--- /dev/null
+---
+ arch/arm/configs/rx51_defconfig | 2
+ drivers/block/Kconfig | 2
+ drivers/block/Makefile | 1
+ drivers/block/ramzswap/Kconfig | 22
+ drivers/block/ramzswap/Makefile | 3
+ drivers/block/ramzswap/compat.h | 13
+ drivers/block/ramzswap/ramzswap.txt | 51 +
+ drivers/block/ramzswap/ramzswap_drv.c | 1557 ++++++++++++++++++++++++++++++++
+ drivers/block/ramzswap/ramzswap_drv.h | 210 ++++
+ drivers/block/ramzswap/ramzswap_ioctl.h | 50 +
+ drivers/block/ramzswap/xvmalloc.c | 507 ++++++++++
+ drivers/block/ramzswap/xvmalloc.h | 30
+ drivers/block/ramzswap/xvmalloc_int.h | 86 +
+ 13 files changed, 2534 insertions(+)
+
+Index: kernel-power-2.6.28/arch/arm/configs/rx51_defconfig
+===================================================================
+--- kernel-power-2.6.28.orig/arch/arm/configs/rx51_defconfig
++++ kernel-power-2.6.28/arch/arm/configs/rx51_defconfig
+@@ -830,6 +830,8 @@
+ # CONFIG_BLK_DEV_XIP is not set
+ # CONFIG_CDROM_PKTCDVD is not set
+ # CONFIG_ATA_OVER_ETH is not set
++CONFIG_RAMZSWAP=m
++# CONFIG_RAMZSWAP_STATS is not set
+ CONFIG_MISC_DEVICES=y
+ # CONFIG_EEPROM_93CX6 is not set
+ CONFIG_NOKIA_AV_DETECT=m
+Index: kernel-power-2.6.28/drivers/block/Kconfig
+===================================================================
+--- kernel-power-2.6.28.orig/drivers/block/Kconfig
++++ kernel-power-2.6.28/drivers/block/Kconfig
+@@ -446,4 +446,6 @@
+
+ If unsure, say N.
+
++source "drivers/block/ramzswap/Kconfig"
++
+ endif # BLK_DEV
+Index: kernel-power-2.6.28/drivers/block/Makefile
+===================================================================
+--- kernel-power-2.6.28.orig/drivers/block/Makefile
++++ kernel-power-2.6.28/drivers/block/Makefile
+@@ -30,5 +30,6 @@
+ obj-$(CONFIG_BLK_DEV_SX8) += sx8.o
+ obj-$(CONFIG_BLK_DEV_UB) += ub.o
+ obj-$(CONFIG_BLK_DEV_HD) += hd.o
++obj-$(CONFIG_RAMZSWAP) += ramzswap/
+
+ obj-$(CONFIG_XEN_BLKDEV_FRONTEND) += xen-blkfront.o
+Index: kernel-power-2.6.28/drivers/block/ramzswap/Kconfig
+===================================================================
+--- /dev/null
++++ kernel-power-2.6.28/drivers/block/ramzswap/Kconfig
+@@ -0,0 +1,22 @@
++
++config RAMZSWAP
++ tristate "Compressed in-memory swap device (ramzswap)"
++ depends on SWAP
++ select LZO_COMPRESS
++ select LZO_DECOMPRESS
++ default n
++ help
++ Creates virtual block devices which can (only) be used as swap
++ disks. Pages swapped to these disks are compressed and stored in
++ memory itself.
++
++ See ramzswap.txt for more information.
++ Project home: http://compcache.googlecode.com/
++
++config RAMZSWAP_STATS
++ bool "Enable ramzswap stats"
++ depends on RAMZSWAP
++ default y
++ help
++ Enable statistics collection for ramzswap. This adds only a minimal
++ overhead. In unsure, say Y.
+Index: kernel-power-2.6.28/drivers/block/ramzswap/Makefile
+===================================================================
+--- /dev/null
++++ kernel-power-2.6.28/drivers/block/ramzswap/Makefile
+@@ -0,0 +1,3 @@
++ramzswap-objs := ramzswap_drv.o xvmalloc.o
++
++obj-$(CONFIG_RAMZSWAP) += ramzswap.o
+Index: kernel-power-2.6.28/drivers/block/ramzswap/compat.h
+===================================================================
+--- /dev/null
++++ kernel-power-2.6.28/drivers/block/ramzswap/compat.h
+@@ -0,0 +1,13 @@
++#ifndef _RAMZSWAP_COMPAT_H_
++#define _RAMZSWAP_COMPAT_H_
++
++/* Uncomment this if you are using swap free notify patch */
++#define CONFIG_SWAP_FREE_NOTIFY
++
++#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,31))
++#define blk_queue_physical_block_size(q, size) \
++ blk_queue_hardsect_size(q, size)
++#define blk_queue_logical_block_size(q, size)
++#endif
++
++#endif
+Index: kernel-power-2.6.28/drivers/block/ramzswap/ramzswap.txt
+===================================================================
+--- /dev/null
++++ kernel-power-2.6.28/drivers/block/ramzswap/ramzswap.txt
+@@ -0,0 +1,51 @@
++ramzswap: Compressed RAM based swap device
++-------------------------------------------
++
++Project home: http://compcache.googlecode.com/
++
++* Introduction
++
++The ramzswap module creates RAM based block devices which can (only) be used as
++swap disks. Pages swapped to these devices are compressed and stored in memory
++itself. See project home for use cases, performance numbers and a lot more.
++
++Individual ramzswap devices are configured and initialized using rzscontrol
++userspace utility as shown in examples below. See rzscontrol man page for more
++details.
++
++* Usage
++
++Following shows a typical sequence of steps for using ramzswap.
++
++1) Load Modules:
++ modprobe ramzswap num_devices=4
++ This creates 4 (uninitialized) devices: /dev/ramzswap{0,1,2,3}
++ (num_devices parameter is optional. Default: 1)
++
++2) Initialize:
++ Use rzscontrol utility to configure and initialize individual
++ ramzswap devices. Example:
++ rzscontrol /dev/ramzswap2 --init # uses default value of disksize_kb
++
++ *See rzscontrol man page for more details and examples*
++
++3) Activate:
++ swapon /dev/ramzswap2 # or any other initialized ramzswap device
++
++4) Stats:
++ rzscontrol /dev/ramzswap2 --stats
++
++5) Deactivate:
++ swapoff /dev/ramzswap2
++
++6) Reset:
++ rzscontrol /dev/ramzswap2 --reset
++ (This frees all the memory allocated for this device).
++
++
++Please report any problems at:
++ - Mailing list: linux-mm-cc at laptop dot org
++ - Issue tracker: http://code.google.com/p/compcache/issues/list
++
++Nitin Gupta
++ngupta@vflare.org
+Index: kernel-power-2.6.28/drivers/block/ramzswap/ramzswap_drv.c
+===================================================================
+--- /dev/null
++++ kernel-power-2.6.28/drivers/block/ramzswap/ramzswap_drv.c
+@@ -0,0 +1,1557 @@
++/*
++ * Compressed RAM based swap device
++ *
++ * Copyright (C) 2008, 2009, 2010 Nitin Gupta
++ *
++ * This code is released using a dual license strategy: BSD/GPL
++ * You can choose the licence that better fits your requirements.
++ *
++ * Released under the terms of 3-clause BSD License
++ * Released under the terms of GNU General Public License Version 2.0
++ *
++ * Project home: http://compcache.googlecode.com
++ */
++
++#define KMSG_COMPONENT "ramzswap"
++#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
++
++#include <linux/module.h>
++#include <linux/kernel.h>
++#include <linux/bitops.h>
++#include <linux/blkdev.h>
++#include <linux/buffer_head.h>
++#include <linux/device.h>
++#include <linux/genhd.h>
++#include <linux/highmem.h>
++#include <linux/lzo.h>
++#include <linux/string.h>
++#include <linux/swap.h>
++#include <linux/swapops.h>
++#include <linux/vmalloc.h>
++#include <linux/version.h>
++
++#include "compat.h"
++#include "ramzswap_drv.h"
++
++/* Module params (documentation at end) */
++static unsigned int num_devices;
++static unsigned long disksize_kb;
++static unsigned long memlimit_kb;
++static char backing_swap[MAX_SWAP_NAME_LEN];
++
++/* Globals */
++static int ramzswap_major;
++static struct ramzswap *devices;
++
++/*
++ * Pages that compress to larger than this size are
++ * forwarded to backing swap, if present or stored
++ * uncompressed in memory otherwise.
++ */
++static unsigned int max_zpage_size;
++
++static int rzs_test_flag(struct ramzswap *rzs, u32 index,
++ enum rzs_pageflags flag)
++{
++ return rzs->table[index].flags & BIT(flag);
++}
++
++static void rzs_set_flag(struct ramzswap *rzs, u32 index,
++ enum rzs_pageflags flag)
++{
++ rzs->table[index].flags |= BIT(flag);
++}
++
++static void rzs_clear_flag(struct ramzswap *rzs, u32 index,
++ enum rzs_pageflags flag)
++{
++ rzs->table[index].flags &= ~BIT(flag);
++}
++
++static int page_zero_filled(void *ptr)
++{
++ unsigned int pos;
++ unsigned long *page;
++
++ page = (unsigned long *)ptr;
++
++ for (pos = 0; pos != PAGE_SIZE / sizeof(*page); pos++) {
++ if (page[pos])
++ return 0;
++ }
++
++ return 1;
++}
++
++/*
++ * memlimit cannot be greater than backing disk size.
++ */
++static void ramzswap_set_memlimit(struct ramzswap *rzs, size_t totalram_bytes)
++{
++ int memlimit_valid = 1;
++
++ if (!rzs->memlimit) {
++ pr_info("Memory limit not set.\n");
++ memlimit_valid = 0;
++ }
++
++ if (rzs->memlimit > rzs->disksize) {
++ pr_info("Memory limit cannot be greater than "
++ "disksize: limit=%zu, disksize=%zu\n",
++ rzs->memlimit, rzs->disksize);
++ memlimit_valid = 0;
++ }
++
++ if (!memlimit_valid) {
++ size_t mempart, disksize;
++ pr_info("Using default: smaller of (%u%% of RAM) and "
++ "(backing disk size).\n",
++ default_memlimit_perc_ram);
++ mempart = default_memlimit_perc_ram * (totalram_bytes / 100);
++ disksize = rzs->disksize;
++ rzs->memlimit = mempart > disksize ? disksize : mempart;
++ }
++
++ if (rzs->memlimit > totalram_bytes / 2) {
++ pr_info(
++ "Its not advisable setting limit more than half of "
++ "size of memory since we expect a 2:1 compression ratio. "
++ "Limit represents amount of *compressed* data we can keep "
++ "in memory!\n"
++ "\tMemory Size: %zu kB\n"
++ "\tLimit you selected: %zu kB\n"
++ "Continuing anyway ...\n",
++ totalram_bytes >> 10, rzs->memlimit >> 10
++ );
++ }
++
++ rzs->memlimit &= PAGE_MASK;
++ BUG_ON(!rzs->memlimit);
++}
++
++static void ramzswap_set_disksize(struct ramzswap *rzs, size_t totalram_bytes)
++{
++ if (!rzs->disksize) {
++ pr_info(
++ "disk size not provided. You can use disksize_kb module "
++ "param to specify size.\nUsing default: (%u%% of RAM).\n",
++ default_disksize_perc_ram
++ );
++ rzs->disksize = default_disksize_perc_ram *
++ (totalram_bytes / 100);
++ }
++
++ if (rzs->disksize > 2 * (totalram_bytes)) {
++ pr_info(
++ "There is little point creating a ramzswap of greater than "
++ "twice the size of memory since we expect a 2:1 compression "
++ "ratio. Note that ramzswap uses about 0.1%% of the size of "
++ "the swap device when not in use so a huge ramzswap is "
++ "wasteful.\n"
++ "\tMemory Size: %zu kB\n"
++ "\tSize you selected: %zu kB\n"
++ "Continuing anyway ...\n",
++ totalram_bytes >> 10, rzs->disksize
++ );
++ }
++
++ rzs->disksize &= PAGE_MASK;
++}
++
++/*
++ * Swap header (1st page of swap device) contains information
++ * to indentify it as a swap partition. Prepare such a header
++ * for ramzswap device (ramzswap0) so that swapon can identify
++ * it as swap partition. In case backing swap device is provided,
++ * copy its swap header.
