[PATCH v2 4/6] zram: remove zram_meta structure

From: Minchan Kim
Date: Wed Apr 12 2017 - 23:00:24 EST

It's redundant now. Instead, remove it and use zram structure
directly.

Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 189 +++++++++++++++++-------------------------
drivers/block/zram/zram_drv.h | 6 +-
2 files changed, 78 insertions(+), 117 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 931fe099dbc8..002019a552af 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -58,46 +58,46 @@ static inline struct zram *dev_to_zram(struct device *dev)
}

/* flag operations require table entry bit_spin_lock() being held */
-static int zram_test_flag(struct zram_meta *meta, u32 index,
+static int zram_test_flag(struct zram *zram, u32 index,
enum zram_pageflags flag)
{
- return meta->table[index].value & BIT(flag);
+ return zram->table[index].value & BIT(flag);
}

-static void zram_set_flag(struct zram_meta *meta, u32 index,
+static void zram_set_flag(struct zram *zram, u32 index,
enum zram_pageflags flag)
{
- meta->table[index].value |= BIT(flag);
+ zram->table[index].value |= BIT(flag);
}

-static void zram_clear_flag(struct zram_meta *meta, u32 index,
+static void zram_clear_flag(struct zram *zram, u32 index,
enum zram_pageflags flag)
{
- meta->table[index].value &= ~BIT(flag);
+ zram->table[index].value &= ~BIT(flag);
}

-static inline void zram_set_element(struct zram_meta *meta, u32 index,
+static inline void zram_set_element(struct zram *zram, u32 index,
unsigned long element)
{
- meta->table[index].element = element;
+ zram->table[index].element = element;
}

-static inline void zram_clear_element(struct zram_meta *meta, u32 index)
+static inline void zram_clear_element(struct zram *zram, u32 index)
{
- meta->table[index].element = 0;
+ zram->table[index].element = 0;
}

-static size_t zram_get_obj_size(struct zram_meta *meta, u32 index)
+static size_t zram_get_obj_size(struct zram *zram, u32 index)
{
- return meta->table[index].value & (BIT(ZRAM_FLAG_SHIFT) - 1);
+ return zram->table[index].value & (BIT(ZRAM_FLAG_SHIFT) - 1);
}

-static void zram_set_obj_size(struct zram_meta *meta,
+static void zram_set_obj_size(struct zram *zram,
u32 index, size_t size)
{
- unsigned long flags = meta->table[index].value >> ZRAM_FLAG_SHIFT;
+ unsigned long flags = zram->table[index].value >> ZRAM_FLAG_SHIFT;

- meta->table[index].value = (flags << ZRAM_FLAG_SHIFT) | size;
+ zram->table[index].value = (flags << ZRAM_FLAG_SHIFT) | size;
}

#if PAGE_SIZE != 4096
@@ -252,9 +252,8 @@ static ssize_t mem_used_max_store(struct device *dev,

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));
+ zs_get_total_pages(zram->mem_pool));
}
up_read(&zram->init_lock);

@@ -327,7 +326,6 @@ static ssize_t compact_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
struct zram *zram = dev_to_zram(dev);
- struct zram_meta *meta;

down_read(&zram->init_lock);
if (!init_done(zram)) {
@@ -335,8 +333,7 @@ static ssize_t compact_store(struct device *dev,
return -EINVAL;
}

- meta = zram->meta;
- zs_compact(meta->mem_pool);
+ zs_compact(zram->mem_pool);
up_read(&zram->init_lock);

return len;
@@ -373,8 +370,8 @@ static ssize_t mm_stat_show(struct device *dev,

down_read(&zram->init_lock);
if (init_done(zram)) {
- mem_used = zs_get_total_pages(zram->meta->mem_pool);
- zs_pool_stats(zram->meta->mem_pool, &pool_stats);
+ mem_used = zs_get_total_pages(zram->mem_pool);
+ zs_pool_stats(zram->mem_pool, &pool_stats);
}

orig_size = atomic64_read(&zram->stats.pages_stored);
@@ -417,32 +414,26 @@ static DEVICE_ATTR_RO(debug_stat);

