From: Ming Lei <ming.lei@redhat.com>
To: Jens Axboe <axboe@fb.com>, Christoph Hellwig <hch@infradead.org>,
Kent Overstreet <kent.overstreet@gmail.com>
Cc: David Sterba <dsterba@suse.cz>, Huang Ying <ying.huang@intel.com>,
Mike Snitzer <snitzer@redhat.com>,
linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
Theodore Ts'o <tytso@mit.edu>,
"Darrick J . Wong" <darrick.wong@oracle.com>,
Coly Li <colyli@suse.de>, Filipe Manana <fdmanana@gmail.com>,
Randy Dunlap <rdunlap@infradead.org>,
Ming Lei <ming.lei@redhat.com>
Subject: [PATCH V7 14/24] block: introduce bvec_last_segment()
Date: Wed, 27 Jun 2018 20:45:38 +0800 [thread overview]
Message-ID: <20180627124548.3456-15-ming.lei@redhat.com> (raw)
In-Reply-To: <20180627124548.3456-1-ming.lei@redhat.com>
BTRFS and guard_bio_eod() need to get the last singlepage segment
from one multipage bvec, so introduce this helper to make them happy.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
include/linux/bvec.h | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index 417d44cf1e82..2269c7608a3e 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -219,4 +219,29 @@ static inline bool mp_bvec_iter_advance(const struct bio_vec *bv,
.bi_bvec_done = 0, \
}
+/*
+ * Get the last singlepage segment from the multipage bvec and store it
+ * in @seg
+ */
+static inline void bvec_last_segment(const struct bio_vec *bvec,
+ struct bio_vec *seg)
+{
+ unsigned total = bvec->bv_offset + bvec->bv_len;
+ unsigned last_page = total / PAGE_SIZE;
+
+ if (last_page * PAGE_SIZE == total)
+ last_page--;
+
+ seg->bv_page = nth_page(bvec->bv_page, last_page);
+
+ /* the whole segment is inside the last page */
+ if (bvec->bv_offset >= last_page * PAGE_SIZE) {
+ seg->bv_offset = bvec->bv_offset % PAGE_SIZE;
+ seg->bv_len = bvec->bv_len;
+ } else {
+ seg->bv_offset = 0;
+ seg->bv_len = total - last_page * PAGE_SIZE;
+ }
+}
+
#endif /* __LINUX_BVEC_ITER_H */
--
2.9.5
next prev parent reply other threads:[~2018-06-27 12:45 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-27 12:45 [PATCH V7 00/24] block: support multipage bvec Ming Lei
2018-06-27 12:45 ` [PATCH V7 01/24] dm: use bio_split() when splitting out the already processed bio Ming Lei
2018-06-27 13:17 ` Mike Snitzer
2018-06-27 12:45 ` [PATCH V7 02/24] bcache: don't clone bio in bch_data_verify Ming Lei
2018-06-27 12:45 ` [PATCH V7 03/24] exofs: use bio_clone_fast in _write_mirror Ming Lei
2018-06-27 12:45 ` [PATCH V7 04/24] block: remove bio_clone_kmalloc Ming Lei
2018-06-27 12:45 ` [PATCH V7 05/24] md: remove a bogus comment Ming Lei
2018-06-27 12:45 ` [PATCH V7 06/24] block: unexport bio_clone_bioset Ming Lei
2018-06-27 12:45 ` [PATCH V7 07/24] block: simplify bio_check_pages_dirty Ming Lei
2018-06-27 12:45 ` [PATCH V7 08/24] block: bio_set_pages_dirty can't see NULL bv_page in a valid bio_vec Ming Lei
2018-06-27 12:45 ` [PATCH V7 09/24] block: use bio_add_page in bio_iov_iter_get_pages Ming Lei
2018-06-27 12:45 ` [PATCH V7 10/24] block: introduce multipage page bvec helpers Ming Lei
2018-06-27 15:59 ` kbuild test robot
2018-11-09 11:15 ` Ming Lei
2018-06-27 12:45 ` [PATCH V7 11/24] block: introduce bio_for_each_bvec() Ming Lei
2018-06-27 12:45 ` [PATCH V7 12/24] block: use bio_for_each_bvec() to compute multipage bvec count Ming Lei
2018-06-27 12:45 ` [PATCH V7 13/24] block: use bio_for_each_bvec() to map sg Ming Lei
2018-06-27 12:45 ` Ming Lei [this message]
2018-06-27 12:45 ` [PATCH V7 15/24] fs/buffer.c: use bvec iterator to truncate the bio Ming Lei
2018-06-27 12:45 ` [PATCH V7 16/24] btrfs: use bvec_last_segment to get bio's last page Ming Lei
2018-06-27 12:45 ` [PATCH V7 17/24] btrfs: move bio_pages_all() to btrfs Ming Lei
2018-06-27 12:45 ` [PATCH V7 18/24] block: introduce bio_bvecs() Ming Lei
2018-06-27 12:45 ` [PATCH V7 19/24] block: loop: pass multipage bvec to iov_iter Ming Lei
2018-06-27 12:45 ` [PATCH V7 20/24] bcache: avoid to use bio_for_each_segment_all() in bch_bio_alloc_pages() Ming Lei
2018-06-27 15:55 ` Coly Li
2018-06-28 1:28 ` Ming Lei
2018-06-28 2:01 ` Coly Li
2018-06-27 12:45 ` [PATCH V7 21/24] block: allow bio_for_each_segment_all() to iterate over multipage bvec Ming Lei
2018-06-27 12:45 ` [PATCH V7 22/24] block: enable multipage bvecs Ming Lei
2018-06-27 12:45 ` [PATCH V7 23/24] block: always define BIO_MAX_PAGES as 256 Ming Lei
2018-06-27 12:45 ` [PATCH V7 24/24] block: document usage of bio iterator helpers Ming Lei
2018-06-27 18:13 ` Randy Dunlap
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