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-rw-r--r--drivers/md/dm.c75
1 files changed, 71 insertions, 4 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 0cf68b478878..52b39f335bb3 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -37,6 +37,8 @@ static const char *_name = DM_NAME;
static unsigned int major = 0;
static unsigned int _major = 0;
+static DEFINE_IDR(_minor_idr);
+
static DEFINE_SPINLOCK(_minor_lock);
/*
* For bio-based dm.
@@ -109,6 +111,7 @@ EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
#define DMF_FREEING 3
#define DMF_DELETING 4
#define DMF_NOFLUSH_SUSPENDING 5
+#define DMF_MERGE_IS_OPTIONAL 6
/*
* Work processed by per-device workqueue.
@@ -313,6 +316,12 @@ static void __exit dm_exit(void)
while (i--)
_exits[i]();
+
+ /*
+ * Should be empty by this point.
+ */
+ idr_remove_all(&_minor_idr);
+ idr_destroy(&_minor_idr);
}
/*
@@ -1171,7 +1180,8 @@ static int __clone_and_map_discard(struct clone_info *ci)
/*
* Even though the device advertised discard support,
- * reconfiguration might have changed that since the
+ * 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)
@@ -1705,8 +1715,6 @@ static int dm_any_congested(void *congested_data, int bdi_bits)
/*-----------------------------------------------------------------
* An IDR is used to keep track of allocated minor numbers.
*---------------------------------------------------------------*/
-static DEFINE_IDR(_minor_idr);
-
static void free_minor(int minor)
{
spin_lock(&_minor_lock);
@@ -1800,7 +1808,6 @@ static void dm_init_md_queue(struct mapped_device *md)
blk_queue_make_request(md->queue, dm_request);
blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
blk_queue_merge_bvec(md->queue, dm_merge_bvec);
- blk_queue_flush(md->queue, REQ_FLUSH | REQ_FUA);
}
/*
@@ -1986,6 +1993,59 @@ static void __set_size(struct mapped_device *md, sector_t size)
}
/*
+ * Return 1 if the queue has a compulsory merge_bvec_fn function.
+ *
+ * If this function returns 0, then the device is either a non-dm
+ * device without a merge_bvec_fn, or it is a dm device that is
+ * able to split any bios it receives that are too big.
+ */
+int dm_queue_merge_is_compulsory(struct request_queue *q)
+{
+ struct mapped_device *dev_md;
+
+ if (!q->merge_bvec_fn)
+ return 0;
+
+ if (q->make_request_fn == dm_request) {
+ dev_md = q->queuedata;
+ if (test_bit(DMF_MERGE_IS_OPTIONAL, &dev_md->flags))
+ return 0;
+ }
+
+ return 1;
+}
+
+static int dm_device_merge_is_compulsory(struct dm_target *ti,
+ struct dm_dev *dev, sector_t start,
+ sector_t len, void *data)
+{
+ struct block_device *bdev = dev->bdev;
+ struct request_queue *q = bdev_get_queue(bdev);
+
+ return dm_queue_merge_is_compulsory(q);
+}
+
+/*
+ * Return 1 if it is acceptable to ignore merge_bvec_fn based
+ * on the properties of the underlying devices.
+ */
+static int dm_table_merge_is_optional(struct dm_table *table)
+{
+ unsigned i = 0;
+ struct dm_target *ti;
+
+ while (i < dm_table_get_num_targets(table)) {
+ ti = dm_table_get_target(table, i++);
+
+ if (ti->type->iterate_devices &&
+ ti->type->iterate_devices(ti, dm_device_merge_is_compulsory, NULL))
+ return 0;
+ }
+
+ return 1;
+}
+
+/*
* Returns old map, which caller must destroy.
*/
static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
@@ -1995,6 +2055,7 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
struct request_queue *q = md->queue;
sector_t size;
unsigned long flags;
+ int merge_is_optional;
size = dm_table_get_size(t);
@@ -2020,10 +2081,16 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
__bind_mempools(md, t);
+ merge_is_optional = dm_table_merge_is_optional(t);
+
write_lock_irqsave(&md->map_lock, flags);
old_map = md->map;
md->map = t;
dm_table_set_restrictions(t, q, limits);
+ if (merge_is_optional)
+ set_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
+ else
+ clear_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
write_unlock_irqrestore(&md->map_lock, flags);
return old_map;