/* * Copyright (C) 2017 Intel Corporation. * * This file is released under the GPL. */ #include "dm.h" #include <linux/module.h> struct unstripe_c { struct dm_dev *dev; sector_t physical_start; uint32_t stripes; uint32_t unstripe; sector_t unstripe_width; sector_t unstripe_offset; uint32_t chunk_size; u8 chunk_shift; }; #define DM_MSG_PREFIX "unstriped" static void cleanup_unstripe(struct unstripe_c *uc, struct dm_target *ti) { if (uc->dev) dm_put_device(ti, uc->dev); kfree(uc); } /* * Contruct an unstriped mapping. * <number of stripes> <chunk size> <stripe #> <dev_path> <offset> */ static int unstripe_ctr(struct dm_target *ti, unsigned int argc, char **argv) { struct unstripe_c *uc; sector_t tmp_len; unsigned long long start; char dummy; if (argc != 5) { ti->error = "Invalid number of arguments"; return -EINVAL; } uc = kzalloc(sizeof(*uc), GFP_KERNEL); if (!uc) { ti->error = "Memory allocation for unstriped context failed"; return -ENOMEM; } if (kstrtouint(argv[0], 10, &uc->stripes) || !uc->stripes) { ti->error = "Invalid stripe count"; goto err; } if (kstrtouint(argv[1], 10, &uc->chunk_size) || !uc->chunk_size) { ti->error = "Invalid chunk_size"; goto err; } if (kstrtouint(argv[2], 10, &uc->unstripe)) { ti->error = "Invalid stripe number"; goto err; } if (uc->unstripe > uc->stripes && uc->stripes > 1) { ti->error = "Please provide stripe between [0, # of stripes]"; goto err; } if (dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &uc->dev)) { ti->error = "Couldn't get striped device"; goto err; } if (sscanf(argv[4], "%llu%c", &start, &dummy) != 1 || start != (sector_t)start) { ti->error = "Invalid striped device offset"; goto err; } uc->physical_start = start; uc->unstripe_offset = uc->unstripe * uc->chunk_size; uc->unstripe_width = (uc->stripes - 1) * uc->chunk_size; uc->chunk_shift = is_power_of_2(uc->chunk_size) ? fls(uc->chunk_size) - 1 : 0; tmp_len = ti->len; if (sector_div(tmp_len, uc->chunk_size)) { ti->error = "Target length not divisible by chunk size"; goto err; } if (dm_set_target_max_io_len(ti, uc->chunk_size)) { ti->error = "Failed to set max io len"; goto err; } ti->private = uc; return 0; err: cleanup_unstripe(uc, ti); return -EINVAL; } static void unstripe_dtr(struct dm_target *ti) { struct unstripe_c *uc = ti->private; cleanup_unstripe(uc, ti); } static sector_t map_to_core(struct dm_target *ti, struct bio *bio) { struct unstripe_c *uc = ti->private; sector_t sector = bio->bi_iter.bi_sector; sector_t tmp_sector = sector; /* Shift us up to the right "row" on the stripe */ if (uc->chunk_shift) tmp_sector >>= uc->chunk_shift; else sector_div(tmp_sector, uc->chunk_size); sector += uc->unstripe_width * tmp_sector; /* Account for what stripe we're operating on */ return sector + uc->unstripe_offset; } static int unstripe_map(struct dm_target *ti, struct bio *bio) { struct unstripe_c *uc = ti->private; bio_set_dev(bio, uc->dev->bdev); bio->bi_iter.bi_sector = map_to_core(ti, bio) + uc->physical_start; return DM_MAPIO_REMAPPED; } static void unstripe_status(struct dm_target *ti, status_type_t type, unsigned int status_flags, char *result, unsigned int maxlen) { struct unstripe_c *uc = ti->private; unsigned int sz = 0; switch (type) { case STATUSTYPE_INFO: break; case STATUSTYPE_TABLE: DMEMIT("%d %llu %d %s %llu", uc->stripes, (unsigned long long)uc->chunk_size, uc->unstripe, uc->dev->name, (unsigned long long)uc->physical_start); break; } } static int unstripe_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data) { struct unstripe_c *uc = ti->private; return fn(ti, uc->dev, uc->physical_start, ti->len, data); } static void unstripe_io_hints(struct dm_target *ti, struct queue_limits *limits) { struct unstripe_c *uc = ti->private; limits->chunk_sectors = uc->chunk_size; } static struct target_type unstripe_target = { .name = "unstriped", .version = {1, 1, 0}, .module = THIS_MODULE, .ctr = unstripe_ctr, .dtr = unstripe_dtr, .map = unstripe_map, .status = unstripe_status, .iterate_devices = unstripe_iterate_devices, .io_hints = unstripe_io_hints, }; static int __init dm_unstripe_init(void) { return dm_register_target(&unstripe_target); } static void __exit dm_unstripe_exit(void) { dm_unregister_target(&unstripe_target); } module_init(dm_unstripe_init); module_exit(dm_unstripe_exit); MODULE_DESCRIPTION(DM_NAME " unstriped target"); MODULE_ALIAS("dm-unstriped"); MODULE_AUTHOR("Scott Bauer <scott.bauer@intel.com>"); MODULE_LICENSE("GPL");