++ */
++static int setup_swap_header(struct ramzswap *rzs, union swap_header *s)
++{
++ int ret = 0;
++ struct page *page;
++ struct address_space *mapping;
++ union swap_header *backing_swap_header;
++
++ /*
++ * There is no backing swap device. Create a swap header
++ * that is acceptable by swapon.
++ */
++ if (!rzs->backing_swap) {
++ s->info.version = 1;
++ s->info.last_page = (rzs->disksize >> PAGE_SHIFT) - 1;
++ s->info.nr_badpages = 0;
++ memcpy(s->magic.magic, "SWAPSPACE2", 10);
++ return 0;
++ }
++
++ /*
++ * We have a backing swap device. Copy its swap header
++ * to ramzswap device header. If this header contains
++ * invalid information (backing device not a swap
++ * partition, etc.), swapon will fail for ramzswap
++ * which is correct behavior - we don't want to swap
++ * over filesystem partition!
++ */
++
++ /* Read the backing swap header (code from sys_swapon) */
++ mapping = rzs->swap_file->f_mapping;
++ if (!mapping->a_ops->readpage) {
++ ret = -EINVAL;
++ goto out;
++ }
++
++ page = read_mapping_page(mapping, 0, rzs->swap_file);
++ if (IS_ERR(page)) {
++ ret = PTR_ERR(page);
++ goto out;
++ }
++
++ backing_swap_header = kmap(page);
++ memcpy(s, backing_swap_header, sizeof(*s));
++ if (s->info.nr_badpages) {
++ pr_info("Cannot use backing swap with bad pages (%u)\n",
++ s->info.nr_badpages);
++ ret = -EINVAL;
++ }
++ /*
++ * ramzswap disksize equals number of usable pages in backing
++ * swap. Set last_page in swap header to match this disksize
++ * ('last_page' means 0-based index of last usable swap page).
++ */
++ s->info.last_page = (rzs->disksize >> PAGE_SHIFT) - 1;
++ kunmap(page);
++
++out:
++ return ret;
++}
++
++/*static void flush_dcache_page(struct page *page)
++{
++#if defined(CONFIG_ARM)
++ int flag = 0;*/
++ /*
++ * Ugly hack to get flush_dcache_page() work on ARM.
++ * page_mapping(page) == NULL after clearing this swap cache flag.
++ * Without clearing this flag, flush_dcache_page() will simply set
++ * "PG_dcache_dirty" bit and return.
++ */
++ /*if (PageSwapCache(page)) {
++ flag = 1;
++ ClearPageSwapCache(page);
++ }
++#endif
++ flush_dcache_page(page);
++#if defined(CONFIG_ARM)
++ if (flag)
++ SetPageSwapCache(page);
++#endif
++}*/
++
++static void ramzswap_ioctl_get_stats(struct ramzswap *rzs,
++ struct ramzswap_ioctl_stats *s)
++{
++ strncpy(s->backing_swap_name, rzs->backing_swap_name,
++ MAX_SWAP_NAME_LEN - 1);
++ s->backing_swap_name[MAX_SWAP_NAME_LEN - 1] = '\0';
++
++ s->disksize = rzs->disksize;
++ s->memlimit = rzs->memlimit;
++
++#if defined(CONFIG_RAMZSWAP_STATS)
++ {
++ struct ramzswap_stats *rs = &rzs->stats;
++ size_t succ_writes, mem_used;
++ unsigned int good_compress_perc = 0, no_compress_perc = 0;
++
++ mem_used = xv_get_total_size_bytes(rzs->mem_pool)
++ + (rs->pages_expand << PAGE_SHIFT);
++ succ_writes = stat64_read(rzs, &rs->num_writes) -
++ stat64_read(rzs, &rs->failed_writes);
++
++ if (succ_writes && rs->pages_stored) {
++ good_compress_perc = rs->good_compress * 100
++ / rs->pages_stored;
++ no_compress_perc = rs->pages_expand * 100
++ / rs->pages_stored;
++ }
++
++ s->num_reads = stat64_read(rzs, &rs->num_reads);
++ s->num_writes = stat64_read(rzs, &rs->num_writes);
++ s->failed_reads = stat64_read(rzs, &rs->failed_reads);
++ s->failed_writes = stat64_read(rzs, &rs->failed_writes);
++ s->invalid_io = stat64_read(rzs, &rs->invalid_io);
++ s->notify_free = stat64_read(rzs, &rs->notify_free);
++ s->pages_zero = rs->pages_zero;
++
++ s->good_compress_pct = good_compress_perc;
++ s->pages_expand_pct = no_compress_perc;
++
++ s->pages_stored = rs->pages_stored;
++ s->pages_used = mem_used >> PAGE_SHIFT;
++ s->orig_data_size = rs->pages_stored << PAGE_SHIFT;
++ s->compr_data_size = rs->compr_size;
++ s->mem_used_total = mem_used;
++
++ s->bdev_num_reads = stat64_read(rzs, &rs->bdev_num_reads);
++ s->bdev_num_writes = stat64_read(rzs, &rs->bdev_num_writes);
++ }
++#endif /* CONFIG_RAMZSWAP_STATS */
++}
++
++static int add_backing_swap_extent(struct ramzswap *rzs,
++ pgoff_t phy_pagenum,
++ pgoff_t num_pages)
++{
++ unsigned int idx;
++ struct list_head *head;
++ struct page *curr_page, *new_page;
++ unsigned int extents_per_page = PAGE_SIZE /
++ sizeof(struct ramzswap_backing_extent);
++
++ idx = rzs->num_extents % extents_per_page;
++ if (!idx) {
++ new_page = alloc_page(__GFP_ZERO);
++ if (!new_page)
++ return -ENOMEM;
++
++ if (rzs->num_extents) {
++ curr_page = virt_to_page(rzs->curr_extent);
++ head = &curr_page->lru;
++ } else {
++ head = &rzs->backing_swap_extent_list;
++ }
++
++ list_add(&new_page->lru, head);
++ rzs->curr_extent = page_address(new_page);
++ }
++
++ rzs->curr_extent->phy_pagenum = phy_pagenum;
++ rzs->curr_extent->num_pages = num_pages;
++
++ pr_debug("add_extent: idx=%u, phy_pgnum=%lu, num_pgs=%lu, "
++ "pg_last=%lu, curr_ext=%p\n", idx, phy_pagenum, num_pages,
++ phy_pagenum + num_pages - 1, rzs->curr_extent);
++
++ if (idx != extents_per_page - 1)
++ rzs->curr_extent++;
++
++ return 0;
++}
++
++static int setup_backing_swap_extents(struct ramzswap *rzs,
++ struct inode *inode, unsigned long *num_pages)
++{
++ int ret = 0;
++ unsigned blkbits;
++ unsigned blocks_per_page;
++ pgoff_t contig_pages = 0, total_pages = 0;
++ pgoff_t pagenum = 0, prev_pagenum = 0;
++ sector_t probe_block = 0;
++ sector_t last_block;
++
++ blkbits = inode->i_blkbits;
++ blocks_per_page = PAGE_SIZE >> blkbits;
++
++ last_block = i_size_read(inode) >> blkbits;
++ while (probe_block + blocks_per_page <= last_block) {
++ unsigned block_in_page;
++ sector_t first_block;
++
++ first_block = bmap(inode, probe_block);
++ if (first_block == 0)
++ goto bad_bmap;
++
++ /* It must be PAGE_SIZE aligned on-disk */
++ if (first_block & (blocks_per_page - 1)) {
++ probe_block++;
++ goto probe_next;
++ }
++
++ /* All blocks within this page must be contiguous on disk */
++ for (block_in_page = 1; block_in_page < blocks_per_page;
++ block_in_page++) {
++ sector_t block;
++
++ block = bmap(inode, probe_block + block_in_page);
++ if (block == 0)
++ goto bad_bmap;
++ if (block != first_block + block_in_page) {
++ /* Discontiguity */
++ probe_block++;
++ goto probe_next;
++ }
++ }
++
++ /*
++ * We found a PAGE_SIZE length, PAGE_SIZE aligned
++ * run of blocks.
++ */
++ pagenum = first_block >> (PAGE_SHIFT - blkbits);
++
++ if (total_pages && (pagenum != prev_pagenum + 1)) {
++ ret = add_backing_swap_extent(rzs, prev_pagenum -
++ (contig_pages - 1), contig_pages);
++ if (ret < 0)
++ goto out;
++ rzs->num_extents++;
++ contig_pages = 0;
++ }
++ total_pages++;
++ contig_pages++;
++ prev_pagenum = pagenum;
++ probe_block += blocks_per_page;
++
++probe_next:
++ continue;
++ }
++
++ if (contig_pages) {
++ pr_debug("adding last extent: pagenum=%lu, "
++ "contig_pages=%lu\n", pagenum, contig_pages);
++ ret = add_backing_swap_extent(rzs,
++ prev_pagenum - (contig_pages - 1), contig_pages);
++ if (ret < 0)
++ goto out;
++ rzs->num_extents++;
++ }
++ if (!rzs->num_extents) {
++ pr_err("No swap extents found!\n");
++ ret = -EINVAL;
++ }
++
++ if (!ret) {
++ *num_pages = total_pages;
++ pr_info("Found %lu extents containing %luk\n",
++ rzs->num_extents, *num_pages << (PAGE_SHIFT - 10));
++ }
++ goto out;
++
++bad_bmap:
++ pr_err("Backing swapfile has holes\n");
++ ret = -EINVAL;
++
++out:
++ while (ret && !list_empty(&rzs->backing_swap_extent_list)) {
++ struct page *page;
++ struct list_head *entry = rzs->backing_swap_extent_list.next;
++ page = list_entry(entry, struct page, lru);
++ list_del(entry);
++ __free_page(page);
++ }
++ return ret;
++}
++
++static void map_backing_swap_extents(struct ramzswap *rzs)
++{
++ struct ramzswap_backing_extent *se;
++ struct page *table_page, *se_page;
++ unsigned long num_pages, num_table_pages, entry;
++ unsigned long se_idx, span;
++ unsigned entries_per_page = PAGE_SIZE / sizeof(*rzs->table);
++ unsigned extents_per_page = PAGE_SIZE / sizeof(*se);
++
++ /* True for block device */
++ if (!rzs->num_extents)
++ return;
++
++ se_page = list_entry(rzs->backing_swap_extent_list.next,
++ struct page, lru);
++ se = page_address(se_page);
++ span = se->num_pages;
++ num_pages = rzs->disksize >> PAGE_SHIFT;
++ num_table_pages = DIV_ROUND_UP(num_pages * sizeof(*rzs->table),
++ PAGE_SIZE);
++
++ entry = 0;
++ se_idx = 0;
++ while (num_table_pages--) {
++ table_page = vmalloc_to_page(&rzs->table[entry]);
++ while (span <= entry) {
++ se_idx++;
++ if (se_idx == rzs->num_extents)
++ BUG();
++
++ if (!(se_idx % extents_per_page)) {
++ se_page = list_entry(se_page->lru.next,
++ struct page, lru);
++ se = page_address(se_page);
++ } else
++ se++;
++
++ span += se->num_pages;
++ }
++ table_page->mapping = (struct address_space *)se;
++ table_page->private = se->num_pages - (span - entry);
++ pr_debug("map_table: entry=%lu, span=%lu, map=%p, priv=%lu\n",
++ entry, span, table_page->mapping, table_page->private);
++ entry += entries_per_page;
++ }
++}
++
++/*
++ * Check if value of backing_swap module param is sane.
