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/*
* Copyright (C) 2011
* Boaz Harrosh <bharrosh@panasas.com>
*
* This file is part of the objects raid engine (ore).
*
* It is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
* You should have received a copy of the GNU General Public License
* along with "ore". If not, write to the Free Software Foundation, Inc:
* "Free Software Foundation <info@fsf.org>"
*/
#include <linux/gfp.h>
#include "ore_raid.h"
struct page *_raid_page_alloc(void)
{
return alloc_page(GFP_KERNEL);
}
void _raid_page_free(struct page *p)
{
__free_page(p);
}
void _ore_add_sg_seg(struct ore_per_dev_state *per_dev, unsigned cur_len,
bool not_last)
{
struct osd_sg_entry *sge;
ORE_DBGMSG("dev=%d cur_len=0x%x not_last=%d cur_sg=%d "
"offset=0x%llx length=0x%x last_sgs_total=0x%x\n",
per_dev->dev, cur_len, not_last, per_dev->cur_sg,
_LLU(per_dev->offset), per_dev->length,
per_dev->last_sgs_total);
if (!per_dev->cur_sg) {
sge = per_dev->sglist;
/* First time we prepare two entries */
if (per_dev->length) {
++per_dev->cur_sg;
sge->offset = per_dev->offset;
sge->len = per_dev->length;
} else {
/* Here the parity is the first unit of this object.
* This happens every time we reach a parity device on
* the same stripe as the per_dev->offset. We need to
* just skip this unit.
*/
per_dev->offset += cur_len;
return;
}
} else {
/* finalize the last one */
sge = &per_dev->sglist[per_dev->cur_sg - 1];
sge->len = per_dev->length - per_dev->last_sgs_total;
}
if (not_last) {
/* Partly prepare the next one */
struct osd_sg_entry *next_sge = sge + 1;
++per_dev->cur_sg;
next_sge->offset = sge->offset + sge->len + cur_len;
/* Save cur len so we know how mutch was added next time */
per_dev->last_sgs_total = per_dev->length;
next_sge->len = 0;
} else if (!sge->len) {
/* Optimize for when the last unit is a parity */
--per_dev->cur_sg;
}
}
/* In writes @cur_len means length left. .i.e cur_len==0 is the last parity U */
int _ore_add_parity_unit(struct ore_io_state *ios,
struct ore_striping_info *si,
struct ore_per_dev_state *per_dev,
unsigned cur_len)
{
if (ios->reading) {
BUG_ON(per_dev->cur_sg >= ios->sgs_per_dev);
_ore_add_sg_seg(per_dev, cur_len, true);
} else {
struct page **pages = ios->parity_pages + ios->cur_par_page;
unsigned num_pages = ios->layout->stripe_unit / PAGE_SIZE;
unsigned array_start = 0;
unsigned i;
int ret;
for (i = 0; i < num_pages; i++) {
pages[i] = _raid_page_alloc();
if (unlikely(!pages[i]))
return -ENOMEM;
++(ios->cur_par_page);
/* TODO: only read support for now */
clear_highpage(pages[i]);
}
ORE_DBGMSG("writing dev=%d num_pages=%d cur_par_page=%d",
per_dev->dev, num_pages, ios->cur_par_page);
ret = _ore_add_stripe_unit(ios, &array_start, 0, pages,
per_dev, num_pages * PAGE_SIZE);
if (unlikely(ret))
return ret;
}
return 0;
}
int _ore_post_alloc_raid_stuff(struct ore_io_state *ios)
{
/*TODO: Only raid writes has stuff to add here */
return 0;
}
void _ore_free_raid_stuff(struct ore_io_state *ios)
{
if (ios->parity_pages) { /* writing and raid */
unsigned i;
for (i = 0; i < ios->cur_par_page; i++) {
struct page *page = ios->parity_pages[i];
if (page)
_raid_page_free(page);
}
if (ios->extra_part_alloc)
kfree(ios->parity_pages);
} else {
/* Will only be set if raid reading && sglist is big */
if (ios->extra_part_alloc)
kfree(ios->per_dev[0].sglist);
}
}
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