[PATCH] md: Add missing md-linear.c

Song Liu
2025-01-13T06:13:29Z

md-linear.c was missed during manual fix-up of a git-am conflict.
Add it back.

Fixes: 7ad00dd67641 ("md: reintroduce md-linear")
Signed-off-by: Song Liu <song@kernel.org>
---
drivers/md/md-linear.c | 354 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 354 insertions(+)
create mode 100644 drivers/md/md-linear.c

diff --git a/drivers/md/md-linear.c b/drivers/md/md-linear.c
new file mode 100644
index 000000000000..53bc3fda9edb
--- /dev/null
+++ b/drivers/md/md-linear.c
@@ -0,0 +1,354 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * linear.c : Multiple Devices driver for Linux Copyright (C) 1994-96 Marc
+ * ZYNGIER <zyngier@ufr-info-p7.ibp.fr> or <maz@gloups.fdn.fr>
+ */
+
+#include <linux/blkdev.h>
+#include <linux/raid/md_u.h>
+#include <linux/seq_file.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <trace/events/block.h>
+#include "md.h"
+
+struct dev_info {
+ struct md_rdev *rdev;
+ sector_t end_sector;
+};
+
+struct linear_conf {
+ struct rcu_head rcu;
+ sector_t array_sectors;
+ /* a copy of mddev->raid_disks */
+ int raid_disks;
+ struct dev_info disks[] __counted_by(raid_disks);
+};
+
+/*
+ * find which device holds a particular offset
+ */
+static inline struct dev_info *which_dev(struct mddev *mddev, sector_t sector)
+{
+ int lo, mid, hi;
+ struct linear_conf *conf;
+
+ lo = 0;
+ hi = mddev->raid_disks - 1;
+ conf = mddev->private;
+
+ /*
+ * Binary Search
+ */
+
+ while (hi > lo) {
+
+ mid = (hi + lo) / 2;
+ if (sector < conf->disks[mid].end_sector)
+ hi = mid;
+ else
+ lo = mid + 1;
+ }
+
+ return conf->disks + lo;
+}
+
+static sector_t linear_size(struct mddev *mddev, sector_t sectors, int raid_disks)
+{
+ struct linear_conf *conf;
+ sector_t array_sectors;
+
+ conf = mddev->private;
+ WARN_ONCE(sectors || raid_disks,
+ "%s does not support generic reshape\n", __func__);
+ array_sectors = conf->array_sectors;
+
+ return array_sectors;
+}
+
+static int linear_set_limits(struct mddev *mddev)
+{
+ struct queue_limits lim;
+ int err;
+
+ md_init_stacking_limits(&lim);
+ lim.max_hw_sectors = mddev->chunk_sectors;
+ lim.max_write_zeroes_sectors = mddev->chunk_sectors;
+ lim.io_min = mddev->chunk_sectors << 9;
+ err = mddev_stack_rdev_limits(mddev, &lim, MDDEV_STACK_INTEGRITY);
+ if (err) {
+ queue_limits_cancel_update(mddev->gendisk->queue);
+ return err;
+ }
+
+ return queue_limits_set(mddev->gendisk->queue, &lim);
+}
+
+static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks)
+{
+ struct linear_conf *conf;
+ struct md_rdev *rdev;
+ int ret = -EINVAL;
+ int cnt;
+ int i;
+
+ conf = kzalloc(struct_size(conf, disks, raid_disks), GFP_KERNEL);
+ if (!conf)
+ return ERR_PTR(-ENOMEM);
+
+ /*
+ * conf->raid_disks is copy of mddev->raid_disks. The reason to
+ * keep a copy of mddev->raid_disks in struct linear_conf is,
+ * mddev->raid_disks may not be consistent with pointers number of
+ * conf->disks[] when it is updated in linear_add() and used to
+ * iterate old conf->disks[] earray in linear_congested().
+ * Here conf->raid_disks is always consitent with number of
+ * pointers in conf->disks[] array, and mddev->private is updated
+ * with rcu_assign_pointer() in linear_addr(), such race can be
+ * avoided.