++ * Claim this device and set ramzswap size equal to
++ * size of this block device.
++ */
++static int setup_backing_swap(struct ramzswap *rzs)
++{
++ int ret = 0;
++ size_t disksize;
++ unsigned long num_pages = 0;
++ struct inode *inode;
++ struct file *swap_file;
++ struct address_space *mapping;
++ struct block_device *bdev = NULL;
++
++ if (!rzs->backing_swap_name[0]) {
++ pr_debug("backing_swap param not given\n");
++ goto out;
++ }
++
++ pr_debug("Using backing swap device: %s\n", rzs->backing_swap_name);
++
++ swap_file = filp_open(rzs->backing_swap_name,
++ O_RDWR | O_LARGEFILE, 0);
++ if (IS_ERR(swap_file)) {
++ pr_err("Error opening backing device: %s\n",
++ rzs->backing_swap_name);
++ ret = -EINVAL;
++ goto out;
++ }
++
++ mapping = swap_file->f_mapping;
++ inode = mapping->host;
++
++ if (S_ISBLK(inode->i_mode)) {
++ bdev = I_BDEV(inode);
++ ret = bd_claim(bdev, setup_backing_swap);
++ if (ret < 0) {
++ bdev = NULL;
++ goto bad_param;
++ }
++ disksize = i_size_read(inode);
++ if (!disksize) {
++ pr_err("Error reading backing swap size.\n");
++ goto bad_param;
++ }
++ } else if (S_ISREG(inode->i_mode)) {
++ bdev = inode->i_sb->s_bdev;
++ if (IS_SWAPFILE(inode)) {
++ ret = -EBUSY;
++ goto bad_param;
++ }
++ ret = setup_backing_swap_extents(rzs, inode, &num_pages);
++ if (ret < 0)
++ goto bad_param;
++ disksize = num_pages << PAGE_SHIFT;
++ } else {
++ goto bad_param;
++ }
++
++ rzs->swap_file = swap_file;
++ rzs->backing_swap = bdev;
++ rzs->disksize = disksize;
++
++ return 0;
++
++bad_param:
++ if (bdev)
++ bd_release(bdev);
++ filp_close(swap_file, NULL);
++
++out:
++ rzs->backing_swap = NULL;
++ return ret;
++}
++
++/*
++ * Map logical page number 'pagenum' to physical page number
++ * on backing swap device. For block device, this is a nop.
++ */
++static u32 map_backing_swap_page(struct ramzswap *rzs, u32 pagenum)
++{
++ u32 skip_pages, entries_per_page;
++ size_t delta, se_offset, skipped;
++ struct page *table_page, *se_page;
++ struct ramzswap_backing_extent *se;
++
++ if (!rzs->num_extents)
++ return pagenum;
++
++ entries_per_page = PAGE_SIZE / sizeof(*rzs->table);
++
++ table_page = vmalloc_to_page(&rzs->table[pagenum]);
++ se = (struct ramzswap_backing_extent *)table_page->mapping;
++ se_page = virt_to_page(se);
++
++ skip_pages = pagenum - (pagenum / entries_per_page * entries_per_page);
++ se_offset = table_page->private + skip_pages;
++
++ if (se_offset < se->num_pages)
++ return se->phy_pagenum + se_offset;
++
++ skipped = se->num_pages - table_page->private;
++ do {
++ struct ramzswap_backing_extent *se_base;
++ u32 se_entries_per_page = PAGE_SIZE / sizeof(*se);
++
++ /* Get next swap extent */
++ se_base = (struct ramzswap_backing_extent *)
++ page_address(se_page);
++ if (se - se_base == se_entries_per_page - 1) {
++ se_page = list_entry(se_page->lru.next,
++ struct page, lru);
++ se = page_address(se_page);
++ } else {
++ se++;
++ }
++
++ skipped += se->num_pages;
++ } while (skipped < skip_pages);
++
++ delta = skipped - skip_pages;
++ se_offset = se->num_pages - delta;
++
++ return se->phy_pagenum + se_offset;
++}
++
++static void ramzswap_free_page(struct ramzswap *rzs, size_t index)
++{
++#if defined(CONFIG_RAMZSWAP_STATS)
++ u32 clen;
++ void *obj;
++#endif
++ struct page *page = rzs->table[index].page;
++ u32 offset = rzs->table[index].offset;
++
++ if (unlikely(!page)) {
++ /*
++ * No memory is allocated for zero filled pages.
++ * Simply clear zero page flag.
++ */
++ if (rzs_test_flag(rzs, index, RZS_ZERO)) {
++ rzs_clear_flag(rzs, index, RZS_ZERO);
++ stat_dec(&rzs->stats.pages_zero);
++ }
++ return;
++ }
++
++ if (unlikely(rzs_test_flag(rzs, index, RZS_UNCOMPRESSED))) {
++#if defined(CONFIG_RAMZSWAP_STATS)
++ clen = PAGE_SIZE;
++#endif
++ stat_dec(&rzs->stats.pages_expand);
++ __free_page(page);
++ rzs_clear_flag(rzs, index, RZS_UNCOMPRESSED);
++ goto out;
++ }
++
++#if defined(CONFIG_RAMZSWAP_STATS)
++ obj = kmap_atomic(page, KM_USER0) + offset;
++ clen = xv_get_object_size(obj) - sizeof(struct zobj_header);
++ kunmap_atomic(obj, KM_USER0);
++ if (clen <= PAGE_SIZE / 2)
++ stat_dec(&rzs->stats.good_compress);
++#endif
++ xv_free(rzs->mem_pool, page, offset);
++
++out:
++#if defined(CONFIG_RAMZSWAP_STATS)
++ rzs->stats.compr_size -= clen;
++ stat_dec(&rzs->stats.pages_stored);
++#endif
++
++ rzs->table[index].page = NULL;
++ rzs->table[index].offset = 0;
++}
++
++static int handle_zero_page(struct bio *bio)
++{
++ void *user_mem;
++ struct page *page = bio->bi_io_vec[0].bv_page;
++
++ user_mem = kmap_atomic(page, KM_USER0);
++ memset(user_mem, 0, PAGE_SIZE);
++ kunmap_atomic(user_mem, KM_USER0);
++
++ flush_dcache_page(page);
++
++ set_bit(BIO_UPTODATE, &bio->bi_flags);
++ bio_endio(bio, 0);
++ return 0;
++}
++
++static int handle_uncompressed_page(struct ramzswap *rzs, struct bio *bio)
++{
++ u32 index;
++ struct page *page;
++ unsigned char *user_mem, *cmem;
++
++ page = bio->bi_io_vec[0].bv_page;
++ index = bio->bi_sector >> SECTORS_PER_PAGE_SHIFT;
++
++ user_mem = kmap_atomic(page, KM_USER0);
++ cmem = kmap_atomic(rzs->table[index].page, KM_USER1) +
++ rzs->table[index].offset;
++
++ memcpy(user_mem, cmem, PAGE_SIZE);
++ kunmap_atomic(user_mem, KM_USER0);
++ kunmap_atomic(cmem, KM_USER1);
++
++ flush_dcache_page(page);
++
++ set_bit(BIO_UPTODATE, &bio->bi_flags);
++ bio_endio(bio, 0);
++ return 0;
++}
++
++
++/*
++ * Called when request page is not present in ramzswap.
++ * Its either in backing swap device (if present) or
++ * this is an attempt to read before any previous write
++ * to this location - this happens due to readahead when
++ * swap device is read from user-space (e.g. during swapon)
++ */
++static int handle_ramzswap_fault(struct ramzswap *rzs, struct bio *bio)
++{
++ /*
++ * Always forward such requests to backing swap
++ * device (if present)
++ */
++ if (rzs->backing_swap) {
++ u32 pagenum;
++ stat64_dec(rzs, &rzs->stats.num_reads);
++ stat64_inc(rzs, &rzs->stats.bdev_num_reads);
++ bio->bi_bdev = rzs->backing_swap;
++
++ /*
++ * In case backing swap is a file, find the right offset within
++ * the file corresponding to logical position 'index'. For block
++ * device, this is a nop.
