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-rw-r--r--drivers/md/dm-linear.c1
-rw-r--r--drivers/md/dm-table.c44
-rw-r--r--drivers/md/dm.c65
-rw-r--r--drivers/md/dm.h1
-rw-r--r--include/linux/device-mapper.h6
5 files changed, 105 insertions, 12 deletions
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index 9200dbf2391a..f043b5f433b2 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -53,6 +53,7 @@ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
}
ti->num_flush_requests = 1;
+ ti->num_discard_requests = 1;
ti->private = lc;
return 0;
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index bc60ef77a0d8..f9fc07d7a4b9 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -54,6 +54,8 @@ struct dm_table {
sector_t *highs;
struct dm_target *targets;
+ unsigned discards_supported:1;
+
/*
* Indicates the rw permissions for the new logical
* device. This should be a combination of FMODE_READ
@@ -203,6 +205,7 @@ int dm_table_create(struct dm_table **result, fmode_t mode,
INIT_LIST_HEAD(&t->devices);
atomic_set(&t->holders, 0);
+ t->discards_supported = 1;
if (!num_targets)
num_targets = KEYS_PER_NODE;
@@ -770,6 +773,9 @@ int dm_table_add_target(struct dm_table *t, const char *type,
t->highs[t->num_targets++] = tgt->begin + tgt->len - 1;
+ if (!tgt->num_discard_requests)
+ t->discards_supported = 0;
+
return 0;
bad:
@@ -1135,6 +1141,11 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
else
queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, q);
+ if (!dm_table_supports_discards(t))
+ queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
+ else
+ queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
+
dm_table_set_integrity(t);
/*
@@ -1281,6 +1292,39 @@ struct mapped_device *dm_table_get_md(struct dm_table *t)
return t->md;
}
+static int device_discard_capable(struct dm_target *ti, struct dm_dev *dev,
+ sector_t start, sector_t len, void *data)
+{
+ struct request_queue *q = bdev_get_queue(dev->bdev);
+
+ return q && blk_queue_discard(q);
+}
+
+bool dm_table_supports_discards(struct dm_table *t)
+{
+ struct dm_target *ti;
+ unsigned i = 0;
+
+ if (!t->discards_supported)
+ return 0;
+
+ /*
+ * Ensure that at least one underlying device supports discards.
+ * t->devices includes internal dm devices such as mirror logs
+ * so we need to use iterate_devices here, which targets
+ * supporting discard must provide.
+ */
+ while (i < dm_table_get_num_targets(t)) {
+ ti = dm_table_get_target(t, i++);
+
+ if (ti->type->iterate_devices &&
+ ti->type->iterate_devices(ti, device_discard_capable, NULL))
+ return 1;
+ }
+
+ return 0;
+}
+
EXPORT_SYMBOL(dm_vcalloc);
EXPORT_SYMBOL(dm_get_device);
EXPORT_SYMBOL(dm_put_device);
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 0d4710175885..44aba29154fc 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);
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 0d7b374c5dc2..0c2dd5f4af76 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -61,6 +61,7 @@ int dm_table_any_congested(struct dm_table *t, int bdi_bits);
int dm_table_any_busy_target(struct dm_table *t);
unsigned dm_table_get_type(struct dm_table *t);
bool dm_table_request_based(struct dm_table *t);
+bool dm_table_supports_discards(struct dm_table *t);
int dm_table_alloc_md_mempools(struct dm_table *t);
void dm_table_free_md_mempools(struct dm_table *t);
struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t);
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 531a6f2635ae..751ce21dea7b 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -180,6 +180,12 @@ struct dm_target {
*/
unsigned num_flush_requests;
+ /*
+ * The number of discard requests that will be submitted to the
+ * target. map_info->request_nr is used just like num_flush_requests.
+ */
+ unsigned num_discard_requests;
+
/* target specific data */
void *private;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.