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yaml
---
r: 259833
b: refs/heads/master
c: 924bd88
h: refs/heads/master
i:
  259831: d6e0122
v: v3
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Jerome Marchand authored and Greg Kroah-Hartman committed Jul 5, 2011
1 parent 07e6160 commit 44f4e5c
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Showing 3 changed files with 170 additions and 39 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 8c921b2b43d47faa7c11eac1d2673bbe7fbc41dc
refs/heads/master: 924bd88d703e53d30f393fac6117f8f1bc79aab6
202 changes: 165 additions & 37 deletions trunk/drivers/staging/zram/zram_drv.c
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Original file line number Diff line number Diff line change
Expand Up @@ -177,71 +177,95 @@ static void zram_free_page(struct zram *zram, size_t index)
zram->table[index].offset = 0;
}

static void handle_zero_page(struct page *page)
static void handle_zero_page(struct bio_vec *bvec)
{
struct page *page = bvec->bv_page;
void *user_mem;

user_mem = kmap_atomic(page, KM_USER0);
memset(user_mem, 0, PAGE_SIZE);
memset(user_mem + bvec->bv_offset, 0, bvec->bv_len);
kunmap_atomic(user_mem, KM_USER0);

flush_dcache_page(page);
}

static void handle_uncompressed_page(struct zram *zram,
struct page *page, u32 index)
static void handle_uncompressed_page(struct zram *zram, struct bio_vec *bvec,
u32 index, int offset)
{
struct page *page = bvec->bv_page;
unsigned char *user_mem, *cmem;

user_mem = kmap_atomic(page, KM_USER0);
cmem = kmap_atomic(zram->table[index].page, KM_USER1);

memcpy(user_mem, cmem, PAGE_SIZE);
memcpy(user_mem + bvec->bv_offset, cmem + offset, bvec->bv_len);
kunmap_atomic(user_mem, KM_USER0);
kunmap_atomic(cmem, KM_USER1);

flush_dcache_page(page);
}

static inline int is_partial_io(struct bio_vec *bvec)
{
return bvec->bv_len != PAGE_SIZE;
}

static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
u32 index, struct bio *bio)
u32 index, int offset, struct bio *bio)
{
int ret;
size_t clen;
struct page *page;
struct zobj_header *zheader;
unsigned char *user_mem, *cmem;
unsigned char *user_mem, *cmem, *uncmem = NULL;

page = bvec->bv_page;

if (zram_test_flag(zram, index, ZRAM_ZERO)) {
handle_zero_page(page);
handle_zero_page(bvec);
return 0;
}

/* Requested page is not present in compressed area */
if (unlikely(!zram->table[index].page)) {
pr_debug("Read before write: sector=%lu, size=%u",
(ulong)(bio->bi_sector), bio->bi_size);
handle_zero_page(page);
handle_zero_page(bvec);
return 0;
}

/* Page is stored uncompressed since it's incompressible */
if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED))) {
handle_uncompressed_page(zram, page, index);
handle_uncompressed_page(zram, bvec, index, offset);
return 0;
}

if (is_partial_io(bvec)) {
/* Use a temporary buffer to decompress the page */
uncmem = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!uncmem) {
pr_info("Error allocating temp memory!\n");
return -ENOMEM;
}
}

user_mem = kmap_atomic(page, KM_USER0);
if (!is_partial_io(bvec))
uncmem = user_mem;
clen = PAGE_SIZE;

cmem = kmap_atomic(zram->table[index].page, KM_USER1) +
zram->table[index].offset;

ret = lzo1x_decompress_safe(cmem + sizeof(*zheader),
xv_get_object_size(cmem) - sizeof(*zheader),
user_mem, &clen);
uncmem, &clen);

if (is_partial_io(bvec)) {
memcpy(user_mem + bvec->bv_offset, uncmem + offset,
bvec->bv_len);
kfree(uncmem);
}

kunmap_atomic(user_mem, KM_USER0);
kunmap_atomic(cmem, KM_USER1);
Expand All @@ -258,18 +282,75 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
return 0;
}

static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
static int zram_read_before_write(struct zram *zram, char *mem, u32 index)
{
int ret;
size_t clen = PAGE_SIZE;
struct zobj_header *zheader;
unsigned char *cmem;

if (zram_test_flag(zram, index, ZRAM_ZERO) ||
!zram->table[index].page) {
memset(mem, 0, PAGE_SIZE);
return 0;
}

cmem = kmap_atomic(zram->table[index].page, KM_USER0) +
zram->table[index].offset;

/* Page is stored uncompressed since it's incompressible */
if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED))) {
memcpy(mem, cmem, PAGE_SIZE);
kunmap_atomic(cmem, KM_USER0);
return 0;
}

ret = lzo1x_decompress_safe(cmem + sizeof(*zheader),
xv_get_object_size(cmem) - sizeof(*zheader),
mem, &clen);
kunmap_atomic(cmem, KM_USER0);

/* Should NEVER happen. Return bio error if it does. */
if (unlikely(ret != LZO_E_OK)) {
pr_err("Decompression failed! err=%d, page=%u\n", ret, index);
zram_stat64_inc(zram, &zram->stats.failed_reads);
return ret;
}

return 0;
}

static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
int offset)
{
int ret;
u32 offset;
u32 store_offset;
size_t clen;
struct zobj_header *zheader;
struct page *page, *page_store;
unsigned char *user_mem, *cmem, *src;
unsigned char *user_mem, *cmem, *src, *uncmem = NULL;

