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19#include <linux/blkdev.h>
20#include <linux/raid/md_u.h>
21#include <linux/seq_file.h>
22#include "md.h"
23#include "linear.h"
24
25
26
27
28static inline dev_info_t *which_dev(mddev_t *mddev, sector_t sector)
29{
30 int lo, mid, hi;
31 linear_conf_t *conf;
32
33 lo = 0;
34 hi = mddev->raid_disks - 1;
35 conf = rcu_dereference(mddev->private);
36
37
38
39
40
41 while (hi > lo) {
42
43 mid = (hi + lo) / 2;
44 if (sector < conf->disks[mid].end_sector)
45 hi = mid;
46 else
47 lo = mid + 1;
48 }
49
50 return conf->disks + lo;
51}
52
53
54
55
56
57
58
59
60
61static int linear_mergeable_bvec(struct request_queue *q,
62 struct bvec_merge_data *bvm,
63 struct bio_vec *biovec)
64{
65 mddev_t *mddev = q->queuedata;
66 dev_info_t *dev0;
67 unsigned long maxsectors, bio_sectors = bvm->bi_size >> 9;
68 sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
69
70 rcu_read_lock();
71 dev0 = which_dev(mddev, sector);
72 maxsectors = dev0->end_sector - sector;
73 rcu_read_unlock();
74
75 if (maxsectors < bio_sectors)
76 maxsectors = 0;
77 else
78 maxsectors -= bio_sectors;
79
80 if (maxsectors <= (PAGE_SIZE >> 9 ) && bio_sectors == 0)
81 return biovec->bv_len;
82
83
84 if (maxsectors > (1 << (31-9)))
85 return 1<<31;
86 return maxsectors << 9;
87}
88
89static void linear_unplug(struct request_queue *q)
90{
91 mddev_t *mddev = q->queuedata;
92 linear_conf_t *conf;
93 int i;
94
95 rcu_read_lock();
96 conf = rcu_dereference(mddev->private);
97
98 for (i=0; i < mddev->raid_disks; i++) {
99 struct request_queue *r_queue = bdev_get_queue(conf->disks[i].rdev->bdev);
100 blk_unplug(r_queue);
101 }
102 rcu_read_unlock();
103}
104
105static int linear_congested(void *data, int bits)
106{
107 mddev_t *mddev = data;
108 linear_conf_t *conf;
109 int i, ret = 0;
110
111 if (mddev_congested(mddev, bits))
112 return 1;
113
114 rcu_read_lock();
115 conf = rcu_dereference(mddev->private);
116
117 for (i = 0; i < mddev->raid_disks && !ret ; i++) {
118 struct request_queue *q = bdev_get_queue(conf->disks[i].rdev->bdev);
119 ret |= bdi_congested(&q->backing_dev_info, bits);
120 }
121
122 rcu_read_unlock();
123 return ret;
124}
125
126static sector_t linear_size(mddev_t *mddev, sector_t sectors, int raid_disks)
127{
128 linear_conf_t *conf;
129 sector_t array_sectors;
130
131 rcu_read_lock();
132 conf = rcu_dereference(mddev->private);
133 WARN_ONCE(sectors || raid_disks,
134 "%s does not support generic reshape\n", __func__);
135 array_sectors = conf->array_sectors;
136 rcu_read_unlock();
137
138 return array_sectors;
139}
140
141static linear_conf_t *linear_conf(mddev_t *mddev, int raid_disks)
142{
143 linear_conf_t *conf;
144 mdk_rdev_t *rdev;
145 int i, cnt;
146
147 conf = kzalloc (sizeof (*conf) + raid_disks*sizeof(dev_info_t),
148 GFP_KERNEL);
149 if (!conf)
150 return NULL;
151
152 cnt = 0;
153 conf->array_sectors = 0;
154
155 list_for_each_entry(rdev, &mddev->disks, same_set) {
156 int j = rdev->raid_disk;
157 dev_info_t *disk = conf->disks + j;
158 sector_t sectors;
159
160 if (j < 0 || j >= raid_disks || disk->rdev) {
161 printk("linear: disk numbering problem. Aborting!\n");
162 goto out;
163 }
164
165 disk->rdev = rdev;
166 if (mddev->chunk_sectors) {
167 sectors = rdev->sectors;
168 sector_div(sectors, mddev->chunk_sectors);
169 rdev->sectors = sectors * mddev->chunk_sectors;
170 }
171
172 disk_stack_limits(mddev->gendisk, rdev->bdev,
173 rdev->data_offset << 9);
174
175
176
177
178 if (rdev->bdev->bd_disk->queue->merge_bvec_fn &&
179 queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9))
180 blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9);
181
182 conf->array_sectors += rdev->sectors;
183 cnt++;
184
185 }
186 if (cnt != raid_disks) {
187 printk("linear: not enough drives present. Aborting!\n");
188 goto out;
189 }
190
191
192
193
194 conf->disks[0].end_sector = conf->disks[0].rdev->sectors;
195
196 for (i = 1; i < raid_disks; i++)
197 conf->disks[i].end_sector =
198 conf->disks[i-1].end_sector +
199 conf->disks[i].rdev->sectors;
200
201 return conf;
202
203out:
204 kfree(conf);
205 return NULL;
206}
207
208static int linear_run (mddev_t *mddev)
209{
210 linear_conf_t *conf;
211
212 if (md_check_no_bitmap(mddev))
213 return -EINVAL;
