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-rw-r--r--drivers/block/zram/Kconfig34
-rw-r--r--drivers/block/zram/Makefile5
-rw-r--r--drivers/block/zram/zcomp.c353
-rw-r--r--drivers/block/zram/zcomp.h68
-rw-r--r--drivers/block/zram/zcomp_lz4.c47
-rw-r--r--drivers/block/zram/zcomp_lz4.h17
-rw-r--r--drivers/block/zram/zcomp_lzo.c47
-rw-r--r--drivers/block/zram/zcomp_lzo.h17
-rw-r--r--drivers/block/zram/zram_drv.c1322
-rw-r--r--drivers/block/zram/zram_drv.h125
10 files changed, 2035 insertions, 0 deletions
diff --git a/drivers/block/zram/Kconfig b/drivers/block/zram/Kconfig
new file mode 100644
index 000000000..6489c0fd0
--- /dev/null
+++ b/drivers/block/zram/Kconfig
@@ -0,0 +1,34 @@
+config ZRAM
+ tristate "Compressed RAM block device support"
+ depends on BLOCK && SYSFS && ZSMALLOC
+ select LZO_COMPRESS
+ select LZO_DECOMPRESS
+ default n
+ help
+ Creates virtual block devices called /dev/zramX (X = 0, 1, ...).
+ Pages written to these disks are compressed and stored in memory
+ itself. These disks allow very fast I/O and compression provides
+ good amounts of memory savings.
+
+ It has several use cases, for example: /tmp storage, use as swap
+ disks and maybe many more.
+
+ See zram.txt for more information.
+
+config ZRAM_LZ4_COMPRESS
+ bool "Enable LZ4 algorithm support"
+ depends on ZRAM
+ select LZ4_COMPRESS
+ select LZ4_DECOMPRESS
+ default n
+ help
+ This option enables LZ4 compression algorithm support. Compression
+ algorithm can be changed using `comp_algorithm' device attribute.
+
+config ZRAM_DEBUG
+ bool "Compressed RAM block device debug support"
+ depends on ZRAM
+ default n
+ help
+ This option adds additional debugging code to the compressed
+ RAM block device driver.
diff --git a/drivers/block/zram/Makefile b/drivers/block/zram/Makefile
new file mode 100644
index 000000000..be0763ff5
--- /dev/null
+++ b/drivers/block/zram/Makefile
@@ -0,0 +1,5 @@
+zram-y := zcomp_lzo.o zcomp.o zram_drv.o
+
+zram-$(CONFIG_ZRAM_LZ4_COMPRESS) += zcomp_lz4.o
+
+obj-$(CONFIG_ZRAM) += zram.o
diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
new file mode 100644
index 000000000..f1ff39a3d
--- /dev/null
+++ b/drivers/block/zram/zcomp.c
@@ -0,0 +1,353 @@
+/*
+ * Copyright (C) 2014 Sergey Senozhatsky.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/sched.h>
+
+#include "zcomp.h"
+#include "zcomp_lzo.h"
+#ifdef CONFIG_ZRAM_LZ4_COMPRESS
+#include "zcomp_lz4.h"
+#endif
+
+/*
+ * single zcomp_strm backend
+ */
+struct zcomp_strm_single {
+ struct mutex strm_lock;
+ struct zcomp_strm *zstrm;
+};
+
+/*
+ * multi zcomp_strm backend
+ */
+struct zcomp_strm_multi {
+ /* protect strm list */
+ spinlock_t strm_lock;
+ /* max possible number of zstrm streams */
+ int max_strm;
+ /* number of available zstrm streams */
+ int avail_strm;
+ /* list of available strms */
+ struct list_head idle_strm;
+ wait_queue_head_t strm_wait;
+};
+
+static struct zcomp_backend *backends[] = {
+ &zcomp_lzo,
+#ifdef CONFIG_ZRAM_LZ4_COMPRESS
+ &zcomp_lz4,
+#endif
+ NULL
+};
+
+static struct zcomp_backend *find_backend(const char *compress)
+{
+ int i = 0;
+ while (backends[i]) {
+ if (sysfs_streq(compress, backends[i]->name))
+ break;
+ i++;
+ }
+ return backends[i];
+}
+
+static void zcomp_strm_free(struct zcomp *comp, struct zcomp_strm *zstrm)
+{
+ if (zstrm->private)
+ comp->backend->destroy(zstrm->private);
+ free_pages((unsigned long)zstrm->buffer, 1);
+ kfree(zstrm);
+}
+
+/*
+ * allocate new zcomp_strm structure with ->private initialized by
+ * backend, return NULL on error
+ */
+static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp)
+{
+ struct zcomp_strm *zstrm = kmalloc(sizeof(*zstrm), GFP_KERNEL);
+ if (!zstrm)
+ return NULL;
+
+ zstrm->private = comp->backend->create();
+ /*
+ * allocate 2 pages. 1 for compressed data, plus 1 extra for the
+ * case when compressed size is larger than the original one
+ */
+ zstrm->buffer = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1);
+ if (!zstrm->private || !zstrm->buffer) {
+ zcomp_strm_free(comp, zstrm);
+ zstrm = NULL;
+ }
+ return zstrm;
+}
+
+/*
+ * get idle zcomp_strm or wait until other process release
+ * (zcomp_strm_release()) one for us
+ */
+static struct zcomp_strm *zcomp_strm_multi_find(struct zcomp *comp)
+{
+ struct zcomp_strm_multi *zs = comp->stream;
+ struct zcomp_strm *zstrm;
+
+ while (1) {
+ spin_lock(&zs->strm_lock);
+ if (!list_empty(&zs->idle_strm)) {
+ zstrm = list_entry(zs->idle_strm.next,
+ struct zcomp_strm, list);
+ list_del(&zstrm->list);
+ spin_unlock(&zs->strm_lock);
+ return zstrm;
+ }
+ /* zstrm streams limit reached, wait for idle stream */
+ if (zs->avail_strm >= zs->max_strm) {
+ spin_unlock(&zs->strm_lock);
+ wait_event(zs->strm_wait, !list_empty(&zs->idle_strm));
+ continue;
+ }
+ /* allocate new zstrm stream */
+ zs->avail_strm++;
+ spin_unlock(&zs->strm_lock);
+
+ zstrm = zcomp_strm_alloc(comp);
+ if (!zstrm) {
+ spin_lock(&zs->strm_lock);
+ zs->avail_strm--;
+ spin_unlock(&zs->strm_lock);
+ wait_event(zs->strm_wait, !list_empty(&zs->idle_strm));
+ continue;
+ }
+ break;
+ }
+ return zstrm;
+}
+
+/* add stream back to idle list and wake up waiter or free the stream */
+static void zcomp_strm_multi_release(struct zcomp *comp, struct zcomp_strm *zstrm)
+{
+ struct zcomp_strm_multi *zs = comp->stream;
+
+ spin_lock(&zs->strm_lock);
+ if (zs->avail_strm <= zs->max_strm) {
+ list_add(&zstrm->list, &zs->idle_strm);
+ spin_unlock(&zs->strm_lock);
+ wake_up(&zs->strm_wait);
+ return;
+ }
+
+ zs->avail_strm--;
+ spin_unlock(&zs->strm_lock);
+ zcomp_strm_free(comp, zstrm);
+}
+
+/* change max_strm limit */
+static bool zcomp_strm_multi_set_max_streams(struct zcomp *comp, int num_strm)
+{
+ struct zcomp_strm_multi *zs = comp->stream;
+ struct zcomp_strm *zstrm;
+
+ spin_lock(&zs->strm_lock);
+ zs->max_strm = num_strm;
+ /*
+ * if user has lowered the limit and there are idle streams,
+ * immediately free as much streams (and memory) as we can.
