Re: [PATCH v2 06/13] md: raid1: don't use bio's vec table to manage resync pages

Now we allocate one page array for managing resync pages, instead
of using bio's vec table to do that, and the old way is very hacky
and won't work any more if multipage bvec is enabled.

The introduced cost is that we need to allocate (128 + 16) * raid_disks
bytes per r1_bio, and it is fine because the inflight r1_bio for
resync shouldn't be much, as pointed by Shaohua.

Also the bio_reset() in raid1_sync_request() is removed because
all bios are freshly new now and not necessary to reset any more.

This patch can be thought as a cleanup too

Suggested-by: Shaohua Li <shli@kernel.org>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
---
 drivers/md/raid1.c | 83 ++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 53 insertions(+), 30 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index c442b4657e2f..900144f39630 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c

@@ -77,6 +77,16 @@ static void lower_barrier(struct r1conf *conf, sector_t sector_nr);
 #define raid1_log(md, fmt, args...)				\
 	do { if ((md)->queue) blk_add_trace_msg((md)->queue, "raid1 " fmt, ##args); } while (0)
 
+static inline struct resync_pages *get_resync_pages(struct bio *bio)
+{
+	return bio->bi_private;
+}
+
+static inline struct r1bio *get_resync_r1bio(struct bio *bio)
+{
+	return get_resync_pages(bio)->raid_bio;
+}