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