1/*
  2 * Copyright (C) 2016 CNEX Labs
  3 * Initial release: Javier Gonzalez <javier@cnexlabs.com>
  4 *                  Matias Bjorling <matias@cnexlabs.com>
  5 *
  6 * This program is free software; you can redistribute it and/or
  7 * modify it under the terms of the GNU General Public License version
  8 * 2 as published by the Free Software Foundation.
  9 *
 10 * This program is distributed in the hope that it will be useful, but
 11 * WITHOUT ANY WARRANTY; without even the implied warranty of
 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 13 * General Public License for more details.
 14 *
 15 * pblk-cache.c - pblk's write cache
 16 */
 17
 18#include "pblk.h"
 19
 20int pblk_write_to_cache(struct pblk *pblk, struct bio *bio, unsigned long flags)
 21{
 22	struct request_queue *q = pblk->dev->q;
 23	struct pblk_w_ctx w_ctx;
 24	sector_t lba = pblk_get_lba(bio);
 25	unsigned long start_time = jiffies;
 26	unsigned int bpos, pos;
 27	int nr_entries = pblk_get_secs(bio);
 28	int i, ret;
 29
 30	generic_start_io_acct(q, WRITE, bio_sectors(bio), &pblk->disk->part0);
 31
 32	/* Update the write buffer head (mem) with the entries that we can
 33	 * write. The write in itself cannot fail, so there is no need to
 34	 * rollback from here on.
 35	 */
 36retry:
 37	ret = pblk_rb_may_write_user(&pblk->rwb, bio, nr_entries, &bpos);
 38	switch (ret) {
 39	case NVM_IO_REQUEUE:
 40		io_schedule();
 41		goto retry;
 42	case NVM_IO_ERR:
 43		pblk_pipeline_stop(pblk);
 44		goto out;
 45	}
 46
 47	if (unlikely(!bio_has_data(bio)))
 48		goto out;
 49
 50	pblk_ppa_set_empty(&w_ctx.ppa);
 51	w_ctx.flags = flags;
 52	if (bio->bi_opf & REQ_PREFLUSH)
 53		w_ctx.flags |= PBLK_FLUSH_ENTRY;
 54
 55	for (i = 0; i < nr_entries; i++) {
 56		void *data = bio_data(bio);
 57
 58		w_ctx.lba = lba + i;
 59
 60		pos = pblk_rb_wrap_pos(&pblk->rwb, bpos + i);
 61		pblk_rb_write_entry_user(&pblk->rwb, data, w_ctx, pos);
 62
 63		bio_advance(bio, PBLK_EXPOSED_PAGE_SIZE);
 64	}
 65
 66	atomic64_add(nr_entries, &pblk->user_wa);
 67
 68#ifdef CONFIG_NVM_DEBUG
 69	atomic_long_add(nr_entries, &pblk->inflight_writes);
 70	atomic_long_add(nr_entries, &pblk->req_writes);
 71#endif
 72
 73	pblk_rl_inserted(&pblk->rl, nr_entries);
 74
 75out:
 76	generic_end_io_acct(q, WRITE, &pblk->disk->part0, start_time);
 77	pblk_write_should_kick(pblk);
 78	return ret;
 79}
 80
 81/*
 82 * On GC the incoming lbas are not necessarily sequential. Also, some of the
 83 * lbas might not be valid entries, which are marked as empty by the GC thread
 84 */
 85int pblk_write_gc_to_cache(struct pblk *pblk, struct pblk_gc_rq *gc_rq)
 86{
 87	struct pblk_w_ctx w_ctx;
 88	unsigned int bpos, pos;
 89	void *data = gc_rq->data;
 90	int i, valid_entries;
 91
 92	/* Update the write buffer head (mem) with the entries that we can
 93	 * write. The write in itself cannot fail, so there is no need to
 94	 * rollback from here on.
 95	 */
 96retry:
 97	if (!pblk_rb_may_write_gc(&pblk->rwb, gc_rq->secs_to_gc, &bpos)) {
 98		io_schedule();
 99		goto retry;
100	}
101
102	w_ctx.flags = PBLK_IOTYPE_GC;
103	pblk_ppa_set_empty(&w_ctx.ppa);
104
105	for (i = 0, valid_entries = 0; i < gc_rq->nr_secs; i++) {
106		if (gc_rq->lba_list[i] == ADDR_EMPTY)
107			continue;
108
109		w_ctx.lba = gc_rq->lba_list[i];
110
111		pos = pblk_rb_wrap_pos(&pblk->rwb, bpos + valid_entries);
112		pblk_rb_write_entry_gc(&pblk->rwb, data, w_ctx, gc_rq->line,
113						gc_rq->paddr_list[i], pos);
114
115		data += PBLK_EXPOSED_PAGE_SIZE;
116		valid_entries++;
117	}
118
119	WARN_ONCE(gc_rq->secs_to_gc != valid_entries,
120					"pblk: inconsistent GC write\n");
121
122	atomic64_add(valid_entries, &pblk->gc_wa);
123
124#ifdef CONFIG_NVM_DEBUG
125	atomic_long_add(valid_entries, &pblk->inflight_writes);
126	atomic_long_add(valid_entries, &pblk->recov_gc_writes);
127#endif
128
129	pblk_write_should_kick(pblk);
130	return NVM_IO_OK;
131}