diff options
Diffstat (limited to 'drivers/md/dm-stripe.c')
| -rw-r--r-- | drivers/md/dm-stripe.c | 89 |
1 files changed, 75 insertions, 14 deletions
diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c index e610725db76..c297f6da91e 100644 --- a/drivers/md/dm-stripe.c +++ b/drivers/md/dm-stripe.c @@ -25,6 +25,8 @@ struct stripe { struct stripe_c { uint32_t stripes; + int stripes_shift; + sector_t stripes_mask; /* The size of this target / num. stripes */ sector_t stripe_width; @@ -162,16 +164,22 @@ static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv) /* Set pointer to dm target; used in trigger_event */ sc->ti = ti; - sc->stripes = stripes; sc->stripe_width = width; + + if (stripes & (stripes - 1)) + sc->stripes_shift = -1; + else { + sc->stripes_shift = ffs(stripes) - 1; + sc->stripes_mask = ((sector_t) stripes) - 1; + } + ti->split_io = chunk_size; ti->num_flush_requests = stripes; + ti->num_discard_requests = stripes; + sc->chunk_shift = ffs(chunk_size) - 1; sc->chunk_mask = ((sector_t) chunk_size) - 1; - for (sc->chunk_shift = 0; chunk_size; sc->chunk_shift++) - chunk_size >>= 1; - sc->chunk_shift--; /* * Get the stripe destinations. @@ -207,26 +215,79 @@ static void stripe_dtr(struct dm_target *ti) kfree(sc); } +static void stripe_map_sector(struct stripe_c *sc, sector_t sector, + uint32_t *stripe, sector_t *result) +{ + sector_t offset = dm_target_offset(sc->ti, sector); + sector_t chunk = offset >> sc->chunk_shift; + + if (sc->stripes_shift < 0) + *stripe = sector_div(chunk, sc->stripes); + else { + *stripe = chunk & sc->stripes_mask; + chunk >>= sc->stripes_shift; + } + + *result = (chunk << sc->chunk_shift) | (offset & sc->chunk_mask); +} + +static void stripe_map_range_sector(struct stripe_c *sc, sector_t sector, + uint32_t target_stripe, sector_t *result) +{ + uint32_t stripe; + + stripe_map_sector(sc, sector, &stripe, result); + if (stripe == target_stripe) + return; + *result &= ~sc->chunk_mask; /* round down */ + if (target_stripe < stripe) + *result += sc->chunk_mask + 1; /* next chunk */ +} + +static int stripe_map_discard(struct stripe_c *sc, struct bio *bio, + uint32_t target_stripe) +{ + sector_t begin, end; + + stripe_map_range_sector(sc, bio->bi_sector, target_stripe, &begin); + stripe_map_range_sector(sc, bio->bi_sector + bio_sectors(bio), + target_stripe, &end); + if (begin < end) { + bio->bi_bdev = sc->stripe[target_stripe].dev->bdev; + bio->bi_sector = begin + sc->stripe[target_stripe].physical_start; + bio->bi_size = to_bytes(end - begin); + return DM_MAPIO_REMAPPED; + } else { + /* The range doesn't map to the target stripe */ + bio_endio(bio, 0); + return DM_MAPIO_SUBMITTED; + } +} + static int stripe_map(struct dm_target *ti, struct bio *bio, union map_info *map_context) { - struct stripe_c *sc = (struct stripe_c *) ti->private; - sector_t offset, chunk; + struct stripe_c *sc = ti->private; uint32_t stripe; + unsigned target_request_nr; if (unlikely(bio_empty_barrier(bio))) { - BUG_ON(map_context->flush_request >= sc->stripes); - bio->bi_bdev = sc->stripe[map_context->flush_request].dev->bdev; + target_request_nr = map_context->target_request_nr; + BUG_ON(target_request_nr >= sc->stripes); + bio->bi_bdev = sc->stripe[target_request_nr].dev->bdev; return DM_MAPIO_REMAPPED; } + if (unlikely(bio->bi_rw & REQ_DISCARD)) { + target_request_nr = map_context->target_request_nr; + BUG_ON(target_request_nr >= sc->stripes); + return stripe_map_discard(sc, bio, target_request_nr); + } - offset = bio->bi_sector - ti->begin; - chunk = offset >> sc->chunk_shift; - stripe = sector_div(chunk, sc->stripes); + stripe_map_sector(sc, bio->bi_sector, &stripe, &bio->bi_sector); + bio->bi_sector += sc->stripe[stripe].physical_start; bio->bi_bdev = sc->stripe[stripe].dev->bdev; - bio->bi_sector = sc->stripe[stripe].physical_start + - (chunk << sc->chunk_shift) + (offset & sc->chunk_mask); + return DM_MAPIO_REMAPPED; } @@ -284,7 +345,7 @@ static int stripe_end_io(struct dm_target *ti, struct bio *bio, if (!error) return 0; /* I/O complete */ - if ((error == -EWOULDBLOCK) && bio_rw_flagged(bio, BIO_RW_AHEAD)) + if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD)) return error; if (error == -EOPNOTSUPP) |