3 files changed, 15 insertions, 112 deletions

diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index 0cdc303..2036a90 100644
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -136,6 +136,7 @@ static void zram_set_disksize(struct zram *zram, size_t totalram_bytes)
 static void zram_free_page(struct zram *zram, size_t index)
 {
 	unsigned long handle = zram->table[index].handle;
+	u16 size = zram->table[index].size;
 
 	if (unlikely(!handle)) {
 		/*
@@ -149,19 +150,14 @@ static void zram_free_page(struct zram *zram, size_t index)
 		return;
 	}
 
-	if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED))) {
-		__free_page((struct page *)handle);
-		zram_clear_flag(zram, index, ZRAM_UNCOMPRESSED);
-		zram_stat_dec(&zram->stats.pages_expand);
-		goto out;
-	}
+	if (unlikely(size > max_zpage_size))
+		zram_stat_dec(&zram->stats.bad_compress);
 
 	zs_free(zram->mem_pool, handle);
 
-	if (zram->table[index].size <= PAGE_SIZE / 2)
+	if (size <= PAGE_SIZE / 2)
 		zram_stat_dec(&zram->stats.good_compress);
 
-out:
 	zram_stat64_sub(zram, &zram->stats.compr_size,
 			zram->table[index].size);
 	zram_stat_dec(&zram->stats.pages_stored);
@@ -182,22 +178,6 @@ static void handle_zero_page(struct bio_vec *bvec)
 	flush_dcache_page(page);
 }
 
-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);
-	cmem = kmap_atomic((struct page *)zram->table[index].handle);
-
-	memcpy(user_mem + bvec->bv_offset, cmem + offset, bvec->bv_len);
-	kunmap_atomic(cmem);
-	kunmap_atomic(user_mem);
-
-	flush_dcache_page(page);
-}
-
 static inline int is_partial_io(struct bio_vec *bvec)
 {
 	return bvec->bv_len != PAGE_SIZE;
@@ -209,7 +189,6 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
 	int ret;
 	size_t clen;
 	struct page *page;
-	struct zobj_header *zheader;
 	unsigned char *user_mem, *cmem, *uncmem = NULL;
 
 	page = bvec->bv_page;
@@ -227,12 +206,6 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
 		return 0;
 	}
 
-	/* Page is stored uncompressed since it's incompressible */
-	if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED))) {
-		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);
@@ -249,8 +222,7 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
 
 	cmem = zs_map_object(zram->mem_pool, zram->table[index].handle);
 
-	ret = lzo1x_decompress_safe(cmem + sizeof(*zheader),
-				    zram->table[index].size,
+	ret = lzo1x_decompress_safe(cmem, zram->table[index].size,
 				    uncmem, &clen);
 
 	if (is_partial_io(bvec)) {
@@ -278,7 +250,6 @@ 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;
 	unsigned long handle = zram->table[index].handle;
 
@@ -287,18 +258,8 @@ static int zram_read_before_write(struct zram *zram, char *mem, u32 index)
 		return 0;
 	}
 
-	/* Page is stored uncompressed since it's incompressible */
-	if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED))) {
-		char *src = kmap_atomic((struct page *)handle);
-		memcpy(mem, src, PAGE_SIZE);
-		kunmap_atomic(src);
-		return 0;
-	}
-
 	cmem = zs_map_object(zram->mem_pool, handle);
-
-	ret = lzo1x_decompress_safe(cmem + sizeof(*zheader),
-				    zram->table[index].size,
+	ret = lzo1x_decompress_safe(cmem, zram->table[index].size,
 				    mem, &clen);
 	zs_unmap_object(zram->mem_pool, handle);
 
@@ -316,11 +277,9 @@ 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;
-	struct page *page, *page_store;
+	struct page *page;
 	unsigned char *user_mem, *cmem, *src, *uncmem = NULL;
 
 	page = bvec->bv_page;
@@ -382,31 +341,10 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 		goto out;
 	}
 
