Re: [PATCH 15/26] range: Add range_overlaps()

Dave Jiang
2024-03-28T20:10:01Z

On 3/24/24 4:18 PM, Ira Weiny wrote:
> Code to support CXL Dynamic Capacity devices will have extent ranges
> which need to be compared for intersection not a subset as is being
> checked in range_contains().
>
> range_overlaps() is defined in btrfs with a different meaning from what
> is required in the standard range code. Dan Williams pointed this out
> in [1]. Adjust the btrfs call according to his suggestion there.
>
> Then add a generic range_overlaps().
>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Chris Mason <clm@fb.com>
> Cc: Josef Bacik <josef@toxicpanda.com>
> Cc: David Sterba <dsterba@suse.com>
> Cc: linux-btrfs@vger.kernel.org
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>
>
> [1] https://lore.kernel.org/all/65949f79ef908_8dc68294f2@dwillia2-xfh.jf.intel.com.notmuch/
> ---
> fs/btrfs/ordered-data.c | 10 +++++-----
> include/linux/range.h | 7 +++++++
> 2 files changed, 12 insertions(+), 5 deletions(-)
>
> diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
> index 59850dc17b22..032d30a49edc 100644
> --- a/fs/btrfs/ordered-data.c
> +++ b/fs/btrfs/ordered-data.c
> @@ -111,8 +111,8 @@ static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
> return NULL;
> }
>
> -static int range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
> - u64 len)
> +static int btrfs_range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
> + u64 len)
> {
> if (file_offset + len <= entry->file_offset ||
> entry->file_offset + entry->num_bytes <= file_offset)
> @@ -914,7 +914,7 @@ struct btrfs_ordered_extent *btrfs_lookup_ordered_range(
>
> while (1) {
> entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
> - if (range_overlaps(entry, file_offset, len))
> + if (btrfs_range_overlaps(entry, file_offset, len))
> break;
>
> if (entry->file_offset >= file_offset + len) {
> @@ -1043,12 +1043,12 @@ struct btrfs_ordered_extent *btrfs_lookup_first_ordered_range(
> }
> if (prev) {
> entry = rb_entry(prev, struct btrfs_ordered_extent, rb_node);
> - if (range_overlaps(entry, file_offset, len))
> + if (btrfs_range_overlaps(entry, file_offset, len))
> goto out;
> }
> if (next) {
> entry = rb_entry(next, struct btrfs_ordered_extent, rb_node);
> - if (range_overlaps(entry, file_offset, len))
> + if (btrfs_range_overlaps(entry, file_offset, len))
> goto out;
> }
> /* No ordered extent in the range */
> diff --git a/include/linux/range.h b/include/linux/range.h
> index 6ad0b73cb7ad..9a46f3212965 100644
> --- a/include/linux/range.h
> +++ b/include/linux/range.h
> @@ -13,11 +13,18 @@ static inline u64 range_len(const struct range *range)
> return range->end - range->start + 1;
> }
>
> +/* True if r1 completely contains r2 */
> static inline bool range_contains(struct range *r1, struct range *r2)
> {
> return r1->start <= r2->start && r1->end >= r2->end;
> }
>
> +/* True if any part of r1 overlaps r2 */
> +static inline bool range_overlaps(struct range *r1, struct range *r2)
> +{
> + return r1->start <= r2->end && r1->end >= r2->start;
> +}
> +
> int add_range(struct range *range, int az, int nr_range,
> u64 start, u64 end);
>
>