1 files changed, 226 insertions, 157 deletions

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 51c557cfd92b..9849b5233bf4 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -29,19 +29,36 @@
 #include <linux/genhd.h>
 #include <linux/highmem.h>
 #include <linux/slab.h>
-#include <linux/lzo.h>
 #include <linux/string.h>
 #include <linux/vmalloc.h>
+#include <linux/err.h>
 
 #include "zram_drv.h"
 
 /* Globals */
 static int zram_major;
 static struct zram *zram_devices;
+static const char *default_compressor = "lzo";
 
 /* Module params (documentation at end) */
 static unsigned int num_devices = 1;
 
+#define ZRAM_ATTR_RO(name)						\
+static ssize_t zram_attr_##name##_show(struct device *d,		\
+				struct device_attribute *attr, char *b)	\
+{									\
+	struct zram *zram = dev_to_zram(d);				\
+	return scnprintf(b, PAGE_SIZE, "%llu\n",			\
+		(u64)atomic64_read(&zram->stats.name));			\
+}									\
+static struct device_attribute dev_attr_##name =			\
+	__ATTR(name, S_IRUGO, zram_attr_##name##_show, NULL);
+
+static inline int init_done(struct zram *zram)
+{
+	return zram->meta != NULL;
+}
+
 static inline struct zram *dev_to_zram(struct device *dev)
 {
 	return (struct zram *)dev_to_disk(dev)->private_data;
@@ -52,92 +69,114 @@ static ssize_t disksize_show(struct device *dev,
 {
 	struct zram *zram = dev_to_zram(dev);
 
-	return sprintf(buf, "%llu\n", zram->disksize);
+	return scnprintf(buf, PAGE_SIZE, "%llu\n", zram->disksize);
 }
 
 static ssize_t initstate_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
+	u32 val;
 	struct zram *zram = dev_to_zram(dev);
 
-	return sprintf(buf, "%u\n", zram->init_done);
-}
-
-static ssize_t num_reads_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
-{
-	struct zram *zram = dev_to_zram(dev);
+	down_read(&zram->init_lock);
+	val = init_done(zram);
+	up_read(&zram->init_lock);
 
-	return sprintf(buf, "%llu\n",
-			(u64)atomic64_read(&zram->stats.num_reads));
+	return scnprintf(buf, PAGE_SIZE, "%u\n", val);
 }
 
-static ssize_t num_writes_show(struct device *dev,
+static ssize_t orig_data_size_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
 	struct zram *zram = dev_to_zram(dev);
 
-	return sprintf(buf, "%llu\n",
-			(u64)atomic64_read(&zram->stats.num_writes));
+	return scnprintf(buf, PAGE_SIZE, "%llu\n",
+		(u64)(atomic64_read(&zram->stats.pages_stored)) << PAGE_SHIFT);
 }
 
-static ssize_t invalid_io_show(struct device *dev,
+static ssize_t mem_used_total_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
+	u64 val = 0;
 	struct zram *zram = dev_to_zram(dev);
+	struct zram_meta *meta = zram->meta;
 
-	return sprintf(buf, "%llu\n",
-			(u64)atomic64_read(&zram->stats.invalid_io));
-}
-
-static ssize_t notify_free_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
-{
-	struct zram *zram = dev_to_zram(dev);
+	down_read(&zram->init_lock);
+	if (init_done(zram))
+		val = zs_get_total_size_bytes(meta->mem_pool);
+	up_read(&zram->init_lock);
 
-	return sprintf(buf, "%llu\n",
-			(u64)atomic64_read(&zram->stats.notify_free));
+	return scnprintf(buf, PAGE_SIZE, "%llu\n", val);
 }
 
-static ssize_t zero_pages_show(struct device *dev,
+static ssize_t max_comp_streams_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
+	int val;
 	struct zram *zram = dev_to_zram(dev);
 
-	return sprintf(buf, "%u\n", atomic_read(&zram->stats.pages_zero));
+	down_read(&zram->init_lock);
+	val = zram->max_comp_streams;
+	up_read(&zram->init_lock);
+
+	return scnprintf(buf, PAGE_SIZE, "%d\n", val);
 }
 
-static ssize_t orig_data_size_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
+static ssize_t max_comp_streams_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t len)
 {
+	int num;
 	struct zram *zram = dev_to_zram(dev);
+	int ret;
 
