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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2016 CNEX Labs
4 * Initial release: Javier Gonzalez <javier@cnexlabs.com>
5 * Matias Bjorling <matias@cnexlabs.com>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License version
9 * 2 as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
15 *
16 * pblk-read.c - pblk's read path
17 */
18
19#include "pblk.h"
20
21/*
22 * There is no guarantee that the value read from cache has not been updated and
23 * resides at another location in the cache. We guarantee though that if the
24 * value is read from the cache, it belongs to the mapped lba. In order to
25 * guarantee and order between writes and reads are ordered, a flush must be
26 * issued.
27 */
28static int pblk_read_from_cache(struct pblk *pblk, struct bio *bio,
29 sector_t lba, struct ppa_addr ppa)
30{
31#ifdef CONFIG_NVM_PBLK_DEBUG
32 /* Callers must ensure that the ppa points to a cache address */
33 BUG_ON(pblk_ppa_empty(ppa));
34 BUG_ON(!pblk_addr_in_cache(ppa));
35#endif
36
37 return pblk_rb_copy_to_bio(&pblk->rwb, bio, lba, ppa);
38}
39
40static int pblk_read_ppalist_rq(struct pblk *pblk, struct nvm_rq *rqd,
41 struct bio *bio, sector_t blba,
42 bool *from_cache)
43{
44 void *meta_list = rqd->meta_list;
45 int nr_secs, i;
46
47retry:
48 nr_secs = pblk_lookup_l2p_seq(pblk, rqd->ppa_list, blba, rqd->nr_ppas,
49 from_cache);
50
51 if (!*from_cache)
52 goto end;
53
54 for (i = 0; i < nr_secs; i++) {
55 struct pblk_sec_meta *meta = pblk_get_meta(pblk, meta_list, i);
56 sector_t lba = blba + i;
57
58 if (pblk_ppa_empty(rqd->ppa_list[i])) {
59 __le64 addr_empty = cpu_to_le64(ADDR_EMPTY);
60
61 meta->lba = addr_empty;
62 } else if (pblk_addr_in_cache(rqd->ppa_list[i])) {
63 /*
64 * Try to read from write buffer. The address is later
65 * checked on the write buffer to prevent retrieving
66 * overwritten data.
67 */
68 if (!pblk_read_from_cache(pblk, bio, lba,
69 rqd->ppa_list[i])) {
70 if (i == 0) {
71 /*
72 * We didn't call with bio_advance()
73 * yet, so we can just retry.
74 */
75 goto retry;
76 } else {
77 /*
78 * We already call bio_advance()
79 * so we cannot retry and we need
80 * to quit that function in order
81 * to allow caller to handle the bio
82 * splitting in the current sector
83 * position.
84 */
85 nr_secs = i;
86 goto end;
87 }
88 }
89 meta->lba = cpu_to_le64(lba);
90#ifdef CONFIG_NVM_PBLK_DEBUG
91 atomic_long_inc(&pblk->cache_reads);
92#endif
93 }
94 bio_advance(bio, PBLK_EXPOSED_PAGE_SIZE);
95 }
96
97end:
98 if (pblk_io_aligned(pblk, nr_secs))
99 rqd->is_seq = 1;
100
101#ifdef CONFIG_NVM_PBLK_DEBUG
102 atomic_long_add(nr_secs, &pblk->inflight_reads);
103#endif
104
105 return nr_secs;
106}
107
108
109static void pblk_read_check_seq(struct pblk *pblk, struct nvm_rq *rqd,
110 sector_t blba)
111{
112 void *meta_list = rqd->meta_list;
113 int nr_lbas = rqd->nr_ppas;
114 int i;
115
116 if (!pblk_is_oob_meta_supported(pblk))
117 return;
118
119 for (i = 0; i < nr_lbas; i++) {
120 struct pblk_sec_meta *meta = pblk_get_meta(pblk, meta_list, i);
121 u64 lba = le64_to_cpu(meta->lba);
122
123 if (lba == ADDR_EMPTY)
124 continue;
125
126 if (lba != blba + i) {
127#ifdef CONFIG_NVM_PBLK_DEBUG
128 struct ppa_addr *ppa_list = nvm_rq_to_ppa_list(rqd);
129
130 print_ppa(pblk, &ppa_list[i], "seq", i);
131#endif
132 pblk_err(pblk, "corrupted read LBA (%llu/%llu)\n",
133 lba, (u64)blba + i);
134 WARN_ON(1);
135 }
136 }
137}
138
139/*
140 * There can be holes in the lba list.