++ */
++ pagenum = bio->bi_sector >> SECTORS_PER_PAGE_SHIFT;
++ bio->bi_sector = map_backing_swap_page(rzs, pagenum)
++ << SECTORS_PER_PAGE_SHIFT;
++ return 1;
++ }
++
++ /*
++ * Its unlikely event in case backing dev is
++ * not present
++ */
++ pr_debug("Read before write on swap device: "
++ "sector=%lu, size=%u, offset=%u\n",
++ (ulong)(bio->bi_sector), bio->bi_size,
++ bio->bi_io_vec[0].bv_offset);
++
++ /* Do nothing. Just return success */
++ set_bit(BIO_UPTODATE, &bio->bi_flags);
++ bio_endio(bio, 0);
++ return 0;
++}
++
++static int ramzswap_read(struct ramzswap *rzs, struct bio *bio)
++{
++ int ret;
++ u32 index;
++ size_t clen;
++ struct page *page;
++ struct zobj_header *zheader;
++ unsigned char *user_mem, *cmem;
++
++ stat64_inc(rzs, &rzs->stats.num_reads);
++
++ page = bio->bi_io_vec[0].bv_page;
++ index = bio->bi_sector >> SECTORS_PER_PAGE_SHIFT;
++
++ if (rzs_test_flag(rzs, index, RZS_ZERO))
++ return handle_zero_page(bio);
++
++ /* Requested page is not present in compressed area */
++ if (!rzs->table[index].page)
++ return handle_ramzswap_fault(rzs, bio);
++
++ /* Page is stored uncompressed since it's incompressible */
++ if (unlikely(rzs_test_flag(rzs, index, RZS_UNCOMPRESSED)))
++ return handle_uncompressed_page(rzs, bio);
++
++ user_mem = kmap_atomic(page, KM_USER0);
++ clen = PAGE_SIZE;
++
++ cmem = kmap_atomic(rzs->table[index].page, KM_USER1) +
++ rzs->table[index].offset;
++
++ ret = lzo1x_decompress_safe(
++ cmem + sizeof(*zheader),
++ xv_get_object_size(cmem) - sizeof(*zheader),
++ user_mem, &clen);
++
++ kunmap_atomic(user_mem, KM_USER0);
++ kunmap_atomic(cmem, KM_USER1);
++
++ /* should NEVER happen */
++ if (unlikely(ret != LZO_E_OK)) {
++ pr_err("Decompression failed! err=%d, page=%u\n",
++ ret, index);
++ stat64_inc(rzs, &rzs->stats.failed_reads);
++ goto out;
++ }
++
++ flush_dcache_page(page);
++
++ set_bit(BIO_UPTODATE, &bio->bi_flags);
++ bio_endio(bio, 0);
++ return 0;
++
++out:
++ bio_io_error(bio);
++ return 0;
++}
++
++static int ramzswap_write(struct ramzswap *rzs, struct bio *bio)
++{
++ int ret, fwd_write_request = 0;
++ u32 offset, index;
++ size_t clen;
++ struct zobj_header *zheader;
++ struct page *page, *page_store;
++ unsigned char *user_mem, *cmem, *src;
++
++ stat64_inc(rzs, &rzs->stats.num_writes);
++
++ page = bio->bi_io_vec[0].bv_page;
++ index = bio->bi_sector >> SECTORS_PER_PAGE_SHIFT;
++
++ src = rzs->compress_buffer;
++
++ if (rzs->table[index].page || rzs_test_flag(rzs, index, RZS_ZERO))
++ ramzswap_free_page(rzs, index);
++
++ mutex_lock(&rzs->lock);
++
++ user_mem = kmap_atomic(page, KM_USER0);
++ if (page_zero_filled(user_mem)) {
++ kunmap_atomic(user_mem, KM_USER0);
++ rzs_set_flag(rzs, index, RZS_ZERO);
++ mutex_unlock(&rzs->lock);
++ stat_inc(&rzs->stats.pages_zero);
++
++ set_bit(BIO_UPTODATE, &bio->bi_flags);
++ bio_endio(bio, 0);
++ return 0;
++ }
++
++ if (rzs->backing_swap &&
++ (rzs->stats.compr_size > rzs->memlimit - PAGE_SIZE)) {
++ kunmap_atomic(user_mem, KM_USER0);
++ mutex_unlock(&rzs->lock);
++ fwd_write_request = 1;
++ goto out;
++ }
++
++ ret = lzo1x_1_compress(user_mem, PAGE_SIZE, src, &clen,
++ rzs->compress_workmem);
++
++ kunmap_atomic(user_mem, KM_USER0);
++
++ if (unlikely(ret != LZO_E_OK)) {
++ mutex_unlock(&rzs->lock);
++ pr_err("Compression failed! err=%d\n", ret);
++ stat64_inc(rzs, &rzs->stats.failed_writes);
++ goto out;
++ }
++
++ /*
++ * Page is incompressible. Forward it to backing swap
++ * if present. Otherwise, store it as-is (uncompressed)
++ * since we do not want to return too many swap write
++ * errors which has side effect of hanging the system.
++ */
++ if (unlikely(clen > max_zpage_size)) {
++ if (rzs->backing_swap) {
++ mutex_unlock(&rzs->lock);
++ fwd_write_request = 1;
++ goto out;
++ }
++
++ clen = PAGE_SIZE;
++ page_store = alloc_page(GFP_NOIO | __GFP_HIGHMEM);
++ if (unlikely(!page_store)) {
++ mutex_unlock(&rzs->lock);
++ pr_info("Error allocating memory for incompressible "
++ "page: %u\n", index);
++ stat64_inc(rzs, &rzs->stats.failed_writes);
++ goto out;
++ }
++
++ offset = 0;
++ rzs_set_flag(rzs, index, RZS_UNCOMPRESSED);
++ stat_inc(&rzs->stats.pages_expand);
++ rzs->table[index].page = page_store;
++ src = kmap_atomic(page, KM_USER0);
++ goto memstore;
++ }
++
++ if (xv_malloc(rzs->mem_pool, clen + sizeof(*zheader),
++ &rzs->table[index].page, &offset,
++ GFP_NOIO | __GFP_HIGHMEM)) {
++ mutex_unlock(&rzs->lock);
++ pr_info("Error allocating memory for compressed "
++ "page: %u, size=%zu\n", index, clen);
++ stat64_inc(rzs, &rzs->stats.failed_writes);
++ if (rzs->backing_swap)
++ fwd_write_request = 1;
++ goto out;
++ }
++
++memstore:
++ rzs->table[index].offset = offset;
++
++ cmem = kmap_atomic(rzs->table[index].page, KM_USER1) +
++ rzs->table[index].offset;
++
++#if 0
++ /* Back-reference needed for memory defragmentation */
++ if (!rzs_test_flag(rzs, index, RZS_UNCOMPRESSED)) {
++ zheader = (struct zobj_header *)cmem;
++ zheader->table_idx = index;
++ cmem += sizeof(*zheader);
++ }
++#endif
++
++ memcpy(cmem, src, clen);
++
++ kunmap_atomic(cmem, KM_USER1);
++ if (unlikely(rzs_test_flag(rzs, index, RZS_UNCOMPRESSED)))
++ kunmap_atomic(src, KM_USER0);
++
++ /* Update stats */
++ rzs->stats.compr_size += clen;
++ stat_inc(&rzs->stats.pages_stored);
++ if (clen <= PAGE_SIZE / 2)
++ stat_inc(&rzs->stats.good_compress);
++
++ mutex_unlock(&rzs->lock);
++
++ set_bit(BIO_UPTODATE, &bio->bi_flags);
++ bio_endio(bio, 0);
++ return 0;
++
++out:
++ if (fwd_write_request) {
++ stat64_inc(rzs, &rzs->stats.bdev_num_writes);
++ bio->bi_bdev = rzs->backing_swap;
++#if 0
++ /*
++ * TODO: We currently have linear mapping of ramzswap and
++ * backing swap sectors. This is not desired since we want
++ * to optimize writes to backing swap to minimize disk seeks
++ * or have effective wear leveling (for SSDs). Also, a
++ * non-linear mapping is required to implement compressed
++ * on-disk swapping.
++ */
++ bio->bi_sector = get_backing_swap_page()
++ << SECTORS_PER_PAGE_SHIFT;
++#endif
++ /*
++ * In case backing swap is a file, find the right offset within
++ * the file corresponding to logical position 'index'. For block
++ * device, this is a nop.
++ */
++ bio->bi_sector = map_backing_swap_page(rzs, index)
++ << SECTORS_PER_PAGE_SHIFT;
++ return 1;
++ }
++
++ bio_io_error(bio);
++ return 0;
++}
++
++
++/*
++ * Check if request is within bounds and page aligned.
++ */
++static inline int valid_swap_request(struct ramzswap *rzs, struct bio *bio)
++{
++ if (unlikely(
++ (bio->bi_sector >= (rzs->disksize >> SECTOR_SHIFT)) ||
++ (bio->bi_sector & (SECTORS_PER_PAGE - 1)) ||
++ (bio->bi_vcnt != 1) ||
++ (bio->bi_size != PAGE_SIZE) ||
++ (bio->bi_io_vec[0].bv_offset != 0))) {
++
++ return 0;
++ }
++
++ /* swap request is valid */
++ return 1;
++}
++
++/*
++ * Handler function for all ramzswap I/O requests.
++ */
++static int ramzswap_make_request(struct request_queue *queue, struct bio *bio)
++{
++ int ret = 0;
++ struct ramzswap *rzs = queue->queuedata;
++
++ if (unlikely(!rzs->init_done)) {
++ bio_io_error(bio);
++ return 0;
++ }
++
++ if (!valid_swap_request(rzs, bio)) {
++ stat64_inc(rzs, &rzs->stats.invalid_io);
++ bio_io_error(bio);
++ return 0;
++ }
++
++ switch (bio_data_dir(bio)) {
++ case READ:
++ ret = ramzswap_read(rzs, bio);
++ break;
++
++ case WRITE:
++ ret = ramzswap_write(rzs, bio);
++ break;
++ }
++
++ return ret;
++}
++
++static void reset_device(struct ramzswap *rzs, struct block_device *bdev)
++{
++ int is_backing_blkdev = 0;
++ size_t index, num_pages;
++ unsigned entries_per_page;
++ unsigned long num_table_pages, entry = 0;
++
++ if (bdev)
++ fsync_bdev(bdev);
++
++ rzs->init_done = 0;
++
++ if (rzs->backing_swap && !rzs->num_extents)
++ is_backing_blkdev = 1;
++
++ num_pages = rzs->disksize >> PAGE_SHIFT;
++
++ /* Free various per-device buffers */
++ kfree(rzs->compress_workmem);
++ free_pages((unsigned long)rzs->compress_buffer, 1);
++
++ rzs->compress_workmem = NULL;
++ rzs->compress_buffer = NULL;
++
++ /* Free all pages that are still in this ramzswap device */
++ for (index = 0; index < num_pages; index++) {
++ struct page *page;
++ u16 offset;
++
++ page = rzs->table[index].page;
++ offset = rzs->table[index].offset;
++
++ if (!page)
++ continue;
++
++ if (unlikely(rzs_test_flag(rzs, index, RZS_UNCOMPRESSED)))
++ __free_page(page);
++ else
++ xv_free(rzs->mem_pool, page, offset);
++ }
++
++ entries_per_page = PAGE_SIZE / sizeof(*rzs->table);
++ num_table_pages = DIV_ROUND_UP(num_pages * sizeof(*rzs->table),
++ PAGE_SIZE);
++ /*
++ * Set page->mapping to NULL for every table page.
++ * Otherwise, we will hit bad_page() during free.