-	return sprintf(buf, "%llu\n",
-		(u64)(atomic_read(&zram->stats.pages_stored)) << PAGE_SHIFT);
-}
+	ret = kstrtoint(buf, 0, &num);
+	if (ret < 0)
+		return ret;
+	if (num < 1)
+		return -EINVAL;
 
-static ssize_t compr_data_size_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
-{
-	struct zram *zram = dev_to_zram(dev);
+	down_write(&zram->init_lock);
+	if (init_done(zram)) {
+		if (!zcomp_set_max_streams(zram->comp, num)) {
+			pr_info("Cannot change max compression streams\n");
+			ret = -EINVAL;
+			goto out;
+		}
+	}
 
-	return sprintf(buf, "%llu\n",
-			(u64)atomic64_read(&zram->stats.compr_size));
+	zram->max_comp_streams = num;
+	ret = len;
+out:
+	up_write(&zram->init_lock);
+	return ret;
 }
 
-static ssize_t mem_used_total_show(struct device *dev,
+static ssize_t comp_algorithm_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
-	u64 val = 0;
+	size_t sz;
 	struct zram *zram = dev_to_zram(dev);
-	struct zram_meta *meta = zram->meta;
 
 	down_read(&zram->init_lock);
-	if (zram->init_done)
-		val = zs_get_total_size_bytes(meta->mem_pool);
+	sz = zcomp_available_show(zram->compressor, buf);
 	up_read(&zram->init_lock);
 
-	return sprintf(buf, "%llu\n", val);
+	return sz;
+}
+
+static ssize_t comp_algorithm_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t len)
+{
+	struct zram *zram = dev_to_zram(dev);
+	down_write(&zram->init_lock);
+	if (init_done(zram)) {
+		up_write(&zram->init_lock);
+		pr_info("Can't change algorithm for initialized device\n");
+		return -EBUSY;
+	}
+	strlcpy(zram->compressor, buf, sizeof(zram->compressor));
+	up_write(&zram->init_lock);
+	return len;
 }
 
 /* flag operations needs meta->tb_lock */
@@ -192,8 +231,6 @@ static inline int valid_io_request(struct zram *zram, struct bio *bio)
 static 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);
 }
@@ -205,22 +242,11 @@ static struct zram_meta *zram_meta_alloc(u64 disksize)
 	if (!meta)
 		goto out;
 
-	meta->compress_workmem = kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
-	if (!meta->compress_workmem)
-		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;
+		goto free_meta;
 	}
 
 	meta->mem_pool = zs_create_pool(GFP_NOIO | __GFP_HIGHMEM);
@@ -230,15 +256,10 @@ static struct zram_meta *zram_meta_alloc(u64 disksize)
 	}
 
 	rwlock_init(&meta->tb_lock);
-	mutex_init(&meta->buffer_lock);
 	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;
@@ -288,7 +309,6 @@ static void zram_free_page(struct zram *zram, size_t index)
 {
 	struct zram_meta *meta = zram->meta;
 	unsigned long handle = meta->table[index].handle;
-	u16 size = meta->table[index].size;
 
 	if (unlikely(!handle)) {
 		/*
@@ -297,21 +317,15 @@ static void zram_free_page(struct zram *zram, size_t index)
 		 */
 		if (zram_test_flag(meta, index, ZRAM_ZERO)) {
 			zram_clear_flag(meta, index, ZRAM_ZERO);
-			atomic_dec(&zram->stats.pages_zero);
+			atomic64_dec(&zram->stats.zero_pages);
 		}
 		return;
 	}
 
-	if (unlikely(size > max_zpage_size))
-		atomic_dec(&zram->stats.bad_compress);
-
 	zs_free(meta->mem_pool, handle);
 
