[PATCH 11 of 33] DM Snapshot: exception function changes 3

[Jonathan Brassow <jbrassow@redhat.com>]

Patch name: dm-snap-exception-function-changes-3.patch

This patch adds the 'dm_exception_table_internal' structure.  It is used
to track the [de]allocation functions used for dm_exception's.  This is
necessary because some functions, like dm_insert_exception and
dm_exception_table_destroy must access them to do the right thing when
freeing exceptions.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>

Index: linux-2.6/drivers/md/dm-snap.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-snap.c
+++ linux-2.6/drivers/md/dm-snap.c
@@ -343,6 +343,16 @@ static void unregister_snapshot(struct d
 	up_write(&_origins_lock);
 }
 
+struct dm_exception_table_internal {
+	struct dm_exception_table et;
+
+	struct dm_exception *(*alloc_exception)(void *context);
+	void *alloc_context;
+
+	void (*free_exception)(struct dm_exception *e, void *context);
+	void *free_context;
+};
+
 /*
  * Implementation of the exception hash tables.
  * The lowest hash_shift bits of the chunk number are ignored, allowing
@@ -352,12 +362,15 @@ static struct dm_exception_table *
 dm_exception_table_create(uint32_t size, unsigned hash_shift)
 {
 	unsigned int i;
+	struct dm_exception_table_internal *eti;
 	struct dm_exception_table *et;
 
-	et = kmalloc(sizeof(*et), GFP_KERNEL);
-	if (!et)
+	eti = kmalloc(sizeof(*eti), GFP_KERNEL);
+	if (!eti)
 		return NULL;
 
+	et = &eti->et;
+
 	et->hash_shift = hash_shift;
 	et->hash_mask = size - 1;
 	et->table = dm_vcalloc(size, sizeof(struct list_head));
@@ -375,10 +388,13 @@ dm_exception_table_create(uint32_t size,
 static void dm_exception_table_destroy(struct dm_exception_table *et,
 				       struct kmem_cache *mem)
 {
+	struct dm_exception_table_internal *eti;
 	struct list_head *slot;
 	struct dm_exception *ex, *next;
 	int i, size;
 
+	eti = container_of(et, struct dm_exception_table_internal, et);
+
 	size = et->hash_mask + 1;
 	for (i = 0; i < size; i++) {
 		slot = et->table + i;
@@ -388,7 +404,7 @@ static void dm_exception_table_destroy(s
 	}
 
 	vfree(et->table);
-	kfree(et);
+	kfree(eti);
 }
 
 static uint32_t exception_hash(struct dm_exception_table *et, chunk_t chunk)