drivers/lightnvm/pblk-cache.c

   1 /*
   2  * Copyright (C) 2016 CNEX Labs
   3  * Initial release: Javier Gonzalez <[email protected]>
   4  *                  Matias Bjorling <[email protected]>
   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
  20 int 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          */
  36 retry:
  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 #ifdef CONFIG_NVM_DEBUG
  67         atomic_long_add(nr_entries, &pblk->inflight_writes);
  68         atomic_long_add(nr_entries, &pblk->req_writes);
  69 #endif
  70
  71         pblk_rl_inserted(&pblk->rl, nr_entries);
  72
  73 out:
  74         generic_end_io_acct(q, WRITE, &pblk->disk->part0, start_time);
  75         pblk_write_should_kick(pblk);
  76         return ret;
  77 }
  78
  79 /*
  80  * On GC the incoming lbas are not necessarily sequential. Also, some of the
  81  * lbas might not be valid entries, which are marked as empty by the GC thread
  82  */
  83 int pblk_write_gc_to_cache(struct pblk *pblk, struct pblk_gc_rq *gc_rq)
  84 {
  85         struct pblk_w_ctx w_ctx;
  86         unsigned int bpos, pos;
  87         void *data = gc_rq->data;
  88         int i, valid_entries;
  89
  90         /* Update the write buffer head (mem) with the entries that we can
  91          * write. The write in itself cannot fail, so there is no need to
  92          * rollback from here on.
  93          */
  94 retry:
  95         if (!pblk_rb_may_write_gc(&pblk->rwb, gc_rq->secs_to_gc, &bpos)) {
  96                 io_schedule();
  97                 goto retry;
  98         }
  99
 100         w_ctx.flags = PBLK_IOTYPE_GC;
 101         pblk_ppa_set_empty(&w_ctx.ppa);
 102
 103         for (i = 0, valid_entries = 0; i < gc_rq->nr_secs; i++) {
 104                 if (gc_rq->lba_list[i] == ADDR_EMPTY)
 105                         continue;
 106
 107                 w_ctx.lba = gc_rq->lba_list[i];
 108
 109                 pos = pblk_rb_wrap_pos(&pblk->rwb, bpos + valid_entries);
 110                 pblk_rb_write_entry_gc(&pblk->rwb, data, w_ctx, gc_rq->line,
 111                                                 gc_rq->paddr_list[i], pos);
 112
 113                 data += PBLK_EXPOSED_PAGE_SIZE;
 114                 valid_entries++;
 115         }
 116
 117         WARN_ONCE(gc_rq->secs_to_gc != valid_entries,
 118                                         "pblk: inconsistent GC write\n");
 119
 120 #ifdef CONFIG_NVM_DEBUG
 121         atomic_long_add(valid_entries, &pblk->inflight_writes);
 122         atomic_long_add(valid_entries, &pblk->recov_gc_writes);
 123 #endif
 124
 125         pblk_write_should_kick(pblk);
 126         return NVM_IO_OK;
 127 }