-	if (size <= PAGE_SIZE / 2)
-		atomic_dec(&zram->stats.good_compress);
-
-	atomic64_sub(meta->table[index].size, &zram->stats.compr_size);
-	atomic_dec(&zram->stats.pages_stored);
+	atomic64_sub(meta->table[index].size, &zram->stats.compr_data_size);
+	atomic64_dec(&zram->stats.pages_stored);
 
 	meta->table[index].handle = 0;
 	meta->table[index].size = 0;
@@ -319,8 +333,7 @@ static void zram_free_page(struct zram *zram, size_t index)
 
 static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
 {
-	int ret = LZO_E_OK;
-	size_t clen = PAGE_SIZE;
+	int ret = 0;
 	unsigned char *cmem;
 	struct zram_meta *meta = zram->meta;
 	unsigned long handle;
@@ -340,12 +353,12 @@ static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
 	if (size == PAGE_SIZE)
 		copy_page(mem, cmem);
 	else
-		ret = lzo1x_decompress_safe(cmem, size,	mem, &clen);
+		ret = zcomp_decompress(zram->comp, cmem, size, mem);
 	zs_unmap_object(meta->mem_pool, handle);
 	read_unlock(&meta->tb_lock);
 
 	/* Should NEVER happen. Return bio error if it does. */
-	if (unlikely(ret != LZO_E_OK)) {
+	if (unlikely(ret)) {
 		pr_err("Decompression failed! err=%d, page=%u\n", ret, index);
 		atomic64_inc(&zram->stats.failed_reads);
 		return ret;
@@ -388,7 +401,7 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
 
 	ret = zram_decompress_page(zram, uncmem, index);
 	/* Should NEVER happen. Return bio error if it does. */
-	if (unlikely(ret != LZO_E_OK))
+	if (unlikely(ret))
 		goto out_cleanup;
 
 	if (is_partial_io(bvec))
@@ -413,11 +426,10 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 	struct page *page;
 	unsigned char *user_mem, *cmem, *src, *uncmem = NULL;
 	struct zram_meta *meta = zram->meta;
+	struct zcomp_strm *zstrm;
 	bool locked = false;
 
 	page = bvec->bv_page;
-	src = meta->compress_buffer;
-
 	if (is_partial_io(bvec)) {
 		/*
 		 * This is a partial IO. We need to read the full page
@@ -433,7 +445,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 			goto out;
 	}
 
-	mutex_lock(&meta->buffer_lock);
+	zstrm = zcomp_strm_find(zram->comp);
 	locked = true;
 	user_mem = kmap_atomic(page);
 
@@ -454,28 +466,25 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 		zram_set_flag(meta, index, ZRAM_ZERO);
 		write_unlock(&zram->meta->tb_lock);
 
-		atomic_inc(&zram->stats.pages_zero);
+		atomic64_inc(&zram->stats.zero_pages);
 		ret = 0;
 		goto out;
 	}
 
-	ret = lzo1x_1_compress(uncmem, PAGE_SIZE, src, &clen,
-			       meta->compress_workmem);
+	ret = zcomp_compress(zram->comp, zstrm, uncmem, &clen);
 	if (!is_partial_io(bvec)) {
 		kunmap_atomic(user_mem);
 		user_mem = NULL;
 		uncmem = NULL;
 	}
 
-	if (unlikely(ret != LZO_E_OK)) {
+	if (unlikely(ret)) {
 		pr_err("Compression failed! err=%d\n", ret);
 		goto out;
 	}
-
+	src = zstrm->buffer;
 	if (unlikely(clen > max_zpage_size)) {
-		atomic_inc(&zram->stats.bad_compress);
 		clen = PAGE_SIZE;
-		src = NULL;
 		if (is_partial_io(bvec))
 			src = uncmem;
 	}
@@ -497,6 +506,8 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 		memcpy(cmem, src, clen);
 	}
 
+	zcomp_strm_release(zram->comp, zstrm);
+	locked = false;
 	zs_unmap_object(meta->mem_pool, handle);
 
 	/*
@@ -511,49 +522,88 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 	write_unlock(&zram->meta->tb_lock);
 
 	/* Update stats */
-	atomic64_add(clen, &zram->stats.compr_size);
-	atomic_inc(&zram->stats.pages_stored);
-	if (clen <= PAGE_SIZE / 2)
-		atomic_inc(&zram->stats.good_compress);
-
+	atomic64_add(clen, &zram->stats.compr_data_size);
+	atomic64_inc(&zram->stats.pages_stored);
 out:
 	if (locked)
-		mutex_unlock(&meta->buffer_lock);
+		zcomp_strm_release(zram->comp, zstrm);
 	if (is_partial_io(bvec))
 		kfree(uncmem);
-
 	if (ret)
 		atomic64_inc(&zram->stats.failed_writes);
 	return ret;
 }
 
 static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
-			int offset, struct bio *bio, int rw)
+			int offset, struct bio *bio)
 {
 	int ret;
+	int rw = bio_data_dir(bio);
 
