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From: fan <nifan.cxl@gmail.com>
Date: Wed, 27 Mar 2024 10:36:10 -0700
To: Ira Weiny <ira.weiny@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>, Fan Ni <fan.ni@samsung.com>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	Navneet Singh <navneet.singh@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Davidlohr Bueso <dave@stgolabs.net>,
	Alison Schofield <alison.schofield@intel.com>,
	Vishal Verma <vishal.l.verma@intel.com>,
	linux-btrfs@vger.kernel.org, linux-cxl@vger.kernel.org,
	linux-kernel@vger.kernel.org, Chris Mason <clm@fb.com>,
	Josef Bacik <josef@toxicpanda.com>, David Sterba <dsterba@suse.com>
Subject: Re: [PATCH 15/26] range: Add range_overlaps()
Message-ID: <ZgRZCrxMkAtdT9Ta@debian>
References: <20240324-dcd-type2-upstream-v1-0-b7b00d623625@intel.com>
 <20240324-dcd-type2-upstream-v1-15-b7b00d623625@intel.com>
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In-Reply-To: <20240324-dcd-type2-upstream-v1-15-b7b00d623625@intel.com>

On Sun, Mar 24, 2024 at 04:18:18PM -0700, 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: Fan Ni <fan.ni@samsung.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);
>  
> 
> -- 
> 2.44.0
>