linux/fs/exofs/ore_raid.c
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   1/*
   2 * Copyright (C) 2011
   3 * Boaz Harrosh <ooo@electrozaur.com>
   4 *
   5 * This file is part of the objects raid engine (ore).
   6 *
   7 * It is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License version 2 as published
   9 * by the Free Software Foundation.
  10 *
  11 * You should have received a copy of the GNU General Public License
  12 * along with "ore". If not, write to the Free Software Foundation, Inc:
  13 *      "Free Software Foundation <info@fsf.org>"
  14 */
  15
  16#include <linux/gfp.h>
  17#include <linux/async_tx.h>
  18
  19#include "ore_raid.h"
  20
  21#undef ORE_DBGMSG2
  22#define ORE_DBGMSG2 ORE_DBGMSG
  23
  24static struct page *_raid_page_alloc(void)
  25{
  26        return alloc_page(GFP_KERNEL);
  27}
  28
  29static void _raid_page_free(struct page *p)
  30{
  31        __free_page(p);
  32}
  33
  34/* This struct is forward declare in ore_io_state, but is private to here.
  35 * It is put on ios->sp2d for RAID5/6 writes only. See _gen_xor_unit.
  36 *
  37 * __stripe_pages_2d is a 2d array of pages, and it is also a corner turn.
  38 * Ascending page index access is sp2d(p-minor, c-major). But storage is
  39 * sp2d[p-minor][c-major], so it can be properlly presented to the async-xor
  40 * API.
  41 */
  42struct __stripe_pages_2d {
  43        /* Cache some hot path repeated calculations */
  44        unsigned parity;
  45        unsigned data_devs;
  46        unsigned pages_in_unit;
  47
  48        bool needed ;
  49
  50        /* Array size is pages_in_unit (layout->stripe_unit / PAGE_SIZE) */
  51        struct __1_page_stripe {
  52                bool alloc;
  53                unsigned write_count;
  54                struct async_submit_ctl submit;
  55                struct dma_async_tx_descriptor *tx;
  56
  57                /* The size of this array is data_devs + parity */
  58                struct page **pages;
  59                struct page **scribble;
  60                /* bool array, size of this array is data_devs */
  61                char *page_is_read;
  62        } _1p_stripes[];
  63};
  64
  65/* This can get bigger then a page. So support multiple page allocations
  66 * _sp2d_free should be called even if _sp2d_alloc fails (by returning
  67 * none-zero).
  68 */
  69static int _sp2d_alloc(unsigned pages_in_unit, unsigned group_width,
  70                       unsigned parity, struct __stripe_pages_2d **psp2d)
  71{
  72        struct __stripe_pages_2d *sp2d;
  73        unsigned data_devs = group_width - parity;
  74        struct _alloc_all_bytes {
  75                struct __alloc_stripe_pages_2d {
  76                        struct __stripe_pages_2d sp2d;
  77                        struct __1_page_stripe _1p_stripes[pages_in_unit];
  78                } __asp2d;
  79                struct __alloc_1p_arrays {
  80                        struct page *pages[group_width];
  81                        struct page *scribble[group_width];
  82                        char page_is_read[data_devs];
  83                } __a1pa[pages_in_unit];
  84        } *_aab;
  85        struct __alloc_1p_arrays *__a1pa;
  86        struct __alloc_1p_arrays *__a1pa_end;
  87        const unsigned sizeof__a1pa = sizeof(_aab->__a1pa[0]);
  88        unsigned num_a1pa, alloc_size, i;
  89
  90        /* FIXME: check these numbers in ore_verify_layout */
  91        BUG_ON(sizeof(_aab->__asp2d) > PAGE_SIZE);
  92        BUG_ON(sizeof__a1pa > PAGE_SIZE);
  93
  94        if (sizeof(*_aab) > PAGE_SIZE) {
  95                num_a1pa = (PAGE_SIZE - sizeof(_aab->__asp2d)) / sizeof__a1pa;
  96                alloc_size = sizeof(_aab->__asp2d) + sizeof__a1pa * num_a1pa;