-	if (rw == READ)
+	if (rw == READ) {
+		atomic64_inc(&zram->stats.num_reads);
 		ret = zram_bvec_read(zram, bvec, index, offset, bio);
-	else
+	} else {
+		atomic64_inc(&zram->stats.num_writes);
 		ret = zram_bvec_write(zram, bvec, index, offset);
+	}
 
 	return ret;
 }
 
+/*
+ * zram_bio_discard - handler on discard request
+ * @index: physical block index in PAGE_SIZE units
+ * @offset: byte offset within physical block
+ */
+static void zram_bio_discard(struct zram *zram, u32 index,
+			     int offset, struct bio *bio)
+{
+	size_t n = bio->bi_iter.bi_size;
+
+	/*
+	 * zram manages data in physical block size units. Because logical block
+	 * size isn't identical with physical block size on some arch, we
+	 * could get a discard request pointing to a specific offset within a
+	 * certain physical block.  Although we can handle this request by
+	 * reading that physiclal block and decompressing and partially zeroing
+	 * and re-compressing and then re-storing it, this isn't reasonable
+	 * because our intent with a discard request is to save memory.  So
+	 * skipping this logical block is appropriate here.
+	 */
+	if (offset) {
+		if (n < offset)
+			return;
+
+		n -= offset;
+		index++;
+	}
+
+	while (n >= PAGE_SIZE) {
+		/*
+		 * Discard request can be large so the lock hold times could be
+		 * lengthy.  So take the lock once per page.
+		 */
+		write_lock(&zram->meta->tb_lock);
+		zram_free_page(zram, index);
+		write_unlock(&zram->meta->tb_lock);
+		index++;
+		n -= PAGE_SIZE;
+	}
+}
+
 static void zram_reset_device(struct zram *zram, bool reset_capacity)
 {
 	size_t index;
 	struct zram_meta *meta;
 
 	down_write(&zram->init_lock);
-	if (!zram->init_done) {
+	if (!init_done(zram)) {
 		up_write(&zram->init_lock);
 		return;
 	}
 
 	meta = zram->meta;
-	zram->init_done = 0;
-
 	/* Free all pages that are still in this zram device */
 	for (index = 0; index < zram->disksize >> PAGE_SHIFT; index++) {
 		unsigned long handle = meta->table[index].handle;
@@ -563,6 +613,9 @@ static void zram_reset_device(struct zram *zram, bool reset_capacity)
 		zs_free(meta->mem_pool, handle);
 	}
 
+	zcomp_destroy(zram->comp);
+	zram->max_comp_streams = 1;
+
 	zram_meta_free(zram->meta);
 	zram->meta = NULL;
 	/* Reset stats */
@@ -574,37 +627,14 @@ static void zram_reset_device(struct zram *zram, bool reset_capacity)
 	up_write(&zram->init_lock);
 }
 
-static 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 "
-		"twice the size of memory since we expect a 2:1 compression "
-		"ratio. Note that zram uses about 0.1%% of the size of "
-		"the disk when not in use so a huge zram is "
-		"wasteful.\n"
-		"\tMemory Size: %lu kB\n"
-		"\tSize you selected: %llu kB\n"
-		"Continuing anyway ...\n",
-		(totalram_pages << PAGE_SHIFT) >> 10, zram->disksize >> 10
-		);
-	}
-
-	/* zram devices sort of resembles non-rotational disks */
-	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zram->disk->queue);
-
-	zram->meta = meta;
-	zram->init_done = 1;
-
-	pr_debug("Initialization done!\n");
-}
-
 static ssize_t disksize_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t len)
 {
 	u64 disksize;
+	struct zcomp *comp;
 	struct zram_meta *meta;
 	struct zram *zram = dev_to_zram(dev);
+	int err;
 
