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-rw-r--r--drivers/md/dm-linear.c230
1 files changed, 230 insertions, 0 deletions
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
new file mode 100644
index 0000000000..f4448d520e
--- /dev/null
+++ b/drivers/md/dm-linear.c
@@ -0,0 +1,230 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2001-2003 Sistina Software (UK) Limited.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm.h"
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+#include <linux/dax.h>
+#include <linux/slab.h>
+#include <linux/device-mapper.h>
+
+#define DM_MSG_PREFIX "linear"
+
+/*
+ * Linear: maps a linear range of a device.
+ */
+struct linear_c {
+ struct dm_dev *dev;
+ sector_t start;
+};
+
+/*
+ * Construct a linear mapping: <dev_path> <offset>
+ */
+static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+ struct linear_c *lc;
+ unsigned long long tmp;
+ char dummy;
+ int ret;
+
+ if (argc != 2) {
+ ti->error = "Invalid argument count";
+ return -EINVAL;
+ }
+
+ lc = kmalloc(sizeof(*lc), GFP_KERNEL);
+ if (lc == NULL) {
+ ti->error = "Cannot allocate linear context";
+ return -ENOMEM;
+ }
+
+ ret = -EINVAL;
+ if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1 || tmp != (sector_t)tmp) {
+ ti->error = "Invalid device sector";
+ goto bad;
+ }
+ lc->start = tmp;
+
+ ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &lc->dev);
+ if (ret) {
+ ti->error = "Device lookup failed";
+ goto bad;
+ }
+
+ ti->num_flush_bios = 1;
+ ti->num_discard_bios = 1;
+ ti->num_secure_erase_bios = 1;
+ ti->num_write_zeroes_bios = 1;
+ ti->private = lc;
+ return 0;
+
+bad:
+ kfree(lc);
+ return ret;
+}
+
+static void linear_dtr(struct dm_target *ti)
+{
+ struct linear_c *lc = ti->private;
+
+ dm_put_device(ti, lc->dev);
+ kfree(lc);
+}
+
+static sector_t linear_map_sector(struct dm_target *ti, sector_t bi_sector)
+{
+ struct linear_c *lc = ti->private;
+
+ return lc->start + dm_target_offset(ti, bi_sector);
+}
+
+static int linear_map(struct dm_target *ti, struct bio *bio)
+{
+ struct linear_c *lc = ti->private;
+
+ bio_set_dev(bio, lc->dev->bdev);
+ bio->bi_iter.bi_sector = linear_map_sector(ti, bio->bi_iter.bi_sector);
+
+ return DM_MAPIO_REMAPPED;
+}
+
+static void linear_status(struct dm_target *ti, status_type_t type,
+ unsigned int status_flags, char *result, unsigned int maxlen)
+{
+ struct linear_c *lc = ti->private;
+ size_t sz = 0;
+
+ switch (type) {
+ case STATUSTYPE_INFO:
+ result[0] = '\0';
+ break;
+
+ case STATUSTYPE_TABLE:
+ DMEMIT("%s %llu", lc->dev->name, (unsigned long long)lc->start);
+ break;
+
+ case STATUSTYPE_IMA:
+ DMEMIT_TARGET_NAME_VERSION(ti->type);
+ DMEMIT(",device_name=%s,start=%llu;", lc->dev->name,
+ (unsigned long long)lc->start);
+ break;
+ }
+}
+
+static int linear_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
+{
+ struct linear_c *lc = ti->private;
+ struct dm_dev *dev = lc->dev;
+
+ *bdev = dev->bdev;
+
+ /*
+ * Only pass ioctls through if the device sizes match exactly.
+ */
+ if (lc->start || ti->len != bdev_nr_sectors(dev->bdev))
+ return 1;
+ return 0;
+}
+
+#ifdef CONFIG_BLK_DEV_ZONED
+static int linear_report_zones(struct dm_target *ti,
+ struct dm_report_zones_args *args, unsigned int nr_zones)
+{
+ struct linear_c *lc = ti->private;
+
+ return dm_report_zones(lc->dev->bdev, lc->start,
+ linear_map_sector(ti, args->next_sector),
+ args, nr_zones);
+}
+#else
+#define linear_report_zones NULL
+#endif
+
+static int linear_iterate_devices(struct dm_target *ti,
+ iterate_devices_callout_fn fn, void *data)
+{
+ struct linear_c *lc = ti->private;
+
+ return fn(ti, lc->dev, lc->start, ti->len, data);
+}
+
+#if IS_ENABLED(CONFIG_FS_DAX)
+static struct dax_device *linear_dax_pgoff(struct dm_target *ti, pgoff_t *pgoff)
+{
+ struct linear_c *lc = ti->private;
+ sector_t sector = linear_map_sector(ti, *pgoff << PAGE_SECTORS_SHIFT);
+
+ *pgoff = (get_start_sect(lc->dev->bdev) + sector) >> PAGE_SECTORS_SHIFT;
+ return lc->dev->dax_dev;
+}
+
+static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
+ long nr_pages, enum dax_access_mode mode, void **kaddr,
+ pfn_t *pfn)
+{
+ struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff);
+
+ return dax_direct_access(dax_dev, pgoff, nr_pages, mode, kaddr, pfn);
+}
+
+static int linear_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,
+ size_t nr_pages)
+{
+ struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff);
+
+ return dax_zero_page_range(dax_dev, pgoff, nr_pages);
+}
+
+static size_t linear_dax_recovery_write(struct dm_target *ti, pgoff_t pgoff,
+ void *addr, size_t bytes, struct iov_iter *i)
+{
+ struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff);
+
+ return dax_recovery_write(dax_dev, pgoff, addr, bytes, i);
+}
+
+#else
+#define linear_dax_direct_access NULL
+#define linear_dax_zero_page_range NULL
+#define linear_dax_recovery_write NULL
+#endif
+
+static struct target_type linear_target = {
+ .name = "linear",
+ .version = {1, 4, 0},
+ .features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT |
+ DM_TARGET_ZONED_HM | DM_TARGET_PASSES_CRYPTO,
+ .report_zones = linear_report_zones,
+ .module = THIS_MODULE,
+ .ctr = linear_ctr,
+ .dtr = linear_dtr,
+ .map = linear_map,
+ .status = linear_status,
+ .prepare_ioctl = linear_prepare_ioctl,
+ .iterate_devices = linear_iterate_devices,
+ .direct_access = linear_dax_direct_access,
+ .dax_zero_page_range = linear_dax_zero_page_range,
+ .dax_recovery_write = linear_dax_recovery_write,
+};
+
+int __init dm_linear_init(void)
+{
+ int r = dm_register_target(&linear_target);
+
+ if (r < 0)
+ DMERR("register failed %d", r);
+
+ return r;
+}
+
+void dm_linear_exit(void)
+{
+ dm_unregister_target(&linear_target);
+}