  97        } else {
  98                num_a1pa = pages_in_unit;
  99                alloc_size = sizeof(*_aab);
 100        }
 101
 102        _aab = kzalloc(alloc_size, GFP_KERNEL);
 103        if (unlikely(!_aab)) {
 104                ORE_DBGMSG("!! Failed to alloc sp2d size=%d\n", alloc_size);
 105                return -ENOMEM;
 106        }
 107
 108        sp2d = &_aab->__asp2d.sp2d;
 109        *psp2d = sp2d; /* From here Just call _sp2d_free */
 110
 111        __a1pa = _aab->__a1pa;
 112        __a1pa_end = __a1pa + num_a1pa;
 113
 114        for (i = 0; i < pages_in_unit; ++i) {
 115                if (unlikely(__a1pa >= __a1pa_end)) {
 116                        num_a1pa = min_t(unsigned, PAGE_SIZE / sizeof__a1pa,
 117                                                        pages_in_unit - i);
 118
 119                        __a1pa = kcalloc(num_a1pa, sizeof__a1pa, GFP_KERNEL);
 120                        if (unlikely(!__a1pa)) {
 121                                ORE_DBGMSG("!! Failed to _alloc_1p_arrays=%d\n",
 122                                           num_a1pa);
 123                                return -ENOMEM;
 124                        }
 125                        __a1pa_end = __a1pa + num_a1pa;
 126                        /* First *pages is marked for kfree of the buffer */
 127                        sp2d->_1p_stripes[i].alloc = true;
 128                }
 129
 130                sp2d->_1p_stripes[i].pages = __a1pa->pages;
 131                sp2d->_1p_stripes[i].scribble = __a1pa->scribble ;
 132                sp2d->_1p_stripes[i].page_is_read = __a1pa->page_is_read;
 133                ++__a1pa;
 134        }
 135
 136        sp2d->parity = parity;
 137        sp2d->data_devs = data_devs;
 138        sp2d->pages_in_unit = pages_in_unit;
 139        return 0;
 140}
 141
 142static void _sp2d_reset(struct __stripe_pages_2d *sp2d,
 143                        const struct _ore_r4w_op *r4w, void *priv)
 144{
 145        unsigned data_devs = sp2d->data_devs;
 146        unsigned group_width = data_devs + sp2d->parity;
 147        int p, c;
 148
 149        if (!sp2d->needed)
 150                return;
 151
 152        for (c = data_devs - 1; c >= 0; --c)
 153                for (p = sp2d->pages_in_unit - 1; p >= 0; --p) {
 154                        struct __1_page_stripe *_1ps = &sp2d->_1p_stripes[p];
 155
 156                        if (_1ps->page_is_read[c]) {
 157                                struct page *page = _1ps->pages[c];
 158
 159                                r4w->put_page(priv, page);
 160                                _1ps->page_is_read[c] = false;
 161                        }
 162                }
 163
 164        for (p = 0; p < sp2d->pages_in_unit; p++) {
 165                struct __1_page_stripe *_1ps = &sp2d->_1p_stripes[p];
 166
 167                memset(_1ps->pages, 0, group_width * sizeof(*_1ps->pages));
 168                _1ps->write_count = 0;
 169                _1ps->tx = NULL;
 170        }
 171
 172        sp2d->needed = false;
 173}
 174
 175static void _sp2d_free(struct __stripe_pages_2d *sp2d)
 176{
 177        unsigned i;
 178
 179        if (!sp2d)
 180                return;
 181
 182        for (i = 0; i < sp2d->pages_in_unit; ++i) {
 183                if (sp2d->_1p_stripes[i].alloc)
 184                        kfree(sp2d->_1p_stripes[i].pages);
 185        }
 186
 187        kfree(sp2d);
 188}
 189
 190static unsigned _sp2d_min_pg(struct __stripe_pages_2d *sp2d)
 191{
 192        unsigned p;
 193
 194        for (p = 0; p < sp2d->pages_in_unit; p++) {
 195                struct __1_page_stripe *_1ps = &sp2d->_1p_stripes[p];
 196
 197                if (_1ps->write_count)
