Boaz Harrosh | a1fec1d | 2011-10-12 18:42:22 +0200 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2011 |
| 3 | * Boaz Harrosh <bharrosh@panasas.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 | |
| 18 | #include "ore_raid.h" |
| 19 | |
| 20 | struct page *_raid_page_alloc(void) |
| 21 | { |
| 22 | return alloc_page(GFP_KERNEL); |
| 23 | } |
| 24 | |
| 25 | void _raid_page_free(struct page *p) |
| 26 | { |
| 27 | __free_page(p); |
| 28 | } |
| 29 | |
| 30 | void _ore_add_sg_seg(struct ore_per_dev_state *per_dev, unsigned cur_len, |
| 31 | bool not_last) |
| 32 | { |
| 33 | struct osd_sg_entry *sge; |
| 34 | |
| 35 | ORE_DBGMSG("dev=%d cur_len=0x%x not_last=%d cur_sg=%d " |
| 36 | "offset=0x%llx length=0x%x last_sgs_total=0x%x\n", |
| 37 | per_dev->dev, cur_len, not_last, per_dev->cur_sg, |
| 38 | _LLU(per_dev->offset), per_dev->length, |
| 39 | per_dev->last_sgs_total); |
| 40 | |
| 41 | if (!per_dev->cur_sg) { |
| 42 | sge = per_dev->sglist; |
| 43 | |
| 44 | /* First time we prepare two entries */ |
| 45 | if (per_dev->length) { |
| 46 | ++per_dev->cur_sg; |
| 47 | sge->offset = per_dev->offset; |
| 48 | sge->len = per_dev->length; |
| 49 | } else { |
| 50 | /* Here the parity is the first unit of this object. |
| 51 | * This happens every time we reach a parity device on |
| 52 | * the same stripe as the per_dev->offset. We need to |
| 53 | * just skip this unit. |
| 54 | */ |
| 55 | per_dev->offset += cur_len; |
| 56 | return; |
| 57 | } |
| 58 | } else { |
| 59 | /* finalize the last one */ |
| 60 | sge = &per_dev->sglist[per_dev->cur_sg - 1]; |
| 61 | sge->len = per_dev->length - per_dev->last_sgs_total; |
| 62 | } |
| 63 | |
| 64 | if (not_last) { |
| 65 | /* Partly prepare the next one */ |
| 66 | struct osd_sg_entry *next_sge = sge + 1; |
| 67 | |
| 68 | ++per_dev->cur_sg; |
| 69 | next_sge->offset = sge->offset + sge->len + cur_len; |
| 70 | /* Save cur len so we know how mutch was added next time */ |
| 71 | per_dev->last_sgs_total = per_dev->length; |
| 72 | next_sge->len = 0; |
| 73 | } else if (!sge->len) { |
| 74 | /* Optimize for when the last unit is a parity */ |
| 75 | --per_dev->cur_sg; |
| 76 | } |
| 77 | } |
| 78 | |
| 79 | /* In writes @cur_len means length left. .i.e cur_len==0 is the last parity U */ |
| 80 | int _ore_add_parity_unit(struct ore_io_state *ios, |
| 81 | struct ore_striping_info *si, |
| 82 | struct ore_per_dev_state *per_dev, |
| 83 | unsigned cur_len) |
| 84 | { |
| 85 | if (ios->reading) { |
| 86 | BUG_ON(per_dev->cur_sg >= ios->sgs_per_dev); |
| 87 | _ore_add_sg_seg(per_dev, cur_len, true); |
| 88 | } else { |
| 89 | struct page **pages = ios->parity_pages + ios->cur_par_page; |
| 90 | unsigned num_pages = ios->layout->stripe_unit / PAGE_SIZE; |
| 91 | unsigned array_start = 0; |
| 92 | unsigned i; |
| 93 | int ret; |
| 94 | |
| 95 | for (i = 0; i < num_pages; i++) { |
| 96 | pages[i] = _raid_page_alloc(); |
| 97 | if (unlikely(!pages[i])) |
| 98 | return -ENOMEM; |
| 99 | |
| 100 | ++(ios->cur_par_page); |
| 101 | /* TODO: only read support for now */ |
| 102 | clear_highpage(pages[i]); |
| 103 | } |
| 104 | |
| 105 | ORE_DBGMSG("writing dev=%d num_pages=%d cur_par_page=%d", |
| 106 | per_dev->dev, num_pages, ios->cur_par_page); |
| 107 | |
| 108 | ret = _ore_add_stripe_unit(ios, &array_start, 0, pages, |
| 109 | per_dev, num_pages * PAGE_SIZE); |
| 110 | if (unlikely(ret)) |
| 111 | return ret; |
| 112 | } |
| 113 | return 0; |
| 114 | } |
| 115 | |
| 116 | int _ore_post_alloc_raid_stuff(struct ore_io_state *ios) |
| 117 | { |
| 118 | /*TODO: Only raid writes has stuff to add here */ |
| 119 | return 0; |
| 120 | } |
| 121 | |
| 122 | void _ore_free_raid_stuff(struct ore_io_state *ios) |
| 123 | { |
| 124 | if (ios->parity_pages) { /* writing and raid */ |
| 125 | unsigned i; |
| 126 | |
| 127 | for (i = 0; i < ios->cur_par_page; i++) { |
| 128 | struct page *page = ios->parity_pages[i]; |
| 129 | |
| 130 | if (page) |
| 131 | _raid_page_free(page); |
| 132 | } |
| 133 | if (ios->extra_part_alloc) |
| 134 | kfree(ios->parity_pages); |
| 135 | } else { |
| 136 | /* Will only be set if raid reading && sglist is big */ |
| 137 | if (ios->extra_part_alloc) |
| 138 | kfree(ios->per_dev[0].sglist); |
| 139 | } |
| 140 | } |