-	/*
-	 * Page is incompressible. Store it as-is (uncompressed)
-	 * since we do not want to return too many disk write
-	 * errors which has side effect of hanging the system.
-	 */
-	if (unlikely(clen > max_zpage_size)) {
-		clen = PAGE_SIZE;
-		page_store = alloc_page(GFP_NOIO | __GFP_HIGHMEM);
-		if (unlikely(!page_store)) {
-			pr_info("Error allocating memory for "
-				"incompressible page: %u\n", index);
-			ret = -ENOMEM;
-			goto out;
-		}
+	if (unlikely(clen > max_zpage_size))
+		zram_stat_inc(&zram->stats.bad_compress);
 
-		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;
-	}
-
-	handle = zs_malloc(zram->mem_pool, clen + sizeof(*zheader));
+	handle = zs_malloc(zram->mem_pool, clen);
 	if (!handle) {
 		pr_info("Error allocating memory for compressed "
 			"page: %u, size=%zu\n", index, clen);
@@ -415,24 +353,9 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 	}
 	cmem = zs_map_object(zram->mem_pool, handle);
 
-memstore:
-#if 0
-	/* Back-reference needed for memory defragmentation */
-	if (!zram_test_flag(zram, index, ZRAM_UNCOMPRESSED)) {
-		zheader = (struct zobj_header *)cmem;
-		zheader->table_idx = index;
-		cmem += sizeof(*zheader);
-	}
-#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);
-	}
+	zs_unmap_object(zram->mem_pool, handle);
 
 	zram->table[index].handle = handle;
 	zram->table[index].size = clen;
@@ -597,10 +520,7 @@ void __zram_reset_device(struct zram *zram)
 		if (!handle)
 			continue;
 
-		if (unlikely(zram_test_flag(zram, index, ZRAM_UNCOMPRESSED)))
-			__free_page((struct page *)handle);
-		else
-			zs_free(zram->mem_pool, handle);
+		zs_free(zram->mem_pool, handle);
 	}
 
 	vfree(zram->table);
diff --git a/drivers/staging/zram/zram_drv.h b/drivers/staging/zram/zram_drv.h
index 7a7e256..9711d1e 100644
--- a/drivers/staging/zram/zram_drv.h
+++ b/drivers/staging/zram/zram_drv.h
@@ -26,18 +26,6 @@
  */
 static const unsigned max_num_devices = 32;
 
-/*
- * Stored at beginning of each compressed object.
- *
- * It stores back-reference to table entry which points to this
- * object. This is required to support memory defragmentation.
- */
-struct zobj_header {
-#if 0
-	u32 table_idx;
-#endif
-};
-
 /*-- Configurable parameters */
 
 /* Default zram disk size: 25% of total RAM */
@@ -68,9 +56,6 @@ static const size_t max_zpage_size = PAGE_SIZE / 4 * 3;
 
 /* Flags for zram pages (table[page_no].flags) */
 enum zram_pageflags {
-	/* Page is stored uncompressed */
-	ZRAM_UNCOMPRESSED,
-
 	/* Page consists entirely of zeros */
 	ZRAM_ZERO,
 
@@ -98,7 +83,7 @@ struct zram_stats {
 	u32 pages_zero;		/* no. of zero filled pages */
 	u32 pages_stored;	/* no. of pages currently stored */
 	u32 good_compress;	/* % of pages with compression ratio<=50% */
-	u32 pages_expand;	/* % of incompressible pages */
+	u32 bad_compress;	/* % of pages with compression ratio>=75% */
 };
 
 struct zram {
diff --git a/drivers/staging/zram/zram_sysfs.c b/drivers/staging/zram/zram_sysfs.c
index a7f3771..edb0ed4 100644
--- a/drivers/staging/zram/zram_sysfs.c
+++ b/drivers/staging/zram/zram_sysfs.c
@@ -186,10 +186,8 @@ static ssize_t mem_used_total_show(struct device *dev,
 	u64 val = 0;
 	struct zram *zram = dev_to_zram(dev);
 
-	if (zram->init_done) {
-		val = zs_get_total_size_bytes(zram->mem_pool) +
-			((u64)(zram->stats.pages_expand) << PAGE_SHIFT);
-	}
+	if (zram->init_done)
+		val = zs_get_total_size_bytes(zram->mem_pool);
 
 	return sprintf(buf, "%llu\n", val);
 }