On Tue, Aug 17, 2021 at 03:44:20PM +0530, SelvaKumar S wrote:
> From: Nitesh Shetty <nj.shetty@xxxxxxxxxxx>
>
> Add new BLKCOPY ioctl that offloads copying of one or more sources ranges
> to a destination in the device. COPY ioctl accepts a 'copy_range'
> structure that contains destination (in sectors), no of sources and
> pointer to the array of source ranges. Each source range is represented by
> 'range_entry' that contains start and length of source ranges (in sectors)
>
> MAX_COPY_NR_RANGE, limits the number of entries for the IOCTL and
> MAX_COPY_TOTAL_LENGTH limits the total copy length, IOCTL can handle.
>
> Example code, to issue BLKCOPY:
> /* Sample example to copy three source-ranges [0, 8] [16, 8] [32,8] to
> * [64,24], on the same device */
>
> int main(void)
> {
> int ret, fd;
> struct range_entry source_range[] = {{.src = 0, .len = 8},
> {.src = 16, .len = 8}, {.src = 32, .len = 8},};
> struct copy_range cr;
>
> cr.dest = 64;
> cr.nr_range = 3;
> cr.range_list = (__u64)&source_range;
>
> fd = open("/dev/nvme0n1", O_RDWR);
> if (fd < 0) return 1;
>
> ret = ioctl(fd, BLKCOPY, &cr);
> if (ret < 0) printf("copy failure\n");
>
> close(fd);
>
> return ret;
> }
>
> Signed-off-by: Nitesh Shetty <nj.shetty@xxxxxxxxxxx>
> Signed-off-by: SelvaKumar S <selvakuma.s1@xxxxxxxxxxx>
> Signed-off-by: Kanchan Joshi <joshi.k@xxxxxxxxxxx>
> ---
> block/ioctl.c | 33 +++++++++++++++++++++++++++++++++
> include/uapi/linux/fs.h | 8 ++++++++
> 2 files changed, 41 insertions(+)
>
> diff --git a/block/ioctl.c b/block/ioctl.c
> index eb0491e90b9a..2af56d01e9fe 100644
> --- a/block/ioctl.c
> +++ b/block/ioctl.c
> @@ -143,6 +143,37 @@ static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode,
> GFP_KERNEL, flags);
> }
>
> +static int blk_ioctl_copy(struct block_device *bdev, fmode_t mode,
> + unsigned long arg)
> +{
> + struct copy_range crange;
> + struct range_entry *rlist;
> + int ret;
> +
> + if (!(mode & FMODE_WRITE))
> + return -EBADF;
> +
> + if (copy_from_user(&crange, (void __user *)arg, sizeof(crange)))
> + return -EFAULT;
> +
> + rlist = kmalloc_array(crange.nr_range, sizeof(*rlist),
> + GFP_KERNEL);
> + if (!rlist)
> + return -ENOMEM;
> +
> + if (copy_from_user(rlist, (void __user *)crange.range_list,
> + sizeof(*rlist) * crange.nr_range)) {
> + ret = -EFAULT;
> + goto out;
> + }
> +
> + ret = blkdev_issue_copy(bdev, crange.nr_range, rlist, bdev, crange.dest,
> + GFP_KERNEL, 0);
> +out:
> + kfree(rlist);
> + return ret;
> +}
> +
> static int blk_ioctl_zeroout(struct block_device *bdev, fmode_t mode,
> unsigned long arg)
> {
> @@ -468,6 +499,8 @@ 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 7a97b588d892..4183688ff398 100644
> --- a/include/uapi/linux/fs.h
> +++ b/include/uapi/linux/fs.h
> @@ -76,6 +76,13 @@ struct range_entry {
> __u64 len;
> };
>
> +struct copy_range {
> + __u64 dest;
> + __u64 nr_range;
> + __u64 range_list;
> + __u64 rsvd;
If you have a "reserved" field, you HAVE to check that it is 0. If not,
you can never use it in the future.
Also, you can spell it out, we have lots of vowels :)
thanks,
greg k-h
