SDamien Le Moal } 150*a9511043SDamien Le Moal 151*a9511043SDamien Le Moal tt->private = ioec; 152*a9511043SDamien Le Moal 153*a9511043SDamien Le Moal return 0; 154*a9511043SDamien Le Moal 155*a9511043SDamien Le Moal bad: 156*a9511043SDamien Le Moal kfree(ioec); 157*a9511043SDamien Le Moal 158*a9511043SDamien Le Moal return ret; 159*a9511043SDamien Le Moal } 160*a9511043SDamien Le Moal 16145194e4fSCheng Renquan static int io_err_ctr(struct dm_target *tt, unsigned int argc, char **args) 1621da177e4SLinus Torvalds { 16338e1b257SMike Snitzer /* 164*a9511043SDamien Le Moal * If we have arguments, assume it is the path to the backing 165*a9511043SDamien Le Moal * block device and its mapping start sector (same as dm-linear). 166*a9511043SDamien Le Moal * In this case, get the device so that we can get its limits. 167*a9511043SDamien Le Moal */ 168*a9511043SDamien Le Moal if (argc == 2) { 169*a9511043SDamien Le Moal int ret = io_err_get_args(tt, argc, args); 170*a9511043SDamien Le Moal 171*a9511043SDamien Le Moal if (ret) 172*a9511043SDamien Le Moal return ret; 173*a9511043SDamien Le Moal } 174*a9511043SDamien Le Moal 175*a9511043SDamien Le Moal /* 17638e1b257SMike Snitzer * Return error for discards instead of -EOPNOTSUPP 17738e1b257SMike Snitzer */ 17855a62eefSAlasdair G Kergon tt->num_discard_bios = 1; 179b6bcb844SMikulas Patocka tt->discards_supported = true; 18038e1b257SMike Snitzer 1811da177e4SLinus Torvalds return 0; 1821da177e4SLinus Torvalds } 1831da177e4SLinus Torvalds 18445194e4fSCheng Renquan static void io_err_dtr(struct dm_target *tt) 1851da177e4SLinus Torvalds { 186*a9511043SDamien Le Moal struct io_err_c *ioec = tt->private; 187*a9511043SDamien Le Moal 188*a9511043SDamien Le Moal if (ioec) { 189*a9511043SDamien Le Moal dm_put_device(tt, ioec->dev); 190*a9511043SDamien Le Moal kfree(ioec); 191*a9511043SDamien Le Moal } 1921da177e4SLinus Torvalds } 1931da177e4SLinus Torvalds 1947de3ee57SMikulas Patocka static int io_err_map(struct dm_target *tt, struct bio *bio) 1951da177e4SLinus Torvalds { 196846785e6SChristoph Hellwig return DM_MAPIO_KILL; 1971da177e4SLinus Torvalds } 1981da177e4SLinus Torvalds 199e5863d9aSMike Snitzer static int io_err_clone_and_map_rq(struct dm_target *ti, struct request *rq, 200e5863d9aSMike Snitzer union map_info *map_context, 201e5863d9aSMike Snitzer struct request **clone) 202e5863d9aSMike Snitzer { 203412445acSChristoph Hellwig return DM_MAPIO_KILL; 204e5863d9aSMike Snitzer } 205e5863d9aSMike Snitzer 2065de719e3SYufen Yu static void io_err_release_clone_rq(struct request *clone, 2075de719e3SYufen Yu union map_info *map_context) 208e5863d9aSMike Snitzer { 209e5863d9aSMike Snitzer } 210e5863d9aSMike Snitzer 211*a9511043SDamien Le Moal #ifdef CONFIG_BLK_DEV_ZONED 212*a9511043SDamien Le Moal static sector_t io_err_map_sector(struct dm_target *ti, sector_t bi_sector) 213*a9511043SDamien Le Moal { 214*a9511043SDamien Le Moal struct io_err_c *ioec = ti->private; 215*a9511043SDamien Le Moal 216*a9511043SDamien Le Moal return ioec->start + dm_target_offset(ti, bi_sector); 217*a9511043SDamien Le Moal } 218*a9511043SDamien Le Moal 219*a9511043SDamien Le Moal static int io_err_report_zones(struct dm_target *ti, 220*a9511043SDamien Le Moal struct dm_report_zones_args *args, unsigned int nr_zones) 