From: Ming Lei <tom.leiming@gmail.com>
To: Jens Axboe <axboe@fb.com>, linux-kernel@vger.kernel.org
Cc: linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Christoph Hellwig <hch@infradead.org>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Ming Lei <tom.leiming@gmail.com>,
Kent Overstreet <kent.overstreet@gmail.com>,
Shaohua Li <shli@kernel.org>, Mike Christie <mchristi@redhat.com>,
Hannes Reinecke <hare@suse.com>, Guoqing Jiang <gqjiang@suse.com>,
Jiri Kosina <jkosina@suse.cz>, Zheng Liu <gnehzuil.liu@gmail.com>,
Eric Wheeler <git@linux.ewheeler.net>,
Yijing Wang <wangyijing@huawei.com>, Coly Li <colyli@suse.de>,
Al Viro <viro@ZenIV.linux.org.uk>,
linux-bcache@vger.kernel.org (open list:BCACHE (BLOCK LAYER
CACHE)),
linux-raid@vger.kernel.org (open list:SOFTWARE RAID (Multiple
Disks) SUPPORT)
Subject: [PATCH 21/60] bcache: comment on direct access to bvec table
Date: Sat, 29 Oct 2016 16:08:20 +0800 [thread overview]
Message-ID: <1477728600-12938-22-git-send-email-tom.leiming@gmail.com> (raw)
In-Reply-To: <1477728600-12938-1-git-send-email-tom.leiming@gmail.com>
Looks all are safe after multipage bvec is supported.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
---
drivers/md/bcache/btree.c | 1 +
drivers/md/bcache/super.c | 6 ++++++
drivers/md/bcache/util.c | 7 +++++++
3 files changed, 14 insertions(+)
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 81d3db40cd7b..b419bc91ba32 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -428,6 +428,7 @@ static void do_btree_node_write(struct btree *b)
continue_at(cl, btree_node_write_done, NULL);
} else {
+ /* No harm for multipage bvec since the new is just allocated */
b->bio->bi_vcnt = 0;
bch_bio_map(b->bio, i);
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index d8a6d807b498..52876fcf2b36 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -207,6 +207,7 @@ static void write_bdev_super_endio(struct bio *bio)
static void __write_super(struct cache_sb *sb, struct bio *bio)
{
+ /* single page bio, safe for multipage bvec */
struct cache_sb *out = page_address(bio->bi_io_vec[0].bv_page);
unsigned i;
@@ -1153,6 +1154,8 @@ static void register_bdev(struct cache_sb *sb, struct page *sb_page,
dc->bdev->bd_holder = dc;
bio_init_with_vec_table(&dc->sb_bio, dc->sb_bio.bi_inline_vecs, 1);
+
+ /* single page bio, safe for multipage bvec */
dc->sb_bio.bi_io_vec[0].bv_page = sb_page;
get_page(sb_page);
@@ -1794,6 +1797,7 @@ void bch_cache_release(struct kobject *kobj)
for (i = 0; i < RESERVE_NR; i++)
free_fifo(&ca->free[i]);
+ /* single page bio, safe for multipage bvec */
if (ca->sb_bio.bi_inline_vecs[0].bv_page)
put_page(ca->sb_bio.bi_io_vec[0].bv_page);
@@ -1850,6 +1854,8 @@ static int register_cache(struct cache_sb *sb, struct page *sb_page,
ca->bdev->bd_holder = ca;
bio_init_with_vec_table(&ca->sb_bio, ca->sb_bio.bi_inline_vecs, 1);
+
+ /* single page bio, safe for multipage bvec */
ca->sb_bio.bi_io_vec[0].bv_page = sb_page;
get_page(sb_page);
diff --git a/drivers/md/bcache/util.c b/drivers/md/bcache/util.c
index dde6172f3f10..5cc0b49a65fb 100644
--- a/drivers/md/bcache/util.c
+++ b/drivers/md/bcache/util.c
@@ -222,6 +222,13 @@ uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done)
: 0;
}
+/*
+ * Generally it isn't good to access .bi_io_vec and .bi_vcnt
+ * directly, the preferred way is bio_add_page, but in
+ * this case, bch_bio_map() supposes that the bvec table
+ * is empty, so it is safe to access .bi_vcnt & .bi_io_vec
+ * in this way even after multipage bvec is supported.