static void zram_slot_lock(struct zram *zram, u32 index)
{
- struct zram_meta *meta = zram->meta;
-
- bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ bit_spin_lock(ZRAM_ACCESS, &zram->table[index].value);
}

static void zram_slot_unlock(struct zram *zram, u32 index)
{
- struct zram_meta *meta = zram->meta;
-
- bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+ bit_spin_unlock(ZRAM_ACCESS, &zram->table[index].value);
}

static bool zram_same_page_read(struct zram *zram, u32 index,
struct page *page,
unsigned int offset, unsigned int len)
{
- struct zram_meta *meta = zram->meta;
-
zram_slot_lock(zram, index);
- if (unlikely(!meta->table[index].handle) ||
- zram_test_flag(meta, index, ZRAM_SAME)) {
+ if (unlikely(!zram->table[index].handle) ||
+ zram_test_flag(zram, index, ZRAM_SAME)) {
void *mem;

zram_slot_unlock(zram, index);
mem = kmap_atomic(page);
- zram_fill_page(mem + offset, len, meta->table[index].element);
+ zram_fill_page(mem + offset, len, zram->table[index].element);
kunmap_atomic(mem);
return true;
}
@@ -458,14 +449,12 @@ static bool zram_same_page_write(struct zram *zram, u32 index,
void *mem = kmap_atomic(page);

if (page_same_filled(mem, &element)) {
- struct zram_meta *meta = zram->meta;
-
kunmap_atomic(mem);
/* Free memory associated with this sector now. */
zram_slot_lock(zram, index);
zram_free_page(zram, index);
- zram_set_flag(meta, index, ZRAM_SAME);
- zram_set_element(meta, index, element);
+ zram_set_flag(zram, index, ZRAM_SAME);
+ zram_set_element(zram, index, element);
zram_slot_unlock(zram, index);

atomic64_inc(&zram->stats.same_pages);
@@ -476,56 +465,44 @@ static bool zram_same_page_write(struct zram *zram, u32 index,
return false;
}

-static void zram_meta_free(struct zram_meta *meta, u64 disksize)
+static void zram_meta_free(struct zram *zram, 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;
+ unsigned long handle = zram->table[index].handle;
/*
* No memory is allocated for same element filled pages.
* Simply clear same page flag.
*/
- if (!handle || zram_test_flag(meta, index, ZRAM_SAME))
+ if (!handle || zram_test_flag(zram, index, ZRAM_SAME))
continue;

- zs_free(meta->mem_pool, handle);
+ zs_free(zram->mem_pool, handle);
}

- zs_destroy_pool(meta->mem_pool);
- vfree(meta->table);
- kfree(meta);
+ zs_destroy_pool(zram->mem_pool);
+ vfree(zram->table);
}

-static struct zram_meta *zram_meta_alloc(char *pool_name, u64 disksize)
+static bool zram_meta_alloc(struct zram *zram, u64 disksize)
{
size_t num_pages;
- 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;
- }
+ zram->table = vzalloc(num_pages * sizeof(*zram->table));
+ if (!zram->table)
+ return false;

- meta->mem_pool = zs_create_pool(pool_name);
- if (!meta->mem_pool) {
- pr_err("Error creating memory pool\n");
- goto out_error;
+ zram->mem_pool = zs_create_pool(zram->disk->disk_name);
+ if (!zram->mem_pool) {
+ vfree(zram->table);
+ return false;
}

- return meta;
-
-out_error:
- vfree(meta->table);
- kfree(meta);
- return NULL;
+ return true;
}

/*
@@ -535,16 +512,15 @@ static struct zram_meta *zram_meta_alloc(char *pool_name, u64 disksize)
*/
static void zram_free_page(struct zram *zram, size_t index)
{
- struct zram_meta *meta = zram->meta;
- unsigned long handle = meta->table[index].handle;
+ unsigned long handle = zram->table[index].handle;

/*
* No memory is allocated for same element filled pages.
* Simply clear same page flag.
*/
- if (zram_test_flag(meta, index, ZRAM_SAME)) {
- zram_clear_flag(meta, index, ZRAM_SAME);
- zram_clear_element(meta, index);
+ if (zram_test_flag(zram, index, ZRAM_SAME)) {
+ zram_clear_flag(zram, index, ZRAM_SAME);
+ zram_clear_element(zram, index);
atomic64_dec(&zram->stats.same_pages);
return;
}
@@ -552,14 +528,14 @@ static void zram_free_page(struct zram *zram, size_t index)
if (!handle)
return;