141 */
142static void pblk_read_check_rand(struct pblk *pblk, struct nvm_rq *rqd,
143 u64 *lba_list, int nr_lbas)
144{
145 void *meta_lba_list = rqd->meta_list;
146 int i, j;
147
148 if (!pblk_is_oob_meta_supported(pblk))
149 return;
150
151 for (i = 0, j = 0; i < nr_lbas; i++) {
152 struct pblk_sec_meta *meta = pblk_get_meta(pblk,
153 meta_lba_list, j);
154 u64 lba = lba_list[i];
155 u64 meta_lba;
156
157 if (lba == ADDR_EMPTY)
158 continue;
159
160 meta_lba = le64_to_cpu(meta->lba);
161
162 if (lba != meta_lba) {
163#ifdef CONFIG_NVM_PBLK_DEBUG
164 struct ppa_addr *ppa_list = nvm_rq_to_ppa_list(rqd);
165
166 print_ppa(pblk, &ppa_list[j], "rnd", j);
167#endif
168 pblk_err(pblk, "corrupted read LBA (%llu/%llu)\n",
169 meta_lba, lba);
170 WARN_ON(1);
171 }
172
173 j++;
174 }
175
176 WARN_ONCE(j != rqd->nr_ppas, "pblk: corrupted random request\n");
177}
178
179static void pblk_end_user_read(struct bio *bio, int error)
180{
181 if (error && error != NVM_RSP_WARN_HIGHECC)
182 bio_io_error(bio);
183 else
184 bio_endio(bio);
185}
186
187static void __pblk_end_io_read(struct pblk *pblk, struct nvm_rq *rqd,
188 bool put_line)
189{
190 struct pblk_g_ctx *r_ctx = nvm_rq_to_pdu(rqd);
191 struct bio *int_bio = rqd->bio;
192 unsigned long start_time = r_ctx->start_time;
193
194 bio_end_io_acct(int_bio, start_time);
195
196 if (rqd->error)
197 pblk_log_read_err(pblk, rqd);
198
199 pblk_read_check_seq(pblk, rqd, r_ctx->lba);
200 bio_put(int_bio);
201
202 if (put_line)
203 pblk_rq_to_line_put(pblk, rqd);
204
205#ifdef CONFIG_NVM_PBLK_DEBUG
206 atomic_long_add(rqd->nr_ppas, &pblk->sync_reads);
207 atomic_long_sub(rqd->nr_ppas, &pblk->inflight_reads);
208#endif
209
210 pblk_free_rqd(pblk, rqd, PBLK_READ);
211 atomic_dec(&pblk->inflight_io);
212}
213
214static void pblk_end_io_read(struct nvm_rq *rqd)
215{
216 struct pblk *pblk = rqd->private;
217 struct pblk_g_ctx *r_ctx = nvm_rq_to_pdu(rqd);
218 struct bio *bio = (struct bio *)r_ctx->private;
219
220 pblk_end_user_read(bio, rqd->error);
221 __pblk_end_io_read(pblk, rqd, true);
222}
223
224static void pblk_read_rq(struct pblk *pblk, struct nvm_rq *rqd, struct bio *bio,
225 sector_t lba, bool *from_cache)
226{
227 struct pblk_sec_meta *meta = pblk_get_meta(pblk, rqd->meta_list, 0);
228 struct ppa_addr ppa;
229
230 pblk_lookup_l2p_seq(pblk, &ppa, lba, 1, from_cache);
231
232#ifdef CONFIG_NVM_PBLK_DEBUG
233 atomic_long_inc(&pblk->inflight_reads);
234#endif
235
236retry:
237 if (pblk_ppa_empty(ppa)) {
238 __le64 addr_empty = cpu_to_le64(ADDR_EMPTY);
239
240 meta->lba = addr_empty;
241 return;
242 }
243
244 /* Try to read from write buffer. The address is later checked on the
245 * write buffer to prevent retrieving overwritten data.