+ */
+ while (zs->avail_strm > num_strm && !list_empty(&zs->idle_strm)) {
+ zstrm = list_entry(zs->idle_strm.next,
+ struct zcomp_strm, list);
+ list_del(&zstrm->list);
+ zcomp_strm_free(comp, zstrm);
+ zs->avail_strm--;
+ }
+ spin_unlock(&zs->strm_lock);
+ return true;
+}
+
+static void zcomp_strm_multi_destroy(struct zcomp *comp)
+{
+ struct zcomp_strm_multi *zs = comp->stream;
+ struct zcomp_strm *zstrm;
+
+ while (!list_empty(&zs->idle_strm)) {
+ zstrm = list_entry(zs->idle_strm.next,
+ struct zcomp_strm, list);
+ list_del(&zstrm->list);
+ zcomp_strm_free(comp, zstrm);
+ }
+ kfree(zs);
+}
+
+static int zcomp_strm_multi_create(struct zcomp *comp, int max_strm)
+{
+ struct zcomp_strm *zstrm;
+ struct zcomp_strm_multi *zs;
+
+ comp->destroy = zcomp_strm_multi_destroy;
+ comp->strm_find = zcomp_strm_multi_find;
+ comp->strm_release = zcomp_strm_multi_release;
+ comp->set_max_streams = zcomp_strm_multi_set_max_streams;
+ zs = kmalloc(sizeof(struct zcomp_strm_multi), GFP_KERNEL);
+ if (!zs)
+ return -ENOMEM;
+
+ comp->stream = zs;
+ spin_lock_init(&zs->strm_lock);
+ INIT_LIST_HEAD(&zs->idle_strm);
+ init_waitqueue_head(&zs->strm_wait);
+ zs->max_strm = max_strm;
+ zs->avail_strm = 1;
+
+ zstrm = zcomp_strm_alloc(comp);
+ if (!zstrm) {
+ kfree(zs);
+ return -ENOMEM;
+ }
+ list_add(&zstrm->list, &zs->idle_strm);
+ return 0;
+}
+
+static struct zcomp_strm *zcomp_strm_single_find(struct zcomp *comp)
+{
+ struct zcomp_strm_single *zs = comp->stream;
+ mutex_lock(&zs->strm_lock);
+ return zs->zstrm;
+}
+
+static void zcomp_strm_single_release(struct zcomp *comp,
+ struct zcomp_strm *zstrm)
+{
+ struct zcomp_strm_single *zs = comp->stream;
+ mutex_unlock(&zs->strm_lock);
+}
+
+static bool zcomp_strm_single_set_max_streams(struct zcomp *comp, int num_strm)
+{
+ /* zcomp_strm_single support only max_comp_streams == 1 */
+ return false;
+}
+
+static void zcomp_strm_single_destroy(struct zcomp *comp)
+{
+ struct zcomp_strm_single *zs = comp->stream;
+ zcomp_strm_free(comp, zs->zstrm);
+ kfree(zs);
+}
+
+static int zcomp_strm_single_create(struct zcomp *comp)
+{
+ struct zcomp_strm_single *zs;
+
+ comp->destroy = zcomp_strm_single_destroy;
+ comp->strm_find = zcomp_strm_single_find;
+ comp->strm_release = zcomp_strm_single_release;
+ comp->set_max_streams = zcomp_strm_single_set_max_streams;
+ zs = kmalloc(sizeof(struct zcomp_strm_single), GFP_KERNEL);
+ if (!zs)
+ return -ENOMEM;
+
+ comp->stream = zs;
+ mutex_init(&zs->strm_lock);
+ zs->zstrm = zcomp_strm_alloc(comp);
+ if (!zs->zstrm) {
+ kfree(zs);
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+/* show available compressors */
+ssize_t zcomp_available_show(const char *comp, char *buf)
+{
+ ssize_t sz = 0;
+ int i = 0;
+
+ while (backends[i]) {
+ if (sysfs_streq(comp, backends[i]->name))
+ sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
+ "[%s] ", backends[i]->name);
+ else
+ sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
+ "%s ", backends[i]->name);
+ i++;
+ }
+ sz += scnprintf(buf + sz, PAGE_SIZE - sz, "\n");
+ return sz;
+}
+
+bool zcomp_set_max_streams(struct zcomp *comp, int num_strm)
+{
+ return comp->set_max_streams(comp, num_strm);
+}
+
+struct zcomp_strm *zcomp_strm_find(struct zcomp *comp)
+{
+ return comp->strm_find(comp);
+}
+
+void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm)
+{
+ comp->strm_release(comp, zstrm);
+}
+
+int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
+ const unsigned char *src, size_t *dst_len)
+{
+ return comp->backend->compress(src, zstrm->buffer, dst_len,
+ zstrm->private);
+}
+
+int zcomp_decompress(struct zcomp *comp, const unsigned char *src,
+ size_t src_len, unsigned char *dst)
+{
+ return comp->backend->decompress(src, src_len, dst);
+}
+
+void zcomp_destroy(struct zcomp *comp)
+{
+ comp->destroy(comp);
+ kfree(comp);
+}
+
+/*
+ * search available compressors for requested algorithm.
+ * allocate new zcomp and initialize it. return compressing
+ * backend pointer or ERR_PTR if things went bad. ERR_PTR(-EINVAL)
+ * if requested algorithm is not supported, ERR_PTR(-ENOMEM) in
+ * case of allocation error.
+ */
+struct zcomp *zcomp_create(const char *compress, int max_strm)
+{
+ struct zcomp *comp;
+ struct zcomp_backend *backend;
+
+ backend = find_backend(compress);
+ if (!backend)
+ return ERR_PTR(-EINVAL);
+
+ comp = kzalloc(sizeof(struct zcomp), GFP_KERNEL);
+ if (!comp)
+ return ERR_PTR(-ENOMEM);
+
+ comp->backend = backend;
+ if (max_strm > 1)
+ zcomp_strm_multi_create(comp, max_strm);
+ else
+ zcomp_strm_single_create(comp);
+ if (!comp->stream) {
+ kfree(comp);
+ return ERR_PTR(-ENOMEM);
+ }
+ return comp;
+}
diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h
new file mode 100644
index 000000000..c59d1fca7
--- /dev/null
+++ b/drivers/block/zram/zcomp.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2014 Sergey Senozhatsky.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _ZCOMP_H_
+#define _ZCOMP_H_
+
+#include <linux/mutex.h>
+
+struct zcomp_strm {
+ /* compression/decompression buffer */
+ void *buffer;
+ /*
+ * The private data of the compression stream, only compression
+ * stream backend can touch this (e.g. compression algorithm
+ * working memory)
+ */
+ void *private;
+ /* used in multi stream backend, protected by backend strm_lock */
+ struct list_head list;
+};
+
+/* static compression backend */
+struct zcomp_backend {
+ int (*compress)(const unsigned char *src, unsigned char *dst,
+ size_t *dst_len, void *private);
+
+ int (*decompress)(const unsigned char *src, size_t src_len,
+ unsigned char *dst);
+
+ void *(*create)(void);
+ void (*destroy)(void *private);
+
+ const char *name;
+};
+
+/* dynamic per-device compression frontend */
+struct zcomp {
+ void *stream;
+ struct zcomp_backend *backend;
+
+ struct zcomp_strm *(*strm_find)(struct zcomp *comp);
+ void (*strm_release)(struct zcomp *comp, struct zcomp_strm *zstrm);
+ bool (*set_max_streams)(struct zcomp *comp, int num_strm);
+ void (*destroy)(struct zcomp *comp);
+};
+
+ssize_t zcomp_available_show(const char *comp, char *buf);
+
+struct zcomp *zcomp_create(const char *comp, int max_strm);
+void zcomp_destroy(struct zcomp *comp);
+
+struct zcomp_strm *zcomp_strm_find(struct zcomp *comp);
+void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm);
+
+int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
+ const unsigned char *src, size_t *dst_len);
+
+int zcomp_decompress(struct zcomp *comp, const unsigned char *src,
+ size_t src_len, unsigned char *dst);
+
+bool zcomp_set_max_streams(struct zcomp *comp, int num_strm);
+#endif /* _ZCOMP_H_ */