 198                        return p;
 199        }
 200
 201        return ~0;
 202}
 203
 204static unsigned _sp2d_max_pg(struct __stripe_pages_2d *sp2d)
 205{
 206        int p;
 207
 208        for (p = sp2d->pages_in_unit - 1; p >= 0; --p) {
 209                struct __1_page_stripe *_1ps = &sp2d->_1p_stripes[p];
 210
 211                if (_1ps->write_count)
 212                        return p;
 213        }
 214
 215        return ~0;
 216}
 217
 218static void _gen_xor_unit(struct __stripe_pages_2d *sp2d)
 219{
 220        unsigned p;
 221        unsigned tx_flags = ASYNC_TX_ACK;
 222
 223        if (sp2d->parity == 1)
 224                tx_flags |= ASYNC_TX_XOR_ZERO_DST;
 225
 226        for (p = 0; p < sp2d->pages_in_unit; p++) {
 227                struct __1_page_stripe *_1ps = &sp2d->_1p_stripes[p];
 228
 229                if (!_1ps->write_count)
 230                        continue;
 231
 232                init_async_submit(&_1ps->submit, tx_flags,
 233                        NULL, NULL, NULL, (addr_conv_t *)_1ps->scribble);
 234
 235                if (sp2d->parity == 1)
 236                        _1ps->tx = async_xor(_1ps->pages[sp2d->data_devs],
 237                                                _1ps->pages, 0, sp2d->data_devs,
 238                                                PAGE_SIZE, &_1ps->submit);
 239                else /* parity == 2 */
 240                        _1ps->tx = async_gen_syndrome(_1ps->pages, 0,
 241                                                sp2d->data_devs + sp2d->parity,
 242                                                PAGE_SIZE, &_1ps->submit);
 243        }
 244
 245        for (p = 0; p < sp2d->pages_in_unit; p++) {
 246                struct __1_page_stripe *_1ps = &sp2d->_1p_stripes[p];
 247                /* NOTE: We wait for HW synchronously (I don't have such HW
 248                 * to test with.) Is parallelism needed with today's multi
 249                 * cores?
 250                 */
 251                async_tx_issue_pending(_1ps->tx);
 252        }
 253}
 254
 255void _ore_add_stripe_page(struct __stripe_pages_2d *sp2d,
 256                       struct ore_striping_info *si, struct page *page)
 257{
 258        struct __1_page_stripe *_1ps;
 259
 260        sp2d->needed = true;
 261
 262        _1ps = &sp2d->_1p_stripes[si->cur_pg];
 263        _1ps->pages[si->cur_comp] = page;
 264        ++_1ps->write_count;
 265
 266        si->cur_pg = (si->cur_pg + 1) % sp2d->pages_in_unit;
 267        /* si->cur_comp is advanced outside at main loop */
 268}
 269
 270void _ore_add_sg_seg(struct ore_per_dev_state *per_dev, unsigned cur_len,
 271                     bool not_last)
 272{
 273        struct osd_sg_entry *sge;
 274
 275        ORE_DBGMSG("dev=%d cur_len=0x%x not_last=%d cur_sg=%d "
 276                     "offset=0x%llx length=0x%x last_sgs_total=0x%x\n",
 277                     per_dev->dev, cur_len, not_last, per_dev->cur_sg,
 278                     _LLU(per_dev->offset), per_dev->length,
 279                     per_dev->last_sgs_total);
 280
 281        if (!per_dev->cur_sg) {
 282                sge = per_dev->sglist;
 283
 284                /* First time we prepare two entries */
 285                if (per_dev->length) {
 286                        ++per_dev->cur_sg;
 287                        sge->offset = per_dev->offset;
 288                        sge->len = per_dev->length;
 289                } else {
 290                        /* Here the parity is the first unit of this object.
 291                         * This happens every time we reach a parity device on
 292                         * the same stripe as the per_dev->offset. We need to
 293                         * just skip this unit.