 	disksize = memparse(buf, NULL);
 	if (!disksize)
@@ -614,20 +644,35 @@ static ssize_t disksize_store(struct device *dev,
 	meta = zram_meta_alloc(disksize);
 	if (!meta)
 		return -ENOMEM;
+
+	comp = zcomp_create(zram->compressor, zram->max_comp_streams);
+	if (IS_ERR(comp)) {
+		pr_info("Cannot initialise %s compressing backend\n",
+				zram->compressor);
+		err = PTR_ERR(comp);
+		goto out_free_meta;
+	}
+
 	down_write(&zram->init_lock);
-	if (zram->init_done) {
-		up_write(&zram->init_lock);
-		zram_meta_free(meta);
+	if (init_done(zram)) {
 		pr_info("Cannot change disksize for initialized device\n");
-		return -EBUSY;
+		err = -EBUSY;
+		goto out_destroy_comp;
 	}
 
+	zram->meta = meta;
+	zram->comp = comp;
 	zram->disksize = disksize;
 	set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
-	zram_init_device(zram, meta);
 	up_write(&zram->init_lock);
-
 	return len;
+
+out_destroy_comp:
+	up_write(&zram->init_lock);
+	zcomp_destroy(comp);
+out_free_meta:
+	zram_meta_free(meta);
+	return err;
 }
 
 static ssize_t reset_store(struct device *dev,
@@ -671,26 +716,23 @@ out:
 	return ret;
 }
 
-static void __zram_make_request(struct zram *zram, struct bio *bio, int rw)
+static void __zram_make_request(struct zram *zram, struct bio *bio)
 {
 	int offset;
 	u32 index;
 	struct bio_vec bvec;
 	struct bvec_iter iter;
 
-	switch (rw) {
-	case READ:
-		atomic64_inc(&zram->stats.num_reads);
-		break;
-	case WRITE:
-		atomic64_inc(&zram->stats.num_writes);
-		break;
-	}
-
 	index = bio->bi_iter.bi_sector >> SECTORS_PER_PAGE_SHIFT;
 	offset = (bio->bi_iter.bi_sector &
 		  (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT;
 
+	if (unlikely(bio->bi_rw & REQ_DISCARD)) {
+		zram_bio_discard(zram, index, offset, bio);
+		bio_endio(bio, 0);
+		return;
+	}
+
 	bio_for_each_segment(bvec, bio, iter) {
 		int max_transfer_size = PAGE_SIZE - offset;
 
@@ -705,16 +747,15 @@ static void __zram_make_request(struct zram *zram, struct bio *bio, int rw)
 			bv.bv_len = max_transfer_size;
 			bv.bv_offset = bvec.bv_offset;
 
-			if (zram_bvec_rw(zram, &bv, index, offset, bio, rw) < 0)
+			if (zram_bvec_rw(zram, &bv, index, offset, bio) < 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)
+			if (zram_bvec_rw(zram, &bv, index + 1, 0, bio) < 0)
 				goto out;
 		} else
-			if (zram_bvec_rw(zram, &bvec, index, offset, bio, rw)
-			    < 0)
+			if (zram_bvec_rw(zram, &bvec, index, offset, bio) < 0)
 				goto out;
 
 		update_position(&index, &offset, &bvec);
@@ -736,7 +777,7 @@ static void zram_make_request(struct request_queue *queue, struct bio *bio)
 	struct zram *zram = queue->queuedata;
 
 	down_read(&zram->init_lock);
-	if (unlikely(!zram->init_done))
+	if (unlikely(!init_done(zram)))
 		goto error;
 
 	if (!valid_io_request(zram, bio)) {
@@ -744,7 +785,7 @@ static void zram_make_request(struct request_queue *queue, struct bio *bio)
 		goto error;
 	}
 
-	__zram_make_request(zram, bio, bio_data_dir(bio));
+	__zram_make_request(zram, bio);
 	up_read(&zram->init_lock);
 