- zs_free(meta->mem_pool, handle);
+ zs_free(zram->mem_pool, handle);

- atomic64_sub(zram_get_obj_size(meta, index),
+ atomic64_sub(zram_get_obj_size(zram, index),
&zram->stats.compr_data_size);
atomic64_dec(&zram->stats.pages_stored);

- meta->table[index].handle = 0;
- zram_set_obj_size(meta, index, 0);
+ zram->table[index].handle = 0;
+ zram_set_obj_size(zram, index, 0);
}

static int zram_decompress_page(struct zram *zram, struct page *page, u32 index)
@@ -568,16 +544,15 @@ static int zram_decompress_page(struct zram *zram, struct page *page, u32 index)
unsigned long handle;
unsigned int size;
void *src, *dst;
- struct zram_meta *meta = zram->meta;

if (zram_same_page_read(zram, index, page, 0, PAGE_SIZE))
return 0;

zram_slot_lock(zram, index);
- handle = meta->table[index].handle;
- size = zram_get_obj_size(meta, index);
+ handle = zram->table[index].handle;
+ size = zram_get_obj_size(zram, index);

- src = zs_map_object(meta->mem_pool, handle, ZS_MM_RO);
+ src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO);
if (size == PAGE_SIZE) {
dst = kmap_atomic(page);
memcpy(dst, src, PAGE_SIZE);
@@ -591,7 +566,7 @@ static int zram_decompress_page(struct zram *zram, struct page *page, u32 index)
kunmap_atomic(dst);
zcomp_stream_put(zram->comp);
}
- zs_unmap_object(meta->mem_pool, handle);
+ zs_unmap_object(zram->mem_pool, handle);
zram_slot_unlock(zram, index);

/* Should NEVER happen. Return bio error if it does. */
@@ -643,7 +618,6 @@ static int zram_compress(struct zram *zram, struct zcomp_strm **zstrm,
void *src;
unsigned long alloced_pages;
unsigned long handle = 0;
- struct zram_meta *meta = zram->meta;

compress_again:
src = kmap_atomic(page);
@@ -653,7 +627,7 @@ static int zram_compress(struct zram *zram, struct zcomp_strm **zstrm,
if (unlikely(ret)) {
pr_err("Compression failed! err=%d\n", ret);
if (handle)
- zs_free(meta->mem_pool, handle);
+ zs_free(zram->mem_pool, handle);
return ret;
}

@@ -674,7 +648,7 @@ static int zram_compress(struct zram *zram, struct zcomp_strm **zstrm,
* from the slow path and handle has already been allocated.
*/
if (!handle)
- handle = zs_malloc(meta->mem_pool, comp_len,
+ handle = zs_malloc(zram->mem_pool, comp_len,
__GFP_KSWAPD_RECLAIM |
__GFP_NOWARN |
__GFP_HIGHMEM |
@@ -682,7 +656,7 @@ static int zram_compress(struct zram *zram, struct zcomp_strm **zstrm,
if (!handle) {
zcomp_stream_put(zram->comp);
atomic64_inc(&zram->stats.writestall);
- handle = zs_malloc(meta->mem_pool, comp_len,
+ handle = zs_malloc(zram->mem_pool, comp_len,
GFP_NOIO | __GFP_HIGHMEM |
__GFP_MOVABLE);
*zstrm = zcomp_stream_get(zram->comp);
@@ -691,11 +665,11 @@ static int zram_compress(struct zram *zram, struct zcomp_strm **zstrm,
return -ENOMEM;
}

- alloced_pages = zs_get_total_pages(meta->mem_pool);
+ alloced_pages = zs_get_total_pages(zram->mem_pool);
update_used_max(zram, alloced_pages);

if (zram->limit_pages && alloced_pages > zram->limit_pages) {
- zs_free(meta->mem_pool, handle);
+ zs_free(zram->mem_pool, handle);
return -ENOMEM;
}

