[v4,1/2] btrfs: volumes: Use more straightforward way to calculate map length
diff mbox series

Message ID 20191025085956.48352-2-wqu@suse.com
State New
Headers show
Series
  • btrfs: trim: Fix a bug certain range may not be trimmed properly
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Commit Message

Qu Wenruo Oct. 25, 2019, 8:59 a.m. UTC
The old code goes:

 	offset = logical - em->start;
	length = min_t(u64, em->len - offset, length);

Where @length calculate is dependent on offset, it can take reader
several more seconds to find it's just the same code as:

 	offset = logical - em->start;
	length = min_t(u64, em->start + em->len - logical, length);

Use above code to make the length calculate independent from other
variable, thus slightly increase the readability.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/volumes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Josef Bacik Oct. 25, 2019, 12:17 p.m. UTC | #1
On Fri, Oct 25, 2019 at 04:59:55PM +0800, Qu Wenruo wrote:
> The old code goes:
> 
>  	offset = logical - em->start;
> 	length = min_t(u64, em->len - offset, length);
> 
> Where @length calculate is dependent on offset, it can take reader
> several more seconds to find it's just the same code as:
> 
>  	offset = logical - em->start;
> 	length = min_t(u64, em->start + em->len - logical, length);
> 
> Use above code to make the length calculate independent from other
> variable, thus slightly increase the readability.
> 
> Signed-off-by: Qu Wenruo <wqu@suse.com>

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef

Patch
diff mbox series

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index cdd7af424033..a6db11e821a5 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5616,7 +5616,7 @@  static int __btrfs_map_block_for_discard(struct btrfs_fs_info *fs_info,
 	}
 
 	offset = logical - em->start;
-	length = min_t(u64, em->len - offset, length);
+	length = min_t(u64, em->start + em->len - logical, length);
 
 	stripe_len = map->stripe_len;
 	/*