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-rw-r--r--drivers/md/dm.c65
1 files changed, 53 insertions, 12 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 0d47101..44aba29 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1212,6 +1212,53 @@ static int __clone_and_map_empty_barrier(struct clone_info *ci)
return 0;
}
+/*
+ * Perform all io with a single clone.
+ */
+static void __clone_and_map_simple(struct clone_info *ci, struct dm_target *ti)
+{
+ struct bio *clone, *bio = ci->bio;
+ struct dm_target_io *tio;
+
+ tio = alloc_tio(ci, ti);
+ clone = clone_bio(bio, ci->sector, ci->idx,
+ bio->bi_vcnt - ci->idx, ci->sector_count,
+ ci->md->bs);
+ __map_bio(ti, clone, tio);
+ ci->sector_count = 0;
+}
+
+static int __clone_and_map_discard(struct clone_info *ci)
+{
+ struct dm_target *ti;
+ sector_t max;
+
+ ti = dm_table_find_target(ci->map, ci->sector);
+ if (!dm_target_is_valid(ti))
+ return -EIO;
+
+ /*
+ * Even though the device advertised discard support,
+ * reconfiguration might have changed that since the
+ * check was performed.
+ */
+
+ if (!ti->num_discard_requests)
+ return -EOPNOTSUPP;
+
+ max = max_io_len(ci->md, ci->sector, ti);
+
+ if (ci->sector_count > max)
+ /*
+ * FIXME: Handle a discard that spans two or more targets.
+ */
+ return -EOPNOTSUPP;
+
+ __clone_and_map_simple(ci, ti);
+
+ return 0;
+}
+
static int __clone_and_map(struct clone_info *ci)
{
struct bio *clone, *bio = ci->bio;
@@ -1222,27 +1269,21 @@ static int __clone_and_map(struct clone_info *ci)
if (unlikely(bio_empty_barrier(bio)))
return __clone_and_map_empty_barrier(ci);
+ if (unlikely(bio->bi_rw & REQ_DISCARD))
+ return __clone_and_map_discard(ci);
+
ti = dm_table_find_target(ci->map, ci->sector);
if (!dm_target_is_valid(ti))
return -EIO;
max = max_io_len(ci->md, ci->sector, ti);
- /*
- * Allocate a target io object.
- */
- tio = alloc_tio(ci, ti);
-
if (ci->sector_count <= max) {
/*
* Optimise for the simple case where we can do all of
* the remaining io with a single clone.
*/
- clone = clone_bio(bio, ci->sector, ci->idx,
- bio->bi_vcnt - ci->idx, ci->sector_count,
- ci->md->bs);
- __map_bio(ti, clone, tio);
- ci->sector_count = 0;
+ __clone_and_map_simple(ci, ti);
} else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) {
/*
@@ -1263,6 +1304,7 @@ static int __clone_and_map(struct clone_info *ci)
len += bv_len;
}
+ tio = alloc_tio(ci, ti);
clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len,
ci->md->bs);
__map_bio(ti, clone, tio);
@@ -1286,12 +1328,11 @@ static int __clone_and_map(struct clone_info *ci)
return -EIO;
max = max_io_len(ci->md, ci->sector, ti);
-
- tio = alloc_tio(ci, ti);
}
len = min(remaining, max);
+ tio = alloc_tio(ci, ti);
clone = split_bvec(bio, ci->sector, ci->idx,
bv->bv_offset + offset, len,
ci->md->bs);