++ */
++ while (rzs->num_extents && num_table_pages--) {
++ struct page *page;
++ page = vmalloc_to_page(&rzs->table[entry]);
++ page->mapping = NULL;
++ entry += entries_per_page;
++ }
++ vfree(rzs->table);
++ rzs->table = NULL;
++
++ xv_destroy_pool(rzs->mem_pool);
++ rzs->mem_pool = NULL;
++
++ /* Free all swap extent pages */
++ while (!list_empty(&rzs->backing_swap_extent_list)) {
++ struct page *page;
++ struct list_head *entry;
++ entry = rzs->backing_swap_extent_list.next;
++ page = list_entry(entry, struct page, lru);
++ list_del(entry);
++ __free_page(page);
++ }
++ INIT_LIST_HEAD(&rzs->backing_swap_extent_list);
++ rzs->num_extents = 0;
++
++ /* Close backing swap device, if present */
++ if (rzs->backing_swap) {
++ if (is_backing_blkdev)
++ bd_release(rzs->backing_swap);
++ filp_close(rzs->swap_file, NULL);
++ rzs->backing_swap = NULL;
++ memset(rzs->backing_swap_name, 0, MAX_SWAP_NAME_LEN);
++ }
++
++ /* Reset stats */
++ memset(&rzs->stats, 0, sizeof(rzs->stats));
++
++ rzs->disksize = 0;
++ rzs->memlimit = 0;
++}
++
++static int ramzswap_ioctl_init_device(struct ramzswap *rzs)
++{
++ int ret, dev_id;
++ size_t num_pages;
++ struct page *page;
++ union swap_header *swap_header;
++
++ if (rzs->init_done) {
++ pr_info("Device already initialized!\n");
++ return -EBUSY;
++ }
++
++ dev_id = rzs - devices;
++
++ ret = setup_backing_swap(rzs);
++ if (ret)
++ goto fail;
++
++ if (rzs->backing_swap)
++ ramzswap_set_memlimit(rzs, totalram_pages << PAGE_SHIFT);
++ else
++ ramzswap_set_disksize(rzs, totalram_pages << PAGE_SHIFT);
++
++ rzs->compress_workmem = kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
++ if (!rzs->compress_workmem) {
++ pr_err("Error allocating compressor working memory!\n");
++ ret = -ENOMEM;
++ goto fail;
++ }
++
++ rzs->compress_buffer = (void *)__get_free_pages(__GFP_ZERO, 1);
++ if (!rzs->compress_buffer) {
++ pr_err("Error allocating compressor buffer space\n");
++ ret = -ENOMEM;
++ goto fail;
++ }
++
++ num_pages = rzs->disksize >> PAGE_SHIFT;
++ rzs->table = vmalloc(num_pages * sizeof(*rzs->table));
++ if (!rzs->table) {
++ pr_err("Error allocating ramzswap address table\n");
++ /* To prevent accessing table entries during cleanup */
++ rzs->disksize = 0;
++ ret = -ENOMEM;
++ goto fail;
++ }
++ memset(rzs->table, 0, num_pages * sizeof(*rzs->table));
++
++ map_backing_swap_extents(rzs);
++
++ page = alloc_page(__GFP_ZERO);
++ if (!page) {
++ pr_err("Error allocating swap header page\n");
++ ret = -ENOMEM;
++ goto fail;
++ }
++ rzs->table[0].page = page;
++ rzs_set_flag(rzs, 0, RZS_UNCOMPRESSED);
++
++ swap_header = kmap(page);
++ ret = setup_swap_header(rzs, swap_header);
++ kunmap(page);
++ if (ret) {
++ pr_err("Error setting swap header\n");
++ goto fail;
++ }
++
++ set_capacity(rzs->disk, rzs->disksize >> SECTOR_SHIFT);
++
++ /*
++ * We have ident mapping of sectors for ramzswap and
++ * and the backing swap device. So, this queue flag
++ * should be according to backing dev.
++ */
++ if (!rzs->backing_swap ||
++ blk_queue_nonrot(rzs->backing_swap->bd_disk->queue))
++ queue_flag_set_unlocked(QUEUE_FLAG_NONROT, rzs->disk->queue);
++
++ rzs->mem_pool = xv_create_pool();
++ if (!rzs->mem_pool) {
++ pr_err("Error creating memory pool\n");
++ ret = -ENOMEM;
++ goto fail;
++ }
++
++ /*
++ * Pages that compress to size greater than this are forwarded
++ * to physical swap disk (if backing dev is provided)
++ * TODO: make this configurable
++ */
++ if (rzs->backing_swap)
++ max_zpage_size = max_zpage_size_bdev;
++ else
++ max_zpage_size = max_zpage_size_nobdev;
++ pr_debug("Max compressed page size: %u bytes\n", max_zpage_size);
++
++ rzs->init_done = 1;
++
++ if (rzs->backing_swap) {
++ pr_info("/dev/ramzswap%d initialized: "
++ "backing_swap=%s, memlimit_kb=%zu\n",
++ dev_id, rzs->backing_swap_name, rzs->memlimit >> 10);
++ } else {
++ pr_info("/dev/ramzswap%d initialized: "
++ "disksize_kb=%zu", dev_id, rzs->disksize >> 10);
++ }
++ return 0;
++
++fail:
++ reset_device(rzs, NULL);
++
++ pr_err("Initialization failed: err=%d\n", ret);
++ return ret;
++}
++
++static int ramzswap_ioctl_reset_device(struct ramzswap *rzs,
++ struct block_device *bdev)
++{
++ if (rzs->init_done)
++ reset_device(rzs, bdev);
++
++ return 0;
++}
++
++static int ramzswap_ioctl(struct block_device *bdev, fmode_t mode,
++ unsigned int cmd, unsigned long arg)
++{
++ int ret = 0;
++ size_t disksize_kb, memlimit_kb;
++
++ struct ramzswap *rzs = bdev->bd_disk->private_data;
++
++ switch (cmd) {
++ case RZSIO_SET_DISKSIZE_KB:
++ if (rzs->init_done) {
++ ret = -EBUSY;
++ goto out;
++ }
++ if (copy_from_user(&disksize_kb, (void *)arg,
++ _IOC_SIZE(cmd))) {
++ ret = -EFAULT;
++ goto out;
++ }
++ rzs->disksize = disksize_kb << 10;
++ pr_debug("Disk size set to %zu kB\n", disksize_kb);
++ break;
++
++ case RZSIO_SET_MEMLIMIT_KB:
++ if (rzs->init_done) {
++ /* TODO: allow changing memlimit */
++ ret = -EBUSY;
++ goto out;
++ }
++ if (copy_from_user(&memlimit_kb, (void *)arg,
++ _IOC_SIZE(cmd))) {
++ ret = -EFAULT;
++ goto out;
++ }
++ rzs->memlimit = memlimit_kb << 10;
++ pr_debug("Memory limit set to %zu kB\n", memlimit_kb);
++ break;
++
++ case RZSIO_SET_BACKING_SWAP:
++ if (rzs->init_done) {
++ ret = -EBUSY;
++ goto out;
++ }
++
++ if (copy_from_user(&rzs->backing_swap_name, (void *)arg,
++ _IOC_SIZE(cmd))) {
++ ret = -EFAULT;
++ goto out;
++ }
++ rzs->backing_swap_name[MAX_SWAP_NAME_LEN - 1] = '\0';
++ pr_debug("Backing swap set to %s\n", rzs->backing_swap_name);
++ break;
++
++ case RZSIO_GET_STATS:
++ {
++ struct ramzswap_ioctl_stats *stats;
++ if (!rzs->init_done) {
++ ret = -ENOTTY;
++ goto out;
++ }
++ stats = kzalloc(sizeof(*stats), GFP_KERNEL);
++ if (!stats) {
++ ret = -ENOMEM;
++ goto out;
++ }
++ ramzswap_ioctl_get_stats(rzs, stats);
++ if (copy_to_user((void *)arg, stats, sizeof(*stats))) {
++ kfree(stats);
++ ret = -EFAULT;
++ goto out;
++ }
++ kfree(stats);
++ break;
++ }
++ case RZSIO_INIT:
++ ret = ramzswap_ioctl_init_device(rzs);
++ break;
++
++ case RZSIO_RESET:
++ /* Do not reset an active device! */
++ if (bdev->bd_holders) {
++ ret = -EBUSY;
++ goto out;
++ }
++ ret = ramzswap_ioctl_reset_device(rzs, bdev);
++ break;
++
++ default:
++ pr_info("Invalid ioctl %u\n", cmd);
++ ret = -ENOTTY;
++ }
++
++out:
++ return ret;
++}
++
++#if defined(CONFIG_SWAP_FREE_NOTIFY)
++
++void ramzswap_slot_free_notify(struct block_device *bdev, sector_t bi_sector)
++{
++ struct ramzswap *rzs = bdev->bd_disk->private_data;
++ ramzswap_free_page(rzs, bi_sector >> SECTORS_PER_PAGE_SHIFT);
++ stat64_inc(rzs, &rzs->stats.notify_free);
++}
++
++#endif
++
++static struct block_device_operations ramzswap_devops = {
++ .ioctl = ramzswap_ioctl,
++#if defined(CONFIG_SWAP_FREE_NOTIFY)
++ .swap_slot_free_notify = ramzswap_slot_free_notify,
++#endif
++ .owner = THIS_MODULE
++};
++
++static int create_device(struct ramzswap *rzs, int device_id)
++{
++ int ret = 0;
++
++ mutex_init(&rzs->lock);
++ spin_lock_init(&rzs->stat64_lock);
++ INIT_LIST_HEAD(&rzs->backing_swap_extent_list);
++
++ rzs->queue = blk_alloc_queue(GFP_KERNEL);
++ if (!rzs->queue) {
++ pr_err("Error allocating disk queue for device %d\n",
++ device_id);
++ ret = -ENOMEM;
++ goto out;
++ }
++
++ blk_queue_make_request(rzs->queue, ramzswap_make_request);
++ rzs->queue->queuedata = rzs;
++
++ /* gendisk structure */
++ rzs->disk = alloc_disk(1);
++ if (!rzs->disk) {
++ blk_cleanup_queue(rzs->queue);
++ pr_warning("Error allocating disk structure for device %d\n",
++ device_id);
++ ret = -ENOMEM;
++ goto out;
++ }
++
++ rzs->disk->major = ramzswap_major;
++ rzs->disk->first_minor = device_id;
++ rzs->disk->fops = &ramzswap_devops;
++ rzs->disk->queue = rzs->queue;
++ rzs->disk->private_data = rzs;
++ snprintf(rzs->disk->disk_name, 16, "ramzswap%d", device_id);
++ /*
++ * Actual capacity set using RZSIO_SET_DISKSIZE_KB ioctl
++ * or set equal to backing swap device (if provided)
++ */
++ set_capacity(rzs->disk, 0);
++
++ blk_queue_physical_block_size(rzs->disk->queue, PAGE_SIZE);
++ blk_queue_logical_block_size(rzs->disk->queue, PAGE_SIZE);
++
++ add_disk(rzs->disk);
++ rzs->disk->flags &= ~GENHD_FL_REMAP_SWAPPED_PAGES;
++
++ rzs->init_done = 0;
++
++out:
++ return ret;
++}
++
++static void destroy_device(struct ramzswap *rzs)
++{
++ if (rzs->disk) {
++ del_gendisk(rzs->disk);
++ put_disk(rzs->disk);
++ }
++
++ if (rzs->queue)
++ blk_cleanup_queue(rzs->queue);
++}
++
++static int __init ramzswap_init(void)
++{
++ int ret, dev_id;
++ struct ramzswap *rzs;
++
++ if (num_devices > max_num_devices) {
++ pr_warning("Invalid value for num_devices: %u\n",
++ num_devices);
++ ret = -EINVAL;
++ goto out;
++ }
++
++ ramzswap_major = register_blkdev(0, "ramzswap");
++ if (ramzswap_major <= 0) {
++ pr_warning("Unable to get major number\n");
++ ret = -EBUSY;
++ goto out;
++ }
++
++ if (!num_devices) {
++ pr_info("num_devices not specified. Using default: 1\n");
++ num_devices = 1;
++ }
++
++ /* Allocate the device array and initialize each one */
++ pr_debug("Creating %u devices ...\n", num_devices);
++ devices = kzalloc(num_devices * sizeof(struct ramzswap), GFP_KERNEL);
++ if (!devices) {
++ ret = -ENOMEM;
++ goto unregister;
++ }
++
++ for (dev_id = 0; dev_id < num_devices; dev_id++) {
++ if (create_device(&devices[dev_id], dev_id)) {
++ ret = -ENOMEM;
++ goto free_devices;
++ }
++ }
++
++ /*
++ * Initialize the first device (/dev/ramzswap0)
++ * if parameters are provided
++ */
++ rzs = &devices[0];
++
++ /*
++ * User specifies either <disksize_kb> or <backing_swap, memlimit_kb>
++ */
++ if (disksize_kb) {
++ rzs->disksize = disksize_kb << 10;
++ ret = ramzswap_ioctl_init_device(rzs);
++ if (ret)
++ goto free_devices;
++ goto out;
++ }
++
++ if (backing_swap[0]) {
++ rzs->memlimit = memlimit_kb << 10;
++ strncpy(rzs->backing_swap_name, backing_swap,
++ MAX_SWAP_NAME_LEN);
++ rzs->backing_swap_name[MAX_SWAP_NAME_LEN - 1] = '\0';
++ ret = ramzswap_ioctl_init_device(rzs);
++ if (ret)
++ goto free_devices;
++ goto out;
++ }
++
++ /* User specified memlimit_kb but not backing_swap */
++ if (memlimit_kb) {
++ pr_info("memlimit_kb parameter is valid only when "
++ "backing_swap is also specified. Aborting.\n");
++ ret = -EINVAL;
++ goto free_devices;
++ }
++
++ return 0;
++
++free_devices:
++ while(dev_id)
++ destroy_device(&devices[--dev_id]);
++unregister:
++ unregister_blkdev(ramzswap_major, "ramzswap");
++out:
++ return ret;
++}
++
++static void __exit ramzswap_exit(void)
++{
++ int i;
++ struct ramzswap *rzs;
++
++ for (i = 0; i < num_devices; i++) {
++ rzs = &devices[i];
++
++ destroy_device(rzs);
++ if (rzs->init_done)
++ reset_device(rzs, NULL);
++ }
++
++ unregister_blkdev(ramzswap_major, "ramzswap");
++
++ kfree(devices);
++ pr_debug("Cleanup done!\n");
++}
++
++/*
++ * Module parameters
++ */
++
++/* Optional: default = 1 */
++module_param(num_devices, uint, 0);
++MODULE_PARM_DESC(num_devices, "Number of ramzswap devices");
++
++/*
++ * User specifies either <disksize_kb> or <backing_swap, memlimit_kb>
++ * parameters. You must specify these parameters if the first device
++ * has to be initialized on module load without using rzscontrol utility.
