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Date: Tue, 5 Jun 2012 16:23:51 +0900
From: Minchan Kim <minchan@...nel.org>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: linux-kernel@...r.kernel.org, linux-mm@...ck.org,
Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
Dan Magenheimer <dan.magenheimer@...cle.com>,
Seth Jennings <sjenning@...ux.vnet.ibm.com>,
Nitin Gupta <ngupta@...are.org>,
Minchan Kim <minchan@...nel.org>
Subject: [PATCH 2/2] zram: clean up handle
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@...are.org>
Acked-by: Seth Jennings <sjenning@...ux.vnet.ibm.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Signed-off-by: Minchan Kim <minchan@...nel.org>
---
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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