[PATCH v10 4/9] 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.
Modify checks to allow bdevs to use copy_file_range.

Suggested-by: Ming Lei <ming.lei@xxxxxxxxxx>
Signed-off-by: Anuj Gupta <anuj20.g@xxxxxxxxxxx>
Signed-off-by: Nitesh Shetty <nj.shetty@xxxxxxxxxxx>
---
 block/blk-lib.c        | 23 +++++++++++++++++++++++
 block/fops.c           | 20 ++++++++++++++++++++
 fs/read_write.c        | 11 +++++++++--
 include/linux/blkdev.h |  3 +++
 4 files changed, 55 insertions(+), 2 deletions(-)

diff --git a/block/blk-lib.c b/block/blk-lib.c
index ba32545eb8d5..7d6ef85692a6 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -523,6 +523,29 @@ int blkdev_issue_copy(struct block_device *bdev_in, loff_t pos_in,
 }
 EXPORT_SYMBOL_GPL(blkdev_issue_copy);
 
+/* Returns the length of bytes copied */
+int blkdev_copy_offload(struct block_device *bdev_in, loff_t pos_in,
+		      struct block_device *bdev_out, loff_t pos_out, size_t len,
+		      gfp_t gfp_mask)
+{
+	struct request_queue *in_q = bdev_get_queue(bdev_in);
+	struct request_queue *out_q = bdev_get_queue(bdev_out);
+	int ret = 0;
+
+	if (blkdev_copy_sanity_check(bdev_in, pos_in, bdev_out, pos_out, len))
+		return 0;
+
+	if (blk_queue_copy(in_q) && blk_queue_copy(out_q)) {
+		ret = __blkdev_copy_offload(bdev_in, pos_in, bdev_out, pos_out,
+				len, NULL, NULL, gfp_mask);
+		if (ret < 0)
+			return 0;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(blkdev_copy_offload);
+
 static int __blkdev_issue_write_zeroes(struct block_device *bdev,
 		sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
 		struct bio **biop, unsigned flags)
diff --git a/block/fops.c b/block/fops.c
index d2e6be4e3d1c..042a62c81468 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -611,6 +611,25 @@ 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));
+	int comp_len = 0;
+
+	if ((file_in->f_iocb_flags & IOCB_DIRECT) &&
+		(file_out->f_iocb_flags & IOCB_DIRECT))
+		comp_len = blkdev_copy_offload(in_bdev, pos_in, out_bdev,
+				 pos_out, len, GFP_KERNEL);
+	if (comp_len != len)
+		comp_len = generic_copy_file_range(file_in, pos_in + comp_len,
+			file_out, pos_out + comp_len, len - comp_len, flags);
+
+	return comp_len;
+}
+
 #define	BLKDEV_FALLOC_FL_SUPPORTED					\
 		(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |		\
 		 FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE)
@@ -694,6 +713,7 @@ const struct file_operations def_blk_fops = {
 	.splice_read	= generic_file_splice_read,
 	.splice_write	= iter_file_splice_write,
 	.fallocate	= blkdev_fallocate,
+	.copy_file_range = blkdev_copy_file_range,
 };
 
 static __init int blkdev_init(void)
diff --git a/fs/read_write.c b/fs/read_write.c
index a21ba3be7dbe..47e848fcfd42 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -20,6 +20,7 @@
 #include <linux/compat.h>
 #include <linux/mount.h>
 #include <linux/fs.h>
+#include <linux/blkdev.h>
 #include "internal.h"
 
 #include <linux/uaccess.h>
@@ -1447,7 +1448,11 @@ static int generic_copy_file_checks(struct file *file_in, loff_t pos_in,
 		return -EOVERFLOW;
 
 	/* Shorten the copy to EOF */
-	size_in = i_size_read(inode_in);
+	if (S_ISBLK(inode_in->i_mode))
+		size_in = bdev_nr_bytes(I_BDEV(file_in->f_mapping->host));
+	else
+		size_in = i_size_read(inode_in);
+
 	if (pos_in >= size_in)
 		count = 0;
 	else
@@ -1708,7 +1713,9 @@ int generic_file_rw_checks(struct file *file_in, struct file *file_out)
 	/* Don't copy dirs, pipes, sockets... */
 	if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))
 		return -EISDIR;
-	if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
+
+	if ((!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode)) &&
+		(!S_ISBLK(inode_in->i_mode) || !S_ISBLK(inode_out->i_mode)))
 		return -EINVAL;
 
 	if (!(file_in->f_mode & FMODE_READ) ||
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index a54153610800..533ad682e0ca 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1057,6 +1057,9 @@ int blkdev_issue_secure_erase(struct block_device *bdev, sector_t sector,
 int blkdev_issue_copy(struct block_device *bdev_in, loff_t pos_in,
 		      struct block_device *bdev_out, loff_t pos_out, size_t len,
 		      cio_iodone_t end_io, void *private, gfp_t gfp_mask);
+int blkdev_copy_offload(struct block_device *bdev_in, loff_t pos_in,
+		      struct block_device *bdev_out, loff_t pos_out, size_t len,
+		      gfp_t gfp_mask);
 struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
 		gfp_t gfp_mask);
 void bio_map_kern_endio(struct bio *bio);
-- 
2.35.1.500.gb896f729e2