@@ -711,7 +685,6 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
unsigned int comp_len;
void *src, *dst;
struct zcomp_strm *zstrm;
- struct zram_meta *meta = zram->meta;
struct page *page = bvec->bv_page;

if (zram_same_page_write(zram, index, page))
@@ -724,8 +697,7 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
return ret;
}

-
- dst = zs_map_object(meta->mem_pool, handle, ZS_MM_WO);
+ dst = zs_map_object(zram->mem_pool, handle, ZS_MM_WO);

src = zstrm->buffer;
if (comp_len == PAGE_SIZE)
@@ -735,7 +707,7 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
kunmap_atomic(src);

zcomp_stream_put(zram->comp);
- zs_unmap_object(meta->mem_pool, handle);
+ zs_unmap_object(zram->mem_pool, handle);

/*
* Free memory associated with this sector
@@ -743,8 +715,8 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
*/
zram_slot_lock(zram, index);
zram_free_page(zram, index);
- meta->table[index].handle = handle;
- zram_set_obj_size(meta, index, comp_len);
+ zram->table[index].handle = handle;
+ zram_set_obj_size(zram, index, comp_len);
zram_slot_unlock(zram, index);

/* Update stats */
@@ -930,10 +902,8 @@ 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;

zram_slot_lock(zram, index);
zram_free_page(zram, index);
@@ -981,7 +951,6 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector,

static void zram_reset_device(struct zram *zram)
{
- struct zram_meta *meta;
struct zcomp *comp;
u64 disksize;

@@ -994,7 +963,6 @@ static void zram_reset_device(struct zram *zram)
return;
}

- meta = zram->meta;
comp = zram->comp;
disksize = zram->disksize;

@@ -1007,7 +975,7 @@ static void zram_reset_device(struct zram *zram)

up_write(&zram->init_lock);
/* I/O operation under all of CPU are done so let's free */
- zram_meta_free(meta, disksize);
+ zram_meta_free(zram, disksize);
zcomp_destroy(comp);
}

@@ -1016,7 +984,6 @@ static ssize_t disksize_store(struct device *dev,
{
u64 disksize;
struct zcomp *comp;
- struct zram_meta *meta;
struct zram *zram = dev_to_zram(dev);
int err;

@@ -1024,10 +991,18 @@ static ssize_t disksize_store(struct device *dev,
if (!disksize)
return -EINVAL;

+ down_write(&zram->init_lock);
+ if (init_done(zram)) {
+ pr_info("Cannot change disksize for initialized device\n");
+ err = -EBUSY;
+ goto out_unlock;
+ }
+
disksize = PAGE_ALIGN(disksize);
- meta = zram_meta_alloc(zram->disk->disk_name, disksize);
- if (!meta)
- return -ENOMEM;
+ if (!zram_meta_alloc(zram, disksize)) {
+ err = -ENOMEM;
+ goto out_unlock;
+ }

comp = zcomp_create(zram->compressor);
if (IS_ERR(comp)) {
@@ -1037,14 +1012,6 @@ static ssize_t disksize_store(struct device *dev,
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;
- }
-
- zram->meta = meta;
zram->comp = comp;
zram->disksize = disksize;
set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
@@ -1053,11 +1020,10 @@ static ssize_t disksize_store(struct device *dev,

return len;

-out_destroy_comp:
- up_write(&zram->init_lock);
- zcomp_destroy(comp);
out_free_meta:
- zram_meta_free(meta, disksize);
+ zram_meta_free(zram, disksize);
+out_unlock:
+ up_write(&zram->init_lock);
return err;
}

@@ -1246,7 +1212,6 @@ static int zram_add(void)
goto out_free_disk;
}
strlcpy(zram->compressor, default_compressor, sizeof(zram->compressor));
- zram->meta = NULL;

pr_info("Added device: %s\n", zram->disk->disk_name);
return device_id;
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index caeff51f1571..e34e44d02e3e 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -92,13 +92,9 @@ struct zram_stats {
atomic64_t writestall; /* no. of write slow paths */
};

-struct zram_meta {
+struct zram {
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 */
--
2.7.4