[PATCH v15 06/12] fs, block: copy_file_range for def_blk_ops for direct block device

[Nitesh Shetty]

For direct block device opened with O_DIRECT, use copy_file_range to
issue device copy offload, and fallback to generic_copy_file_range incase
device copy offload capability is absent or the device files are not open
with O_DIRECT.

Signed-off-by: Anuj Gupta <anuj20.g at samsung.com>
Signed-off-by: Nitesh Shetty <nj.shetty at samsung.com>
---
 block/fops.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/block/fops.c b/block/fops.c
index a24a624d3bf7..2d96459f3277 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -739,6 +739,30 @@ static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
 	return ret;
 }
 
+static ssize_t blkdev_copy_file_range(struct file *file_in, loff_t pos_in,
+				      struct file *file_out, loff_t pos_out,
+				      size_t len, unsigned int flags)
+{
+	struct block_device *in_bdev = I_BDEV(bdev_file_inode(file_in));
+	struct block_device *out_bdev = I_BDEV(bdev_file_inode(file_out));
+	ssize_t copied = 0;
+
+	if ((in_bdev == out_bdev) && bdev_max_copy_sectors(in_bdev) &&
+	    (file_in->f_iocb_flags & IOCB_DIRECT) &&
+	    (file_out->f_iocb_flags & IOCB_DIRECT)) {
+		copied = blkdev_copy_offload(in_bdev, pos_in, pos_out, len,
+					     NULL, NULL, GFP_KERNEL);
+		if (copied < 0)
+			copied = 0;
+	}
+	if (copied != len)
+		copied = generic_copy_file_range(file_in, pos_in + copied,
+						 file_out, pos_out + copied,
+						 len - copied, flags);
+
+	return copied;
+}
+
 #define	BLKDEV_FALLOC_FL_SUPPORTED					\
 		(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |		\
 		 FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE)
@@ -832,6 +856,7 @@ const struct file_operations def_blk_fops = {
 	.splice_read	= filemap_splice_read,
 	.splice_write	= iter_file_splice_write,
 	.fallocate	= blkdev_fallocate,
+	.copy_file_range = blkdev_copy_file_range,
 };
 
 static __init int blkdev_init(void)
-- 
2.35.1.500.gb896f729e2