diff --git a/drivers/block/zram/zcomp_lz4.c b/drivers/block/zram/zcomp_lz4.c
new file mode 100644
index 000000000..f2afb7e98
--- /dev/null
+++ b/drivers/block/zram/zcomp_lz4.c
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2014 Sergey Senozhatsky.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/lz4.h>
+
+#include "zcomp_lz4.h"
+
+static void *zcomp_lz4_create(void)
+{
+ return kzalloc(LZ4_MEM_COMPRESS, GFP_KERNEL);
+}
+
+static void zcomp_lz4_destroy(void *private)
+{
+ kfree(private);
+}
+
+static int zcomp_lz4_compress(const unsigned char *src, unsigned char *dst,
+ size_t *dst_len, void *private)
+{
+ /* return : Success if return 0 */
+ return lz4_compress(src, PAGE_SIZE, dst, dst_len, private);
+}
+
+static int zcomp_lz4_decompress(const unsigned char *src, size_t src_len,
+ unsigned char *dst)
+{
+ size_t dst_len = PAGE_SIZE;
+ /* return : Success if return 0 */
+ return lz4_decompress_unknownoutputsize(src, src_len, dst, &dst_len);
+}
+
+struct zcomp_backend zcomp_lz4 = {
+ .compress = zcomp_lz4_compress,
+ .decompress = zcomp_lz4_decompress,
+ .create = zcomp_lz4_create,
+ .destroy = zcomp_lz4_destroy,
+ .name = "lz4",
+};
diff --git a/drivers/block/zram/zcomp_lz4.h b/drivers/block/zram/zcomp_lz4.h
new file mode 100644
index 000000000..60613fb29
--- /dev/null
+++ b/drivers/block/zram/zcomp_lz4.h
@@ -0,0 +1,17 @@
+/*
+ * Copyright (C) 2014 Sergey Senozhatsky.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _ZCOMP_LZ4_H_
+#define _ZCOMP_LZ4_H_
+
+#include "zcomp.h"
+
+extern struct zcomp_backend zcomp_lz4;
+
+#endif /* _ZCOMP_LZ4_H_ */
diff --git a/drivers/block/zram/zcomp_lzo.c b/drivers/block/zram/zcomp_lzo.c
new file mode 100644
index 000000000..da1bc47d5
--- /dev/null
+++ b/drivers/block/zram/zcomp_lzo.c
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2014 Sergey Senozhatsky.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/lzo.h>
+
+#include "zcomp_lzo.h"
+
+static void *lzo_create(void)
+{
+ return kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
+}
+
+static void lzo_destroy(void *private)
+{
+ kfree(private);
+}
+
+static int lzo_compress(const unsigned char *src, unsigned char *dst,
+ size_t *dst_len, void *private)
+{
+ int ret = lzo1x_1_compress(src, PAGE_SIZE, dst, dst_len, private);
+ return ret == LZO_E_OK ? 0 : ret;
+}
+
+static int lzo_decompress(const unsigned char *src, size_t src_len,
+ unsigned char *dst)
+{
+ size_t dst_len = PAGE_SIZE;
+ int ret = lzo1x_decompress_safe(src, src_len, dst, &dst_len);
+ return ret == LZO_E_OK ? 0 : ret;
+}
+
+struct zcomp_backend zcomp_lzo = {
+ .compress = lzo_compress,
+ .decompress = lzo_decompress,
+ .create = lzo_create,
+ .destroy = lzo_destroy,
+ .name = "lzo",
+};
diff --git a/drivers/block/zram/zcomp_lzo.h b/drivers/block/zram/zcomp_lzo.h
new file mode 100644
index 000000000..128c5807f
--- /dev/null
+++ b/drivers/block/zram/zcomp_lzo.h
@@ -0,0 +1,17 @@
+/*
+ * Copyright (C) 2014 Sergey Senozhatsky.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _ZCOMP_LZO_H_
+#define _ZCOMP_LZO_H_
+
+#include "zcomp.h"
+
+extern struct zcomp_backend zcomp_lzo;
+
+#endif /* _ZCOMP_LZO_H_ */
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
new file mode 100644
index 000000000..6e134f475
--- /dev/null
+++ b/drivers/block/zram/zram_drv.c
@@ -0,0 +1,1322 @@
+/*
+ * Compressed RAM block device
+ *
+ * Copyright (C) 2008, 2009, 2010 Nitin Gupta
+ * 2012, 2013 Minchan Kim
+ *
+ * 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
+ *
+ */
+
+#define KMSG_COMPONENT "zram"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#ifdef CONFIG_ZRAM_DEBUG
+#define DEBUG
+#endif
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/bio.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/slab.h>
+#include <linux/string.h>
+#include <linux/vmalloc.h>
+#include <linux/err.h>
+
+#include "zram_drv.h"
+
+/* Globals */
+static int zram_major;
+static struct zram *zram_devices;
+static const char *default_compressor = "lzo";
+
+/* Module params (documentation at end) */
+static unsigned int num_devices = 1;
+
+static inline void deprecated_attr_warn(const char *name)
+{
+ pr_warn_once("%d (%s) Attribute %s (and others) will be removed. %s\n",
+ task_pid_nr(current),
+ current->comm,
+ name,
+ "See zram documentation.");
+}
+
+#define ZRAM_ATTR_RO(name) \
+static ssize_t name##_show(struct device *d, \
+ struct device_attribute *attr, char *b) \
+{ \
+ struct zram *zram = dev_to_zram(d); \
+ \
+ deprecated_attr_warn(__stringify(name)); \
+ return scnprintf(b, PAGE_SIZE, "%llu\n", \
+ (u64)atomic64_read(&zram->stats.name)); \
+} \
+static DEVICE_ATTR_RO(name);
+
+static inline bool init_done(struct zram *zram)
+{
+ return zram->disksize;
+}
+
+static inline struct zram *dev_to_zram(struct device *dev)
+{
+ return (struct zram *)dev_to_disk(dev)->private_data;
+}
+
+static ssize_t compact_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ unsigned long nr_migrated;
+ struct zram *zram = dev_to_zram(dev);
+ struct zram_meta *meta;
+
+ down_read(&zram->init_lock);
+ if (!init_done(zram)) {
+ up_read(&zram->init_lock);
+ return -EINVAL;
+ }
+
+ meta = zram->meta;
+ nr_migrated = zs_compact(meta->mem_pool);
+ atomic64_add(nr_migrated, &zram->stats.num_migrated);
+ up_read(&zram->init_lock);
+
+ return len;
+}
+
+static ssize_t disksize_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct zram *zram = dev_to_zram(dev);
+
+ return scnprintf(buf, PAGE_SIZE, "%llu\n", zram->disksize);
+}
+
+static ssize_t initstate_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ u32 val;
+ struct zram *zram = dev_to_zram(dev);
+
+ down_read(&zram->init_lock);
+ val = init_done(zram);
+ up_read(&zram->init_lock);
+
+ return scnprintf(buf, PAGE_SIZE, "%u\n", val);
+}
+
+static ssize_t orig_data_size_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct zram *zram = dev_to_zram(dev);
+
+ deprecated_attr_warn("orig_data_size");
+ return scnprintf(buf, PAGE_SIZE, "%llu\n",
+ (u64)(atomic64_read(&zram->stats.pages_stored)) << PAGE_SHIFT);
+}
+
+static ssize_t mem_used_total_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ u64 val = 0;
+ struct zram *zram = dev_to_zram(dev);
+
+ deprecated_attr_warn("mem_used_total");
+ down_read(&zram->init_lock);
+ if (init_done(zram)) {
+ struct zram_meta *meta = zram->meta;
+ val = zs_get_total_pages(meta->mem_pool);
+ }
+ up_read(&zram->init_lock);
+
+ return scnprintf(buf, PAGE_SIZE, "%llu\n", val << PAGE_SHIFT);
+}
+
+static ssize_t max_comp_streams_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ int val;
+ struct zram *zram = dev_to_zram(dev);
+
+ down_read(&zram->init_lock);
