[PATCH v2 04/10] block: Introduce a new ioctl for copy

[Nitesh Shetty <nj.shetty@xxxxxxxxxxx>]

Add new BLKCOPY ioctl that offloads copying of one or more sources ranges
to one or more destination in a device. COPY ioctl accepts a 'copy_range'
structure that contains no of range, a reserved field , followed by an
array of ranges. Each source range is represented by 'range_entry' that
contains source start offset, destination start offset and length of
source ranges (in bytes)

Signed-off-by: Nitesh Shetty <nj.shetty@xxxxxxxxxxx>
Signed-off-by: Arnav Dawn <arnav.dawn@xxxxxxxxxxx>
---
 block/ioctl.c           | 37 +++++++++++++++++++++++++++++++++++++
 include/uapi/linux/fs.h |  9 +++++++++
 2 files changed, 46 insertions(+)

diff --git a/block/ioctl.c b/block/ioctl.c
index 4a86340133e4..d77f6143287e 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -124,6 +124,41 @@ static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode,
 	return err;
 }
 
+static int blk_ioctl_copy(struct block_device *bdev, fmode_t mode,
+		unsigned long arg)
+{
+	struct copy_range crange, *ranges;
+	size_t payload_size = 0;
+	int ret;
+
+	if (!(mode & FMODE_WRITE))
+		return -EBADF;
+
+	if (copy_from_user(&crange, (void __user *)arg, sizeof(crange)))
+		return -EFAULT;
+
+	if (unlikely(!crange.nr_range || crange.reserved || crange.nr_range >= MAX_COPY_NR_RANGE))
+		return -EINVAL;
+
+	payload_size = (crange.nr_range * sizeof(struct range_entry)) + sizeof(crange);
+
+	ranges = kmalloc(payload_size, GFP_KERNEL);
+	if (!ranges)
+		return -ENOMEM;
+
+	if (copy_from_user(ranges, (void __user *)arg, payload_size)) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	ret = blkdev_issue_copy(bdev, ranges->nr_range, ranges->range_list, bdev, GFP_KERNEL, 0);
+	if (copy_to_user((void __user *)arg, ranges, payload_size))
+		ret = -EFAULT;
+out:
+	kfree(ranges);
+	return ret;
+}
+
 static int blk_ioctl_zeroout(struct block_device *bdev, fmode_t mode,
 		unsigned long arg)
 {
@@ -455,6 +490,8 @@ static int blkdev_common_ioctl(struct block_device *bdev, fmode_t mode,
 	case BLKSECDISCARD:
 		return blk_ioctl_discard(bdev, mode, arg,
 				BLKDEV_DISCARD_SECURE);
+	case BLKCOPY:
+		return blk_ioctl_copy(bdev, mode, arg);
 	case BLKZEROOUT:
 		return blk_ioctl_zeroout(bdev, mode, arg);
 	case BLKGETDISKSEQ:
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 55bca8f6e8ed..190911ea4311 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -78,6 +78,14 @@ struct range_entry {
 	__u64 comp_len;
 };
 
+struct copy_range {
+	__u64 nr_range;
+	__u64 reserved;
+
+	/* Range_list always must be at the end */
+	struct range_entry range_list[];
+};
+
 /* extent-same (dedupe) ioctls; these MUST match the btrfs ioctl definitions */
 #define FILE_DEDUPE_RANGE_SAME		0
 #define FILE_DEDUPE_RANGE_DIFFERS	1
@@ -199,6 +207,7 @@ struct fsxattr {
 #define BLKROTATIONAL _IO(0x12,126)
 #define BLKZEROOUT _IO(0x12,127)
 #define BLKGETDISKSEQ _IOR(0x12,128,__u64)
+#define BLKCOPY _IOWR(0x12, 129, struct copy_range)
 /*
  * A jump here: 130-136 are reserved for zoned block devices
  * (see uapi/linux/blkzoned.h)
-- 
2.30.0-rc0