 294                         */
 295                        per_dev->offset += cur_len;
 296                        return;
 297                }
 298        } else {
 299                /* finalize the last one */
 300                sge = &per_dev->sglist[per_dev->cur_sg - 1];
 301                sge->len = per_dev->length - per_dev->last_sgs_total;
 302        }
 303
 304        if (not_last) {
 305                /* Partly prepare the next one */
 306                struct osd_sg_entry *next_sge = sge + 1;
 307
 308                ++per_dev->cur_sg;
 309                next_sge->offset = sge->offset + sge->len + cur_len;
 310                /* Save cur len so we know how mutch was added next time */
 311                per_dev->last_sgs_total = per_dev->length;
 312                next_sge->len = 0;
 313        } else if (!sge->len) {
 314                /* Optimize for when the last unit is a parity */
 315                --per_dev->cur_sg;
 316        }
 317}
 318
 319static int _alloc_read_4_write(struct ore_io_state *ios)
 320{
 321        struct ore_layout *layout = ios->layout;
 322        int ret;
 323        /* We want to only read those pages not in cache so worst case
 324         * is a stripe populated with every other page
 325         */
 326        unsigned sgs_per_dev = ios->sp2d->pages_in_unit + 2;
 327
 328        ret = _ore_get_io_state(layout, ios->oc,
 329                                layout->group_width * layout->mirrors_p1,
 330                                sgs_per_dev, 0, &ios->ios_read_4_write);
 331        return ret;
 332}
 333
 334/* @si contains info of the to-be-inserted page. Update of @si should be
 335 * maintained by caller. Specificaly si->dev, si->obj_offset, ...
 336 */
 337static int _add_to_r4w(struct ore_io_state *ios, struct ore_striping_info *si,
 338                       struct page *page, unsigned pg_len)
 339{
 340        struct request_queue *q;
 341        struct ore_per_dev_state *per_dev;
 342        struct ore_io_state *read_ios;
 343        unsigned first_dev = si->dev - (si->dev %
 344                          (ios->layout->group_width * ios->layout->mirrors_p1));
 345        unsigned comp = si->dev - first_dev;
 346        unsigned added_len;
 347
 348        if (!ios->ios_read_4_write) {
 349                int ret = _alloc_read_4_write(ios);
 350
 351                if (unlikely(ret))
 352                        return ret;
 353        }
 354
 355        read_ios = ios->ios_read_4_write;
 356        read_ios->numdevs = ios->layout->group_width * ios->layout->mirrors_p1;
 357
 358        per_dev = &read_ios->per_dev[comp];
 359        if (!per_dev->length) {
 360                per_dev->bio = bio_kmalloc(GFP_KERNEL,
 361                                           ios->sp2d->pages_in_unit);
 362                if (unlikely(!per_dev->bio)) {
 363                        ORE_DBGMSG("Failed to allocate BIO size=%u\n",
 364                                     ios->sp2d->pages_in_unit);
 365                        return -ENOMEM;
 366                }
 367                per_dev->offset = si->obj_offset;
 368                per_dev->dev = si->dev;
 369        } else if (si->obj_offset != (per_dev->offset + per_dev->length)) {
 370                u64 gap = si->obj_offset - (per_dev->offset + per_dev->length);
 371
 372                _ore_add_sg_seg(per_dev, gap, true);
 373        }
 374        q = osd_request_queue(ore_comp_dev(read_ios->oc, per_dev->dev));
 375        added_len = bio_add_pc_page(q, per_dev->bio, page, pg_len,
 376                                    si->obj_offset % PAGE_SIZE);
 377        if (unlikely(added_len != pg_len)) {
 378                ORE_DBGMSG("Failed to bio_add_pc_page bi_vcnt=%d\n",
 379                              per_dev->bio->bi_vcnt);
 380                return -ENOMEM;
 381        }
 382
 383        per_dev->length += pg_len;
 384        return 0;
 385}
 386
 387/* read the beginning of an unaligned first page */
 388static int _add_to_r4w_first_page(struct ore_io_state *ios, struct page *page)
 389{
 390        struct ore_striping_info si;
 391        unsigned pg_len;
 392
 393        ore_calc_stripe_info(ios->layout, ios->offset, 0, &si);
 394
 395        pg_len = si.obj_offset % PAGE_SIZE;
 396        si.obj_offset -= pg_len;
 397
 398        ORE_DBGMSG("offset=0x%llx len=0x%x index=0x%lx dev=%x\n",