+ */
+ conf->raid_disks = raid_disks;
+
+ cnt = 0;
+ conf->array_sectors = 0;
+
+ rdev_for_each(rdev, mddev) {
+ int j = rdev->raid_disk;
+ struct dev_info *disk = conf->disks + j;
+ sector_t sectors;
+
+ if (j < 0 || j >= raid_disks || disk->rdev) {
+ pr_warn("md/linear:%s: disk numbering problem. Aborting!\n",
+ mdname(mddev));
+ goto out;
+ }
+
+ disk->rdev = rdev;
+ if (mddev->chunk_sectors) {
+ sectors = rdev->sectors;
+ sector_div(sectors, mddev->chunk_sectors);
+ rdev->sectors = sectors * mddev->chunk_sectors;
+ }
+
+ conf->array_sectors += rdev->sectors;
+ cnt++;
+ }
+ if (cnt != raid_disks) {
+ pr_warn("md/linear:%s: not enough drives present. Aborting!\n",
+ mdname(mddev));
+ goto out;
+ }
+
+ /*
+ * Here we calculate the device offsets.
+ */
+ conf->disks[0].end_sector = conf->disks[0].rdev->sectors;
+
+ for (i = 1; i < raid_disks; i++)
+ conf->disks[i].end_sector =
+ conf->disks[i-1].end_sector +
+ conf->disks[i].rdev->sectors;
+
+ if (!mddev_is_dm(mddev)) {
+ ret = linear_set_limits(mddev);
+ if (ret)
+ goto out;
+ }
+
+ return conf;
+
+out:
+ kfree(conf);
+ return ERR_PTR(ret);
+}
+
+static int linear_run(struct mddev *mddev)
+{
+ struct linear_conf *conf;
+ int ret;
+
+ if (md_check_no_bitmap(mddev))
+ return -EINVAL;
+
+ conf = linear_conf(mddev, mddev->raid_disks);
+ if (IS_ERR(conf))
+ return PTR_ERR(conf);
+
+ mddev->private = conf;
+ md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
+
+ ret = md_integrity_register(mddev);
+ if (ret) {
+ kfree(conf);
+ mddev->private = NULL;
+ }
+ return ret;
+}
+
+static int linear_add(struct mddev *mddev, struct md_rdev *rdev)
+{
+ /* Adding a drive to a linear array allows the array to grow.
+ * It is permitted if the new drive has a matching superblock
+ * already on it, with raid_disk equal to raid_disks.
+ * It is achieved by creating a new linear_private_data structure
+ * and swapping it in in-place of the current one.
+ * The current one is never freed until the array is stopped.
+ * This avoids races.
+ */
+ struct linear_conf *newconf, *oldconf;
+
+ if (rdev->saved_raid_disk != mddev->raid_disks)
+ return -EINVAL;
+
+ rdev->raid_disk = rdev->saved_raid_disk;
+ rdev->saved_raid_disk = -1;
+
+ newconf = linear_conf(mddev, mddev->raid_disks + 1);
+ if (!newconf)
+ return -ENOMEM;
+
+ /* newconf->raid_disks already keeps a copy of * the increased
+ * value of mddev->raid_disks, WARN_ONCE() is just used to make
+ * sure of this. It is possible that oldconf is still referenced
+ * in linear_congested(), therefore kfree_rcu() is used to free
+ * oldconf until no one uses it anymore.
