From: Ming Lei <ming.lei@canonical.com>
To: Jens Axboe <axboe@kernel.dk>, linux-kernel@vger.kernel.org
Cc: linux-block@vger.kernel.org,
Christoph Hellwig <hch@infradead.org>,
Sagi Grimberg <sagig@dev.mellanox.co.il>,
Ming Lei <ming.lei@canonical.com>,
stable@vger.kernel.org
Subject: [PATCH 1/4] block: bio: introduce helpers to get the 1st and last bvec
Date: Mon, 15 Feb 2016 15:01:24 +0800 [thread overview]
Message-ID: <1455519687-23873-2-git-send-email-ming.lei@canonical.com> (raw)
In-Reply-To: <1455519687-23873-1-git-send-email-ming.lei@canonical.com>
After bio splitting is introduced, the splitted bio can
be fast-cloned, which is correct because biovecs has become
immutable since v3.13.
Unfortunately bio_will_gap() isn't ready for this kind of change,
because it figures out the last bvec via 'bi_io_vec[prev->bi_vcnt - 1]'.
This patch introduces two helpers for getting the first and last
bvec of one bio.
Cc: stable@vger.kernel.org # v4.3+
Reported-by: Sagi Grimberg <sagig@dev.mellanox.co.il>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
---
include/linux/bio.h | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 5349e68..56d2db8 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -265,6 +265,26 @@ static inline unsigned bio_segments(struct bio *bio)
return segs;
}
+static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
+{
+ *bv = bio_iovec(bio);
+}
+
+/*
+ * bio_get_last_bvec() is introduced to get the last bvec of one
+ * bio for bio_will_gap().
+ *
+ * TODO: make it more efficient.
+ */
+static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
+{
+ struct bvec_iter iter;
+
+ bio_for_each_segment(*bv, bio, iter)
+ if (bv->bv_len == iter.bi_size)
+ break;
+}
+
/*
* get a reference to a bio, so it won't disappear. the intended use is
* something like:
--
1.9.1
next prev parent reply other threads:[~2016-02-15 7:02 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-15 7:01 [PATCH 0/4] block: fix bio_will_gap() Ming Lei
2016-02-15 7:01 ` Ming Lei [this message]
2016-02-15 8:19 ` [PATCH 1/4] block: bio: introduce helpers to get the 1st and last bvec Sagi Grimberg
2016-02-15 9:42 ` Ming Lei
2016-02-15 20:06 ` Sagi Grimberg
2016-02-16 13:03 ` Ming Lei
2016-02-17 3:08 ` Elliott, Robert (Persistent Memory)
2016-02-18 4:24 ` Kent Overstreet
2016-02-18 6:16 ` Ming Lei
2016-02-19 1:47 ` Ming Lei
2016-02-15 7:01 ` [PATCH 2/4] block: check virt boundary in bio_will_gap() Ming Lei
2016-02-15 8:22 ` Sagi Grimberg
2016-02-15 10:27 ` Ming Lei
2016-02-15 20:27 ` Sagi Grimberg
2016-02-16 13:05 ` Ming Lei
2016-02-16 13:08 ` Ming Lei
2016-02-15 8:33 ` [PATCH 0/4] block: fix bio_will_gap() Sagi Grimberg
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