214 mddev->queue->queue_lock = &mddev->queue->__queue_lock;
215 conf = linear_conf(mddev, mddev->raid_disks);
216
217 if (!conf)
218 return 1;
219 mddev->private = conf;
220 md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
221
222 blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec);
223 mddev->queue->unplug_fn = linear_unplug;
224 mddev->queue->backing_dev_info.congested_fn = linear_congested;
225 mddev->queue->backing_dev_info.congested_data = mddev;
226 md_integrity_register(mddev);
227 return 0;
228}
229
230static void free_conf(struct rcu_head *head)
231{
232 linear_conf_t *conf = container_of(head, linear_conf_t, rcu);
233 kfree(conf);
234}
235
236static int linear_add(mddev_t *mddev, mdk_rdev_t *rdev)
237{
238
239
240
241
242
243
244
245
246 linear_conf_t *newconf, *oldconf;
247
248 if (rdev->saved_raid_disk != mddev->raid_disks)
249 return -EINVAL;
250
251 rdev->raid_disk = rdev->saved_raid_disk;
252
253 newconf = linear_conf(mddev,mddev->raid_disks+1);
254
255 if (!newconf)
256 return -ENOMEM;
257
258 oldconf = rcu_dereference(mddev->private);
259 mddev->raid_disks++;
260 rcu_assign_pointer(mddev->private, newconf);
261 md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
262 set_capacity(mddev->gendisk, mddev->array_sectors);
263 revalidate_disk(mddev->gendisk);
264 call_rcu(&oldconf->rcu, free_conf);
265 return 0;
266}
267
268static int linear_stop (mddev_t *mddev)
269{
270 linear_conf_t *conf = mddev->private;
271
272
273
274
275
276
277
278
279 rcu_barrier();
280 blk_sync_queue(mddev->queue);
281 kfree(conf);
282
283 return 0;
284}
285
286static int linear_make_request (struct request_queue *q, struct bio *bio)
287{
288 const int rw = bio_data_dir(bio);
289 mddev_t *mddev = q->queuedata;
290 dev_info_t *tmp_dev;
291 sector_t start_sector;
292 int cpu;
293
294 if (unlikely(bio_rw_flagged(bio, BIO_RW_BARRIER))) {
295 bio_endio(bio, -EOPNOTSUPP);
296 return 0;
297 }
298
299 cpu = part_stat_lock();
300 part_stat_inc(cpu, &mddev->gendisk->part0, ios[rw]);
301 part_stat_add(cpu, &mddev->gendisk->part0, sectors[rw],
302 bio_sectors(bio));
303 part_stat_unlock();
304
305 rcu_read_lock();
306 tmp_dev = which_dev(mddev, bio->bi_sector);
307 start_sector = tmp_dev->end_sector - tmp_dev->rdev->sectors;
308
309
310 if (unlikely(bio->bi_sector >= (tmp_dev->end_sector)
311 || (bio->bi_sector < start_sector))) {
312 char b[BDEVNAME_SIZE];
313
314 printk("linear_make_request: Sector %llu out of bounds on "
315 "dev %s: %llu sectors, offset %llu\n",
316 (unsigned long long)bio->bi_sector,
317 bdevname(tmp_dev->rdev->bdev, b),
318 (unsigned long long)tmp_dev->rdev->sectors,
319 (unsigned long long)start_sector);
320 rcu_read_unlock();
321 bio_io_error(bio);
322 return 0;
323 }
324 if (unlikely(bio->bi_sector + (bio->bi_size >> 9) >
325 tmp_dev->end_sector)) {
326
327
328
329 struct bio_pair *bp;
330 sector_t end_sector = tmp_dev->end_sector;
331
332 rcu_read_unlock();
333
334 bp = bio_split(bio, end_sector - bio->bi_sector);
335
336 if (linear_make_request(q, &bp->bio1))
337 generic_make_request(&bp->bio1);
338 if (linear_make_request(q, &bp->bio2))
339 generic_make_request(&bp->bio2);
340 bio_pair_release(bp);
341 return 0;
342 }
343
344 bio->bi_bdev = tmp_dev->rdev->bdev;
345 bio->bi_sector = bio->bi_sector - start_sector
346 + tmp_dev->rdev->data_offset;
347 rcu_read_unlock();
348
349 return 1;
350}
351
352static void linear_status (struct seq_file *seq, mddev_t *mddev)
353{
354
355 seq_printf(seq, " %dk rounding", mddev->chunk_sectors / 2);
356}
357
358
359static struct mdk_personality linear_personality =
360{
361 .name = "linear",
362 .level = LEVEL_LINEAR,
363 .owner = THIS_MODULE,
364 .make_request = linear_make_request,
365 .run = linear_run,
366 .stop = linear_stop,
367 .status = linear_status,
368 .hot_add_disk = linear_add,
369 .size = linear_size,
370};
371
372static int __init linear_init (void)
373{
374 return register_md_personality (&linear_personality);
375}
376
377static void linear_exit (void)
378{
379 unregister_md_personality (&linear_personality);
380}
381
382
383module_init(linear_init);
384module_exit(linear_exit);
385MODULE_LICENSE("GPL");
386MODULE_ALIAS("md-personality-1");
387MODULE_ALIAS("md-linear");
388MODULE_ALIAS("md-level--1");
389