1 files changed, 55 insertions, 41 deletions

diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index d70ec1ad10d..b9926ee0052 100644
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -37,10 +37,10 @@
 
 /* Globals */
 static int zram_major;
-struct zram *devices;
+struct zram *zram_devices;
 
 /* Module params (documentation at end) */
-unsigned int num_devices;
+unsigned int zram_num_devices;
 
 static void zram_stat_inc(u32 *v)
 {
@@ -560,27 +560,34 @@ static int zram_make_request(struct request_queue *queue, struct bio *bio)
 {
 	struct zram *zram = queue->queuedata;
 
+	if (unlikely(!zram->init_done) && zram_init_device(zram))
+		goto error;
+
+	down_read(&zram->init_lock);
+	if (unlikely(!zram->init_done))
+		goto error_unlock;
+
 	if (!valid_io_request(zram, bio)) {
 		zram_stat64_inc(zram, &zram->stats.invalid_io);
-		bio_io_error(bio);
-		return 0;
-	}
-
-	if (unlikely(!zram->init_done) && zram_init_device(zram)) {
-		bio_io_error(bio);
-		return 0;
+		goto error_unlock;
 	}
 
 	__zram_make_request(zram, bio, bio_data_dir(bio));
+	up_read(&zram->init_lock);
 
 	return 0;
+
+error_unlock:
+	up_read(&zram->init_lock);
+error:
+	bio_io_error(bio);
+	return 0;
 }
 
-void zram_reset_device(struct zram *zram)
+void __zram_reset_device(struct zram *zram)
 {
 	size_t index;
 
-	mutex_lock(&zram->init_lock);
 	zram->init_done = 0;
 
 	/* Free various per-device buffers */
@@ -617,7 +624,13 @@ void zram_reset_device(struct zram *zram)
 	memset(&zram->stats, 0, sizeof(zram->stats));
 
 	zram->disksize = 0;
-	mutex_unlock(&zram->init_lock);
+}
+
+void zram_reset_device(struct zram *zram)
+{
+	down_write(&zram->init_lock);
+	__zram_reset_device(zram);
+	up_write(&zram->init_lock);
 }
 
 int zram_init_device(struct zram *zram)
@@ -625,10 +638,10 @@ int zram_init_device(struct zram *zram)
 	int ret;
 	size_t num_pages;
 
-	mutex_lock(&zram->init_lock);
+	down_write(&zram->init_lock);
 
 	if (zram->init_done) {
-		mutex_unlock(&zram->init_lock);
+		up_write(&zram->init_lock);
 		return 0;
 	}
 
@@ -638,24 +651,22 @@ int zram_init_device(struct zram *zram)
 	if (!zram->compress_workmem) {
 		pr_err("Error allocating compressor working memory!\n");
 		ret = -ENOMEM;
-		goto fail;
+		goto fail_no_table;
 	}
 
 	zram->compress_buffer = (void *)__get_free_pages(__GFP_ZERO, 1);
 	if (!zram->compress_buffer) {
 		pr_err("Error allocating compressor buffer space\n");
 		ret = -ENOMEM;
-		goto fail;
+		goto fail_no_table;
 	}
 
 	num_pages = zram->disksize >> PAGE_SHIFT;
 	zram->table = vzalloc(num_pages * sizeof(*zram->table));
 	if (!zram->table) {
 		pr_err("Error allocating zram address table\n");
-		/* To prevent accessing table entries during cleanup */
-		zram->disksize = 0;
 		ret = -ENOMEM;
-		goto fail;
+		goto fail_no_table;
 	}
 
 	set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
@@ -671,20 +682,23 @@ int zram_init_device(struct zram *zram)
 	}
 
 	zram->init_done = 1;
-	mutex_unlock(&zram->init_lock);
+	up_write(&zram->init_lock);
 
 	pr_debug("Initialization done!\n");
 	return 0;
 
+fail_no_table:
+	/* To prevent accessing table entries during cleanup */
+	zram->disksize = 0;
 fail:
-	mutex_unlock(&zram->init_lock);
-	zram_reset_device(zram);
-
+	__zram_reset_device(zram);
+	up_write(&zram->init_lock);
 	pr_err("Initialization failed: err=%d\n", ret);
 	return ret;
 }
 
-void zram_slot_free_notify(struct block_device *bdev, unsigned long index)
+static void zram_slot_free_notify(struct block_device *bdev,
+				unsigned long index)
 {
 	struct zram *zram;
 
@@ -703,7 +717,7 @@ static int create_device(struct zram *zram, int device_id)
 	int ret = 0;
 
 	init_rwsem(&zram->lock);
-	mutex_init(&zram->init_lock);
+	init_rwsem(&zram->init_lock);
 	spin_lock_init(&zram->stat64_lock);
 
 	zram->queue = blk_alloc_queue(GFP_KERNEL);
@@ -780,9 +794,9 @@ static int __init zram_init(void)
 {
 	int ret, dev_id;
 
-	if (num_devices > max_num_devices) {
+	if (zram_num_devices > max_num_devices) {
 		pr_warning("Invalid value for num_devices: %u\n",
-				num_devices);
+				zram_num_devices);
 		ret = -EINVAL;
 		goto out;
 	}
@@ -794,21 +808,21 @@ static int __init zram_init(void)
 		goto out;
 	}
 
-	if (!num_devices) {
+	if (!zram_num_devices) {
 		pr_info("num_devices not specified. Using default: 1\n");
-		num_devices = 1;
+		zram_num_devices = 1;
 	}
 
 	/* Allocate the device array and initialize each one */
-	pr_info("Creating %u devices ...\n", num_devices);
-	devices = kzalloc(num_devices * sizeof(struct zram), GFP_KERNEL);
-	if (!devices) {
+	pr_info("Creating %u devices ...\n", zram_num_devices);
+	zram_devices = kzalloc(zram_num_devices * sizeof(struct zram), GFP_KERNEL);
+	if (!zram_devices) {
 		ret = -ENOMEM;
 		goto unregister;
 	}
 
-	for (dev_id = 0; dev_id < num_devices; dev_id++) {
-		ret = create_device(&devices[dev_id], dev_id);
+	for (dev_id = 0; dev_id < zram_num_devices; dev_id++) {
+		ret = create_device(&zram_devices[dev_id], dev_id);
 		if (ret)
 			goto free_devices;
 	}
@@ -817,8 +831,8 @@ static int __init zram_init(void)
 
 free_devices:
 	while (dev_id)
-		destroy_device(&devices[--dev_id]);
-	kfree(devices);
+		destroy_device(&zram_devices[--dev_id]);
+	kfree(zram_devices);
 unregister:
 	unregister_blkdev(zram_major, "zram");
 out:
@@ -830,8 +844,8 @@ static void __exit zram_exit(void)
 	int i;
 	struct zram *zram;
 
-	for (i = 0; i < num_devices; i++) {
-		zram = &devices[i];
+	for (i = 0; i < zram_num_devices; i++) {
+		zram = &zram_devices[i];
 
 		destroy_device(zram);
 		if (zram->init_done)
@@ -840,12 +854,12 @@ static void __exit zram_exit(void)
 
 	unregister_blkdev(zram_major, "zram");
 
-	kfree(devices);
+	kfree(zram_devices);
 	pr_debug("Cleanup done!\n");
 }
 
-module_param(num_devices, uint, 0);
-MODULE_PARM_DESC(num_devices, "Number of zram devices");
+module_param(zram_num_devices, uint, 0);
+MODULE_PARM_DESC(zram_num_devices, "Number of zram devices");
 
 module_init(zram_init);
 module_exit(zram_exit);