zram: Convert to use bdev_open_by_dev()

Convert zram to use bdev_open_by_dev() and pass the handle around.

CC: Minchan Kim <minchan@kernel.org>
CC: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-8-jack@suse.czSigned-off-by: Christian Brauner <brauner@kernel.org>

drivers/block/zram/zram_drv.c

@@ -414,17 +414,14 @@ static ssize_t writeback_limit_show(struct device *dev,
 
 static void reset_bdev(struct zram *zram)
 {
-	struct block_device *bdev;
-
 	if (!zram->backing_dev)
 		return;
 
-	bdev = zram->bdev;
-	blkdev_put(bdev, zram);
+	bdev_release(zram->bdev_handle);
 	/* hope filp_close flush all of IO */
 	filp_close(zram->backing_dev, NULL);
 	zram->backing_dev = NULL;
-	zram->bdev = NULL;
+	zram->bdev_handle = NULL;
 	zram->disk->fops = &zram_devops;
 	kvfree(zram->bitmap);
 	zram->bitmap = NULL;
@@ -470,7 +467,7 @@ static ssize_t backing_dev_store(struct device *dev,
 	struct address_space *mapping;
 	unsigned int bitmap_sz;
 	unsigned long nr_pages, *bitmap = NULL;
-	struct block_device *bdev = NULL;
+	struct bdev_handle *bdev_handle = NULL;
 	int err;
 	struct zram *zram = dev_to_zram(dev);
 
@@ -507,11 +504,11 @@ static ssize_t backing_dev_store(struct device *dev,
 		goto out;
 	}
 
-	bdev = blkdev_get_by_dev(inode->i_rdev, BLK_OPEN_READ | BLK_OPEN_WRITE,
-				 zram, NULL);
-	if (IS_ERR(bdev)) {
-		err = PTR_ERR(bdev);
-		bdev = NULL;
+	bdev_handle = bdev_open_by_dev(inode->i_rdev,
+				BLK_OPEN_READ | BLK_OPEN_WRITE, zram, NULL);
+	if (IS_ERR(bdev_handle)) {
+		err = PTR_ERR(bdev_handle);
+		bdev_handle = NULL;
 		goto out;
 	}
 
@@ -525,7 +522,7 @@ static ssize_t backing_dev_store(struct device *dev,
 
 	reset_bdev(zram);
 
-	zram->bdev = bdev;
+	zram->bdev_handle = bdev_handle;
 	zram->backing_dev = backing_dev;
 	zram->bitmap = bitmap;
 	zram->nr_pages = nr_pages;
@@ -538,8 +535,8 @@ static ssize_t backing_dev_store(struct device *dev,
 out:
 	kvfree(bitmap);
 
-	if (bdev)
-		blkdev_put(bdev, zram);
+	if (bdev_handle)
+		bdev_release(bdev_handle);
 
 	if (backing_dev)
 		filp_close(backing_dev, NULL);
@@ -581,7 +578,7 @@ static void read_from_bdev_async(struct zram *zram, struct page *page,
 {
 	struct bio *bio;
 
-	bio = bio_alloc(zram->bdev, 1, parent->bi_opf, GFP_NOIO);
+	bio = bio_alloc(zram->bdev_handle->bdev, 1, parent->bi_opf, GFP_NOIO);
 	bio->bi_iter.bi_sector = entry * (PAGE_SIZE >> 9);
 	__bio_add_page(bio, page, PAGE_SIZE, 0);
 	bio_chain(bio, parent);
@@ -697,7 +694,7 @@ static ssize_t writeback_store(struct device *dev,
 			continue;
 		}
 
-		bio_init(&bio, zram->bdev, &bio_vec, 1,
+		bio_init(&bio, zram->bdev_handle->bdev, &bio_vec, 1,
 			 REQ_OP_WRITE | REQ_SYNC);
 		bio.bi_iter.bi_sector = blk_idx * (PAGE_SIZE >> 9);
 		__bio_add_page(&bio, page, PAGE_SIZE, 0);
@@ -779,7 +776,7 @@ static void zram_sync_read(struct work_struct *work)
 	struct bio_vec bv;
 	struct bio bio;
 
-	bio_init(&bio, zw->zram->bdev, &bv, 1, REQ_OP_READ);
+	bio_init(&bio, zw->zram->bdev_handle->bdev, &bv, 1, REQ_OP_READ);
 	bio.bi_iter.bi_sector = zw->entry * (PAGE_SIZE >> 9);
 	__bio_add_page(&bio, zw->page, PAGE_SIZE, 0);
 	zw->error = submit_bio_wait(&bio);

drivers/block/zram/zram_drv.h

@@ -132,7 +132,7 @@ struct zram {
 	spinlock_t wb_limit_lock;
 	bool wb_limit_enable;
 	u64 bd_wb_limit;
-	struct block_device *bdev;
+	struct bdev_handle *bdev_handle;
 	unsigned long *bitmap;
 	unsigned long nr_pages;
 #endif