 399                   _LLU(si.obj_offset), pg_len, page->index, si.dev);
 400
 401        return _add_to_r4w(ios, &si, page, pg_len);
 402}
 403
 404/* read the end of an incomplete last page */
 405static int _add_to_r4w_last_page(struct ore_io_state *ios, u64 *offset)
 406{
 407        struct ore_striping_info si;
 408        struct page *page;
 409        unsigned pg_len, p, c;
 410
 411        ore_calc_stripe_info(ios->layout, *offset, 0, &si);
 412
 413        p = si.cur_pg;
 414        c = si.cur_comp;
 415        page = ios->sp2d->_1p_stripes[p].pages[c];
 416
 417        pg_len = PAGE_SIZE - (si.unit_off % PAGE_SIZE);
 418        *offset += pg_len;
 419
 420        ORE_DBGMSG("p=%d, c=%d next-offset=0x%llx len=0x%x dev=%x par_dev=%d\n",
 421                   p, c, _LLU(*offset), pg_len, si.dev, si.par_dev);
 422
 423        BUG_ON(!page);
 424
 425        return _add_to_r4w(ios, &si, page, pg_len);
 426}
 427
 428static void _mark_read4write_pages_uptodate(struct ore_io_state *ios, int ret)
 429{
 430        struct bio_vec *bv;
 431        unsigned i, d;
 432
 433        /* loop on all devices all pages */
 434        for (d = 0; d < ios->numdevs; d++) {
 435                struct bio *bio = ios->per_dev[d].bio;
 436
 437                if (!bio)
 438                        continue;
 439
 440                bio_for_each_segment_all(bv, bio, i) {
 441                        struct page *page = bv->bv_page;
 442
 443                        SetPageUptodate(page);
 444                        if (PageError(page))
 445                                ClearPageError(page);
 446                }
 447        }
 448}
 449
 450/* read_4_write is hacked to read the start of the first stripe and/or
 451 * the end of the last stripe. If needed, with an sg-gap at each device/page.
 452 * It is assumed to be called after the to_be_written pages of the first stripe
 453 * are populating ios->sp2d[][]
 454 *
 455 * NOTE: We call ios->r4w->lock_fn for all pages needed for parity calculations
 456 * These pages are held at sp2d[p].pages[c] but with
 457 * sp2d[p].page_is_read[c] = true. At _sp2d_reset these pages are
 458 * ios->r4w->lock_fn(). The ios->r4w->lock_fn might signal that the page is
 459 * @uptodate=true, so we don't need to read it, only unlock, after IO.
 460 *
 461 * TODO: The read_4_write should calc a need_to_read_pages_count, if bigger then
 462 * to-be-written count, we should consider the xor-in-place mode.
 463 * need_to_read_pages_count is the actual number of pages not present in cache.
 464 * maybe "devs_in_group - ios->sp2d[p].write_count" is a good enough
 465 * approximation? In this mode the read pages are put in the empty places of
 466 * ios->sp2d[p][*], xor is calculated the same way. These pages are
 467 * allocated/freed and don't go through cache
 468 */
 469static int _read_4_write_first_stripe(struct ore_io_state *ios)
 470{
 471        struct ore_striping_info read_si;
 472        struct __stripe_pages_2d *sp2d = ios->sp2d;
 473        u64 offset = ios->si.first_stripe_start;
 474        unsigned c, p, min_p = sp2d->pages_in_unit, max_p = -1;
 475
 476        if (offset == ios->offset) /* Go to start collect $200 */
 477                goto read_last_stripe;
 478
 479        min_p = _sp2d_min_pg(sp2d);
 480        max_p = _sp2d_max_pg(sp2d);
 481
 482        ORE_DBGMSG("stripe_start=0x%llx ios->offset=0x%llx min_p=%d max_p=%d\n",
 483                   offset, ios->offset, min_p, max_p);
 484
 485        for (c = 0; ; c++) {
 486                ore_calc_stripe_info(ios->layout, offset, 0, &read_si);
 487                read_si.obj_offset += min_p * PAGE_SIZE;
 488                offset += min_p * PAGE_SIZE;
 489                for (p = min_p; p <= max_p; p++) {
 490                        struct __1_page_stripe *_1ps = &sp2d->_1p_stripes[p];
 491                        struct page **pp = &_1ps->pages[c];
 492                        bool uptodate;
 493
 494                        if (*pp) {
 495                                if (ios->offset % PAGE_SIZE)
 496                                        /* Read the remainder of the page */
 497                                        _add_to_r4w_first_page(ios, *pp);
 498                                /* to-be-written pages start here */
 499                                goto read_last_stripe;
 500                        }
 501
 502                        *pp = ios->r4w->get_page(ios->private, offset,
