303 lines
6.9 KiB
C
303 lines
6.9 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 lbatpblk {
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struct list_head list;
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u64 pblk;
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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 compress_params* kparams;
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struct compress_stats* kstats;
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struct page* page;
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u8* buf;
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bool dirty;
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};
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static bool
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lbatpblk_ctr(struct lbatpblk* lp,
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struct compress_params* kparams,
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struct compress_stats* kstats)
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{
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memset(lp, 0, sizeof(struct lbatpblk));
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INIT_LIST_HEAD(&lp->list);
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lp->pblk = PBLK_NONE;
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mutex_init(&lp->reflock);
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lp->ref = 0;
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mutex_init(&lp->lock);
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lp->kparams = kparams;
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lp->kstats = kstats;
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lp->page = cbd_alloc_page();
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if (!lp->page) {
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return false;
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}
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lp->buf = page_address(lp->page);
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lp->dirty = false;
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return true;
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}
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static void
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lbatpblk_dtr(struct lbatpblk* lp)
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{
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if (lp->page) {
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lock_page(lp->page);
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}
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lp->buf = NULL;
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cbd_free_page(lp->page);
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lp->page = NULL;
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}
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static bool
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lbatpblk_error(struct lbatpblk* lp)
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{
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return PageError(lp->page);
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}
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static int
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lbatpblk_flush(struct lbatpblk* lp)
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{
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int ret = 0;
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mutex_lock(&lp->lock);
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if (!PageDirty(lp->page)) {
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goto unlock;
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}
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if (lbatpblk_error(lp)) {
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ret = -EIO;
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goto unlock;
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}
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pblk_write(lp->kparams, lp->pblk, 1, lp->page);
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mutex_unlock(&lp->lock);
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mutex_lock(&lp->kstats->lock);
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++lp->kstats->lbatpblk_w;
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mutex_unlock(&lp->kstats->lock);
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return ret;
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unlock:
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unlock_page(lp->page);
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mutex_unlock(&lp->lock);
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return ret;
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}
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static int
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lbatpblk_read(struct lbatpblk* lp)
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{
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int ret = 0;
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BUG_ON(lbatpblk_error(lp));
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ret = pblk_read_wait(lp->kparams, lp->pblk, 1, lp->page);
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mutex_lock(&lp->kstats->lock);
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++lp->kstats->lbatpblk_r;
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mutex_unlock(&lp->kstats->lock);
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return ret;
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}
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static int
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lbatpblk_reset(struct lbatpblk* lp, u64 pblk)
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{
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int ret = 0;
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lock_page(lp->page);
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if (lp->pblk != pblk) {
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lp->pblk = pblk;
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ret = lbatpblk_read(lp);
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}
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if (ret) {
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unlock_page(lp->page);
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lp->pblk = PBLK_NONE;
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}
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return ret;
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}
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u8*
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lbatpblk_get_buf(struct lbatpblk* lp, bool rw)
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{
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mutex_lock(&lp->lock);
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if (rw) {
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SetPageDirty(lp->page);
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}
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return lp->buf;
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}
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void
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lbatpblk_put_buf(struct lbatpblk* lp)
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{
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mutex_unlock(&lp->lock);
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}
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struct lbatpblkcache {
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struct mutex cache_lock;
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struct list_head cache_head;
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unsigned int cache_len;
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struct lbatpblk* cache;
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};
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size_t
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lbatpblkcache_size(void)
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{
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return sizeof(struct lbatpblkcache);
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}
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bool
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lbatpblkcache_ctr(struct lbatpblkcache* lpc,
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struct compress_params* kparams, struct compress_stats* kstats,
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u32 cache_pages)
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{
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struct lbatpblk* cache;
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u32 cache_len;
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u32 n;
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memset(lpc, 0, sizeof(struct lbatpblkcache));
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/* lbatpblkcache gets 15/32 of cache pages */
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cache_len = (cache_pages * 15 / 32);
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if (!cache_len) {
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printk(KERN_ERR "%s: Cache too small\n", __func__);
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return false;
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}
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printk(KERN_INFO "%s: cache_len=%u\n", __func__, cache_len);
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cache = kzalloc(cache_len * sizeof(struct lbatpblk), GFP_KERNEL);
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if (!cache) {
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return false;
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}
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mutex_init(&lpc->cache_lock);
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INIT_LIST_HEAD(&lpc->cache_head);
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lpc->cache_len = cache_len;
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lpc->cache = cache;
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for (n = 0; n < cache_len; ++n) {
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if (!lbatpblk_ctr(&cache[n], kparams, kstats)) {
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return false;
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}
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list_add_tail(&cache[n].list, &lpc->cache_head);
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}
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return true;
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}
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void
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lbatpblkcache_dtr(struct lbatpblkcache* lpc)
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{
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unsigned int n;
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struct lbatpblk* lp;
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for (n = 0; n < lpc->cache_len; ++n) {
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lp = &lpc->cache[n];
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if (!lp) {
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continue;
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}
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lbatpblk_dtr(lp);
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if (lp->ref) {
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printk(KERN_ERR "%s: lbatpblk ref leak: n=%u ref=%u\n", __func__, n, lp->ref);
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}
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}
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kfree(lpc->cache);
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lpc->cache = NULL;
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lpc->cache_len = 0;
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INIT_LIST_HEAD(&lpc->cache_head);
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}
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struct lbatpblk*
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lbatpblkcache_get(struct lbatpblkcache* lpc, u64 pblk)
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{
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struct lbatpblk* lp;
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mutex_lock(&lpc->cache_lock);
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list_for_each_entry(lp, &lpc->cache_head, list) {
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mutex_lock(&lp->reflock);
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if (lp->pblk == pblk) {
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list_move(&lp->list, &lpc->cache_head);
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mutex_unlock(&lpc->cache_lock);
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if (lp->ref == 0) {
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goto found;
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}
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++lp->ref;
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mutex_unlock(&lp->reflock);
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return lp;
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}
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if (lp->pblk == PBLK_NONE) {
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list_move(&lp->list, &lpc->cache_head);
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mutex_unlock(&lpc->cache_lock);
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goto found;
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}
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mutex_unlock(&lp->reflock);
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}
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list_for_each_entry_reverse(lp, &lpc->cache_head, list) {
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mutex_lock(&lp->reflock);
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if (lp->ref == 0 && !lbatpblk_error(lp)) {
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list_move(&lp->list, &lpc->cache_head);
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mutex_unlock(&lpc->cache_lock);
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goto found;
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}
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mutex_unlock(&lp->reflock);
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}
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printk(KERN_ERR "%s: failed to find free entry\n", __func__);
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mutex_unlock(&lpc->cache_lock);
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return NULL;
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found:
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if (lbatpblk_reset(lp, pblk) != 0) {
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mutex_unlock(&lp->reflock);
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return NULL;
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}
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lp->ref = 1;
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mutex_unlock(&lp->reflock);
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return lp;
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}
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int
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lbatpblkcache_put(struct lbatpblkcache* lpc, struct lbatpblk* lp)
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{
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int ret = 0;
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if (!lp) {
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return 0;
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}
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mutex_lock(&lp->reflock);
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if (--lp->ref == 0) {
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ret = lbatpblk_flush(lp);
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if (ret) {
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printk(KERN_ERR "%s: lbatpblk_flush failed\n", __func__);
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}
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}
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mutex_unlock(&lp->reflock);
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return ret;
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}
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