[PATCH 4/6] bcache: clean up bio reuse for struct dirty_io

[Christoph Hellwig]

Instead of reinitializing the bio everytime we can call bio_reuse when
reusing it.  Also moves the private data initialization out of
dirty_init, which is renamed to suit the remaining functionality.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 drivers/md/bcache/writeback.c | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index ad45ebe1a74b..0b6d07eab87c 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -179,19 +179,12 @@ struct dirty_io {
        struct bio              bio;
 };
 
-static void dirty_init(struct keybuf_key *w)
+static void dirty_init_prio(struct keybuf_key *w)
 {
        struct dirty_io *io = w->private;
-       struct bio *bio = &io->bio;
 
-       bio_init(bio, bio->bi_inline_vecs,
-                DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS));
        if (!io->dc->writeback_percent)
-               bio_set_prio(bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0));
-
-       bio->bi_iter.bi_size    = KEY_SIZE(&w->key) << 9;
-       bio->bi_private         = w;
-       bch_bio_map(bio, NULL);
+               bio_set_prio(&io->bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0));
 }
 
 static void dirty_io_destructor(struct closure *cl)
@@ -285,10 +278,12 @@ static void write_dirty(struct closure *cl)
         * to clean up.
         */
        if (KEY_DIRTY(&w->key)) {
-               dirty_init(w);
-               bio_set_op_attrs(&io->bio, REQ_OP_WRITE, 0);
+               bio_reuse(&io->bio, KEY_SIZE(&w->key) << 9);
+               dirty_init_prio(w);
+               io->bio.bi_opf = REQ_OP_WRITE;
                io->bio.bi_iter.bi_sector = KEY_START(&w->key);
                bio_set_dev(&io->bio, io->dc->bdev);
+               io->bio.bi_private      = w;
                io->bio.bi_end_io       = dirty_endio;
 
                /* I/O request sent to backing device */
@@ -399,13 +394,18 @@ static void read_dirty(struct cached_dev *dc)
                        io->dc          = dc;
                        io->sequence    = sequence++;
 
-                       dirty_init(w);
-                       bio_set_op_attrs(&io->bio, REQ_OP_READ, 0);
+                       bio_init(&io->bio, io->bio.bi_inline_vecs,
+                               DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS));
+                       dirty_init_prio(w);
+                       io->bio.bi_opf = REQ_OP_READ;
+                       io->bio.bi_iter.bi_size = KEY_SIZE(&w->key) << 9;
                        io->bio.bi_iter.bi_sector = PTR_OFFSET(&w->key, 0);
                        bio_set_dev(&io->bio,
                                    PTR_CACHE(dc->disk.c, &w->key, 0)->bdev);
+                       io->bio.bi_private      = w;
                        io->bio.bi_end_io       = read_dirty_endio;
 
+                       bch_bio_map(&io->bio, NULL);
                        if (bch_bio_alloc_pages(&io->bio, GFP_KERNEL))
                                goto err_free;
 
-- 
2.17.1