WRITE SAME bios have a payload that contain a single page. When
cloning WRITE SAME bios DM has no need to modify the bi_io_vec
attributes (doing so would be detrimental). DM need only alter the
start and end of the WRITE SAME bio accordingly.
Rather than duplicate __clone_and_map_discard, factor out a common
function that is also used by __clone_and_map_write_same.
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
drivers/md/dm.c | 44 +++++++++++++++++++++++++++++++++++++++-----
1 files changed, 39 insertions(+), 5 deletions(-)
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 739fd2b..cee9926 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1218,7 +1218,28 @@ static void __clone_and_map_simple(struct clone_info *ci, struct dm_target *ti)
ci->sector_count = 0;
}
-static int __clone_and_map_discard(struct clone_info *ci)
+typedef unsigned (*get_num_requests_fn)(struct dm_target *ti);
+
+static unsigned get_num_discard_requests(struct dm_target *ti)
+{
+ return ti->num_discard_requests;
+}
+
+static unsigned get_num_write_same_requests(struct dm_target *ti)
+{
+ return ti->num_write_same_requests;
+}
+
+typedef bool (*is_split_required_fn)(struct dm_target *ti);
+
+static bool is_split_required_for_discard(struct dm_target *ti)
+{
+ return ti->split_discard_requests;
+}
+
+static int __clone_and_map_changing_extent_only(struct clone_info *ci,
+ get_num_requests_fn get_num_requests,
+ is_split_required_fn is_split_required)
{
struct dm_target *ti;
sector_t len;
@@ -1229,15 +1250,15 @@ static int __clone_and_map_discard(struct clone_info *ci)
return -EIO;
/*
- * Even though the device advertised discard support,
- * that does not mean every target supports it, and
+ * Even though the device advertised support for this type of
+ * request, that does not mean every target supports it, and
* reconfiguration might also have changed that since the
* check was performed.
*/
- if (!ti->num_discard_requests)
+ if (!get_num_requests || !get_num_requests(ti))
return -EOPNOTSUPP;
- if (!ti->split_discard_requests)
+ if (is_split_required && !is_split_required(ti))
len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
else
len = min(ci->sector_count, max_io_len(ci->sector, ti));
@@ -1250,6 +1271,17 @@ static int __clone_and_map_discard(struct clone_info *ci)
return 0;
}
+static int __clone_and_map_discard(struct clone_info *ci)
+{
+ return __clone_and_map_changing_extent_only(ci, get_num_discard_requests,
+ is_split_required_for_discard);
+}
+
+static int __clone_and_map_write_same(struct clone_info *ci)
+{
+ return __clone_and_map_changing_extent_only(ci, get_num_write_same_requests, NULL);
+}
+
static int __clone_and_map(struct clone_info *ci)
{
struct bio *bio = ci->bio;
@@ -1258,6 +1290,8 @@ static int __clone_and_map(struct clone_info *ci)
if (unlikely(bio->bi_rw & REQ_DISCARD))
return __clone_and_map_discard(ci);
+ else if (unlikely(bio->bi_rw & REQ_WRITE_SAME))
+ return __clone_and_map_write_same(ci);
ti = dm_table_find_target(ci->map, ci->sector);
if (!dm_target_is_valid(ti))
--
1.7.1
--
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