+ val = zram->max_comp_streams;
+ up_read(&zram->init_lock);
+
+ return scnprintf(buf, PAGE_SIZE, "%d\n", val);
+}
+
+static ssize_t mem_limit_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ u64 val;
+ struct zram *zram = dev_to_zram(dev);
+
+ deprecated_attr_warn("mem_limit");
+ down_read(&zram->init_lock);
+ val = zram->limit_pages;
+ up_read(&zram->init_lock);
+
+ return scnprintf(buf, PAGE_SIZE, "%llu\n", val << PAGE_SHIFT);
+}
+
+static ssize_t mem_limit_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ u64 limit;
+ char *tmp;
+ struct zram *zram = dev_to_zram(dev);
+
+ limit = memparse(buf, &tmp);
+ if (buf == tmp) /* no chars parsed, invalid input */
+ return -EINVAL;
+
+ down_write(&zram->init_lock);
+ zram->limit_pages = PAGE_ALIGN(limit) >> PAGE_SHIFT;
+ up_write(&zram->init_lock);
+
+ return len;
+}
+
+static ssize_t mem_used_max_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ u64 val = 0;
+ struct zram *zram = dev_to_zram(dev);
+
+ deprecated_attr_warn("mem_used_max");
+ down_read(&zram->init_lock);
+ if (init_done(zram))
+ val = atomic_long_read(&zram->stats.max_used_pages);
+ up_read(&zram->init_lock);
+
+ return scnprintf(buf, PAGE_SIZE, "%llu\n", val << PAGE_SHIFT);
+}
+
+static ssize_t mem_used_max_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ int err;
+ unsigned long val;
+ struct zram *zram = dev_to_zram(dev);
+
+ err = kstrtoul(buf, 10, &val);
+ if (err || val != 0)
+ return -EINVAL;
+
+ down_read(&zram->init_lock);
+ if (init_done(zram)) {
+ struct zram_meta *meta = zram->meta;
+ atomic_long_set(&zram->stats.max_used_pages,
+ zs_get_total_pages(meta->mem_pool));
+ }
+ up_read(&zram->init_lock);
+
+ return len;
+}
+
+static ssize_t max_comp_streams_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ int num;
+ struct zram *zram = dev_to_zram(dev);
+ int ret;
+
+ ret = kstrtoint(buf, 0, &num);
+ if (ret < 0)
+ return ret;
+ if (num < 1)
+ return -EINVAL;
+
+ down_write(&zram->init_lock);
+ if (init_done(zram)) {
+ if (!zcomp_set_max_streams(zram->comp, num)) {
+ pr_info("Cannot change max compression streams\n");
+ ret = -EINVAL;
+ goto out;
+ }
+ }
+
+ zram->max_comp_streams = num;
+ ret = len;
+out:
+ up_write(&zram->init_lock);
+ return ret;
+}
+
+static ssize_t comp_algorithm_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ size_t sz;
+ struct zram *zram = dev_to_zram(dev);
+
+ down_read(&zram->init_lock);
+ sz = zcomp_available_show(zram->compressor, buf);
+ up_read(&zram->init_lock);
+
+ return sz;
+}
+
+static ssize_t comp_algorithm_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ struct zram *zram = dev_to_zram(dev);
+ down_write(&zram->init_lock);
+ if (init_done(zram)) {
+ up_write(&zram->init_lock);
+ pr_info("Can't change algorithm for initialized device\n");
+ return -EBUSY;
+ }
+ strlcpy(zram->compressor, buf, sizeof(zram->compressor));
+ up_write(&zram->init_lock);
+ return len;
+}
+
+/* flag operations needs meta->tb_lock */
+static int zram_test_flag(struct zram_meta *meta, u32 index,
+ enum zram_pageflags flag)
+{
+ return meta->table[index].value & BIT(flag);
+}
+
+static void zram_set_flag(struct zram_meta *meta, u32 index,
+ enum zram_pageflags flag)
+{
+ meta->table[index].value |= BIT(flag);
+}
+
+static void zram_clear_flag(struct zram_meta *meta, u32 index,
+ enum zram_pageflags flag)
+{
+ meta->table[index].value &= ~BIT(flag);
+}
+
+static size_t zram_get_obj_size(struct zram_meta *meta, u32 index)
+{
+ return meta->table[index].value & (BIT(ZRAM_FLAG_SHIFT) - 1);
+}
+
+static void zram_set_obj_size(struct zram_meta *meta,
+ u32 index, size_t size)
+{
+ unsigned long flags = meta->table[index].value >> ZRAM_FLAG_SHIFT;
+
+ meta->table[index].value = (flags << ZRAM_FLAG_SHIFT) | size;
+}
+
+static inline int is_partial_io(struct bio_vec *bvec)
+{
+ return bvec->bv_len != PAGE_SIZE;
+}
+
+/*
+ * Check if request is within bounds and aligned on zram logical blocks.
+ */
+static inline int valid_io_request(struct zram *zram,
+ sector_t start, unsigned int size)
+{
+ u64 end, bound;
+
+ /* unaligned request */
+ if (unlikely(start & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1)))
+ return 0;
+ if (unlikely(size & (ZRAM_LOGICAL_BLOCK_SIZE - 1)))
+ return 0;
+
+ end = start + (size >> SECTOR_SHIFT);
+ bound = zram->disksize >> SECTOR_SHIFT;
+ /* out of range range */
+ if (unlikely(start >= bound || end > bound || start > end))
+ return 0;
+
+ /* I/O request is valid */
+ return 1;
+}
+
+static void zram_meta_free(struct zram_meta *meta, u64 disksize)
+{
+ size_t num_pages = disksize >> PAGE_SHIFT;
+ size_t index;
+
+ /* Free all pages that are still in this zram device */
+ for (index = 0; index < num_pages; index++) {
+ unsigned long handle = meta->table[index].handle;
+
+ if (!handle)
+ continue;
+
+ zs_free(meta->mem_pool, handle);
+ }
+
+ zs_destroy_pool(meta->mem_pool);
+ vfree(meta->table);
+ kfree(meta);
+}
+
+static struct zram_meta *zram_meta_alloc(int device_id, u64 disksize)
+{
+ size_t num_pages;
+ char pool_name[8];
+ struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL);
+
+ if (!meta)
+ return NULL;
+
+ num_pages = disksize >> PAGE_SHIFT;
+ meta->table = vzalloc(num_pages * sizeof(*meta->table));
+ if (!meta->table) {
+ pr_err("Error allocating zram address table\n");
+ goto out_error;
+ }
+
+ snprintf(pool_name, sizeof(pool_name), "zram%d", device_id);
+ meta->mem_pool = zs_create_pool(pool_name, GFP_NOIO | __GFP_HIGHMEM);
+ if (!meta->mem_pool) {
+ pr_err("Error creating memory pool\n");
+ goto out_error;
+ }
+
+ return meta;
+
+out_error:
+ vfree(meta->table);
+ kfree(meta);
+ return NULL;
+}
+
+static inline bool zram_meta_get(struct zram *zram)
+{
+ if (atomic_inc_not_zero(&zram->refcount))
+ return true;
+ return false;
+}
+
+static inline void zram_meta_put(struct zram *zram)
+{
+ atomic_dec(&zram->refcount);
+}
+
+static void update_position(u32 *index, int *offset, struct bio_vec *bvec)
+{
+ if (*offset + bvec->bv_len >= PAGE_SIZE)
+ (*index)++;
+ *offset = (*offset + bvec->bv_len) % PAGE_SIZE;
+}
+
+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;
+}
+
+static void handle_zero_page(struct bio_vec *bvec)
+{
+ struct page *page = bvec->bv_page;
+ void *user_mem;
+
+ user_mem = kmap_atomic(page);
+ if (is_partial_io(bvec))
+ memset(user_mem + bvec->bv_offset, 0, bvec->bv_len);
+ else
+ clear_page(user_mem);
+ kunmap_atomic(user_mem);
+
+ flush_dcache_page(page);
+}
+
+
+/*
+ * To protect concurrent access to the same index entry,
+ * caller should hold this table index entry's bit_spinlock to
+ * indicate this index entry is accessing.
