block: add sync_blockdev_range()

sync_blockdev_range() is to support syncing multiple sectors
with as few block device requests as possible, it is helpful
to make the block device to give full play to its performance.

Signed-off-by: Yuezhang Mo <[email protected]>
Suggested-by: Christoph Hellwig <[email protected]>
Reviewed-by: Andy Wu <[email protected]>
Reviewed-by: Aoyama Wataru <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Jens Axboe <[email protected]>
Acked-by: Sungjong Seo <[email protected]>
Signed-off-by: Namjae Jeon <[email protected]>

Author: YuezhangMo

block/bdev.c

@@ -200,6 +200,13 @@ int sync_blockdev(struct block_device *bdev)
 }
 EXPORT_SYMBOL(sync_blockdev);
 
+int sync_blockdev_range(struct block_device *bdev, loff_t lstart, loff_t lend)
+{
+	return filemap_write_and_wait_range(bdev->bd_inode->i_mapping,
+			lstart, lend);
+}
+EXPORT_SYMBOL(sync_blockdev_range);
+
 /*
  * Write out and wait upon all dirty data associated with this
  * device.   Filesystem data as well as the underlying block

include/linux/blkdev.h

@@ -1547,6 +1547,7 @@ int truncate_bdev_range(struct block_device *bdev, fmode_t mode, loff_t lstart,
 #ifdef CONFIG_BLOCK
 void invalidate_bdev(struct block_device *bdev);
 int sync_blockdev(struct block_device *bdev);
+int sync_blockdev_range(struct block_device *bdev, loff_t lstart, loff_t lend);
 int sync_blockdev_nowait(struct block_device *bdev);
 void sync_bdevs(bool wait);
 void printk_all_partitions(void);