+ */
void bch_bio_map(struct bio *bio, void *base)
{
size_t size = bio->bi_iter.bi_size;
--
2.7.4
next prev parent reply other threads:[~2016-10-29 8:08 UTC|newest]
Thread overview: 107+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-29 8:07 [PATCH 00/60] block: support multipage bvec Ming Lei
2016-10-29 8:08 ` [PATCH 01/60] block: bio: introduce bio_init_with_vec_table() Ming Lei
2016-10-29 15:21 ` Christoph Hellwig
2016-10-29 8:08 ` [PATCH 02/60] block drivers: convert to bio_init_with_vec_table() Ming Lei
2016-10-29 8:08 ` [PATCH 03/60] block: drbd: remove impossible failure handling Ming Lei
2016-10-31 15:25 ` Christoph Hellwig
2016-10-29 8:08 ` [PATCH 04/60] block: floppy: use bio_add_page() Ming Lei
2016-10-31 15:26 ` Christoph Hellwig
2016-10-31 22:54 ` Ming Lei
2016-10-29 8:08 ` [PATCH 05/60] target: avoid to access .bi_vcnt directly Ming Lei
2016-10-31 15:26 ` Christoph Hellwig
2016-10-29 8:08 ` [PATCH 06/60] bcache: debug: avoid to access .bi_io_vec directly Ming Lei
2016-10-29 8:08 ` [PATCH 07/60] dm: crypt: use bio_add_page() Ming Lei
2016-10-29 8:08 ` [PATCH 08/60] dm: use bvec iterator helpers to implement .get_page and .next_page Ming Lei
2016-10-29 8:08 ` [PATCH 09/60] dm: dm.c: replace 'bio->bi_vcnt == 1' with !bio_multiple_segments Ming Lei
2016-10-31 15:29 ` Christoph Hellwig
2016-10-31 22:59 ` Ming Lei
2016-11-02 3:09 ` Kent Overstreet
2016-11-02 7:56 ` Ming Lei
2016-11-02 14:24 ` Mike Snitzer
2016-11-02 23:47 ` Ming Lei
2016-10-29 8:08 ` [PATCH 10/60] fs: logfs: convert to bio_add_page() in sync_request() Ming Lei
2016-10-29 8:08 ` [PATCH 11/60] fs: logfs: use bio_add_page() in __bdev_writeseg() Ming Lei
2016-10-31 15:29 ` Christoph Hellwig
2016-10-29 8:08 ` [PATCH 12/60] fs: logfs: use bio_add_page() in do_erase() Ming Lei
2016-10-31 15:29 ` Christoph Hellwig
2016-10-29 8:08 ` [PATCH 13/60] fs: logfs: remove unnecesary check Ming Lei
2016-10-31 15:29 ` Christoph Hellwig
2016-10-29 8:08 ` [PATCH 14/60] block: drbd: comment on direct access bvec table Ming Lei
2016-10-29 8:08 ` [PATCH 15/60] block: loop: comment on direct access to " Ming Lei
2016-10-31 15:31 ` Christoph Hellwig
2016-10-31 23:08 ` Ming Lei
2016-10-29 8:08 ` [PATCH 16/60] block: pktcdvd: " Ming Lei
2016-10-31 15:33 ` Christoph Hellwig
2016-10-31 23:08 ` Ming Lei
2016-10-29 8:08 ` [PATCH 17/60] kernel/power/swap.c: " Ming Lei
2016-10-29 8:08 ` [PATCH 18/60] mm: page_io.c: " Ming Lei
2016-10-29 8:08 ` [PATCH 19/60] fs/buffer: " Ming Lei
2016-10-31 15:35 ` Christoph Hellwig
2016-10-31 23:12 ` Ming Lei
2016-10-29 8:08 ` [PATCH 20/60] f2fs: f2fs_read_end_io: " Ming Lei
2016-10-29 8:08 ` Ming Lei [this message]
2016-10-29 8:08 ` [PATCH 22/60] block: comment on bio_alloc_pages() Ming Lei
2016-10-29 8:08 ` [PATCH 23/60] block: introduce flag QUEUE_FLAG_NO_MP Ming Lei
2016-10-29 15:29 ` Christoph Hellwig
2016-10-29 22:20 ` Ming Lei
2016-10-29 8:08 ` [PATCH 24/60] md: set NO_MP for request queue of md Ming Lei
2016-10-29 8:08 ` [PATCH 25/60] block: pktcdvd: set NO_MP for pktcdvd request queue Ming Lei
2016-10-29 8:08 ` [PATCH 26/60] btrfs: set NO_MP for request queues behind BTRFS Ming Lei
2016-10-31 15:36 ` Christoph Hellwig
2016-10-31 17:58 ` Chris Mason
2016-10-31 18:00 ` Christoph Hellwig
2016-10-29 8:08 ` [PATCH 27/60] block: introduce BIO_SP_MAX_SECTORS Ming Lei
