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19#include <linux/blkdev.h>
20#include <linux/raid/md_u.h>
21#include <linux/seq_file.h>
22#include <linux/module.h>
23#include <linux/slab.h>
24#include <trace/events/block.h>
25#include "md.h"
26#include "linear.h"
27
28
29
30
31static inline struct dev_info *which_dev(struct mddev *mddev, sector_t sector)
32{
33 int lo, mid, hi;
34 struct linear_conf *conf;
35
36 lo = 0;
37 hi = mddev->raid_disks - 1;
38 conf = mddev->private;
39
40
41
42
43
44 while (hi > lo) {
45
46 mid = (hi + lo) / 2;
47 if (sector < conf->disks[mid].end_sector)
48 hi = mid;
49 else
50 lo = mid + 1;
51 }
52
53 return conf->disks + lo;
54}
55
56static int linear_congested(struct mddev *mddev, int bits)
57{
58 struct linear_conf *conf;
59 int i, ret = 0;
60
61 conf = mddev->private;
62
63 for (i = 0; i < mddev->raid_disks && !ret ; i++) {
64 struct request_queue *q = bdev_get_queue(conf->disks[i].rdev->bdev);
65 ret |= bdi_congested(&q->backing_dev_info, bits);
66 }
67
68 return ret;
69}
70
71static sector_t linear_size(struct mddev *mddev, sector_t sectors, int raid_disks)
72{
73 struct linear_conf *conf;
74 sector_t array_sectors;
75
76 conf = mddev->private;
77 WARN_ONCE(sectors || raid_disks,
78 "%s does not support generic reshape\n", __func__);
79 array_sectors = conf->array_sectors;
80
81 return array_sectors;
82}
83
84static struct linear_conf *linear_conf(struct mddev *mddev, int raid_disks)
85{
86 struct linear_conf *conf;
87 struct md_rdev *rdev;
88 int i, cnt;
89 bool discard_supported = false;
90
91 conf = kzalloc (sizeof (*conf) + raid_disks*sizeof(struct dev_info),
92 GFP_KERNEL);
93 if (!conf)
94 return NULL;
95
96 cnt = 0;
97 conf->array_sectors = 0;
98
99 rdev_for_each(rdev, mddev) {
100 int j = rdev->raid_disk;
101 struct dev_info *disk = conf->disks + j;
102 sector_t sectors;
103
104 if (j < 0 || j >= raid_disks || disk->rdev) {
105 pr_warn("md/linear:%s: disk numbering problem. Aborting!\n",
106 mdname(mddev));
107 goto out;
108 }
109
110 disk->rdev = rdev;
111 if (mddev->chunk_sectors) {
112 sectors = rdev->sectors;
113 sector_div(sectors, mddev->chunk_sectors);
114 rdev->sectors = sectors * mddev->chunk_sectors;
115 }
116
117 disk_stack_limits(mddev->gendisk, rdev->bdev,
118 rdev->data_offset << 9);
119
120 conf->array_sectors += rdev->sectors;
121 cnt++;
122
123 if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
124 discard_supported = true;
125 }
126 if (cnt != raid_disks) {
127 pr_warn("md/linear:%s: not enough drives present. Aborting!\n",
128 mdname(mddev));
129 goto out;
130 }
131
132 if (!discard_supported)
133 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
134 else
135 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
136
137
138
139
140 conf->disks[0].end_sector = conf->disks[0].rdev->sectors;
141
142 for (i = 1; i < raid_disks; i++)
143 conf->disks[i].end_sector =
144 conf->disks[i-1].end_sector +
145 conf->disks[i].rdev->sectors;
146
147 return conf;
148
149out:
150 kfree(conf);
151 return NULL;
152}
153
154static int linear_run (struct mddev *mddev)
155{
156 struct linear_conf *conf;
157 int ret;
158
159 if (md_check_no_bitmap(mddev))
160 return -EINVAL;
161 conf = linear_conf(mddev, mddev->raid_disks);
162
163 if (!conf)
164 return 1;
165 mddev->private = conf;
166 md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
167
168 ret = md_integrity_register(mddev);
169 if (ret) {
170 kfree(conf);
171 mddev->private = NULL;
172 }
173 return ret;
174}
175
176static int linear_add(struct mddev *mddev, struct md_rdev *rdev)
177{
178
179
180
181
182
183
184
185