+ */
+static void zram_free_page(struct zram *zram, size_t index)
+{
+ struct zram_meta *meta = zram->meta;
+ unsigned long handle = meta->table[index].handle;
+
+ if (unlikely(!handle)) {
+ /*
+ * No memory is allocated for zero filled pages.
+ * Simply clear zero page flag.
+ */
+ if (zram_test_flag(meta, index, ZRAM_ZERO)) {
+ zram_clear_flag(meta, index, ZRAM_ZERO);
+ atomic64_dec(&zram->stats.zero_pages);
+ }
+ return;
+ }
+
+ zs_free(meta->mem_pool, handle);
+
+ atomic64_sub(zram_get_obj_size(meta, index),
+ &zram->stats.compr_data_size);
+ atomic64_dec(&zram->stats.pages_stored);
+
+ meta->table[index].handle = 0;
+ zram_set_obj_size(meta, index, 0);
+}
+
+static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
+{
+ int ret = 0;
+ unsigned char *cmem;
+ struct zram_meta *meta = zram->meta;
+ unsigned long handle;
+ size_t size;
+
+ bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ handle = meta->table[index].handle;
+ size = zram_get_obj_size(meta, index);
+
+ if (!handle || zram_test_flag(meta, index, ZRAM_ZERO)) {
+ bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+ clear_page(mem);
+ return 0;
+ }
+
+ cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_RO);
+ if (size == PAGE_SIZE)
+ copy_page(mem, cmem);
+ else
+ ret = zcomp_decompress(zram->comp, cmem, size, mem);
+ zs_unmap_object(meta->mem_pool, handle);
+ bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+
+ /* Should NEVER happen. Return bio error if it does. */
+ if (unlikely(ret)) {
+ pr_err("Decompression failed! err=%d, page=%u\n", ret, index);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
+ u32 index, int offset)
+{
+ int ret;
+ struct page *page;
+ unsigned char *user_mem, *uncmem = NULL;
+ struct zram_meta *meta = zram->meta;
+ page = bvec->bv_page;
+
+ bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ if (unlikely(!meta->table[index].handle) ||
+ zram_test_flag(meta, index, ZRAM_ZERO)) {
+ bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+ handle_zero_page(bvec);
+ return 0;
+ }
+ bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+
+ if (is_partial_io(bvec))
+ /* Use a temporary buffer to decompress the page */
+ uncmem = kmalloc(PAGE_SIZE, GFP_NOIO);
+
+ user_mem = kmap_atomic(page);
+ if (!is_partial_io(bvec))
+ uncmem = user_mem;
+
+ if (!uncmem) {
+ pr_info("Unable to allocate temp memory\n");
+ ret = -ENOMEM;
+ goto out_cleanup;
+ }
+
+ ret = zram_decompress_page(zram, uncmem, index);
+ /* Should NEVER happen. Return bio error if it does. */
+ if (unlikely(ret))
+ goto out_cleanup;
+
+ if (is_partial_io(bvec))
+ memcpy(user_mem + bvec->bv_offset, uncmem + offset,
+ bvec->bv_len);
+
+ flush_dcache_page(page);
+ ret = 0;
+out_cleanup:
+ kunmap_atomic(user_mem);
+ if (is_partial_io(bvec))
+ kfree(uncmem);
+ return ret;
+}
+
+static inline void update_used_max(struct zram *zram,
+ const unsigned long pages)
+{
+ unsigned long old_max, cur_max;
+
+ old_max = atomic_long_read(&zram->stats.max_used_pages);
+
+ do {
+ cur_max = old_max;
+ if (pages > cur_max)
+ old_max = atomic_long_cmpxchg(
+ &zram->stats.max_used_pages, cur_max, pages);
+ } while (old_max != cur_max);
+}
+
+static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
+ int offset)
+{
+ int ret = 0;
+ size_t clen;
+ unsigned long handle;
+ struct page *page;
+ unsigned char *user_mem, *cmem, *src, *uncmem = NULL;
+ struct zram_meta *meta = zram->meta;
+ struct zcomp_strm *zstrm;
+ bool locked = false;
+ unsigned long alloced_pages;
+
+ page = bvec->bv_page;
+ if (is_partial_io(bvec)) {
+ /*
+ * This is a partial IO. We need to read the full page
+ * before to write the changes.
+ */
+ uncmem = kmalloc(PAGE_SIZE, GFP_NOIO);
+ if (!uncmem) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ ret = zram_decompress_page(zram, uncmem, index);
+ if (ret)
+ goto out;
+ }
+
+ zstrm = zcomp_strm_find(zram->comp);
+ locked = true;
+ user_mem = kmap_atomic(page);
+
+ if (is_partial_io(bvec)) {
+ memcpy(uncmem + offset, user_mem + bvec->bv_offset,
+ bvec->bv_len);
+ kunmap_atomic(user_mem);
+ user_mem = NULL;
+ } else {
+ uncmem = user_mem;
+ }
+
+ if (page_zero_filled(uncmem)) {
+ if (user_mem)
+ kunmap_atomic(user_mem);
+ /* Free memory associated with this sector now. */
+ bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_free_page(zram, index);
+ zram_set_flag(meta, index, ZRAM_ZERO);
+ bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+
+ atomic64_inc(&zram->stats.zero_pages);
+ ret = 0;
+ goto out;
+ }
+
+ ret = zcomp_compress(zram->comp, zstrm, uncmem, &clen);
+ if (!is_partial_io(bvec)) {
+ kunmap_atomic(user_mem);
+ user_mem = NULL;
+ uncmem = NULL;
+ }
+
+ if (unlikely(ret)) {
+ pr_err("Compression failed! err=%d\n", ret);
+ goto out;
+ }
+ src = zstrm->buffer;
+ if (unlikely(clen > max_zpage_size)) {
+ clen = PAGE_SIZE;
+ if (is_partial_io(bvec))
+ src = uncmem;
+ }
+
+ handle = zs_malloc(meta->mem_pool, clen);
+ if (!handle) {
+ pr_info("Error allocating memory for compressed page: %u, size=%zu\n",
+ index, clen);
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ alloced_pages = zs_get_total_pages(meta->mem_pool);
+ if (zram->limit_pages && alloced_pages > zram->limit_pages) {
+ zs_free(meta->mem_pool, handle);
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ update_used_max(zram, alloced_pages);
+
+ cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_WO);
+
+ if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) {
+ src = kmap_atomic(page);
+ copy_page(cmem, src);
+ kunmap_atomic(src);
+ } else {
+ memcpy(cmem, src, clen);
+ }
+
+ zcomp_strm_release(zram->comp, zstrm);
+ locked = false;
+ zs_unmap_object(meta->mem_pool, handle);
+
+ /*
+ * Free memory associated with this sector
+ * before overwriting unused sectors.
+ */
+ bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_free_page(zram, index);
+
+ meta->table[index].handle = handle;
+ zram_set_obj_size(meta, index, clen);
+ bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+
+ /* Update stats */
+ atomic64_add(clen, &zram->stats.compr_data_size);
+ atomic64_inc(&zram->stats.pages_stored);
+out:
+ if (locked)
+ zcomp_strm_release(zram->comp, zstrm);
+ if (is_partial_io(bvec))
+ kfree(uncmem);
+ return ret;
+}
+
+static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
+ int offset, int rw)
+{
+ unsigned long start_time = jiffies;
+ int ret;
+
+ generic_start_io_acct(rw, bvec->bv_len >> SECTOR_SHIFT,
+ &zram->disk->part0);
+
+ if (rw == READ) {
+ atomic64_inc(&zram->stats.num_reads);
+ ret = zram_bvec_read(zram, bvec, index, offset);
+ } else {
+ atomic64_inc(&zram->stats.num_writes);
+ ret = zram_bvec_write(zram, bvec, index, offset);
+ }
+
+ generic_end_io_acct(rw, &zram->disk->part0, start_time);
+
+ if (unlikely(ret)) {
+ if (rw == READ)
+ atomic64_inc(&zram->stats.failed_reads);
+ else
+ atomic64_inc(&zram->stats.failed_writes);
+ }
+
+ return ret;
+}
+
+/*
+ * zram_bio_discard - handler on discard request
+ * @index: physical block index in PAGE_SIZE units
+ * @offset: byte offset within physical block
+ */
+static void zram_bio_discard(struct zram *zram, u32 index,
+ int offset, struct bio *bio)
+{
+ size_t n = bio->bi_iter.bi_size;
+ struct zram_meta *meta = zram->meta;
+
+ /*
+ * zram manages data in physical block size units. Because logical block
+ * size isn't identical with physical block size on some arch, we
+ * could get a discard request pointing to a specific offset within a
+ * certain physical block. Although we can handle this request by
+ * reading that physiclal block and decompressing and partially zeroing
+ * and re-compressing and then re-storing it, this isn't reasonable
+ * because our intent with a discard request is to save memory. So
+ * skipping this logical block is appropriate here.