 503                                                 &uptodate);
 504                        if (unlikely(!*pp))
 505                                return -ENOMEM;
 506
 507                        if (!uptodate)
 508                                _add_to_r4w(ios, &read_si, *pp, PAGE_SIZE);
 509
 510                        /* Mark read-pages to be cache_released */
 511                        _1ps->page_is_read[c] = true;
 512                        read_si.obj_offset += PAGE_SIZE;
 513                        offset += PAGE_SIZE;
 514                }
 515                offset += (sp2d->pages_in_unit - p) * PAGE_SIZE;
 516        }
 517
 518read_last_stripe:
 519        return 0;
 520}
 521
 522static int _read_4_write_last_stripe(struct ore_io_state *ios)
 523{
 524        struct ore_striping_info read_si;
 525        struct __stripe_pages_2d *sp2d = ios->sp2d;
 526        u64 offset;
 527        u64 last_stripe_end;
 528        unsigned bytes_in_stripe = ios->si.bytes_in_stripe;
 529        unsigned c, p, min_p = sp2d->pages_in_unit, max_p = -1;
 530
 531        offset = ios->offset + ios->length;
 532        if (offset % PAGE_SIZE)
 533                _add_to_r4w_last_page(ios, &offset);
 534                /* offset will be aligned to next page */
 535
 536        last_stripe_end = div_u64(offset + bytes_in_stripe - 1, bytes_in_stripe)
 537                                 * bytes_in_stripe;
 538        if (offset == last_stripe_end) /* Optimize for the aligned case */
 539                goto read_it;
 540
 541        ore_calc_stripe_info(ios->layout, offset, 0, &read_si);
 542        p = read_si.cur_pg;
 543        c = read_si.cur_comp;
 544
 545        if (min_p == sp2d->pages_in_unit) {
 546                /* Didn't do it yet */
 547                min_p = _sp2d_min_pg(sp2d);
 548                max_p = _sp2d_max_pg(sp2d);
 549        }
 550
 551        ORE_DBGMSG("offset=0x%llx stripe_end=0x%llx min_p=%d max_p=%d\n",
 552                   offset, last_stripe_end, min_p, max_p);
 553
 554        while (offset < last_stripe_end) {
 555                struct __1_page_stripe *_1ps = &sp2d->_1p_stripes[p];
 556
 557                if ((min_p <= p) && (p <= max_p)) {
 558                        struct page *page;
 559                        bool uptodate;
 560
 561                        BUG_ON(_1ps->pages[c]);
 562                        page = ios->r4w->get_page(ios->private, offset,
 563                                                  &uptodate);
 564                        if (unlikely(!page))
 565                                return -ENOMEM;
 566
 567                        _1ps->pages[c] = page;
 568                        /* Mark read-pages to be cache_released */
 569                        _1ps->page_is_read[c] = true;
 570                        if (!uptodate)
 571                                _add_to_r4w(ios, &read_si, page, PAGE_SIZE);
 572                }
 573
 574                offset += PAGE_SIZE;
 575                if (p == (sp2d->pages_in_unit - 1)) {
 576                        ++c;
 577                        p = 0;
 578                        ore_calc_stripe_info(ios->layout, offset, 0, &read_si);
 579                } else {
 580                        read_si.obj_offset += PAGE_SIZE;
 581                        ++p;
 582                }
 583        }
 584
 585read_it:
 586        return 0;
 587}
 588
 589static int _read_4_write_execute(struct ore_io_state *ios)
 590{
 591        struct ore_io_state *ios_read;
 592        unsigned i;
 593        int ret;
 594
 595        ios_read = ios->ios_read_4_write;
 596        if (!ios_read)
 597                return 0;
 598
 599        /* FIXME: Ugly to signal _sbi_read_mirror that we have bio(s). Change
 600         * to check for per_dev->bio
 601         */
 602        ios_read->pages = ios->pages;
 603
 604        /* Now read these devices */
 605        for (i = 0; i < ios_read->numdevs; i += ios_read->layout->mirrors_p1) {
 606                ret = _ore_read_mirror(ios_read, i);
 607                if (unlikely(ret))
 608                        return ret;
 609        }
 610
 611        ret = ore_io_execute(ios_read); /* Synchronus execution */
 612        if (unlikely(ret)) {
 613                ORE_DBGMSG("!! ore_io_execute => %d\n", ret);
 614                return ret;
 615        }
 616
 617        _mark_read4write_pages_uptodate(ios_read, ret);