 	return;
@@ -778,14 +819,21 @@ static DEVICE_ATTR(disksize, S_IRUGO | S_IWUSR,
 		disksize_show, disksize_store);
 static DEVICE_ATTR(initstate, S_IRUGO, initstate_show, NULL);
 static DEVICE_ATTR(reset, S_IWUSR, NULL, reset_store);
-static DEVICE_ATTR(num_reads, S_IRUGO, num_reads_show, NULL);
-static DEVICE_ATTR(num_writes, S_IRUGO, num_writes_show, NULL);
-static DEVICE_ATTR(invalid_io, S_IRUGO, invalid_io_show, NULL);
-static DEVICE_ATTR(notify_free, S_IRUGO, notify_free_show, NULL);
-static DEVICE_ATTR(zero_pages, S_IRUGO, zero_pages_show, NULL);
 static DEVICE_ATTR(orig_data_size, S_IRUGO, orig_data_size_show, NULL);
-static DEVICE_ATTR(compr_data_size, S_IRUGO, compr_data_size_show, NULL);
 static DEVICE_ATTR(mem_used_total, S_IRUGO, mem_used_total_show, NULL);
+static DEVICE_ATTR(max_comp_streams, S_IRUGO | S_IWUSR,
+		max_comp_streams_show, max_comp_streams_store);
+static DEVICE_ATTR(comp_algorithm, S_IRUGO | S_IWUSR,
+		comp_algorithm_show, comp_algorithm_store);
+
+ZRAM_ATTR_RO(num_reads);
+ZRAM_ATTR_RO(num_writes);
+ZRAM_ATTR_RO(failed_reads);
+ZRAM_ATTR_RO(failed_writes);
+ZRAM_ATTR_RO(invalid_io);
+ZRAM_ATTR_RO(notify_free);
+ZRAM_ATTR_RO(zero_pages);
+ZRAM_ATTR_RO(compr_data_size);
 
 static struct attribute *zram_disk_attrs[] = {
 	&dev_attr_disksize.attr,
@@ -793,12 +841,16 @@ static struct attribute *zram_disk_attrs[] = {
 	&dev_attr_reset.attr,
 	&dev_attr_num_reads.attr,
 	&dev_attr_num_writes.attr,
+	&dev_attr_failed_reads.attr,
+	&dev_attr_failed_writes.attr,
 	&dev_attr_invalid_io.attr,
 	&dev_attr_notify_free.attr,
 	&dev_attr_zero_pages.attr,
 	&dev_attr_orig_data_size.attr,
 	&dev_attr_compr_data_size.attr,
 	&dev_attr_mem_used_total.attr,
+	&dev_attr_max_comp_streams.attr,
+	&dev_attr_comp_algorithm.attr,
 	NULL,
 };
 
@@ -839,7 +891,8 @@ static int create_device(struct zram *zram, int device_id)
 
 	/* Actual capacity set using syfs (/sys/block/zram<id>/disksize */
 	set_capacity(zram->disk, 0);
-
+	/* zram devices sort of resembles non-rotational disks */
+	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zram->disk->queue);
 	/*
 	 * To ensure that we always get PAGE_SIZE aligned
 	 * and n*PAGE_SIZED sized I/O requests.
@@ -849,6 +902,21 @@ static int create_device(struct zram *zram, int device_id)
 					ZRAM_LOGICAL_BLOCK_SIZE);
 	blk_queue_io_min(zram->disk->queue, PAGE_SIZE);
 	blk_queue_io_opt(zram->disk->queue, PAGE_SIZE);
+	zram->disk->queue->limits.discard_granularity = PAGE_SIZE;
+	zram->disk->queue->limits.max_discard_sectors = UINT_MAX;
+	/*
+	 * zram_bio_discard() will clear all logical blocks if logical block
+	 * size is identical with physical block size(PAGE_SIZE). But if it is
+	 * different, we will skip discarding some parts of logical blocks in
+	 * the part of the request range which isn't aligned to physical block
+	 * size.  So we can't ensure that all discarded logical blocks are
+	 * zeroed.
+	 */
+	if (ZRAM_LOGICAL_BLOCK_SIZE == PAGE_SIZE)
+		zram->disk->queue->limits.discard_zeroes_data = 1;
+	else
+		zram->disk->queue->limits.discard_zeroes_data = 0;
+	queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, zram->disk->queue);
 
 	add_disk(zram->disk);
 
@@ -858,8 +926,9 @@ static int create_device(struct zram *zram, int device_id)
 		pr_warn("Error creating sysfs group");
 		goto out_free_disk;
 	}
-
-	zram->init_done = 0;
+	strlcpy(zram->compressor, default_compressor, sizeof(zram->compressor));
+	zram->meta = NULL;
+	zram->max_comp_streams = 1;
 	return 0;
 
 out_free_disk: