382 lines
8.3 KiB
C
382 lines
8.3 KiB
C
/*
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* Copyright (c) 2019 Tom Marshall <tdm.code@gmail.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/bio.h>
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#include <linux/device-mapper.h>
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#include <linux/workqueue.h>
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#include <linux/mutex.h>
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#include <linux/lz4.h>
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#include <linux/dm-compress.h>
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struct pbat {
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u32 zone;
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struct mutex reflock;
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unsigned int ref;
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struct mutex lock;
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struct cbd_params* params;
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struct page** pagev;
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u8* buf;
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};
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static bool
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pbat_ctr(struct pbat* pbat,
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struct cbd_params* params)
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{
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u32 nr_pages = pbat_len(params);
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memset(pbat, 0, sizeof(struct pbat));
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pbat->zone = ZONE_NONE;
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mutex_init(&pbat->reflock);
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pbat->ref = 0;
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mutex_init(&pbat->lock);
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pbat->params = params;
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pbat->pagev = kzalloc(nr_pages * sizeof(struct page*), GFP_KERNEL);
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if (!pbat->pagev) {
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return false;
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}
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if (!cbd_alloc_pagev(pbat->pagev, nr_pages)) {
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return false;
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}
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pbat->buf = vmap(pbat->pagev, nr_pages, VM_MAP, PAGE_KERNEL);
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if (!pbat->buf) {
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return false;
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}
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return true;
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}
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static void
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pbat_dtr(struct pbat* pbat)
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{
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u32 nr_pages = pbat_len(pbat->params);
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u32 n;
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for (n = 0; n < nr_pages; ++n) {
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lock_page(pbat->pagev[n]);
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}
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vunmap(pbat->buf);
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pbat->buf = NULL;
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cbd_free_pagev(pbat->pagev, nr_pages);
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kfree(pbat->pagev);
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pbat->pagev = NULL;
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}
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static bool
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pbat_error(struct pbat* pbat)
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{
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u32 nr_pages = pbat_len(pbat->params);
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u32 n;
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for (n = 0; n < nr_pages; ++n) {
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if (PageError(pbat->pagev[n])) {
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return true;
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}
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}
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return false;
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}
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static int
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pbat_flush(struct pbat* pbat)
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{
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int ret = 0;
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u32 nr_pages = pbat_len(pbat->params);
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u32 n;
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u64 pblk;
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mutex_lock(&pbat->lock);
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if (!PageDirty(pbat->pagev[0])) {
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goto unlock;
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}
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if (pbat_error(pbat)) {
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ret = -EIO;
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goto unlock;
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}
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pblk = pbat_off(pbat->params, pbat->zone);
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pblk_write(pbat->params->priv, pblk, nr_pages, pbat->pagev);
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mutex_unlock(&pbat->lock);
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return ret;
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unlock:
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for (n = 0; n < nr_pages; ++n) {
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unlock_page(pbat->pagev[n]);
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}
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mutex_unlock(&pbat->lock);
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return ret;
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}
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static int
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pbat_read(struct pbat* pbat)
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{
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int ret = 0;
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u32 nr_pages = pbat_len(pbat->params);
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u64 pblk;
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/* XXX: can't happen because pbatcache will not use a page with an error */
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if (PageError(pbat->pagev[0])) {
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return -EIO;
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}
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pblk = pbat_off(pbat->params, pbat->zone);
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ret = pblk_read_wait(pbat->params->priv, pblk, nr_pages, pbat->pagev);
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return ret;
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}
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static int
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pbat_reset(struct pbat* pbat, u32 zone)
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{
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int ret = 0;
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u32 nr_pages = pbat_len(pbat->params);
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u32 n;
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for (n = 0; n < nr_pages; ++n) {
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lock_page(pbat->pagev[n]);
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}
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if (pbat->zone != zone) {
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pbat->zone = zone;
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ret = pbat_read(pbat);
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}
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if (ret) {
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for (n = 0; n < nr_pages; ++n) {
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unlock_page(pbat->pagev[n]);
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}
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pbat->zone = ZONE_NONE;
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}
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return ret;
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}
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u32
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pbat_zone(struct pbat* pbat)
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{
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return pbat->zone;
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}
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u64
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pbat_alloc(struct pbat* pbat)
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{
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u32 pblk_count = pbat_len(pbat->params) * PBLK_SIZE_BITS;
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u32 idx;
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u64 pblk;
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mutex_lock(&pbat->lock);
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idx = cbd_bitmap_alloc(pbat->buf, pblk_count);
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if (idx == pblk_count) {
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pblk = PBLK_NONE;
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goto out;
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}
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pblk = idx + zone_data_off(pbat->params, pbat->zone);
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SetPageDirty(pbat->pagev[0]);
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out:
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mutex_unlock(&pbat->lock);
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return pblk;
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}
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int
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pbat_free(struct pbat* pbat, u64 pblk)
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{
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u32 pblk_count = pbat_len(pbat->params) * PBLK_SIZE_BITS;
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u32 zone;