 618        ore_put_io_state(ios_read);
 619        ios->ios_read_4_write = NULL; /* Might need a reuse at last stripe */
 620        return 0;
 621}
 622
 623/* In writes @cur_len means length left. .i.e cur_len==0 is the last parity U */
 624int _ore_add_parity_unit(struct ore_io_state *ios,
 625                            struct ore_striping_info *si,
 626                            struct ore_per_dev_state *per_dev,
 627                            unsigned cur_len, bool do_xor)
 628{
 629        if (ios->reading) {
 630                if (per_dev->cur_sg >= ios->sgs_per_dev) {
 631                        ORE_DBGMSG("cur_sg(%d) >= sgs_per_dev(%d)\n" ,
 632                                per_dev->cur_sg, ios->sgs_per_dev);
 633                        return -ENOMEM;
 634                }
 635                _ore_add_sg_seg(per_dev, cur_len, true);
 636        } else {
 637                struct __stripe_pages_2d *sp2d = ios->sp2d;
 638                struct page **pages = ios->parity_pages + ios->cur_par_page;
 639                unsigned num_pages;
 640                unsigned array_start = 0;
 641                unsigned i;
 642                int ret;
 643
 644                si->cur_pg = _sp2d_min_pg(sp2d);
 645                num_pages  = _sp2d_max_pg(sp2d) + 1 - si->cur_pg;
 646
 647                if (!per_dev->length) {
 648                        per_dev->offset += si->cur_pg * PAGE_SIZE;
 649                        /* If first stripe, Read in all read4write pages
 650                         * (if needed) before we calculate the first parity.
 651                         */
 652                        if (do_xor)
 653                                _read_4_write_first_stripe(ios);
 654                }
 655                if (!cur_len && do_xor)
 656                        /* If last stripe r4w pages of last stripe */
 657                        _read_4_write_last_stripe(ios);
 658                _read_4_write_execute(ios);
 659
 660                for (i = 0; i < num_pages; i++) {
 661                        pages[i] = _raid_page_alloc();
 662                        if (unlikely(!pages[i]))
 663                                return -ENOMEM;
 664
 665                        ++(ios->cur_par_page);
 666                }
 667
 668                BUG_ON(si->cur_comp < sp2d->data_devs);
 669                BUG_ON(si->cur_pg + num_pages > sp2d->pages_in_unit);
 670
 671                ret = _ore_add_stripe_unit(ios,  &array_start, 0, pages,
 672                                           per_dev, num_pages * PAGE_SIZE);
 673                if (unlikely(ret))
 674                        return ret;
 675
 676                if (do_xor) {
 677                        _gen_xor_unit(sp2d);
 678                        _sp2d_reset(sp2d, ios->r4w, ios->private);
 679                }
 680        }
 681        return 0;
 682}
 683
 684int _ore_post_alloc_raid_stuff(struct ore_io_state *ios)
 685{
 686        if (ios->parity_pages) {
 687                struct ore_layout *layout = ios->layout;
 688                unsigned pages_in_unit = layout->stripe_unit / PAGE_SIZE;
 689
 690                if (_sp2d_alloc(pages_in_unit, layout->group_width,
 691                                layout->parity, &ios->sp2d)) {
 692                        return -ENOMEM;
 693                }
 694        }
 695        return 0;
 696}
 697
 698void _ore_free_raid_stuff(struct ore_io_state *ios)
 699{
 700        if (ios->sp2d) { /* writing and raid */
 701                unsigned i;
 702
 703                for (i = 0; i < ios->cur_par_page; i++) {
 704                        struct page *page = ios->parity_pages[i];
 705
 706                        if (page)
 707                                _raid_page_free(page);
 708                }
 709                if (ios->extra_part_alloc)
 710                        kfree(ios->parity_pages);
 711                /* If IO returned an error pages might need unlocking */
 712                _sp2d_reset(ios->sp2d, ios->r4w, ios->private);
 713                _sp2d_free(ios->sp2d);
 714        } else {
 715                /* Will only be set if raid reading && sglist is big */
 716                if (ios->extra_part_alloc)
 717                        kfree(ios->per_dev[0].sglist);
 718        }
 719        if (ios->ios_read_4_write)
 720                ore_put_io_state(ios->ios_read_4_write);
 721}
 722