+ */
+ if (offset) {
+ if (n <= (PAGE_SIZE - offset))
+ return;
+
+ n -= (PAGE_SIZE - offset);
+ index++;
+ }
+
+ while (n >= PAGE_SIZE) {
+ bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_free_page(zram, index);
+ bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+ atomic64_inc(&zram->stats.notify_free);
+ index++;
+ n -= PAGE_SIZE;
+ }
+}
+
+static void zram_reset_device(struct zram *zram)
+{
+ struct zram_meta *meta;
+ struct zcomp *comp;
+ u64 disksize;
+
+ down_write(&zram->init_lock);
+
+ zram->limit_pages = 0;
+
+ if (!init_done(zram)) {
+ up_write(&zram->init_lock);
+ return;
+ }
+
+ meta = zram->meta;
+ comp = zram->comp;
+ disksize = zram->disksize;
+ /*
+ * Refcount will go down to 0 eventually and r/w handler
+ * cannot handle further I/O so it will bail out by
+ * check zram_meta_get.
+ */
+ zram_meta_put(zram);
+ /*
+ * We want to free zram_meta in process context to avoid
+ * deadlock between reclaim path and any other locks.
+ */
+ wait_event(zram->io_done, atomic_read(&zram->refcount) == 0);
+
+ /* Reset stats */
+ memset(&zram->stats, 0, sizeof(zram->stats));
+ zram->disksize = 0;
+ zram->max_comp_streams = 1;
+
+ set_capacity(zram->disk, 0);
+ part_stat_set_all(&zram->disk->part0, 0);
+
+ up_write(&zram->init_lock);
+ /* I/O operation under all of CPU are done so let's free */
+ zram_meta_free(meta, disksize);
+ zcomp_destroy(comp);
+}
+
+static ssize_t disksize_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ u64 disksize;
+ struct zcomp *comp;
+ struct zram_meta *meta;
+ struct zram *zram = dev_to_zram(dev);
+ int err;
+
+ disksize = memparse(buf, NULL);
+ if (!disksize)
+ return -EINVAL;
+
+ disksize = PAGE_ALIGN(disksize);
+ meta = zram_meta_alloc(zram->disk->first_minor, disksize);
+ if (!meta)
+ return -ENOMEM;
+
+ comp = zcomp_create(zram->compressor, zram->max_comp_streams);
+ if (IS_ERR(comp)) {
+ pr_info("Cannot initialise %s compressing backend\n",
+ zram->compressor);
+ err = PTR_ERR(comp);
+ goto out_free_meta;
+ }
+
+ down_write(&zram->init_lock);
+ if (init_done(zram)) {
+ pr_info("Cannot change disksize for initialized device\n");
+ err = -EBUSY;
+ goto out_destroy_comp;
+ }
+
+ init_waitqueue_head(&zram->io_done);
+ atomic_set(&zram->refcount, 1);
+ zram->meta = meta;
+ zram->comp = comp;
+ zram->disksize = disksize;
+ set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
+ up_write(&zram->init_lock);
+
+ /*
+ * Revalidate disk out of the init_lock to avoid lockdep splat.
+ * It's okay because disk's capacity is protected by init_lock
+ * so that revalidate_disk always sees up-to-date capacity.
+ */
+ revalidate_disk(zram->disk);
+
+ return len;
+
+out_destroy_comp:
+ up_write(&zram->init_lock);
+ zcomp_destroy(comp);
+out_free_meta:
+ zram_meta_free(meta, disksize);
+ return err;
+}
+
+static ssize_t reset_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t len)
+{
+ int ret;
+ unsigned short do_reset;
+ struct zram *zram;
+ struct block_device *bdev;
+
+ zram = dev_to_zram(dev);
+ bdev = bdget_disk(zram->disk, 0);
+
+ if (!bdev)
+ return -ENOMEM;
+
+ mutex_lock(&bdev->bd_mutex);
+ /* Do not reset an active device! */
+ if (bdev->bd_openers) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ ret = kstrtou16(buf, 10, &do_reset);
+ if (ret)
+ goto out;
+
+ if (!do_reset) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* Make sure all pending I/O is finished */
+ fsync_bdev(bdev);
+ zram_reset_device(zram);
+
+ mutex_unlock(&bdev->bd_mutex);
+ revalidate_disk(zram->disk);
+ bdput(bdev);
+
+ return len;
+
+out:
+ mutex_unlock(&bdev->bd_mutex);
+ bdput(bdev);
+ return ret;
+}
+
+static void __zram_make_request(struct zram *zram, struct bio *bio)
+{
+ int offset, rw;
+ u32 index;
+ struct bio_vec bvec;
+ struct bvec_iter iter;
+
+ index = bio->bi_iter.bi_sector >> SECTORS_PER_PAGE_SHIFT;
+ offset = (bio->bi_iter.bi_sector &
+ (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT;
+
+ if (unlikely(bio->bi_rw & REQ_DISCARD)) {
+ zram_bio_discard(zram, index, offset, bio);
+ bio_endio(bio, 0);
+ return;
+ }
+
+ rw = bio_data_dir(bio);
+ bio_for_each_segment(bvec, bio, iter) {
+ int max_transfer_size = PAGE_SIZE - offset;
+
+ if (bvec.bv_len > max_transfer_size) {
+ /*
+ * zram_bvec_rw() can only make operation on a single
+ * zram page. Split the bio vector.
+ */
+ struct bio_vec bv;
+
+ bv.bv_page = bvec.bv_page;
+ bv.bv_len = max_transfer_size;
+ bv.bv_offset = bvec.bv_offset;
+
+ if (zram_bvec_rw(zram, &bv, index, offset, rw) < 0)
+ goto out;
+
+ bv.bv_len = bvec.bv_len - max_transfer_size;
+ bv.bv_offset += max_transfer_size;
+ if (zram_bvec_rw(zram, &bv, index + 1, 0, rw) < 0)
+ goto out;
+ } else
+ if (zram_bvec_rw(zram, &bvec, index, offset, rw) < 0)
+ goto out;
+
+ update_position(&index, &offset, &bvec);
+ }
+
+ set_bit(BIO_UPTODATE, &bio->bi_flags);
+ bio_endio(bio, 0);
+ return;
+
+out:
+ bio_io_error(bio);
+}
+
+/*
+ * Handler function for all zram I/O requests.
