From: Ming Lin <mlin@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>,
        Kent Overstreet <kent.overstreet@gmail.com>,
        Jens Axboe <axboe@kernel.dk>,
        Dongsu Park <dongsu.park@profitbricks.com>,
        Al Viro <viro@zeniv.linux.org.uk>, linux-fsdevel@vger.kernel.org,
        Ming Lin <mlin@kernel.org>
Subject: [PATCH v3 3/4] fs: make _submit_bh consistent with generic bio chaining
Date: Thu, 23 Apr 2015 16:04:34 -0700
Message-id: <1429830275-6792-4-git-send-email-mlin@kernel.org>
In-reply-to: <1429830275-6792-1-git-send-email-mlin@kernel.org>
References: <1429830275-6792-1-git-send-email-mlin@kernel.org>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1557
Lines: 48

From: Kent Overstreet <kent.overstreet@gmail.com>

Make _submit_bh() handle refcounting by increasing bio->bi_remaining,
followed by bio_endio(). Since bio chaining was introduced with
196d38bccfcf ("block: Generic bio chaining"), refcounting should be
done on bi_remaining instead of ancient bio_cnt. Doing that, calling
convention can be consistent with the immutable biovecs API.

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
[dpark: add more description in commit message]
[mlin: rebase as Jens is changing the bi_remaining rules]
Signed-off-by: Dongsu Park <dongsu.park@profitbricks.com>
Signed-off-by: Ming Lin <mlin@kernel.org>
---
 fs/buffer.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index c7a5602..c1c0e0d 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -3041,13 +3041,13 @@ int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags)
 	if (buffer_prio(bh))
 		rw |= REQ_PRIO;
 
-	bio_get(bio);
+	bio_inc_remaining(bio);
 	submit_bio(rw, bio);
 
 	if (bio_flagged(bio, BIO_EOPNOTSUPP))
 		ret = -EOPNOTSUPP;
 
-	bio_put(bio);
+	bio_endio(bio, 0);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(_submit_bh);
-- 
1.9.1

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