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u32 idx;
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zone = zone_for_pblk(pbat->params, pblk);
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BUG_ON(zone != pbat->zone);
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if (pblk < zone_data_off(pbat->params, zone)) {
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printk(KERN_ERR "%s: pblk in metadata\n", __func__);
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return -EINVAL;
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}
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idx = pblk - zone_data_off(pbat->params, zone);
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BUG_ON(idx >= pblk_count);
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mutex_lock(&pbat->lock);
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cbd_bitmap_free(pbat->buf, idx);
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SetPageDirty(pbat->pagev[0]);
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mutex_unlock(&pbat->lock);
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return 0;
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}
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struct pbatcache {
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struct mutex lock;
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struct cbd_params* params;
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unsigned int len;
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struct pbat** cache;
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};
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size_t
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pbatcache_size(void)
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{
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return sizeof(struct pbatcache);
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}
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static bool
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pbatcache_realloc(struct pbatcache* pc, unsigned int len)
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{
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struct pbat** cache;
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unsigned int n;
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struct pbat* pbat;
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cache = kzalloc(len * sizeof(struct pbat*), GFP_KERNEL);
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if (!cache) {
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return false;
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}
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n = 0;
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if (pc->len) {
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memcpy(cache, pc->cache, pc->len * sizeof(struct pbat*));
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n = pc->len;
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kfree(pc->cache);
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}
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pc->len = len;
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pc->cache = cache;
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while (n < len) {
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pbat = kmalloc(sizeof(struct pbat), GFP_KERNEL);
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if (!pbat) {
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return false;
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}
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cache[n++] = pbat;
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if (!pbat_ctr(pbat, pc->params)) {
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return false;
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}
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}
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return true;
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}
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bool
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pbatcache_ctr(struct pbatcache* pc,
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struct cbd_params* params)
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{
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memset(pc, 0, sizeof(struct pbatcache));
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mutex_init(&pc->lock);
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pc->params = params;
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return pbatcache_realloc(pc, 1);
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}
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void
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pbatcache_dtr(struct pbatcache* pc)
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{
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unsigned int n;
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struct pbat* pbat;
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for (n = 0; n < pc->len; ++n) {
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pbat = pc->cache[n];
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if (!pbat) {
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continue;
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}
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pbat_dtr(pbat);
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if (pbat->ref) {
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printk(KERN_ERR "%s: pbat ref leak: n=%u ref=%u\n", __func__, n, pbat->ref);
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}
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kfree(pbat);
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}
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kfree(pc->cache);
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pc->cache = NULL;
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pc->len = 0;
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pc->params = NULL;
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}
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struct pbat*
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pbatcache_get(struct pbatcache* pc, u32 zone)
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{
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unsigned int n;
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struct pbat* pbat;
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mutex_lock(&pc->lock);
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for (n = 0; n < pc->len; ++n) {
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pbat = pc->cache[n];
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mutex_lock(&pbat->reflock);
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if (pbat->zone == zone) {
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if (pbat->ref == 0) {
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goto found;
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}
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mutex_unlock(&pc->lock);
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++pbat->ref;
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mutex_unlock(&pbat->reflock);
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return pbat;
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}
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mutex_unlock(&pbat->reflock);
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}
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for (n = 0; n < pc->len; ++n) {
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pbat = pc->cache[n];
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mutex_lock(&pbat->reflock);
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if (pbat->zone == ZONE_NONE) {
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goto found;
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}
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mutex_unlock(&pbat->reflock);
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}
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for (n = 0; n < pc->len; ++n) {
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pbat = pc->cache[n];
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mutex_lock(&pbat->reflock);
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if (pbat->ref == 0 && !pbat_error(pbat)) {
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goto found;
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}
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mutex_unlock(&pbat->reflock);
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}
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n = pc->len;
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if (!pbatcache_realloc(pc, pc->len * 2)) {
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printk(KERN_ERR "%s: realloc failed\n", __func__);
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mutex_unlock(&pc->lock);
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return NULL;
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}
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pbat = pc->cache[n];
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mutex_lock(&pbat->reflock);
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found:
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mutex_unlock(&pc->lock);
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if (pbat_reset(pbat, zone) != 0) {
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mutex_unlock(&pbat->reflock);
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return NULL;
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}
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pbat->ref = 1;
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mutex_unlock(&pbat->reflock);
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return pbat;
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}
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int
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pbatcache_put(struct pbatcache* pc, struct pbat* pbat)
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{
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int ret = 0;
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if (!pbat) {
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return 0;
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}
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mutex_lock(&pbat->reflock);
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if (--pbat->ref == 0) {
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ret = pbat_flush(pbat);
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if (ret) {
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printk(KERN_ERR "%s: pbat_flush failed\n", __func__);
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}
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}
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mutex_unlock(&pbat->reflock);
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return ret;
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}
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