++ * This is useful for embedded system, where shipping an additional binary
++ * (rzscontrol) might not be desirable.
++ *
++ * These parameters are used to initialize just the first (/dev/ramzswap0)
++ * device. To initialize additional devices, use rzscontrol utility. If
++ * these parameters are not provided, then the first device is also
++ * left in unitialized state.
++ */
++
++/* Optional: default = 25% of RAM */
++module_param(disksize_kb, ulong, 0);
++MODULE_PARM_DESC(disksize_kb, "Disksize in KB");
++
++/* Optional: default = 15% of RAM */
++module_param(memlimit_kb, ulong, 0);
++MODULE_PARM_DESC(memlimit_kb, "Memlimit in KB");
++
++/* Optional: default = <NULL> */
++module_param_string(backing_swap, backing_swap, sizeof(backing_swap), 0);
++MODULE_PARM_DESC(backing_swap, "Backing swap name");
++
++module_init(ramzswap_init);
++module_exit(ramzswap_exit);
++
++MODULE_LICENSE("Dual BSD/GPL");
++MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>");
++MODULE_DESCRIPTION("Compressed RAM Based Swap Device");
+Index: kernel-power-2.6.28/drivers/block/ramzswap/ramzswap_drv.h
+===================================================================
+--- /dev/null
++++ kernel-power-2.6.28/drivers/block/ramzswap/ramzswap_drv.h
+@@ -0,0 +1,210 @@
++/*
++ * Compressed RAM based swap device
++ *
++ * Copyright (C) 2008, 2009, 2010 Nitin Gupta
++ *
++ * This code is released using a dual license strategy: BSD/GPL
++ * You can choose the licence that better fits your requirements.
++ *
++ * Released under the terms of 3-clause BSD License
++ * Released under the terms of GNU General Public License Version 2.0
++ *
++ * Project home: http://compcache.googlecode.com
++ */
++
++#ifndef _RAMZSWAP_DRV_H_
++#define _RAMZSWAP_DRV_H_
++
++#include <linux/spinlock.h>
++#include <linux/mutex.h>
++
++#include "ramzswap_ioctl.h"
++#include "xvmalloc.h"
++
++/*
++ * Some arbitrary value. This is just to catch
++ * invalid value for num_devices module parameter.
++ */
++static const unsigned max_num_devices = 32;
++
++/*
++ * Stored at beginning of each compressed object.
++ *
++ * It stores back-reference to table entry which points to this
++ * object. This is required to support memory defragmentation or
++ * migrating compressed pages to backing swap disk.
++ */
++struct zobj_header {
++#if 0
++ u32 table_idx;
++#endif
++};
++
++/*-- Configurable parameters */
++
++/* Default ramzswap disk size: 25% of total RAM */
++static const unsigned default_disksize_perc_ram = 25;
++static const unsigned default_memlimit_perc_ram = 15;
++
++/*
++ * Max compressed page size when backing device is provided.
++ * Pages that compress to size greater than this are sent to
++ * physical swap disk.
++ */
++static const unsigned max_zpage_size_bdev = PAGE_SIZE / 2;
++
++/*
++ * Max compressed page size when there is no backing dev.
++ * Pages that compress to size greater than this are stored
++ * uncompressed in memory.
++ */
++static const unsigned max_zpage_size_nobdev = PAGE_SIZE / 4 * 3;
++
++/*
++ * NOTE: max_zpage_size_{bdev,nobdev} sizes must be
++ * less than or equal to:
++ * XV_MAX_ALLOC_SIZE - sizeof(struct zobj_header)
++ * since otherwise xv_malloc would always return failure.
++ */
++
++/*-- End of configurable params */
++
++#define SECTOR_SHIFT 9
++#define SECTOR_SIZE (1 << SECTOR_SHIFT)
++#define SECTORS_PER_PAGE_SHIFT (PAGE_SHIFT - SECTOR_SHIFT)
++#define SECTORS_PER_PAGE (1 << SECTORS_PER_PAGE_SHIFT)
++
++/* Flags for ramzswap pages (table[page_no].flags) */
++enum rzs_pageflags {
++ /* Page is stored uncompressed */
++ RZS_UNCOMPRESSED,
++
++ /* Page consists entirely of zeros */
++ RZS_ZERO,
++
++ __NR_RZS_PAGEFLAGS,
++};
++
++/*-- Data structures */
++
++/*
++ * Allocated for each swap slot, indexed by page no.
++ * These table entries must fit exactly in a page.
++ */
++struct table {
++ struct page *page;
++ u16 offset;
++ u8 count; /* object ref count (not yet used) */
++ u8 flags;
++} __attribute__((aligned(4)));
++
++/*
++ * Swap extent information in case backing swap is a regular
++ * file. These extent entries must fit exactly in a page.
++ */
++struct ramzswap_backing_extent {
++ pgoff_t phy_pagenum;
++ pgoff_t num_pages;
++} __attribute__((aligned(4)));
++
++struct ramzswap_stats {
++ /* basic stats */
++ size_t compr_size; /* compressed size of pages stored -
++ * needed to enforce memlimit */
++ /* more stats */
++#if defined(CONFIG_RAMZSWAP_STATS)
++ u64 num_reads; /* failed + successful */
++ u64 num_writes; /* --do-- */
++ u64 failed_reads; /* should NEVER! happen */
++ u64 failed_writes; /* can happen when memory is too low */
++ u64 invalid_io; /* non-swap I/O requests */
++ u64 notify_free; /* no. of swap slot free notifications */
++ u32 pages_zero; /* no. of zero filled pages */
++ u32 pages_stored; /* no. of pages currently stored */
++ u32 good_compress; /* % of pages with compression ratio<=50% */
++ u32 pages_expand; /* % of incompressible pages */
++ u64 bdev_num_reads; /* no. of reads on backing dev */
++ u64 bdev_num_writes; /* no. of writes on backing dev */
++#endif
++};
++
++struct ramzswap {
++ struct xv_pool *mem_pool;
++ void *compress_workmem;
++ void *compress_buffer;
++ struct table *table;
++ spinlock_t stat64_lock; /* protect 64-bit stats */
++ struct mutex lock;
++ struct request_queue *queue;
++ struct gendisk *disk;
++ int init_done;
++ /*
++ * This is limit on compressed data size (stats.compr_size)
++ * Its applicable only when backing swap device is present.
++ */
++ size_t memlimit; /* bytes */
++ /*
++ * This is limit on amount of *uncompressed* worth of data
++ * we can hold. When backing swap device is provided, it is
++ * set equal to device size.
++ */
++ size_t disksize; /* bytes */
++
++ struct ramzswap_stats stats;
++
++ /* backing swap device info */
++ struct ramzswap_backing_extent *curr_extent;
++ struct list_head backing_swap_extent_list;
++ unsigned long num_extents;
++ char backing_swap_name[MAX_SWAP_NAME_LEN];
++ struct block_device *backing_swap;
++ struct file *swap_file;
++};
++
++/*-- */
++
++/* Debugging and Stats */
++#if defined(CONFIG_RAMZSWAP_STATS)
++static void stat_inc(u32 *v)
++{
++ *v = *v + 1;
++}
++
++static void stat_dec(u32 *v)
++{
++ *v = *v - 1;
++}
++
++static void stat64_inc(struct ramzswap *rzs, u64 *v)
++{
++ spin_lock(&rzs->stat64_lock);
++ *v = *v + 1;
++ spin_unlock(&rzs->stat64_lock);
++}
++
++static void stat64_dec(struct ramzswap *rzs, u64 *v)
++{
++ spin_lock(&rzs->stat64_lock);
++ *v = *v - 1;
++ spin_unlock(&rzs->stat64_lock);
++}
++
++static u64 stat64_read(struct ramzswap *rzs, u64 *v)
++{
++ u64 val;
++
++ spin_lock(&rzs->stat64_lock);
++ val = *v;
++ spin_unlock(&rzs->stat64_lock);
++
++ return val;
++}
++#else
++#define stat_inc(v)
++#define stat_dec(v)
++#define stat64_inc(r, v)
++#define stat64_dec(r, v)
++#define stat64_read(r, v)
++#endif /* CONFIG_RAMZSWAP_STATS */
++
++#endif
+Index: kernel-power-2.6.28/drivers/block/ramzswap/ramzswap_ioctl.h
+===================================================================
+--- /dev/null
++++ kernel-power-2.6.28/drivers/block/ramzswap/ramzswap_ioctl.h
+@@ -0,0 +1,50 @@
++/*
++ * Compressed RAM based swap device
++ *
++ * Copyright (C) 2008, 2009, 2010 Nitin Gupta
++ *
++ * This code is released using a dual license strategy: BSD/GPL
++ * You can choose the licence that better fits your requirements.
