dm unstripe: support non-power-of-2 chunk size

Address "FIXME: must support non power of 2 chunk_size, dm-stripe.c does".

Bump target version to indicate change.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Tested-by: Scott Bauer <Scott.Bauer@intel.com>
Reviewed-by: Scott Bauer <Scott.Bauer@intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-unstripe.c b/drivers/md/dm-unstripe.c
index 65f838fa2e99d2727bba31dd26fd5c715fa3f0c2..05d76f337838ad662ccfaa289516e43c556f301e 100644 (file)
--- a/drivers/md/dm-unstripe.c
+++ b/drivers/md/dm-unstripe.c
@@ -69,12 +69,6 @@ static int unstripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
                goto err;
        }
 
-       // FIXME: must support non power of 2 chunk_size, dm-stripe.c does
-       if (!is_power_of_2(uc->chunk_size)) {
-               ti->error = "Non power of 2 chunk_size is not supported yet";
-               goto err;
-       }
-
        if (kstrtouint(argv[2], 10, &uc->unstripe)) {
                ti->error = "Invalid stripe number";
                goto err;
@@ -98,7 +92,7 @@ static int unstripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
        uc->unstripe_offset = uc->unstripe * uc->chunk_size;
        uc->unstripe_width = (uc->stripes - 1) * uc->chunk_size;
-       uc->chunk_shift = fls(uc->chunk_size) - 1;
+       uc->chunk_shift = is_power_of_2(uc->chunk_size) ? fls(uc->chunk_size) - 1 : 0;
 
        tmp_len = ti->len;
        if (sector_div(tmp_len, uc->chunk_size)) {
@@ -129,14 +123,18 @@ static sector_t map_to_core(struct dm_target *ti, struct bio *bio)
 {
        struct unstripe_c *uc = ti->private;
        sector_t sector = bio->bi_iter.bi_sector;
+       sector_t tmp_sector = sector;
 
        /* Shift us up to the right "row" on the stripe */
-       sector += uc->unstripe_width * (sector >> uc->chunk_shift);
+       if (uc->chunk_shift)
+               tmp_sector >>= uc->chunk_shift;
+       else
+               sector_div(tmp_sector, uc->chunk_size);
 
-       /* Account for what stripe we're operating on */
-       sector += uc->unstripe_offset;
+       sector += uc->unstripe_width * tmp_sector;
 
-       return sector;
+       /* Account for what stripe we're operating on */
+       return sector + uc->unstripe_offset;
 }
 
 static int unstripe_map(struct dm_target *ti, struct bio *bio)
@@ -185,7 +183,7 @@ static void unstripe_io_hints(struct dm_target *ti,
 
 static struct target_type unstripe_target = {
        .name = "unstriped",
-       .version = {1, 0, 0},
+       .version = {1, 1, 0},
        .module = THIS_MODULE,
        .ctr = unstripe_ctr,
        .dtr = unstripe_dtr,