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zram: get rid of lockdep warning
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Lockdep complains about recursive deadlock of zram->init_lock.
[1] made it false positive because we can't request IO to zram
before setting disksize. Anyway, we should shut lockdep up to
avoid many reporting from user.

[1] : zram: force disksize setting before using zram

Acked-by: Jerome Marchand <jmarchan@redhat.com>
Acked-by: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Minchan Kim authored and Greg Kroah-Hartman committed Feb 6, 2013
1 parent 152bce6 commit 8b3cc3e
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Showing 3 changed files with 116 additions and 96 deletions.
189 changes: 99 additions & 90 deletions drivers/staging/zram/zram_drv.c
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Original file line number Diff line number Diff line change
Expand Up @@ -61,22 +61,22 @@ static void zram_stat64_inc(struct zram *zram, u64 *v)
zram_stat64_add(zram, v, 1);
}

static int zram_test_flag(struct zram *zram, u32 index,
static int zram_test_flag(struct zram_meta *meta, u32 index,
enum zram_pageflags flag)
{
return zram->table[index].flags & BIT(flag);
return meta->table[index].flags & BIT(flag);
}

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

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

static int page_zero_filled(void *ptr)
Expand All @@ -96,16 +96,17 @@ static int page_zero_filled(void *ptr)

static void zram_free_page(struct zram *zram, size_t index)
{
unsigned long handle = zram->table[index].handle;
u16 size = zram->table[index].size;
struct zram_meta *meta = zram->meta;
unsigned long handle = meta->table[index].handle;
u16 size = meta->table[index].size;

if (unlikely(!handle)) {
/*
* No memory is allocated for zero filled pages.
* Simply clear zero page flag.
*/
if (zram_test_flag(zram, index, ZRAM_ZERO)) {
zram_clear_flag(zram, index, ZRAM_ZERO);
if (zram_test_flag(meta, index, ZRAM_ZERO)) {
zram_clear_flag(meta, index, ZRAM_ZERO);
zram->stats.pages_zero--;
}
return;
Expand All @@ -114,17 +115,17 @@ static void zram_free_page(struct zram *zram, size_t index)
if (unlikely(size > max_zpage_size))
zram->stats.bad_compress--;

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

if (size <= PAGE_SIZE / 2)
zram->stats.good_compress--;

zram_stat64_sub(zram, &zram->stats.compr_size,
zram->table[index].size);
meta->table[index].size);
zram->stats.pages_stored--;

zram->table[index].handle = 0;
zram->table[index].size = 0;
meta->table[index].handle = 0;
meta->table[index].size = 0;
}

static void handle_zero_page(struct bio_vec *bvec)
Expand All @@ -149,20 +150,21 @@ static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
int ret = LZO_E_OK;
size_t clen = PAGE_SIZE;
unsigned char *cmem;
unsigned long handle = zram->table[index].handle;
struct zram_meta *meta = zram->meta;
unsigned long handle = meta->table[index].handle;

if (!handle || zram_test_flag(zram, index, ZRAM_ZERO)) {
if (!handle || zram_test_flag(meta, index, ZRAM_ZERO)) {
memset(mem, 0, PAGE_SIZE);
return 0;
}

cmem = zs_map_object(zram->mem_pool, handle, ZS_MM_RO);
if (zram->table[index].size == PAGE_SIZE)
cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_RO);
if (meta->table[index].size == PAGE_SIZE)
memcpy(mem, cmem, PAGE_SIZE);
else
ret = lzo1x_decompress_safe(cmem, zram->table[index].size,
ret = lzo1x_decompress_safe(cmem, meta->table[index].size,
mem, &clen);
zs_unmap_object(zram->mem_pool, handle);
zs_unmap_object(meta->mem_pool, handle);