2016-10-29 8:08 ` [PATCH 28/60] block: introduce QUEUE_FLAG_SPLIT_MP Ming Lei
2016-10-31 15:39 ` Christoph Hellwig
2016-10-31 23:56 ` Ming Lei
2016-11-02 3:08 ` Kent Overstreet
2016-11-03 10:38 ` Ming Lei
2016-11-03 11:20 ` Kent Overstreet
2016-11-03 11:26 ` Ming Lei
2016-11-03 11:30 ` Kent Overstreet
2016-10-29 8:08 ` [PATCH 29/60] dm: limit the max bio size as BIO_SP_MAX_SECTORS << SECTOR_SHIFT Ming Lei
2016-10-29 8:08 ` [PATCH 30/60] bcache: set flag of QUEUE_FLAG_SPLIT_MP Ming Lei
2016-10-29 8:08 ` [PATCH 31/60] block: introduce multipage/single page bvec helpers Ming Lei
2016-10-29 8:08 ` [PATCH 32/60] block: implement sp version of bvec iterator helpers Ming Lei
2016-10-29 11:06 ` kbuild test robot
2016-12-17 11:38 ` Ming Lei
2016-10-29 8:08 ` [PATCH 33/60] block: introduce bio_for_each_segment_mp() Ming Lei
2016-10-29 8:08 ` [PATCH 34/60] block: introduce bio_clone_sp() Ming Lei
2016-10-29 8:08 ` [PATCH 35/60] bvec_iter: introduce BVEC_ITER_ALL_INIT Ming Lei
2016-10-29 8:08 ` [PATCH 36/60] block: bounce: avoid direct access to bvec from bio->bi_io_vec Ming Lei
2016-10-29 8:08 ` [PATCH 37/60] block: bounce: don't access bio->bi_io_vec in copy_to_high_bio_irq Ming Lei
2016-10-29 8:08 ` [PATCH 38/60] block: bounce: convert multipage bvecs into singlepage Ming Lei
2016-10-29 8:08 ` [PATCH 39/60] bcache: debug: switch to bio_clone_sp() Ming Lei
2016-10-29 8:08 ` [PATCH 40/60] blk-merge: compute bio->bi_seg_front_size efficiently Ming Lei
2016-10-29 8:08 ` [PATCH 41/60] block: blk-merge: try to make front segments in full size Ming Lei
2016-10-29 8:08 ` [PATCH 42/60] block: use bio_for_each_segment_mp() to compute segments count Ming Lei
2016-10-29 8:08 ` [PATCH 43/60] block: use bio_for_each_segment_mp() to map sg Ming Lei
2016-10-29 8:08 ` [PATCH 44/60] block: introduce bvec_for_each_sp_bvec() Ming Lei
2016-10-29 8:08 ` [PATCH 45/60] block: bio: introduce bio_for_each_segment_all_rd() and its write pair Ming Lei
2016-10-31 13:59 ` Theodore Ts'o
2016-10-31 15:11 ` Christoph Hellwig
2016-10-31 22:50 ` Ming Lei
2016-11-02 3:01 ` Kent Overstreet
2016-10-31 22:46 ` Ming Lei
2016-10-31 23:51 ` Ming Lei
2016-11-01 14:17 ` Theodore Ts'o
2016-11-02 1:58 ` Ming Lei
2016-10-29 8:08 ` [PATCH 46/60] block: deal with dirtying pages for multipage bvec Ming Lei
2016-10-31 15:40 ` Christoph Hellwig
2016-11-01 0:19 ` Ming Lei
2016-10-29 8:08 ` [PATCH 47/60] block: convert to bio_for_each_segment_all_rd() Ming Lei
2016-10-29 8:08 ` [PATCH 48/60] fs/mpage: " Ming Lei
2016-10-29 8:08 ` [PATCH 49/60] fs/direct-io: " Ming Lei
2016-10-29 8:08 ` [PATCH 50/60] ext4: " Ming Lei
2016-10-29 8:08 ` [PATCH 51/60] xfs: " Ming Lei
2016-10-29 8:08 ` [PATCH 52/60] logfs: " Ming Lei
2016-10-29 8:08 ` [PATCH 53/60] gfs2: " Ming Lei
2016-10-29 8:08 ` [PATCH 54/60] f2fs: " Ming Lei
2016-10-29 8:08 ` [PATCH 55/60] exofs: " Ming Lei
2016-10-29 8:08 ` [PATCH 56/60] fs: crypto: " Ming Lei
2016-10-29 8:08 ` [PATCH 57/60] bcache: " Ming Lei
2016-10-29 8:08 ` [PATCH 58/60] dm-crypt: " Ming Lei
2016-10-29 8:08 ` [PATCH 59/60] fs/buffer.c: use bvec iterator to truncate the bio Ming Lei
2016-10-29 8:08 ` [PATCH 60/60] block: enable multipage bvecs Ming Lei
2016-10-31 15:25 ` [PATCH 00/60] block: support multipage bvec Christoph Hellwig
2016-10-31 22:52 ` Ming Lei
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