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

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_KERNEL);
if (!uncmem) {
pr_info("Error allocating temp memory!\n");
ret = -ENOMEM;
goto out;
}
ret = zram_read_before_write(zram, uncmem, index);
if (ret) {
kfree(uncmem);
goto out;
}
}

/*
* System overwrites unused sectors. Free memory associated
* with this sector now.
Expand All @@ -281,24 +362,35 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
mutex_lock(&zram->lock);

user_mem = kmap_atomic(page, KM_USER0);
if (page_zero_filled(user_mem)) {

if (is_partial_io(bvec))
memcpy(uncmem + offset, user_mem + bvec->bv_offset,
bvec->bv_len);
else
uncmem = user_mem;

if (page_zero_filled(uncmem)) {
kunmap_atomic(user_mem, KM_USER0);
mutex_unlock(&zram->lock);
if (is_partial_io(bvec))
kfree(uncmem);
zram_stat_inc(&zram->stats.pages_zero);
zram_set_flag(zram, index, ZRAM_ZERO);
return 0;
ret = 0;
goto out;
}

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

kunmap_atomic(user_mem, KM_USER0);
if (is_partial_io(bvec))
kfree(uncmem);

if (unlikely(ret != LZO_E_OK)) {
mutex_unlock(&zram->lock);
pr_err("Compression failed! err=%d\n", ret);
zram_stat64_inc(zram, &zram->stats.failed_writes);
return ret;
goto out;
}

/*
Expand All @@ -313,11 +405,11 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
mutex_unlock(&zram->lock);
pr_info("Error allocating memory for "
"incompressible page: %u\n", index);
zram_stat64_inc(zram, &zram->stats.failed_writes);
return -ENOMEM;
}
ret = -ENOMEM;
goto out;
}

offset = 0;
store_offset = 0;
zram_set_flag(zram, index, ZRAM_UNCOMPRESSED);
zram_stat_inc(&zram->stats.pages_expand);
zram->table[index].page = page_store;
Expand All @@ -326,17 +418,17 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
}

if (xv_malloc(zram->mem_pool, clen + sizeof(*zheader),
&zram->table[index].page, &offset,
&zram->table[index].page, &store_offset,
GFP_NOIO | __GFP_HIGHMEM)) {
mutex_unlock(&zram->lock);
pr_info("Error allocating memory for compressed "
"page: %u, size=%zu\n", index, clen);
zram_stat64_inc(zram, &zram->stats.failed_writes);
return -ENOMEM;
ret = -ENOMEM;
goto out;
}

memstore:
zram->table[index].offset = offset;
zram->table[index].offset = store_offset;

cmem = kmap_atomic(zram->table[index].page, KM_USER1) +
zram->table[index].offset;
Expand Down Expand Up @@ -365,20 +457,32 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
mutex_unlock(&zram->lock);

return 0;

out:
if (ret)
zram_stat64_inc(zram, &zram->stats.failed_writes);
return ret;
}

static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
struct bio *bio, int rw)
int offset, struct bio *bio, int rw)
{
if (rw == READ)
return zram_bvec_read(zram, bvec, index, bio);
return zram_bvec_read(zram, bvec, index, offset, bio);

return zram_bvec_write(zram, bvec, index);
return zram_bvec_write(zram, bvec, index, offset);
}

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 void __zram_make_request(struct zram *zram, struct bio *bio, int rw)
{
int i;
int i, offset;
u32 index;
struct bio_vec *bvec;

Expand All @@ -392,11 +496,35 @@ static void __zram_make_request(struct zram *zram, struct bio *bio, int rw)
}

index = bio->bi_sector >> SECTORS_PER_PAGE_SHIFT;
offset = (bio->bi_sector & (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT;

bio_for_each_segment(bvec, bio, i) {
if (zram_bvec_rw(zram, bvec, index, bio, rw) < 0)
goto out;
index++;
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, bio, 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, bio, rw) < 0)
goto out;
} else
if (zram_bvec_rw(zram, bvec, index, offset, bio, rw)
< 0)
goto out;

update_position(&index, &offset, bvec);
}

set_bit(BIO_UPTODATE, &bio->bi_flags);
Expand All @@ -408,14 +536,14 @@ static void __zram_make_request(struct zram *zram, struct bio *bio, int rw)
}

/*
* Check if request is within bounds and page aligned.
* Check if request is within bounds and aligned on zram logical blocks.
*/
static inline int valid_io_request(struct zram *zram, struct bio *bio)
{
if (unlikely(
(bio->bi_sector >= (zram->disksize >> SECTOR_SHIFT)) ||
(bio->bi_sector & (SECTORS_PER_PAGE - 1)) ||
(bio->bi_size & (PAGE_SIZE - 1)))) {
(bio->bi_sector & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1)) ||
(bio->bi_size & (ZRAM_LOGICAL_BLOCK_SIZE - 1)))) {

return 0;
}
Expand Down
5 changes: 4 additions & 1 deletion trunk/drivers/staging/zram/zram_drv.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -61,7 +61,10 @@ static const unsigned max_zpage_size = PAGE_SIZE / 4 * 3;
#define SECTOR_SIZE (1 << SECTOR_SHIFT)
#define SECTORS_PER_PAGE_SHIFT (PAGE_SHIFT - SECTOR_SHIFT)
#define SECTORS_PER_PAGE (1 << SECTORS_PER_PAGE_SHIFT)
#define ZRAM_LOGICAL_BLOCK_SIZE 4096
#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))

/* Flags for zram pages (table[page_no].flags) */
enum zram_pageflags {
Expand Down

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