186 struct linear_conf *newconf, *oldconf;
187
188 if (rdev->saved_raid_disk != mddev->raid_disks)
189 return -EINVAL;
190
191 rdev->raid_disk = rdev->saved_raid_disk;
192 rdev->saved_raid_disk = -1;
193
194 newconf = linear_conf(mddev,mddev->raid_disks+1);
195
196 if (!newconf)
197 return -ENOMEM;
198
199 mddev_suspend(mddev);
200 oldconf = mddev->private;
201 mddev->raid_disks++;
202 mddev->private = newconf;
203 md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
204 set_capacity(mddev->gendisk, mddev->array_sectors);
205 mddev_resume(mddev);
206 revalidate_disk(mddev->gendisk);
207 kfree(oldconf);
208 return 0;
209}
210
211static void linear_free(struct mddev *mddev, void *priv)
212{
213 struct linear_conf *conf = priv;
214
215 kfree(conf);
216}
217
218static void linear_make_request(struct mddev *mddev, struct bio *bio)
219{
220 char b[BDEVNAME_SIZE];
221 struct dev_info *tmp_dev;
222 struct bio *split;
223 sector_t start_sector, end_sector, data_offset;
224
225 if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {
226 md_flush_request(mddev, bio);
227 return;
228 }
229
230 do {
231 sector_t bio_sector = bio->bi_iter.bi_sector;
232 tmp_dev = which_dev(mddev, bio_sector);
233 start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors;
234 end_sector = tmp_dev->end_sector;
235 data_offset = tmp_dev->rdev->data_offset;
236 bio->bi_bdev = tmp_dev->rdev->bdev;
237
238 if (unlikely(bio_sector >= end_sector ||
239 bio_sector < start_sector))
240 goto out_of_bounds;
241
242 if (unlikely(bio_end_sector(bio) > end_sector)) {
243
244
245
246 split = bio_split(bio, end_sector - bio_sector,
247 GFP_NOIO, fs_bio_set);
248 bio_chain(split, bio);
249 } else {
250 split = bio;
251 }
252
253 split->bi_iter.bi_sector = split->bi_iter.bi_sector -
254 start_sector + data_offset;
255
256 if (unlikely((bio_op(split) == REQ_OP_DISCARD) &&
257 !blk_queue_discard(bdev_get_queue(split->bi_bdev)))) {
258
259 bio_endio(split);
260 } else {
261 if (mddev->gendisk)
262 trace_block_bio_remap(bdev_get_queue(split->bi_bdev),
263 split, disk_devt(mddev->gendisk),
264 bio_sector);
265 generic_make_request(split);
266 }
267 } while (split != bio);
268 return;
269
270out_of_bounds:
271 pr_err("md/linear:%s: make_request: Sector %llu out of bounds on dev %s: %llu sectors, offset %llu\n",
272 mdname(mddev),
273 (unsigned long long)bio->bi_iter.bi_sector,
274 bdevname(tmp_dev->rdev->bdev, b),
275 (unsigned long long)tmp_dev->rdev->sectors,
276 (unsigned long long)start_sector);
277 bio_io_error(bio);
278}
279
280static void linear_status (struct seq_file *seq, struct mddev *mddev)
281{
282 seq_printf(seq, " %dk rounding", mddev->chunk_sectors / 2);
283}
284
285static void linear_quiesce(struct mddev *mddev, int state)
286{
287}
288
289static struct md_personality linear_personality =
290{
291 .name = "linear",
292 .level = LEVEL_LINEAR,
293 .owner = THIS_MODULE,
294 .make_request = linear_make_request,
295 .run = linear_run,
296 .free = linear_free,
297 .status = linear_status,
298 .hot_add_disk = linear_add,
299 .size = linear_size,
300 .quiesce = linear_quiesce,
301 .congested = linear_congested,
302};
303
304static int __init linear_init (void)
305{
306 return register_md_personality (&linear_personality);
307}
308
309static void linear_exit (void)
310{
311 unregister_md_personality (&linear_personality);
312}
313
314module_init(linear_init);
315module_exit(linear_exit);
316MODULE_LICENSE("GPL");
317MODULE_DESCRIPTION("Linear device concatenation personality for MD");
318MODULE_ALIAS("md-personality-1");
319MODULE_ALIAS("md-linear");
320MODULE_ALIAS("md-level--1");
321
