[PATCH] dmapi: simplify slab cache creation

[Christoph Hellwig <hch@lst.de>]

Currently two out of three slab caches are created on-demand on
dmapi_register.  Move them into dmapi_init as the others are to clean up
all the mess about checking whether dmapi_register has been called
before or is in the process of beeing called.


Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6-xfs/fs/dmapi/dmapi_mountinfo.c
===================================================================
--- linux-2.6-xfs.orig/fs/dmapi/dmapi_mountinfo.c	2007-08-02 16:00:52.000000000 +0200
+++ linux-2.6-xfs/fs/dmapi/dmapi_mountinfo.c	2007-08-02 16:07:13.000000000 +0200
@@ -471,40 +471,7 @@ dmapi_register(
 	struct filesystem_dmapi_operations *dmapiops)
 {
 	dm_vector_map_t *proto;
-	static int initialized = 0;
 
-wait_cache:
-	spin_lock(&dm_fsys_lock);
-	if (initialized == -1) {
-		spin_unlock(&dm_fsys_lock);
-		goto wait_cache;
-	}
-	if (initialized == 0)
-		initialized = -1;
-	spin_unlock(&dm_fsys_lock);
-
-	if (initialized == -1) {
-		ASSERT(dm_fsys_map_cachep == NULL);
-		ASSERT(dm_fsys_vptr_cachep == NULL);
-
-		dm_fsys_map_cachep = kmem_cache_create("dm_fsys_map",
-					sizeof(dm_vector_map_t), 0, 0, NULL, NULL);
-
-		dm_fsys_vptr_cachep = kmem_cache_create("dm_fsys_vptr",
-					sizeof(dm_fsys_vector_t), 0, 0, NULL, NULL);
-
-		spin_lock(&dm_fsys_lock);
-		if ((dm_fsys_map_cachep == NULL) ||
-		    (dm_fsys_map_cachep == NULL)) {
-			initialized = 0;
-			spin_unlock(&dm_fsys_lock);
-			goto out_cache_free;
-		}
-		initialized = 1;
-		spin_unlock(&dm_fsys_lock);
-	}
-
-	ASSERT_ALWAYS(initialized == 1);
 	proto = kmem_cache_alloc(dm_fsys_map_cachep, GFP_KERNEL);
 	if (proto == NULL) {
 		printk("%s/%d: kmem_cache_alloc(dm_fsys_map_cachep) returned NULL\n", __FUNCTION__, __LINE__);
@@ -521,21 +488,8 @@ wait_cache:
 	list_add(&proto->ftype_list, &dm_fsys_map);
 	ftype_list();
 	spin_unlock(&dm_fsys_lock);
-
-	return;
-
-out_cache_free:
-	if (dm_fsys_map_cachep) {
-		kmem_cache_destroy(dm_fsys_map_cachep);
-		dm_fsys_map_cachep = NULL;
-	}
-	if (dm_fsys_vptr_cachep) {
-		kmem_cache_destroy(dm_fsys_vptr_cachep);
-		dm_fsys_vptr_cachep = NULL;
-	}
 }
 
-
 /* Called by a filesystem module that is unloading from the kernel */
 void
 dmapi_unregister(
Index: linux-2.6-xfs/fs/dmapi/dmapi_sysent.c
===================================================================
--- linux-2.6-xfs.orig/fs/dmapi/dmapi_sysent.c	2007-08-02 16:03:21.000000000 +0200
+++ linux-2.6-xfs/fs/dmapi/dmapi_sysent.c	2007-08-02 16:09:46.000000000 +0200
@@ -740,35 +740,47 @@ int __init dmapi_init(void)
 	dm_tokdata_cachep = kmem_cache_create("dm_tokdata",
 				sizeof(struct dm_tokdata), 0, 0, NULL, NULL);
 	if (dm_tokdata_cachep == NULL)
-		goto out_cache_free;
+		goto out;
 
 	dm_fsreg_cachep = kmem_cache_create("dm_fsreg",
 				sizeof(struct dm_fsreg), 0, 0, NULL, NULL);
 	if (dm_fsreg_cachep == NULL)
-		goto out_cache_free;
+		goto out_free_tokdata_cachep;
 
 	dm_session_cachep = kmem_cache_create("dm_session",
 				sizeof(struct dm_session), 0, 0, NULL, NULL);
 	if (dm_session_cachep == NULL)
-		goto out_cache_free;
+		goto out_free_fsreg_cachep;
+
+	dm_fsys_map_cachep = kmem_cache_create("dm_fsys_map",
+				sizeof(dm_vector_map_t), 0, 0, NULL, NULL);
+	if (dm_fsys_map_cachep == NULL)
+		goto out_free_session_cachep;
+	dm_fsys_vptr_cachep = kmem_cache_create("dm_fsys_vptr",
+				sizeof(dm_fsys_vector_t), 0, 0, NULL, NULL);
+	if (dm_fsys_vptr_cachep == NULL)
+		goto out_free_fsys_map_cachep;
 
 	ret = misc_register(&dmapi_dev);
-	if( ret != 0 )
+	if (ret) {
 		printk(KERN_ERR "dmapi_init: misc_register returned %d\n", ret);
+		goto out_free_fsys_vptr_cachep;
+	}
+
 	dmapi_init_procfs(dmapi_dev.minor);
 	return 0;
 
-out_cache_free:
-	if (dm_tokdata_cachep)
-		kmem_cache_destroy(dm_tokdata_cachep);
-	if (dm_fsreg_cachep)
-		kmem_cache_destroy(dm_fsreg_cachep);
-	if (dm_session_cachep)
-		kmem_cache_destroy(dm_session_cachep);
-	if (dm_fsys_map_cachep)
-		kmem_cache_destroy(dm_fsys_map_cachep);
-	if (dm_fsys_vptr_cachep)
-		kmem_cache_destroy(dm_fsys_vptr_cachep);
+ out_free_fsys_vptr_cachep:
+	kmem_cache_destroy(dm_fsys_vptr_cachep);
+ out_free_fsys_map_cachep:
+	kmem_cache_destroy(dm_fsys_map_cachep);
+ out_free_session_cachep:
+	kmem_cache_destroy(dm_session_cachep);
+ out_free_fsreg_cachep:
+	kmem_cache_destroy(dm_fsreg_cachep);
+ out_free_tokdata_cachep:
+	kmem_cache_destroy(dm_tokdata_cachep);
+ out:
 	return -ENOMEM;
 }