++ *
++ * Released under the terms of 3-clause BSD License
++ * Released under the terms of GNU General Public License Version 2.0
++ *
++ * Project home: http://compcache.googlecode.com
++ */
++
++#ifndef _RAMZSWAP_IOCTL_H_
++#define _RAMZSWAP_IOCTL_H_
++
++#define MAX_SWAP_NAME_LEN 128
++
++struct ramzswap_ioctl_stats {
++ char backing_swap_name[MAX_SWAP_NAME_LEN];
++ u64 memlimit; /* only applicable if backing swap present */
++ u64 disksize; /* user specified or equal to backing swap
++ * size (if present) */
++ u64 num_reads; /* failed + successful */
++ u64 num_writes; /* --do-- */
++ u64 failed_reads; /* should NEVER! happen */
++ u64 failed_writes; /* can happen when memory is too low */
++ u64 invalid_io; /* non-swap I/O requests */
++ u64 notify_free; /* no. of swap slot free notifications */
++ u32 pages_zero; /* no. of zero filled pages */
++ u32 good_compress_pct; /* no. of pages with compression ratio<=50% */
++ u32 pages_expand_pct; /* no. of incompressible pages */
++ u32 pages_stored;
++ u32 pages_used;
++ u64 orig_data_size;
++ u64 compr_data_size;
++ u64 mem_used_total;
++ u64 bdev_num_reads; /* no. of reads on backing dev */
++ u64 bdev_num_writes; /* no. of writes on backing dev */
++} __attribute__ ((packed, aligned(4)));
++
++#define RZSIO_SET_DISKSIZE_KB _IOW('z', 0, size_t)
++#define RZSIO_SET_MEMLIMIT_KB _IOW('z', 1, size_t)
++#define RZSIO_SET_BACKING_SWAP _IOW('z', 2, unsigned char[MAX_SWAP_NAME_LEN])
++#define RZSIO_GET_STATS _IOR('z', 3, struct ramzswap_ioctl_stats)
++#define RZSIO_INIT _IO('z', 4)
++#define RZSIO_RESET _IO('z', 5)
++
++#endif
+Index: kernel-power-2.6.28/drivers/block/ramzswap/xvmalloc.c
+===================================================================
+--- /dev/null
++++ kernel-power-2.6.28/drivers/block/ramzswap/xvmalloc.c
+@@ -0,0 +1,507 @@
++/*
++ * xvmalloc memory allocator
++ *
++ * Copyright (C) 2008, 2009, 2010 Nitin Gupta
++ *
++ * This code is released using a dual license strategy: BSD/GPL
++ * You can choose the licence that better fits your requirements.
++ *
++ * Released under the terms of 3-clause BSD License
++ * Released under the terms of GNU General Public License Version 2.0
++ */
++
++#include <linux/bitops.h>
++#include <linux/errno.h>
++#include <linux/highmem.h>
++#include <linux/init.h>
++#include <linux/string.h>
++#include <linux/slab.h>
++
++#include "xvmalloc.h"
++#include "xvmalloc_int.h"
++
++static void stat_inc(u64 *value)
++{
++ *value = *value + 1;
++}
++
++static void stat_dec(u64 *value)
++{
++ *value = *value - 1;
++}
++
++static int test_flag(struct block_header *block, enum blockflags flag)
++{
++ return block->prev & BIT(flag);
++}
++
++static void set_flag(struct block_header *block, enum blockflags flag)
++{
++ block->prev |= BIT(flag);
++}
++
++static void clear_flag(struct block_header *block, enum blockflags flag)
++{
++ block->prev &= ~BIT(flag);
++}
++
++/*
++ * Given <page, offset> pair, provide a derefrencable pointer.
++ * This is called from xv_malloc/xv_free path, so it
++ * needs to be fast.
++ */
++static void *get_ptr_atomic(struct page *page, u16 offset, enum km_type type)
++{
++ unsigned char *base;
++
++ base = kmap_atomic(page, type);
++ return base + offset;
++}
++
++static void put_ptr_atomic(void *ptr, enum km_type type)
++{
++ kunmap_atomic(ptr, type);
++}
++
++static u32 get_blockprev(struct block_header *block)
++{
++ return block->prev & PREV_MASK;
++}
++
++static void set_blockprev(struct block_header *block, u16 new_offset)
++{
++ block->prev = new_offset | (block->prev & FLAGS_MASK);
++}
++
++static struct block_header *BLOCK_NEXT(struct block_header *block)
++{
++ return (struct block_header *)
++ ((char *)block + block->size + XV_ALIGN);
++}
++
++/*
++ * Get index of free list containing blocks of maximum size
++ * which is less than or equal to given size.
++ */
++static u32 get_index_for_insert(u32 size)
++{
++ if (unlikely(size > XV_MAX_ALLOC_SIZE))
++ size = XV_MAX_ALLOC_SIZE;
++ size &= ~FL_DELTA_MASK;
++ return (size - XV_MIN_ALLOC_SIZE) >> FL_DELTA_SHIFT;
++}
++
++/*
++ * Get index of free list having blocks of size greater than
++ * or equal to requested size.
++ */
++static u32 get_index(u32 size)
++{
++ if (unlikely(size < XV_MIN_ALLOC_SIZE))
++ size = XV_MIN_ALLOC_SIZE;
++ size = ALIGN(size, FL_DELTA);
++ return (size - XV_MIN_ALLOC_SIZE) >> FL_DELTA_SHIFT;
++}
++
++/**
++ * find_block - find block of at least given size
++ * @pool: memory pool to search from
++ * @size: size of block required
++ * @page: page containing required block
++ * @offset: offset within the page where block is located.
++ *
++ * Searches two level bitmap to locate block of at least
++ * the given size. If such a block is found, it provides
++ * <page, offset> to identify this block and returns index
++ * in freelist where we found this block.
++ * Otherwise, returns 0 and <page, offset> params are not touched.
++ */
++static u32 find_block(struct xv_pool *pool, u32 size,
++ struct page **page, u32 *offset)
++{
++ ulong flbitmap, slbitmap;
++ u32 flindex, slindex, slbitstart;
++
++ /* There are no free blocks in this pool */
++ if (!pool->flbitmap)
++ return 0;
++
++ /* Get freelist index correspoding to this size */
++ slindex = get_index(size);
++ slbitmap = pool->slbitmap[slindex / BITS_PER_LONG];
++ slbitstart = slindex % BITS_PER_LONG;
++
++ /*
++ * If freelist is not empty at this index, we found the
++ * block - head of this list. This is approximate best-fit match.
++ */
++ if (test_bit(slbitstart, &slbitmap)) {
++ *page = pool->freelist[slindex].page;
++ *offset = pool->freelist[slindex].offset;
++ return slindex;
++ }
++
++ /*
++ * No best-fit found. Search a bit further in bitmap for a free block.
++ * Second level bitmap consists of series of 32-bit chunks. Search
++ * further in the chunk where we expected a best-fit, starting from
++ * index location found above.
++ */
++ slbitstart++;
++ slbitmap >>= slbitstart;
++
++ /* Skip this search if we were already at end of this bitmap chunk */
++ if ((slbitstart != BITS_PER_LONG) && slbitmap) {
++ slindex += __ffs(slbitmap) + 1;
++ *page = pool->freelist[slindex].page;
++ *offset = pool->freelist[slindex].offset;
++ return slindex;
++ }
++
++ /* Now do a full two-level bitmap search to find next nearest fit */
++ flindex = slindex / BITS_PER_LONG;
++
++ flbitmap = (pool->flbitmap) >> (flindex + 1);
++ if (!flbitmap)
++ return 0;
++
++ flindex += __ffs(flbitmap) + 1;
++ slbitmap = pool->slbitmap[flindex];
++ slindex = (flindex * BITS_PER_LONG) + __ffs(slbitmap);
++ *page = pool->freelist[slindex].page;
++ *offset = pool->freelist[slindex].offset;
++
++ return slindex;
++}
++
++/*
++ * Insert block at <page, offset> in freelist of given pool.
++ * freelist used depends on block size.
++ */
++static void insert_block(struct xv_pool *pool, struct page *page, u32 offset,
++ struct block_header *block)
++{
++ u32 flindex, slindex;
++ struct block_header *nextblock;
++
++ slindex = get_index_for_insert(block->size);
++ flindex = slindex / BITS_PER_LONG;
++
++ block->link.prev_page = 0;
++ block->link.prev_offset = 0;
++ block->link.next_page = pool->freelist[slindex].page;
++ block->link.next_offset = pool->freelist[slindex].offset;
++ pool->freelist[slindex].page = page;
++ pool->freelist[slindex].offset = offset;
++
++ if (block->link.next_page) {
++ nextblock = get_ptr_atomic(block->link.next_page,
++ block->link.next_offset, KM_USER1);
++ nextblock->link.prev_page = page;
++ nextblock->link.prev_offset = offset;
++ put_ptr_atomic(nextblock, KM_USER1);
++ }
++
++ __set_bit(slindex % BITS_PER_LONG, &pool->slbitmap[flindex]);
++ __set_bit(flindex, &pool->flbitmap);
++}
++
++/*
++ * Remove block from head of freelist. Index 'slindex' identifies the freelist.
++ */
++static void remove_block_head(struct xv_pool *pool,
++ struct block_header *block, u32 slindex)
++{
++ struct block_header *tmpblock;
++ u32 flindex = slindex / BITS_PER_LONG;
++
++ pool->freelist[slindex].page = block->link.next_page;
++ pool->freelist[slindex].offset = block->link.next_offset;
++ block->link.prev_page = 0;
++ block->link.prev_offset = 0;
++
++ if (!pool->freelist[slindex].page) {
++ __clear_bit(slindex % BITS_PER_LONG, &pool->slbitmap[flindex]);
++ if (!pool->slbitmap[flindex])
++ __clear_bit(flindex, &pool->flbitmap);
++ } else {
++ /*
++ * DEBUG ONLY: We need not reinitialize freelist head previous
++ * pointer to 0 - we never depend on its value. But just for
++ * sanity, lets do it.
++ */
++ tmpblock = get_ptr_atomic(pool->freelist[slindex].page,
++ pool->freelist[slindex].offset, KM_USER1);
++ tmpblock->link.prev_page = 0;
++ tmpblock->link.prev_offset = 0;
++ put_ptr_atomic(tmpblock, KM_USER1);
++ }
++}
++
++/*
++ * Remove block from freelist. Index 'slindex' identifies the freelist.
++ */
++static void remove_block(struct xv_pool *pool, struct page *page, u32 offset,
++ struct block_header *block, u32 slindex)
++{
++ u32 flindex;
++ struct block_header *tmpblock;
++
++ if (pool->freelist[slindex].page == page
++ && pool->freelist[slindex].offset == offset) {
++ remove_block_head(pool, block, slindex);
++ return;
++ }
++
++ flindex = slindex / BITS_PER_LONG;
++
++ if (block->link.prev_page) {
++ tmpblock = get_ptr_atomic(block->link.prev_page,
++ block->link.prev_offset, KM_USER1);
++ tmpblock->link.next_page = block->link.next_page;
++ tmpblock->link.next_offset = block->link.next_offset;
++ put_ptr_atomic(tmpblock, KM_USER1);
++ }
++
++ if (block->link.next_page) {
++ tmpblock = get_ptr_atomic(block->link.next_page,
++ block->link.next_offset, KM_USER1);
++ tmpblock->link.prev_page = block->link.prev_page;
++ tmpblock->link.prev_offset = block->link.prev_offset;
++ put_ptr_atomic(tmpblock, KM_USER1);
++ }
++}
++
++/*
++ * Allocate a page and add it to freelist of given pool.