221*a9511043SDamien Le Moal { 222*a9511043SDamien Le Moal struct io_err_c *ioec = ti->private; 223*a9511043SDamien Le Moal 224*a9511043SDamien Le Moal /* 225*a9511043SDamien Le Moal * This should never be called when we do not have a backing device 226*a9511043SDamien Le Moal * as that mean the target is not a zoned one. 227*a9511043SDamien Le Moal */ 228*a9511043SDamien Le Moal if (WARN_ON_ONCE(!ioec)) 229*a9511043SDamien Le Moal return -EIO; 230*a9511043SDamien Le Moal 231*a9511043SDamien Le Moal return dm_report_zones(ioec->dev->bdev, ioec->start, 232*a9511043SDamien Le Moal io_err_map_sector(ti, args->next_sector), 233*a9511043SDamien Le Moal args, nr_zones); 234*a9511043SDamien Le Moal } 235*a9511043SDamien Le Moal #else 236*a9511043SDamien Le Moal #define io_err_report_zones NULL 237*a9511043SDamien Le Moal #endif 238*a9511043SDamien Le Moal 239*a9511043SDamien Le Moal static int io_err_iterate_devices(struct dm_target *ti, 240*a9511043SDamien Le Moal iterate_devices_callout_fn fn, void *data) 241*a9511043SDamien Le Moal { 242*a9511043SDamien Le Moal struct io_err_c *ioec = ti->private; 243*a9511043SDamien Le Moal 244*a9511043SDamien Le Moal if (!ioec) 245*a9511043SDamien Le Moal return 0; 246*a9511043SDamien Le Moal 247*a9511043SDamien Le Moal return fn(ti, ioec->dev, ioec->start, ti->len, data); 248*a9511043SDamien Le Moal } 249*a9511043SDamien Le Moal 250b6bcb844SMikulas Patocka static void io_err_io_hints(struct dm_target *ti, struct queue_limits *limits) 251b6bcb844SMikulas Patocka { 252b6bcb844SMikulas Patocka limits->max_hw_discard_sectors = UINT_MAX; 253b6bcb844SMikulas Patocka limits->discard_granularity = 512; 254b6bcb844SMikulas Patocka } 255b6bcb844SMikulas Patocka 256817bf402SDan Williams static long io_err_dax_direct_access(struct dm_target *ti, pgoff_t pgoff, 257e511c4a3SJane Chu long nr_pages, enum dax_access_mode mode, void **kaddr, 258e511c4a3SJane Chu pfn_t *pfn) 259f8df1fdfSMike Snitzer { 260f8df1fdfSMike Snitzer return -EIO; 261f8df1fdfSMike Snitzer } 262f8df1fdfSMike Snitzer 2631da177e4SLinus Torvalds static struct target_type error_target = { 2641da177e4SLinus Torvalds .name = "error", 265*a9511043SDamien Le Moal .version = {1, 7, 0}, 266*a9511043SDamien Le Moal .features = DM_TARGET_WILDCARD | DM_TARGET_ZONED_HM, 2671da177e4SLinus Torvalds .ctr = io_err_ctr, 2681da177e4SLinus Torvalds .dtr = io_err_dtr, 2691da177e4SLinus Torvalds .map = io_err_map, 270e5863d9aSMike Snitzer .clone_and_map_rq = io_err_clone_and_map_rq, 271e5863d9aSMike Snitzer .release_clone_rq = io_err_release_clone_rq, 272*a9511043SDamien Le Moal .iterate_devices = io_err_iterate_devices, 273b6bcb844SMikulas Patocka .io_hints = io_err_io_hints, 274817bf402SDan Williams .direct_access = io_err_dax_direct_access, 275*a9511043SDamien Le Moal .report_zones = io_err_report_zones, 2761da177e4SLinus Torvalds }; 2771da177e4SLinus Torvalds 2781da177e4SLinus Torvalds int __init dm_target_init(void) 2791da177e4SLinus Torvalds { 2801da177e4SLinus Torvalds return dm_register_target(&error_target); 2811da177e4SLinus Torvalds } 2821da177e4SLinus Torvalds 2831da177e4SLinus Torvalds void dm_target_exit(void) 2841da177e4SLinus Torvalds { 28510d3bd09SMikulas Patocka dm_unregister_target(&error_target); 2861da177e4SLinus Torvalds } 287