LXR linux/drivers/lightnvm/pblk-cache.c

   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, REQ_OP_WRITE, bio_sectors(bio),
  31                              &pblk->disk->part0);
  32
  33        /* Update the write buffer head (mem) with the entries that we can
  34         * write. The write in itself cannot fail, so there is no need to
  35         * rollback from here on.
  36         */
  37retry:
  38        ret = pblk_rb_may_write_user(&pblk->rwb, bio, nr_entries, &bpos);
  39        switch (ret) {
  40        case NVM_IO_REQUEUE:
  41                io_schedule();
  42                goto retry;
  43        case NVM_IO_ERR:
  44                pblk_pipeline_stop(pblk);
  45                goto out;
  46        }
  47
  48        pblk_ppa_set_empty(&w_ctx.ppa);
  49        w_ctx.flags = flags;
  50        if (bio->bi_opf & REQ_PREFLUSH) {
  51                w_ctx.flags |= PBLK_FLUSH_ENTRY;
  52                pblk_write_kick(pblk);
  53        }
  54
  55        if (unlikely(!bio_has_data(bio)))
  56                goto out;
  57
  58        for (i = 0; i < nr_entries; i++) {
  59                void *data = bio_data(bio);
  60
  61                w_ctx.lba = lba + i;
  62
  63                pos = pblk_rb_wrap_pos(&pblk->rwb, bpos + i);
  64                pblk_rb_write_entry_user(&pblk->rwb, data, w_ctx, pos);
  65
  66                bio_advance(bio, PBLK_EXPOSED_PAGE_SIZE);
  67        }
  68
  69        atomic64_add(nr_entries, &pblk->user_wa);
  70
  71#ifdef CONFIG_NVM_PBLK_DEBUG
  72        atomic_long_add(nr_entries, &pblk->inflight_writes);
  73        atomic_long_add(nr_entries, &pblk->req_writes);
  74#endif
  75
  76        pblk_rl_inserted(&pblk->rl, nr_entries);
  77
  78out:
  79        generic_end_io_acct(q, REQ_OP_WRITE, &pblk->disk->part0, start_time);
  80        pblk_write_should_kick(pblk);
  81        return ret;
  82}
  83
  84/*
  85 * On GC the incoming lbas are not necessarily sequential. Also, some of the
  86 * lbas might not be valid entries, which are marked as empty by the GC thread
  87 */
  88int pblk_write_gc_to_cache(struct pblk *pblk, struct pblk_gc_rq *gc_rq)
  89{
  90        struct pblk_w_ctx w_ctx;
  91        unsigned int bpos, pos;
  92        void *data = gc_rq->data;
  93        int i, valid_entries;
  94
  95        /* Update the write buffer head (mem) with the entries that we can
  96         * write. The write in itself cannot fail, so there is no need to
  97         * rollback from here on.
  98         */
  99retry:
 100        if (!pblk_rb_may_write_gc(&pblk->rwb, gc_rq->secs_to_gc, &bpos)) {
 101                io_schedule();
 102                goto retry;
 103        }
 104
 105        w_ctx.flags = PBLK_IOTYPE_GC;
 106        pblk_ppa_set_empty(&w_ctx.ppa);
 107
 108        for (i = 0, valid_entries = 0; i < gc_rq->nr_secs; i++) {
 109                if (gc_rq->lba_list[i] == ADDR_EMPTY)
 110                        continue;
 111
 112                w_ctx.lba = gc_rq->lba_list[i];
 113
 114                pos = pblk_rb_wrap_pos(&pblk->rwb, bpos + valid_entries);
 115                pblk_rb_write_entry_gc(&pblk->rwb, data, w_ctx, gc_rq->line,
 116                                                gc_rq->paddr_list[i], pos);
 117
 118                data += PBLK_EXPOSED_PAGE_SIZE;
 119                valid_entries++;
 120        }
 121
 122        WARN_ONCE(gc_rq->secs_to_gc != valid_entries,
 123                                        "pblk: inconsistent GC write\n");
 124
 125        atomic64_add(valid_entries, &pblk->gc_wa);
 126
 127#ifdef CONFIG_NVM_PBLK_DEBUG
 128        atomic_long_add(valid_entries, &pblk->inflight_writes);
 129        atomic_long_add(valid_entries, &pblk->recov_gc_writes);
 130#endif
 131
 132        pblk_write_should_kick(pblk);
 133        return NVM_IO_OK;
 134}
 135