+ */
+static void zram_make_request(struct request_queue *queue, struct bio *bio)
+{
+ struct zram *zram = queue->queuedata;
+
+ if (unlikely(!zram_meta_get(zram)))
+ goto error;
+
+ if (!valid_io_request(zram, bio->bi_iter.bi_sector,
+ bio->bi_iter.bi_size)) {
+ atomic64_inc(&zram->stats.invalid_io);
+ goto put_zram;
+ }
+
+ __zram_make_request(zram, bio);
+ zram_meta_put(zram);
+ return;
+put_zram:
+ zram_meta_put(zram);
+error:
+ bio_io_error(bio);
+}
+
+static void zram_slot_free_notify(struct block_device *bdev,
+ unsigned long index)
+{
+ struct zram *zram;
+ struct zram_meta *meta;
+
+ zram = bdev->bd_disk->private_data;
+ meta = zram->meta;
+
+ bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_free_page(zram, index);
+ bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+ atomic64_inc(&zram->stats.notify_free);
+}
+
+static int zram_rw_page(struct block_device *bdev, sector_t sector,
+ struct page *page, int rw)
+{
+ int offset, err = -EIO;
+ u32 index;
+ struct zram *zram;
+ struct bio_vec bv;
+
+ zram = bdev->bd_disk->private_data;
+ if (unlikely(!zram_meta_get(zram)))
+ goto out;
+
+ if (!valid_io_request(zram, sector, PAGE_SIZE)) {
+ atomic64_inc(&zram->stats.invalid_io);
+ err = -EINVAL;
+ goto put_zram;
+ }
+
+ index = sector >> SECTORS_PER_PAGE_SHIFT;
+ offset = sector & (SECTORS_PER_PAGE - 1) << SECTOR_SHIFT;
+
+ bv.bv_page = page;
+ bv.bv_len = PAGE_SIZE;
+ bv.bv_offset = 0;
+
+ err = zram_bvec_rw(zram, &bv, index, offset, rw);
+put_zram:
+ zram_meta_put(zram);
+out:
+ /*
+ * If I/O fails, just return error(ie, non-zero) without
+ * calling page_endio.
+ * It causes resubmit the I/O with bio request by upper functions
+ * of rw_page(e.g., swap_readpage, __swap_writepage) and
+ * bio->bi_end_io does things to handle the error
+ * (e.g., SetPageError, set_page_dirty and extra works).
+ */
+ if (err == 0)
+ page_endio(page, rw, 0);
+ return err;
+}
+
+static const struct block_device_operations zram_devops = {
+ .swap_slot_free_notify = zram_slot_free_notify,
+ .rw_page = zram_rw_page,
+ .owner = THIS_MODULE
+};
+
+static DEVICE_ATTR_WO(compact);
+static DEVICE_ATTR_RW(disksize);
+static DEVICE_ATTR_RO(initstate);
+static DEVICE_ATTR_WO(reset);
+static DEVICE_ATTR_RO(orig_data_size);
+static DEVICE_ATTR_RO(mem_used_total);
+static DEVICE_ATTR_RW(mem_limit);
+static DEVICE_ATTR_RW(mem_used_max);
+static DEVICE_ATTR_RW(max_comp_streams);
+static DEVICE_ATTR_RW(comp_algorithm);
+
+static ssize_t io_stat_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct zram *zram = dev_to_zram(dev);
+ ssize_t ret;
+
+ down_read(&zram->init_lock);
+ ret = scnprintf(buf, PAGE_SIZE,
+ "%8llu %8llu %8llu %8llu\n",
+ (u64)atomic64_read(&zram->stats.failed_reads),
+ (u64)atomic64_read(&zram->stats.failed_writes),
+ (u64)atomic64_read(&zram->stats.invalid_io),
+ (u64)atomic64_read(&zram->stats.notify_free));
+ up_read(&zram->init_lock);
+
+ return ret;
+}
+
+static ssize_t mm_stat_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct zram *zram = dev_to_zram(dev);
+ u64 orig_size, mem_used = 0;
+ long max_used;
+ ssize_t ret;
+
+ down_read(&zram->init_lock);
+ if (init_done(zram))
+ mem_used = zs_get_total_pages(zram->meta->mem_pool);
+
+ orig_size = atomic64_read(&zram->stats.pages_stored);
+ max_used = atomic_long_read(&zram->stats.max_used_pages);
+
+ ret = scnprintf(buf, PAGE_SIZE,
+ "%8llu %8llu %8llu %8lu %8ld %8llu %8llu\n",
+ orig_size << PAGE_SHIFT,
+ (u64)atomic64_read(&zram->stats.compr_data_size),
+ mem_used << PAGE_SHIFT,
+ zram->limit_pages << PAGE_SHIFT,
+ max_used << PAGE_SHIFT,
+ (u64)atomic64_read(&zram->stats.zero_pages),
+ (u64)atomic64_read(&zram->stats.num_migrated));
+ up_read(&zram->init_lock);
+
+ return ret;
+}
+
+static DEVICE_ATTR_RO(io_stat);
+static DEVICE_ATTR_RO(mm_stat);
+ZRAM_ATTR_RO(num_reads);
+ZRAM_ATTR_RO(num_writes);
+ZRAM_ATTR_RO(failed_reads);
+ZRAM_ATTR_RO(failed_writes);
+ZRAM_ATTR_RO(invalid_io);
+ZRAM_ATTR_RO(notify_free);
+ZRAM_ATTR_RO(zero_pages);
+ZRAM_ATTR_RO(compr_data_size);
+
+static struct attribute *zram_disk_attrs[] = {
+ &dev_attr_disksize.attr,
+ &dev_attr_initstate.attr,
+ &dev_attr_reset.attr,
+ &dev_attr_num_reads.attr,
+ &dev_attr_num_writes.attr,
+ &dev_attr_failed_reads.attr,
+ &dev_attr_failed_writes.attr,
+ &dev_attr_compact.attr,
+ &dev_attr_invalid_io.attr,
+ &dev_attr_notify_free.attr,
+ &dev_attr_zero_pages.attr,
+ &dev_attr_orig_data_size.attr,
+ &dev_attr_compr_data_size.attr,
+ &dev_attr_mem_used_total.attr,
+ &dev_attr_mem_limit.attr,
+ &dev_attr_mem_used_max.attr,
+ &dev_attr_max_comp_streams.attr,
+ &dev_attr_comp_algorithm.attr,
+ &dev_attr_io_stat.attr,
+ &dev_attr_mm_stat.attr,
+ NULL,
+};
+
+static struct attribute_group zram_disk_attr_group = {
+ .attrs = zram_disk_attrs,
+};
+
+static int create_device(struct zram *zram, int device_id)
+{
+ struct request_queue *queue;
+ int ret = -ENOMEM;
+
+ init_rwsem(&zram->init_lock);
+
+ queue = blk_alloc_queue(GFP_KERNEL);
+ if (!queue) {
+ pr_err("Error allocating disk queue for device %d\n",
+ device_id);
+ goto out;
+ }
+
+ blk_queue_make_request(queue, zram_make_request);
+
+ /* gendisk structure */
+ zram->disk = alloc_disk(1);
+ if (!zram->disk) {
+ pr_warn("Error allocating disk structure for device %d\n",
+ device_id);
+ ret = -ENOMEM;
+ goto out_free_queue;
+ }
+
+ zram->disk->major = zram_major;
+ zram->disk->first_minor = device_id;
+ zram->disk->fops = &zram_devops;
+ zram->disk->queue = queue;
+ zram->disk->queue->queuedata = zram;
+ zram->disk->private_data = zram;
+ snprintf(zram->disk->disk_name, 16, "zram%d", device_id);
+
+ /* Actual capacity set using syfs (/sys/block/zram<id>/disksize */
+ set_capacity(zram->disk, 0);
+ /* zram devices sort of resembles non-rotational disks */
+ queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zram->disk->queue);
+ queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, zram->disk->queue);
+ /*
+ * To ensure that we always get PAGE_SIZE aligned
+ * and n*PAGE_SIZED sized I/O requests.
+ */
+ blk_queue_physical_block_size(zram->disk->queue, PAGE_SIZE);
+ blk_queue_logical_block_size(zram->disk->queue,
+ ZRAM_LOGICAL_BLOCK_SIZE);
+ blk_queue_io_min(zram->disk->queue, PAGE_SIZE);
+ blk_queue_io_opt(zram->disk->queue, PAGE_SIZE);
+ zram->disk->queue->limits.discard_granularity = PAGE_SIZE;
+ zram->disk->queue->limits.max_discard_sectors = UINT_MAX;
+ /*
+ * zram_bio_discard() will clear all logical blocks if logical block
+ * size is identical with physical block size(PAGE_SIZE). But if it is
+ * different, we will skip discarding some parts of logical blocks in
+ * the part of the request range which isn't aligned to physical block
+ * size. So we can't ensure that all discarded logical blocks are
+ * zeroed.