++ */
++static int grow_pool(struct xv_pool *pool, gfp_t flags)
++{
++ struct page *page;
++ struct block_header *block;
++
++ page = alloc_page(flags);
++ if (unlikely(!page))
++ return -ENOMEM;
++
++ stat_inc(&pool->total_pages);
++
++ spin_lock(&pool->lock);
++ block = get_ptr_atomic(page, 0, KM_USER0);
++
++ block->size = PAGE_SIZE - XV_ALIGN;
++ set_flag(block, BLOCK_FREE);
++ clear_flag(block, PREV_FREE);
++ set_blockprev(block, 0);
++
++ insert_block(pool, page, 0, block);
++
++ put_ptr_atomic(block, KM_USER0);
++ spin_unlock(&pool->lock);
++
++ return 0;
++}
++
++/*
++ * Create a memory pool. Allocates freelist, bitmaps and other
++ * per-pool metadata.
++ */
++struct xv_pool *xv_create_pool(void)
++{
++ u32 ovhd_size;
++ struct xv_pool *pool;
++
++ ovhd_size = roundup(sizeof(*pool), PAGE_SIZE);
++ pool = kzalloc(ovhd_size, GFP_KERNEL);
++ if (!pool)
++ return NULL;
++
++ spin_lock_init(&pool->lock);
++
++ return pool;
++}
++
++void xv_destroy_pool(struct xv_pool *pool)
++{
++ kfree(pool);
++}
++
++/**
++ * xv_malloc - Allocate block of given size from pool.
++ * @pool: pool to allocate from
++ * @size: size of block to allocate
++ * @page: page no. that holds the object
++ * @offset: location of object within page
++ *
++ * On success, <page, offset> identifies block allocated
++ * and 0 is returned. On failure, <page, offset> is set to
++ * 0 and -ENOMEM is returned.
++ *
++ * Allocation requests with size > XV_MAX_ALLOC_SIZE will fail.
++ */
++int xv_malloc(struct xv_pool *pool, u32 size, struct page **page,
++ u32 *offset, gfp_t flags)
++{
++ int error;
++ u32 index, tmpsize, origsize, tmpoffset;
++ struct block_header *block, *tmpblock;
++
++ *page = NULL;
++ *offset = 0;
++ origsize = size;
++
++ if (unlikely(!size || size > XV_MAX_ALLOC_SIZE))
++ return -ENOMEM;
++
++ size = ALIGN(size, XV_ALIGN);
++
++ spin_lock(&pool->lock);
++
++ index = find_block(pool, size, page, offset);
++
++ if (!*page) {
++ spin_unlock(&pool->lock);
++ if (flags & GFP_NOWAIT)
++ return -ENOMEM;
++ error = grow_pool(pool, flags);
++ if (unlikely(error))
++ return error;
++
++ spin_lock(&pool->lock);
++ index = find_block(pool, size, page, offset);
++ }
++
++ if (!*page) {
++ spin_unlock(&pool->lock);
++ return -ENOMEM;
++ }
++
++ block = get_ptr_atomic(*page, *offset, KM_USER0);
++
++ remove_block_head(pool, block, index);
++
++ /* Split the block if required */
++ tmpoffset = *offset + size + XV_ALIGN;
++ tmpsize = block->size - size;
++ tmpblock = (struct block_header *)((char *)block + size + XV_ALIGN);
++ if (tmpsize) {
++ tmpblock->size = tmpsize - XV_ALIGN;
++ set_flag(tmpblock, BLOCK_FREE);
++ clear_flag(tmpblock, PREV_FREE);
++
++ set_blockprev(tmpblock, *offset);
++ if (tmpblock->size >= XV_MIN_ALLOC_SIZE)
++ insert_block(pool, *page, tmpoffset, tmpblock);
++
++ if (tmpoffset + XV_ALIGN + tmpblock->size != PAGE_SIZE) {
++ tmpblock = BLOCK_NEXT(tmpblock);
++ set_blockprev(tmpblock, tmpoffset);
++ }
++ } else {
++ /* This block is exact fit */
++ if (tmpoffset != PAGE_SIZE)
++ clear_flag(tmpblock, PREV_FREE);
++ }
++
++ block->size = origsize;
++ clear_flag(block, BLOCK_FREE);
++
++ put_ptr_atomic(block, KM_USER0);
++ spin_unlock(&pool->lock);
++
++ *offset += XV_ALIGN;
++
++ return 0;
++}
++
++/*
++ * Free block identified with <page, offset>
++ */
++void xv_free(struct xv_pool *pool, struct page *page, u32 offset)
++{
++ void *page_start;
++ struct block_header *block, *tmpblock;
++
++ offset -= XV_ALIGN;
++
++ spin_lock(&pool->lock);
++
++ page_start = get_ptr_atomic(page, 0, KM_USER0);
++ block = (struct block_header *)((char *)page_start + offset);
++
++ /* Catch double free bugs */
++ BUG_ON(test_flag(block, BLOCK_FREE));
++
++ block->size = ALIGN(block->size, XV_ALIGN);
++
++ tmpblock = BLOCK_NEXT(block);
++ if (offset + block->size + XV_ALIGN == PAGE_SIZE)
++ tmpblock = NULL;
++
++ /* Merge next block if its free */
++ if (tmpblock && test_flag(tmpblock, BLOCK_FREE)) {
++ /*
++ * Blocks smaller than XV_MIN_ALLOC_SIZE
++ * are not inserted in any free list.
++ */
++ if (tmpblock->size >= XV_MIN_ALLOC_SIZE) {
++ remove_block(pool, page,
++ offset + block->size + XV_ALIGN, tmpblock,
++ get_index_for_insert(tmpblock->size));
++ }
++ block->size += tmpblock->size + XV_ALIGN;
++ }
++
++ /* Merge previous block if its free */
++ if (test_flag(block, PREV_FREE)) {
++ tmpblock = (struct block_header *)((char *)(page_start) +
++ get_blockprev(block));
++ offset = offset - tmpblock->size - XV_ALIGN;
++
++ if (tmpblock->size >= XV_MIN_ALLOC_SIZE)
++ remove_block(pool, page, offset, tmpblock,
++ get_index_for_insert(tmpblock->size));
++
++ tmpblock->size += block->size + XV_ALIGN;
++ block = tmpblock;
++ }
++
++ /* No used objects in this page. Free it. */
++ if (block->size == PAGE_SIZE - XV_ALIGN) {
++ put_ptr_atomic(page_start, KM_USER0);
++ spin_unlock(&pool->lock);
++
++ __free_page(page);
++ stat_dec(&pool->total_pages);
++ return;
++ }
++
++ set_flag(block, BLOCK_FREE);
++ if (block->size >= XV_MIN_ALLOC_SIZE)
++ insert_block(pool, page, offset, block);
++
++ if (offset + block->size + XV_ALIGN != PAGE_SIZE) {
++ tmpblock = BLOCK_NEXT(block);
++ set_flag(tmpblock, PREV_FREE);
++ set_blockprev(tmpblock, offset);
++ }
++
++ put_ptr_atomic(page_start, KM_USER0);
++ spin_unlock(&pool->lock);
++}
++
++u32 xv_get_object_size(void *obj)
++{
++ struct block_header *blk;
++
++ blk = (struct block_header *)((char *)(obj) - XV_ALIGN);
++ return blk->size;
++}
++
++/*
++ * Returns total memory used by allocator (userdata + metadata)
++ */
++u64 xv_get_total_size_bytes(struct xv_pool *pool)
++{
++ return pool->total_pages << PAGE_SHIFT;
++}
+Index: kernel-power-2.6.28/drivers/block/ramzswap/xvmalloc.h
+===================================================================
+--- /dev/null
++++ kernel-power-2.6.28/drivers/block/ramzswap/xvmalloc.h
+@@ -0,0 +1,30 @@
++/*
++ * xvmalloc memory allocator
++ *
++ * Copyright (C) 2008, 2009, 2010 Nitin Gupta
++ *
++ * This code is released using a dual license strategy: BSD/GPL
++ * You can choose the licence that better fits your requirements.
++ *
++ * Released under the terms of 3-clause BSD License
++ * Released under the terms of GNU General Public License Version 2.0
++ */
++
++#ifndef _XV_MALLOC_H_
++#define _XV_MALLOC_H_
++
++#include <linux/types.h>
++
++struct xv_pool;
++
++struct xv_pool *xv_create_pool(void);
++void xv_destroy_pool(struct xv_pool *pool);
++
++int xv_malloc(struct xv_pool *pool, u32 size, struct page **page,
++ u32 *offset, gfp_t flags);
++void xv_free(struct xv_pool *pool, struct page *page, u32 offset);
++
++u32 xv_get_object_size(void *obj);
++u64 xv_get_total_size_bytes(struct xv_pool *pool);
++
++#endif
+Index: kernel-power-2.6.28/drivers/block/ramzswap/xvmalloc_int.h
+===================================================================
+--- /dev/null
++++ kernel-power-2.6.28/drivers/block/ramzswap/xvmalloc_int.h
+@@ -0,0 +1,86 @@
++/*
++ * xvmalloc memory allocator
++ *
++ * Copyright (C) 2008, 2009, 2010 Nitin Gupta
++ *
++ * This code is released using a dual license strategy: BSD/GPL
++ * You can choose the licence that better fits your requirements.
++ *
++ * Released under the terms of 3-clause BSD License
++ * Released under the terms of GNU General Public License Version 2.0
++ */
++
++#ifndef _XV_MALLOC_INT_H_
++#define _XV_MALLOC_INT_H_
++
++#include <linux/kernel.h>
++#include <linux/types.h>
++
++/* User configurable params */
++
++/* Must be power of two */
++#define XV_ALIGN_SHIFT 2
++#define XV_ALIGN (1 << XV_ALIGN_SHIFT)
++#define XV_ALIGN_MASK (XV_ALIGN - 1)
++
++/* This must be greater than sizeof(link_free) */
++#define XV_MIN_ALLOC_SIZE 32
++#define XV_MAX_ALLOC_SIZE (PAGE_SIZE - XV_ALIGN)
++
++/* Free lists are separated by FL_DELTA bytes */
++#define FL_DELTA_SHIFT 3
++#define FL_DELTA (1 << FL_DELTA_SHIFT)
++#define FL_DELTA_MASK (FL_DELTA - 1)
++#define NUM_FREE_LISTS ((XV_MAX_ALLOC_SIZE - XV_MIN_ALLOC_SIZE) \
++ / FL_DELTA + 1)
++
++#define MAX_FLI DIV_ROUND_UP(NUM_FREE_LISTS, BITS_PER_LONG)
++
++/* End of user params */
++
++enum blockflags {
++ BLOCK_FREE,
++ PREV_FREE,
++ __NR_BLOCKFLAGS,
++};
++
++#define FLAGS_MASK XV_ALIGN_MASK
++#define PREV_MASK (~FLAGS_MASK)
++
++struct freelist_entry {
++ struct page *page;
++ u16 offset;
++ u16 pad;
++};
++
++struct link_free {
++ struct page *prev_page;
++ struct page *next_page;
++ u16 prev_offset;
++ u16 next_offset;
++};
++
++struct block_header {
++ union {
++ /* This common header must be XV_ALIGN bytes */
++ u8 common[XV_ALIGN];
++ struct {
++ u16 size;
++ u16 prev;
++ };
++ };
++ struct link_free link;
++};
++
++struct xv_pool {
++ ulong flbitmap;
++ ulong slbitmap[MAX_FLI];
++ spinlock_t lock;
++
++ struct freelist_entry freelist[NUM_FREE_LISTS];
++
++ /* stats */
++ u64 total_pages;
++};
++
++#endif
projects / kernel-bfs / blobdiff