246 */
247 if (pblk_addr_in_cache(ppa)) {
248 if (!pblk_read_from_cache(pblk, bio, lba, ppa)) {
249 pblk_lookup_l2p_seq(pblk, &ppa, lba, 1, from_cache);
250 goto retry;
251 }
252
253 meta->lba = cpu_to_le64(lba);
254
255#ifdef CONFIG_NVM_PBLK_DEBUG
256 atomic_long_inc(&pblk->cache_reads);
257#endif
258 } else {
259 rqd->ppa_addr = ppa;
260 }
261}
262
263void pblk_submit_read(struct pblk *pblk, struct bio *bio)
264{
265 sector_t blba = pblk_get_lba(bio);
266 unsigned int nr_secs = pblk_get_secs(bio);
267 bool from_cache;
268 struct pblk_g_ctx *r_ctx;
269 struct nvm_rq *rqd;
270 struct bio *int_bio, *split_bio;
271 unsigned long start_time;
272
273 start_time = bio_start_io_acct(bio);
274
275 rqd = pblk_alloc_rqd(pblk, PBLK_READ);
276
277 rqd->opcode = NVM_OP_PREAD;
278 rqd->nr_ppas = nr_secs;
279 rqd->private = pblk;
280 rqd->end_io = pblk_end_io_read;
281
282 r_ctx = nvm_rq_to_pdu(rqd);
283 r_ctx->start_time = start_time;
284 r_ctx->lba = blba;
285
286 if (pblk_alloc_rqd_meta(pblk, rqd)) {
287 bio_io_error(bio);
288 pblk_free_rqd(pblk, rqd, PBLK_READ);
289 return;
290 }
291
292 /* Clone read bio to deal internally with:
293 * -read errors when reading from drive
294 * -bio_advance() calls during cache reads
295 */
296 int_bio = bio_clone_fast(bio, GFP_KERNEL, &pblk_bio_set);
297
298 if (nr_secs > 1)
299 nr_secs = pblk_read_ppalist_rq(pblk, rqd, int_bio, blba,
300 &from_cache);
301 else
302 pblk_read_rq(pblk, rqd, int_bio, blba, &from_cache);
303
304split_retry:
305 r_ctx->private = bio; /* original bio */
306 rqd->bio = int_bio; /* internal bio */
307
308 if (from_cache && nr_secs == rqd->nr_ppas) {
309 /* All data was read from cache, we can complete the IO. */
310 pblk_end_user_read(bio, 0);
311 atomic_inc(&pblk->inflight_io);
312 __pblk_end_io_read(pblk, rqd, false);
313 } else if (nr_secs != rqd->nr_ppas) {
314 /* The read bio request could be partially filled by the write
315 * buffer, but there are some holes that need to be read from
316 * the drive. In order to handle this, we will use block layer
317 * mechanism to split this request in to smaller ones and make
318 * a chain of it.
319 */
320 split_bio = bio_split(bio, nr_secs * NR_PHY_IN_LOG, GFP_KERNEL,
321 &pblk_bio_set);
322 bio_chain(split_bio, bio);
323 submit_bio_noacct(bio);
324
325 /* New bio contains first N sectors of the previous one, so
326 * we can continue to use existing rqd, but we need to shrink
327 * the number of PPAs in it. New bio is also guaranteed that
328 * it contains only either data from cache or from drive, newer
329 * mix of them.
330 */
331 bio = split_bio;
332 rqd->nr_ppas = nr_secs;
333 if (rqd->nr_ppas == 1)
334 rqd->ppa_addr = rqd->ppa_list[0];
335
336 /* Recreate int_bio - existing might have some needed internal
337 * fields modified already.
