Cleanup fs/class shitfest a bit

fs/fs_class.c

@@ -1,54 +1,49 @@
+#include "sys/mem/slab.h"
+#include "sys/assert.h"
 #include "user/errno.h"
 #include "sys/string.h"
-#include "fs/fs.h"
 #include "sys/debug.h"
+#include "fs/fs.h"
 
-// #include <stddef.h>
-// #include <string.h>
-// #include <errno.h>
+static LIST_HEAD(fs_class_list);
+static LIST_HEAD(fs_mount_list);
 
-static struct fs_class *fses[10] = { NULL };
-static struct fs mounts[10];
+static struct slab_cache *fs_mount_cache;
 
 struct fs *fs_create(struct fs_class *cls, struct blkdev *blk, uint32_t flags, const char *opt) {
-    struct fs *fs = NULL;
-    // XXX: I hate heap allocations, but why not use one?
-    for (size_t i = 0; i < 10; ++i) {
-        if (mounts[i].cls == NULL) {
-            mounts[i].cls = cls;
-            mounts[i].blk = blk;
-            fs = &mounts[i];
-            break;
-        }
-    }
-
-    if (!fs) {
-        return NULL;
+    if (!fs_mount_cache) {
+        kdebug("Initialize filesystem instance (mount) cache\n");
+        fs_mount_cache = slab_cache_get(sizeof(struct fs));
+        _assert(fs_mount_cache);
     }
+    struct fs *fs = slab_calloc(fs_mount_cache);
+    _assert(fs);
 
+    list_head_init(&fs->link);
+    fs->cls = cls;
+    fs->blk = blk;
     fs->flags = flags;
 
-    // Try to initialize filesystem instance at device
     if (cls->init) {
         if (cls->init(fs, opt) != 0) {
-            fs->cls = NULL;
-            kerror("%s init failed\n", cls->name);
+            kerror("%s: filesystem instance init failed\n", cls->name);
+            slab_free(fs_mount_cache, fs);
             return NULL;
         }
     } else {
-        kwarn("%s provides no init function\n", cls->name);
+        kwarn("%s: filesystem type has no init func\n", cls->name);
     }
 
+    list_add(&fs->link, &fs_mount_list);
+
     return fs;
 }
 
 struct fs_class *fs_class_by_name(const char *name) {
-    for (size_t i = 0; i < 10; ++i) {
-        if (!fses[i]) {
-            break;
-        }
-        if (!strcmp(name, fses[i]->name)) {
-            return fses[i];
+    struct fs_class *cls;
+    list_for_each_entry(cls, &fs_class_list, link) {
+        if (!strcmp(cls->name, name)) {
+            return cls;
         }
     }
     return NULL;
@@ -59,12 +54,7 @@ int fs_class_register(struct fs_class *cls) {
         return -EEXIST;
     }
 
-    for (size_t i = 0; i < 10; ++i) {
-        if (!fses[i]) {
-            fses[i] = cls;
-            return 0;
-        }
-    }
-
-    return -ENOMEM;
+    list_head_init(&cls->link);
+    list_add(&cls->link, &fs_class_list);
+    return 0;
 }

include/fs/fs.h

@@ -1,5 +1,6 @@
 #pragma once
 #include "sys/types.h"
+#include "sys/list.h"
 
 struct statvfs;
 struct blkdev;
@@ -15,6 +16,8 @@ struct fs_class {
     int (*init) (struct fs *fs, const char *opt);
     void (*destroy) (struct fs *fs);
     int (*statvfs) (struct fs *fs, struct statvfs *st);
+
+    struct list_head link;
 };
 
 // The actual filesystem instance,
@@ -29,6 +32,8 @@ struct fs {
     void *fs_private;
 
     struct fs_class *cls;
+
+    struct list_head link;
 };
 
 struct fs *fs_create(struct fs_class *cls, struct blkdev *blk, uint32_t flags, const char *opt);