ping
2012/9/20 Robin Dong <robin.k.dong@xxxxxxxxx>:
> From: Robin Dong <sanbai@xxxxxxxxxx>
>
> When trying to modify flashcache to request based (current it's bio based), we need
> to make request from bios by ourselves, but dm_io() will submit these bios directly,
> so we propose to modify the dm_io() to return bios instead of submiting it.
>
> This could also improve the flexibility of dm_io().
>
> Signed-off-by: Robin Dong <sanbai@xxxxxxxxxx>
> ---
> drivers/md/dm.c | 11 +++++++++++
> include/linux/device-mapper.h | 3 +++
> 2 files changed, 14 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index 4e09b6f..bf6e3bb 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -1459,11 +1459,22 @@ static int dm_request_based(struct mapped_device *md)
> static void dm_request(struct request_queue *q, struct bio *bio)
> {
> struct mapped_device *md = q->queuedata;
> + struct dm_table *map = dm_get_live_table(md);
> + struct dm_target *ti = dm_table_find_target(map, bio->bi_sector);
> +
> + if (ti->type->mk_rq) {
> + ti->type->mk_rq(ti, q, bio);
> + goto out;
> + }
>
> if (dm_request_based(md))
> blk_queue_bio(q, bio);
> else
> _dm_request(q, bio);
> +
> +out:
> + dm_table_put(map);
> + return;
> }
>
> void dm_dispatch_request(struct request *rq)
> diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
> index 38d27a1..2386389 100644
> --- a/include/linux/device-mapper.h
> +++ b/include/linux/device-mapper.h
> @@ -50,6 +50,8 @@ typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio,
> union map_info *map_context);
> typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone,
> union map_info *map_context);
> +typedef int (*dm_make_request_fn) (struct dm_target *ti,
> + struct request_queue *q, struct bio *bio);
>
> /*
> * Returns:
> @@ -136,6 +138,7 @@ struct target_type {
> dm_dtr_fn dtr;
> dm_map_fn map;
> dm_map_request_fn map_rq;
> + dm_make_request_fn mk_rq;
> dm_endio_fn end_io;
> dm_request_endio_fn rq_end_io;
> dm_presuspend_fn presuspend;
> --
> 1.7.1
>
--
--
Best Regard
Robin Dong
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