/* Should NEVER happen. Return bio error if it does. */
if (unlikely(ret != LZO_E_OK)) {
Expand All @@ -180,11 +182,11 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
int ret;
struct page *page;
unsigned char *user_mem, *uncmem = NULL;

struct zram_meta *meta = zram->meta;
page = bvec->bv_page;

if (unlikely(!zram->table[index].handle) ||
zram_test_flag(zram, index, ZRAM_ZERO)) {
if (unlikely(!meta->table[index].handle) ||
zram_test_flag(meta, index, ZRAM_ZERO)) {
handle_zero_page(bvec);
return 0;
}
Expand Down Expand Up @@ -232,9 +234,10 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
unsigned long handle;
struct page *page;
unsigned char *user_mem, *cmem, *src, *uncmem = NULL;
struct zram_meta *meta = zram->meta;

page = bvec->bv_page;
src = zram->compress_buffer;
src = meta->compress_buffer;

if (is_partial_io(bvec)) {
/*
Expand All @@ -256,8 +259,8 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
* System overwrites unused sectors. Free memory associated
* with this sector now.
*/
if (zram->table[index].handle ||
zram_test_flag(zram, index, ZRAM_ZERO))
if (meta->table[index].handle ||
zram_test_flag(meta, index, ZRAM_ZERO))
zram_free_page(zram, index);

user_mem = kmap_atomic(page);
Expand All @@ -276,13 +279,13 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
if (is_partial_io(bvec))
kfree(uncmem);
zram->stats.pages_zero++;
zram_set_flag(zram, index, ZRAM_ZERO);
zram_set_flag(meta, index, ZRAM_ZERO);
ret = 0;
goto out;
}

ret = lzo1x_1_compress(uncmem, PAGE_SIZE, src, &clen,
zram->compress_workmem);
meta->compress_workmem);

if (!is_partial_io(bvec)) {
kunmap_atomic(user_mem);
Expand All @@ -303,25 +306,25 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
src = uncmem;
}

handle = zs_malloc(zram->mem_pool, clen);
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;
}
cmem = zs_map_object(zram->mem_pool, handle, ZS_MM_WO);
cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_WO);

if ((clen == PAGE_SIZE) && !is_partial_io(bvec))
src = kmap_atomic(page);
memcpy(cmem, src, clen);
if ((clen == PAGE_SIZE) && !is_partial_io(bvec))
kunmap_atomic(src);

zs_unmap_object(zram->mem_pool, handle);
zs_unmap_object(meta->mem_pool, handle);

zram->table[index].handle = handle;
zram->table[index].size = clen;
meta->table[index].handle = handle;
meta->table[index].size = clen;

/* Update stats */
zram_stat64_add(zram, &zram->stats.compr_size, clen);
Expand Down Expand Up @@ -464,34 +467,25 @@ static void zram_make_request(struct request_queue *queue, struct bio *bio)
void __zram_reset_device(struct zram *zram)
{
size_t index;
struct zram_meta *meta;

if (!zram->init_done)
return;

meta = zram->meta;
zram->init_done = 0;

/* Free various per-device buffers */
kfree(zram->compress_workmem);
free_pages((unsigned long)zram->compress_buffer, 1);

zram->compress_workmem = NULL;
zram->compress_buffer = NULL;

/* Free all pages that are still in this zram device */
for (index = 0; index < zram->disksize >> PAGE_SHIFT; index++) {
unsigned long handle = zram->table[index].handle;
unsigned long handle = meta->table[index].handle;
if (!handle)
continue;

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

vfree(zram->table);
zram->table = NULL;

zs_destroy_pool(zram->mem_pool);
zram->mem_pool = NULL;

zram_meta_free(zram->meta);
zram->meta = NULL;
/* Reset stats */
memset(&zram->stats, 0, sizeof(zram->stats));

Expand All @@ -506,12 +500,65 @@ void zram_reset_device(struct zram *zram)
up_write(&zram->init_lock);
}

