From 169e2cc279c443085f7e423561eb1fe6158ade44 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Thu, 22 Aug 2013 18:21:38 -0400 Subject: dm: allow error target to replace bio-based and request-based targets It may be useful to switch a request-based table to the "error" target. Enhance the DM core to allow a hybrid target_type which is capable of handling either bios (via .map) or requests (via .map_rq). Add a request-based map function (.map_rq) to the "error" target_type; making it DM's first hybrid target. Train dm_table_set_type() to prefer the mapped device's established type (request-based or bio-based). If the mapped device doesn't have an established type default to making the table with the hybrid target(s) bio-based. Tested 'dmsetup wipe_table' to work on both bio-based and request-based devices. Signed-off-by: Mike Snitzer Signed-off-by: Joe Jin Signed-off-by: Jun'ichi Nomura Acked-by: Mikulas Patocka Signed-off-by: Alasdair G Kergon --- drivers/md/dm-target.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'drivers/md/dm-target.c') diff --git a/drivers/md/dm-target.c b/drivers/md/dm-target.c index 37ba5db71cd9..242e3cec397a 100644 --- a/drivers/md/dm-target.c +++ b/drivers/md/dm-target.c @@ -131,12 +131,19 @@ static int io_err_map(struct dm_target *tt, struct bio *bio) return -EIO; } +static int io_err_map_rq(struct dm_target *ti, struct request *clone, + union map_info *map_context) +{ + return -EIO; +} + static struct target_type error_target = { .name = "error", - .version = {1, 1, 0}, + .version = {1, 2, 0}, .ctr = io_err_ctr, .dtr = io_err_dtr, .map = io_err_map, + .map_rq = io_err_map_rq, }; int __init dm_target_init(void) -- cgit v1.2.3