md: make merge_bvec_fn more robust in face of personality changes.
There is no locking around calls to merge_bvec_fn(), so
it is possible that calls which coincide with a level (or personality)
change could go wrong.
So create a central dispatch point for these functions and use
rcu_read_lock().
If the array is suspended, reject any merge that can be rejected.
If not, we know it is safe to call the function.
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 9ad7ce7..45c512a 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -701,11 +701,10 @@
return best_disk;
}
-static int raid1_mergeable_bvec(struct request_queue *q,
+static int raid1_mergeable_bvec(struct mddev *mddev,
struct bvec_merge_data *bvm,
struct bio_vec *biovec)
{
- struct mddev *mddev = q->queuedata;
struct r1conf *conf = mddev->private;
sector_t sector = bvm->bi_sector + get_start_sect(bvm->bi_bdev);
int max = biovec->bv_len;
@@ -2946,8 +2945,6 @@
md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
if (mddev->queue) {
- blk_queue_merge_bvec(mddev->queue, raid1_mergeable_bvec);
-
if (discard_supported)
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
mddev->queue);
@@ -3183,6 +3180,7 @@
.quiesce = raid1_quiesce,
.takeover = raid1_takeover,
.congested = raid1_congested,
+ .mergeable_bvec = raid1_mergeable_bvec,
};
static int __init raid_init(void)