/* zram->init_lock should be held */
int zram_init_device(struct zram *zram)
void zram_meta_free(struct zram_meta *meta)
{
zs_destroy_pool(meta->mem_pool);
kfree(meta->compress_workmem);
free_pages((unsigned long)meta->compress_buffer, 1);
vfree(meta->table);
kfree(meta);
}

struct zram_meta *zram_meta_alloc(u64 disksize)
{
int ret;
size_t num_pages;
struct zram_meta *meta = kmalloc(sizeof(*meta), GFP_KERNEL);
if (!meta)
goto out;

meta->compress_workmem = kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
if (!meta->compress_workmem) {
pr_err("Error allocating compressor working memory!\n");
goto free_meta;
}

meta->compress_buffer =
(void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1);
if (!meta->compress_buffer) {
pr_err("Error allocating compressor buffer space\n");
goto free_workmem;
}

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 free_buffer;
}

meta->mem_pool = zs_create_pool(GFP_NOIO | __GFP_HIGHMEM);
if (!meta->mem_pool) {
pr_err("Error creating memory pool\n");
goto free_table;
}

return meta;

free_table:
vfree(meta->table);
free_buffer:
free_pages((unsigned long)meta->compress_buffer, 1);
free_workmem:
kfree(meta->compress_workmem);
free_meta:
kfree(meta);
meta = NULL;
out:
return meta;
}

void zram_init_device(struct zram *zram, struct zram_meta *meta)
{
if (zram->disksize > 2 * (totalram_pages << PAGE_SHIFT)) {
pr_info(
"There is little point creating a zram of greater than "
Expand All @@ -526,51 +573,13 @@ int zram_init_device(struct zram *zram)
);
}

zram->compress_workmem = kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
if (!zram->compress_workmem) {
pr_err("Error allocating compressor working memory!\n");
ret = -ENOMEM;
goto fail_no_table;
}

zram->compress_buffer =
(void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1);
if (!zram->compress_buffer) {
pr_err("Error allocating compressor buffer space\n");
ret = -ENOMEM;
goto fail_no_table;
}

num_pages = zram->disksize >> PAGE_SHIFT;
zram->table = vzalloc(num_pages * sizeof(*zram->table));
if (!zram->table) {
pr_err("Error allocating zram address table\n");
ret = -ENOMEM;
goto fail_no_table;
}

/* zram devices sort of resembles non-rotational disks */
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zram->disk->queue);

zram->mem_pool = zs_create_pool(GFP_NOIO | __GFP_HIGHMEM);
if (!zram->mem_pool) {
pr_err("Error creating memory pool\n");
ret = -ENOMEM;
goto fail;
}

zram->meta = meta;
zram->init_done = 1;

pr_debug("Initialization done!\n");
return 0;

fail_no_table:
/* To prevent accessing table entries during cleanup */
zram->disksize = 0;
fail:
__zram_reset_device(zram);
pr_err("Initialization failed: err=%d\n", ret);
return ret;
}

static void zram_slot_free_notify(struct block_device *bdev,
Expand Down
12 changes: 9 additions & 3 deletions drivers/staging/zram/zram_drv.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -83,11 +83,15 @@ struct zram_stats {
u32 bad_compress; /* % of pages with compression ratio>=75% */
};

struct zram {
struct zs_pool *mem_pool;
struct zram_meta {
void *compress_workmem;
void *compress_buffer;
struct table *table;
struct zs_pool *mem_pool;
};

struct zram {
struct zram_meta *meta;
spinlock_t stat64_lock; /* protect 64-bit stats */
struct rw_semaphore lock; /* protect compression buffers and table
* against concurrent read and writes */
Expand All @@ -111,7 +115,9 @@ unsigned int zram_get_num_devices(void);
extern struct attribute_group zram_disk_attr_group;
#endif

extern int zram_init_device(struct zram *zram);
extern void zram_reset_device(struct zram *zram);
extern struct zram_meta *zram_meta_alloc(u64 disksize);
extern void zram_meta_free(struct zram_meta *meta);
extern void zram_init_device(struct zram *zram, struct zram_meta *meta);

#endif
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