[PATCH] dmapi: simplify slab cache creation

[Christoph Hellwig <hch@xxxxxx>]

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@xxxxxx>

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;
 }