338 */
339 bio_put(int_bio);
340 int_bio = bio_clone_fast(bio, GFP_KERNEL, &pblk_bio_set);
341 goto split_retry;
342 } else if (pblk_submit_io(pblk, rqd, NULL)) {
343 /* Submitting IO to drive failed, let's report an error */
344 rqd->error = -ENODEV;
345 pblk_end_io_read(rqd);
346 }
347}
348
349static int read_ppalist_rq_gc(struct pblk *pblk, struct nvm_rq *rqd,
350 struct pblk_line *line, u64 *lba_list,
351 u64 *paddr_list_gc, unsigned int nr_secs)
352{
353 struct ppa_addr ppa_list_l2p[NVM_MAX_VLBA];
354 struct ppa_addr ppa_gc;
355 int valid_secs = 0;
356 int i;
357
358 pblk_lookup_l2p_rand(pblk, ppa_list_l2p, lba_list, nr_secs);
359
360 for (i = 0; i < nr_secs; i++) {
361 if (lba_list[i] == ADDR_EMPTY)
362 continue;
363
364 ppa_gc = addr_to_gen_ppa(pblk, paddr_list_gc[i], line->id);
365 if (!pblk_ppa_comp(ppa_list_l2p[i], ppa_gc)) {
366 paddr_list_gc[i] = lba_list[i] = ADDR_EMPTY;
367 continue;
368 }
369
370 rqd->ppa_list[valid_secs++] = ppa_list_l2p[i];
371 }
372
373#ifdef CONFIG_NVM_PBLK_DEBUG
374 atomic_long_add(valid_secs, &pblk->inflight_reads);
375#endif
376
377 return valid_secs;
378}
379
380static int read_rq_gc(struct pblk *pblk, struct nvm_rq *rqd,
381 struct pblk_line *line, sector_t lba,
382 u64 paddr_gc)
383{
384 struct ppa_addr ppa_l2p, ppa_gc;
385 int valid_secs = 0;
386
387 if (lba == ADDR_EMPTY)
388 goto out;
389
390 /* logic error: lba out-of-bounds */
391 if (lba >= pblk->capacity) {
392 WARN(1, "pblk: read lba out of bounds\n");
393 goto out;
394 }
395
396 spin_lock(&pblk->trans_lock);
397 ppa_l2p = pblk_trans_map_get(pblk, lba);
398 spin_unlock(&pblk->trans_lock);
399
400 ppa_gc = addr_to_gen_ppa(pblk, paddr_gc, line->id);
401 if (!pblk_ppa_comp(ppa_l2p, ppa_gc))
402 goto out;
403
404 rqd->ppa_addr = ppa_l2p;
405 valid_secs = 1;
406
407#ifdef CONFIG_NVM_PBLK_DEBUG
408 atomic_long_inc(&pblk->inflight_reads);
409#endif
410
411out:
412 return valid_secs;
413}
414
415int pblk_submit_read_gc(struct pblk *pblk, struct pblk_gc_rq *gc_rq)
416{
417 struct nvm_rq rqd;
418 int ret = NVM_IO_OK;
419
420 memset(&rqd, 0, sizeof(struct nvm_rq));
421
422 ret = pblk_alloc_rqd_meta(pblk, &rqd);
423 if (ret)
424 return ret;
425
426 if (gc_rq->nr_secs > 1) {
427 gc_rq->secs_to_gc = read_ppalist_rq_gc(pblk, &rqd, gc_rq->line,
428 gc_rq->lba_list,
429 gc_rq->paddr_list,
430 gc_rq->nr_secs);
431 if (gc_rq->secs_to_gc == 1)
432 rqd.ppa_addr = rqd.ppa_list[0];
433 } else {
434 gc_rq->secs_to_gc = read_rq_gc(pblk, &rqd, gc_rq->line,
435 gc_rq->lba_list[0],
436 gc_rq->paddr_list[0]);
437 }
438
439 if (!(gc_rq->secs_to_gc))
440 goto out;
441
442 rqd.opcode = NVM_OP_PREAD;
443 rqd.nr_ppas = gc_rq->secs_to_gc;
444
445 if (pblk_submit_io_sync(pblk, &rqd, gc_rq->data)) {
446 ret = -EIO;
447 goto err_free_dma;
448 }
449
450 pblk_read_check_rand(pblk, &rqd, gc_rq->lba_list, gc_rq->nr_secs);
451
452 atomic_dec(&pblk->inflight_io);
453
454 if (rqd.error) {
455 atomic_long_inc(&pblk->read_failed_gc);
456#ifdef CONFIG_NVM_PBLK_DEBUG
457 pblk_print_failed_rqd(pblk, &rqd, rqd.error);
458#endif
459 }
460
461#ifdef CONFIG_NVM_PBLK_DEBUG
462 atomic_long_add(gc_rq->secs_to_gc, &pblk->sync_reads);
463 atomic_long_add(gc_rq->secs_to_gc, &pblk->recov_gc_reads);
464 atomic_long_sub(gc_rq->secs_to_gc, &pblk->inflight_reads);
465#endif
466
467out:
468 pblk_free_rqd_meta(pblk, &rqd);
469 return ret;
470
471err_free_dma:
472 pblk_free_rqd_meta(pblk, &rqd);
473 return ret;
474}