zram's handle variable can store handle of zsmalloc in case of
compressing efficiently. Otherwise, it stores point of page descriptor.
This patch clean up the mess by union struct.
changelog
* from v1
- none(new add in v2)
Cc: Nitin Gupta <ngupta@xxxxxxxxxx>
Acked-by: Seth Jennings <sjenning@xxxxxxxxxxxxxxxxxx>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
---
drivers/staging/zram/zram_drv.c | 77 ++++++++++++++++++++-------------------
drivers/staging/zram/zram_drv.h | 5 ++-
2 files changed, 44 insertions(+), 38 deletions(-)
diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index abd69d1..ceab5ca 100644
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -150,7 +150,7 @@ static void zram_free_page(struct zram *zram, size_t index)
}
if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED))) {
- __free_page((struct page *)handle);
+ __free_page(zram->table[index].page);
zram_clear_flag(zram, index, ZRAM_UNCOMPRESSED);
zram_stat_dec(&zram->stats.pages_expand);
goto out;
@@ -189,7 +189,7 @@ static void handle_uncompressed_page(struct zram *zram, struct bio_vec *bvec,
unsigned char *user_mem, *cmem;
user_mem = kmap_atomic(page);
- cmem = kmap_atomic((struct page *)zram->table[index].handle);
+ cmem = kmap_atomic(zram->table[index].page);
memcpy(user_mem + bvec->bv_offset, cmem + offset, bvec->bv_len);
kunmap_atomic(cmem);
@@ -315,7 +315,6 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
int offset)
{
int ret;
- u32 store_offset;
size_t clen;
unsigned long handle;
struct zobj_header *zheader;
@@ -396,25 +395,33 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
goto out;
}
- store_offset = 0;
- zram_set_flag(zram, index, ZRAM_UNCOMPRESSED);
- zram_stat_inc(&zram->stats.pages_expand);
- handle = (unsigned long)page_store;
src = kmap_atomic(page);
cmem = kmap_atomic(page_store);
- goto memstore;
- }
+ memcpy(cmem, src, clen);
+ kunmap_atomic(cmem);
+ kunmap_atomic(src);
- handle = zs_malloc(zram->mem_pool, clen + sizeof(*zheader));
- 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);
+ zram->table[index].page = page_store;
+ zram->table[index].size = PAGE_SIZE;
+
+ zram_set_flag(zram, index, ZRAM_UNCOMPRESSED);
+ zram_stat_inc(&zram->stats.pages_expand);
+ } else {
+ handle = zs_malloc(zram->mem_pool, clen + sizeof(*zheader));
+ if (!handle) {
+ pr_info("Error allocating memory for "
+ "compressed page: %u, size=%zu\n", index, clen);
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ zram->table[index].handle = handle;
+ zram->table[index].size = clen;
-memstore:
+ cmem = zs_map_object(zram->mem_pool, handle);
+ memcpy(cmem, src, clen);
+ zs_unmap_object(zram->mem_pool, handle);
+ }
#if 0
/* Back-reference needed for memory defragmentation */
if (!zram_test_flag(zram, index, ZRAM_UNCOMPRESSED)) {
@@ -424,18 +431,6 @@ memstore:
}
#endif
- memcpy(cmem, src, clen);
-
- if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED))) {
- kunmap_atomic(cmem);
- kunmap_atomic(src);
- } else {
- zs_unmap_object(zram->mem_pool, handle);
- }
-
- zram->table[index].handle = handle;
- zram->table[index].size = clen;
-
/* Update stats */
zram_stat64_add(zram, &zram->stats.compr_size, clen);
zram_stat_inc(&zram->stats.pages_stored);
@@ -580,6 +575,8 @@ error:
void __zram_reset_device(struct zram *zram)
{
size_t index;
+ unsigned long handle;
+ struct page *page;
zram->init_done = 0;
@@ -592,14 +589,17 @@ void __zram_reset_device(struct zram *zram)
/* 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;
- if (!handle)
- continue;
-
- if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED)))
- __free_page((struct page *)handle);
- else
+ if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED))) {
+ page = zram->table[index].page;
+ if (!page)
+ continue;
+ __free_page(page);
+ } else {
+ handle = zram->table[index].handle;
+ if (!handle)
+ continue;
zs_free(zram->mem_pool, handle);
+ }
}
vfree(zram->table);
@@ -788,6 +788,9 @@ static int __init zram_init(void)
{
int ret, dev_id;
+ BUILD_BUG_ON(sizeof(((struct table *)0)->page) !=
+ sizeof(((struct table *)0)->handle));
+
if (num_devices > max_num_devices) {
pr_warning("Invalid value for num_devices: %u\n",
num_devices);
diff --git a/drivers/staging/zram/zram_drv.h b/drivers/staging/zram/zram_drv.h
index 7a7e256..54d082f 100644
--- a/drivers/staging/zram/zram_drv.h
+++ b/drivers/staging/zram/zram_drv.h
@@ -81,7 +81,10 @@ enum zram_pageflags {
/* Allocated for each disk page */
struct table {
- unsigned long handle;
+ union {
+ unsigned long handle; /* compressible */
+ struct page *page; /* incompressible */
+ };
u16 size; /* object size (excluding header) */
u8 count; /* object ref count (not yet used) */
u8 flags;
--
1.7.9.5
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