+ */
+ if (ZRAM_LOGICAL_BLOCK_SIZE == PAGE_SIZE)
+ zram->disk->queue->limits.discard_zeroes_data = 1;
+ else
+ zram->disk->queue->limits.discard_zeroes_data = 0;
+ queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, zram->disk->queue);
+
+ add_disk(zram->disk);
+
+ ret = sysfs_create_group(&disk_to_dev(zram->disk)->kobj,
+ &zram_disk_attr_group);
+ if (ret < 0) {
+ pr_warn("Error creating sysfs group");
+ goto out_free_disk;
+ }
+ strlcpy(zram->compressor, default_compressor, sizeof(zram->compressor));
+ zram->meta = NULL;
+ zram->max_comp_streams = 1;
+ return 0;
+
+out_free_disk:
+ del_gendisk(zram->disk);
+ put_disk(zram->disk);
+out_free_queue:
+ blk_cleanup_queue(queue);
+out:
+ return ret;
+}
+
+static void destroy_devices(unsigned int nr)
+{
+ struct zram *zram;
+ unsigned int i;
+
+ for (i = 0; i < nr; i++) {
+ zram = &zram_devices[i];
+ /*
+ * Remove sysfs first, so no one will perform a disksize
+ * store while we destroy the devices
+ */
+ sysfs_remove_group(&disk_to_dev(zram->disk)->kobj,
+ &zram_disk_attr_group);
+
+ zram_reset_device(zram);
+
+ blk_cleanup_queue(zram->disk->queue);
+ del_gendisk(zram->disk);
+ put_disk(zram->disk);
+ }
+
+ kfree(zram_devices);
+ unregister_blkdev(zram_major, "zram");
+ pr_info("Destroyed %u device(s)\n", nr);
+}
+
+static int __init zram_init(void)
+{
+ int ret, dev_id;
+
+ if (num_devices > max_num_devices) {
+ pr_warn("Invalid value for num_devices: %u\n",
+ num_devices);
+ return -EINVAL;
+ }
+
+ zram_major = register_blkdev(0, "zram");
+ if (zram_major <= 0) {
+ pr_warn("Unable to get major number\n");
+ return -EBUSY;
+ }
+
+ /* Allocate the device array and initialize each one */
+ zram_devices = kzalloc(num_devices * sizeof(struct zram), GFP_KERNEL);
+ if (!zram_devices) {
+ unregister_blkdev(zram_major, "zram");
+ return -ENOMEM;
+ }
+
+ for (dev_id = 0; dev_id < num_devices; dev_id++) {
+ ret = create_device(&zram_devices[dev_id], dev_id);
+ if (ret)
+ goto out_error;
+ }
+
+ pr_info("Created %u device(s)\n", num_devices);
+ return 0;
+
+out_error:
+ destroy_devices(dev_id);
+ return ret;
+}
+
+static void __exit zram_exit(void)
+{
+ destroy_devices(num_devices);
+}
+
+module_init(zram_init);
+module_exit(zram_exit);
+
+module_param(num_devices, uint, 0);
+MODULE_PARM_DESC(num_devices, "Number of zram devices");
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("Nitin Gupta <ngupta@vflare.org>");
+MODULE_DESCRIPTION("Compressed RAM Block Device");
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
new file mode 100644
index 000000000..570c598f4
--- /dev/null
+++ b/drivers/block/zram/zram_drv.h
@@ -0,0 +1,125 @@
+/*
+ * Compressed RAM block device
+ *
+ * Copyright (C) 2008, 2009, 2010 Nitin Gupta
+ * 2012, 2013 Minchan Kim
+ *
+ * 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 _ZRAM_DRV_H_
+#define _ZRAM_DRV_H_
+
+#include <linux/spinlock.h>
+#include <linux/zsmalloc.h>
+
+#include "zcomp.h"
+
+/*
+ * Some arbitrary value. This is just to catch
+ * invalid value for num_devices module parameter.
+ */
+static const unsigned max_num_devices = 32;
+
+/*-- Configurable parameters */
+
+/*
+ * Pages that compress to size greater than this are stored
+ * uncompressed in memory.
+ */
+static const size_t max_zpage_size = PAGE_SIZE / 4 * 3;
+
+/*
+ * NOTE: max_zpage_size must be less than or equal to:
+ * ZS_MAX_ALLOC_SIZE. Otherwise, zs_malloc() would
+ * always return failure.
+ */
+
+/*-- End of configurable params */
+
+#define SECTOR_SHIFT 9
+#define SECTORS_PER_PAGE_SHIFT (PAGE_SHIFT - SECTOR_SHIFT)
+#define SECTORS_PER_PAGE (1 << SECTORS_PER_PAGE_SHIFT)
+#define ZRAM_LOGICAL_BLOCK_SHIFT 12
+#define ZRAM_LOGICAL_BLOCK_SIZE (1 << ZRAM_LOGICAL_BLOCK_SHIFT)
+#define ZRAM_SECTOR_PER_LOGICAL_BLOCK \
+ (1 << (ZRAM_LOGICAL_BLOCK_SHIFT - SECTOR_SHIFT))
+
+
+/*
+ * The lower ZRAM_FLAG_SHIFT bits of table.value is for
+ * object size (excluding header), the higher bits is for
+ * zram_pageflags.
+ *
+ * zram is mainly used for memory efficiency so we want to keep memory
+ * footprint small so we can squeeze size and flags into a field.
+ * The lower ZRAM_FLAG_SHIFT bits is for object size (excluding header),
+ * the higher bits is for zram_pageflags.
+ */
+#define ZRAM_FLAG_SHIFT 24
+
+/* Flags for zram pages (table[page_no].value) */
+enum zram_pageflags {
+ /* Page consists entirely of zeros */
+ ZRAM_ZERO = ZRAM_FLAG_SHIFT,
+ ZRAM_ACCESS, /* page is now accessed */
+
+ __NR_ZRAM_PAGEFLAGS,
+};
+
+/*-- Data structures */
+
+/* Allocated for each disk page */
+struct zram_table_entry {
+ unsigned long handle;
+ unsigned long value;
+};
+
+struct zram_stats {
+ atomic64_t compr_data_size; /* compressed size of pages stored */
+ atomic64_t num_reads; /* failed + successful */
+ atomic64_t num_writes; /* --do-- */
+ atomic64_t num_migrated; /* no. of migrated object */
+ atomic64_t failed_reads; /* can happen when memory is too low */
+ atomic64_t failed_writes; /* can happen when memory is too low */
+ atomic64_t invalid_io; /* non-page-aligned I/O requests */
+ atomic64_t notify_free; /* no. of swap slot free notifications */
+ atomic64_t zero_pages; /* no. of zero filled pages */
+ atomic64_t pages_stored; /* no. of pages currently stored */
+ atomic_long_t max_used_pages; /* no. of maximum pages stored */
+};
+
+struct zram_meta {
+ struct zram_table_entry *table;
+ struct zs_pool *mem_pool;
+};
+
+struct zram {
+ struct zram_meta *meta;
+ struct zcomp *comp;
+ struct gendisk *disk;
+ /* Prevent concurrent execution of device init */
+ struct rw_semaphore init_lock;
+ /*
+ * the number of pages zram can consume for storing compressed data
+ */
+ unsigned long limit_pages;
+ int max_comp_streams;
+
+ struct zram_stats stats;
+ atomic_t refcount; /* refcount for zram_meta */
+ /* wait all IO under all of cpu are done */
+ wait_queue_head_t io_done;
+ /*
+ * This is the limit on amount of *uncompressed* worth of data
+ * we can store in a disk.
+ */
+ u64 disksize; /* bytes */
+ char compressor[10];
+};
+#endif