+ */
+ oldconf = rcu_dereference_protected(mddev->private,
+ lockdep_is_held(&mddev->reconfig_mutex));
+ mddev->raid_disks++;
+ WARN_ONCE(mddev->raid_disks != newconf->raid_disks,
+ "copied raid_disks doesn't match mddev->raid_disks");
+ rcu_assign_pointer(mddev->private, newconf);
+ md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
+ set_capacity_and_notify(mddev->gendisk, mddev->array_sectors);
+ kfree_rcu(oldconf, rcu);
+ return 0;
+}
+
+static void linear_free(struct mddev *mddev, void *priv)
+{
+ struct linear_conf *conf = priv;
+
+ kfree(conf);
+}
+
+static bool linear_make_request(struct mddev *mddev, struct bio *bio)
+{
+ struct dev_info *tmp_dev;
+ sector_t start_sector, end_sector, data_offset;
+ sector_t bio_sector = bio->bi_iter.bi_sector;
+
+ if (unlikely(bio->bi_opf & REQ_PREFLUSH)
+ && md_flush_request(mddev, bio))
+ return true;
+
+ tmp_dev = which_dev(mddev, bio_sector);
+ start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors;
+ end_sector = tmp_dev->end_sector;
+ data_offset = tmp_dev->rdev->data_offset;
+
+ if (unlikely(bio_sector >= end_sector ||
+ bio_sector < start_sector))
+ goto out_of_bounds;
+
+ if (unlikely(is_rdev_broken(tmp_dev->rdev))) {
+ md_error(mddev, tmp_dev->rdev);
+ bio_io_error(bio);
+ return true;
+ }
+
+ if (unlikely(bio_end_sector(bio) > end_sector)) {
+ /* This bio crosses a device boundary, so we have to split it */
+ struct bio *split = bio_split(bio, end_sector - bio_sector,
+ GFP_NOIO, &mddev->bio_set);
+
+ if (IS_ERR(split)) {
+ bio->bi_status = errno_to_blk_status(PTR_ERR(split));
+ bio_endio(bio);
+ return true;
+ }
+
+ bio_chain(split, bio);
+ submit_bio_noacct(bio);
+ bio = split;
+ }
+
+ md_account_bio(mddev, &bio);
+ bio_set_dev(bio, tmp_dev->rdev->bdev);
+ bio->bi_iter.bi_sector = bio->bi_iter.bi_sector -
+ start_sector + data_offset;
+
+ if (unlikely((bio_op(bio) == REQ_OP_DISCARD) &&
+ !bdev_max_discard_sectors(bio->bi_bdev))) {
+ /* Just ignore it */
+ bio_endio(bio);
+ } else {
+ if (mddev->gendisk)
+ trace_block_bio_remap(bio, disk_devt(mddev->gendisk),
+ bio_sector);
+ mddev_check_write_zeroes(mddev, bio);
+ submit_bio_noacct(bio);
+ }
+ return true;
+
+out_of_bounds:
+ pr_err("md/linear:%s: make_request: Sector %llu out of bounds on dev %pg: %llu sectors, offset %llu\n",
+ mdname(mddev),
+ (unsigned long long)bio->bi_iter.bi_sector,
+ tmp_dev->rdev->bdev,
+ (unsigned long long)tmp_dev->rdev->sectors,
+ (unsigned long long)start_sector);
+ bio_io_error(bio);
+ return true;
+}
+
+static void linear_status(struct seq_file *seq, struct mddev *mddev)
+{
+ seq_printf(seq, " %dk rounding", mddev->chunk_sectors / 2);
+}
+
+static void linear_error(struct mddev *mddev, struct md_rdev *rdev)
+{
+ if (!test_and_set_bit(MD_BROKEN, &mddev->flags)) {
+ char *md_name = mdname(mddev);
+
+ pr_crit("md/linear%s: Disk failure on %pg detected, failing array.\n",
+ md_name, rdev->bdev);
+ }
+}
+
+static void linear_quiesce(struct mddev *mddev, int state)
+{
+}
+
+static struct md_personality linear_personality = {
+ .name = "linear",
+ .level = LEVEL_LINEAR,
+ .owner = THIS_MODULE,
+ .make_request = linear_make_request,
+ .run = linear_run,
+ .free = linear_free,
+ .status = linear_status,
+ .hot_add_disk = linear_add,
+ .size = linear_size,
+ .quiesce = linear_quiesce,
+ .error_handler = linear_error,
+};
+
+static int __init linear_init(void)
+{
+ return register_md_personality(&linear_personality);
+}
+
+static void linear_exit(void)
+{
+ unregister_md_personality(&linear_personality);
+}
+
+module_init(linear_init);
+module_exit(linear_exit);
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Linear device concatenation personality for MD (deprecated)");
+MODULE_ALIAS("md-personality-1"); /* LINEAR - deprecated*/
+MODULE_ALIAS("md-linear");
+MODULE_ALIAS("md-level--1");
--
2.43.5