[PATCH] dm: remove dynamic table resizing

From: Joe Thornber <thornber@sistina.com>

The dm table size is always known in advance, so we can specify it in
dm_table_create(), rather than relying on dynamic resizing.

drivers/md/dm-ioctl-v1.c

@@ -566,7 +566,7 @@ static int create(struct dm_ioctl *param, struct dm_ioctl *user)
 	if (r)
 		return r;
 
-	r = dm_table_create(&t, get_mode(param));
+	r = dm_table_create(&t, get_mode(param), param->target_count);
 	if (r)
 		return r;
 
@@ -894,7 +894,7 @@ static int reload(struct dm_ioctl *param, struct dm_ioctl *user)
 	struct mapped_device *md;
 	struct dm_table *t;
 
-	r = dm_table_create(&t, get_mode(param));
+	r = dm_table_create(&t, get_mode(param), param->target_count);
 	if (r)
 		return r;
 

drivers/md/dm-ioctl-v4.c

@@ -872,7 +872,7 @@ static int table_load(struct dm_ioctl *param, size_t param_size)
 	struct hash_cell *hc;
 	struct dm_table *t;
 
-	r = dm_table_create(&t, get_mode(param));
+	r = dm_table_create(&t, get_mode(param), param->target_count);
 	if (r)
 		return r;
 

drivers/md/dm-table.c

@@ -202,7 +202,7 @@ static int alloc_targets(struct dm_table *t, unsigned int num)
 	return 0;
 }
 
-int dm_table_create(struct dm_table **result, int mode)
+int dm_table_create(struct dm_table **result, int mode, unsigned num_targets)
 {
 	struct dm_table *t = kmalloc(sizeof(*t), GFP_NOIO);
 
@@ -213,8 +213,12 @@ int dm_table_create(struct dm_table **result, int mode)
 	INIT_LIST_HEAD(&t->devices);
 	atomic_set(&t->holders, 1);
 
-	/* allocate a single nodes worth of targets to begin with */
-	if (alloc_targets(t, KEYS_PER_NODE)) {
+	if (!num_targets)
+		num_targets = KEYS_PER_NODE;
+
+	num_targets = dm_round_up(num_targets, KEYS_PER_NODE);
+
+	if (alloc_targets(t, num_targets)) {
 		kfree(t);
 		t = NULL;
 		return -ENOMEM;

drivers/md/dm.h

@@ -95,7 +95,7 @@ int dm_suspended(struct mapped_device *md);
  * Functions for manipulating a table.  Tables are also reference
  * counted.
  *---------------------------------------------------------------*/
-int dm_table_create(struct dm_table **result, int mode);
+int dm_table_create(struct dm_table **result, int mode, unsigned num_targets);
 
 void dm_table_get(struct dm_table *t);
 void dm_table_put(struct dm_table *t);