From: David Sterba <dsterba@suse.com>
Date: Mon, 12 Jun 2017 15:29:36 +0000 (+0200)
Subject: btrfs: document mandatory order of bio in btrfs_io_bio
X-Git-Tag: v4.13-rc1~150^2~47
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=fa1bcbe0a54c67a293c557a21641565516c96a8f;p=karo-tx-linux.git

btrfs: document mandatory order of bio in btrfs_io_bio

Signed-off-by: David Sterba <dsterba@suse.com>
---

diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 58b97b6f5f02..35327efecdbb 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -281,6 +281,10 @@ struct btrfs_io_bio {
 	u8 *csum_allocated;
 	btrfs_io_bio_end_io_t *end_io;
 	struct bvec_iter iter;
+	/*
+	 * This member must come last, bio_alloc_bioset will allocate enough
+	 * bytes for entire btrfs_io_bio but relies on bio being last.
+	 */
 	struct bio bio;
 };