new: devfs设备卸载

kernel/filesystem/devfs/devfs-types.h

@@ -43,4 +43,5 @@ struct devfs_private_inode_info_t
     uint16_t sub_type; // 设备子类型
     struct vfs_file_operations_t *f_ops;
     uint64_t uuid;
+    struct vfs_index_node_t * inode;    // 当前私有信息所绑定的inode
 };

kernel/filesystem/devfs/devfs.c

@@ -5,6 +5,7 @@
 #include <common/string.h>
 #include <mm/slab.h>
 #include <common/spinlock.h>
+#include <debug/bug.h>
 
 struct vfs_super_block_operations_t devfs_sb_ops;
 struct vfs_dir_entry_operations_t devfs_dentry_ops;
@@ -257,6 +258,70 @@ failed:;
     return retval;
 }
 
+/**
+ * @brief 卸载设备
+ *
+ * @param private_inode_info 待卸载的设备的inode私有信息
+ * @param put_private_info 设备被卸载后，执行的函数
+ * @return int 错误码
+ */
+int devfs_unregister_device(struct devfs_private_inode_info_t *private_inode_info)
+{
+    int retval = 0;
+    spin_lock(&devfs_global_lock);
+    struct vfs_dir_entry_t *base_dentry = NULL;
+    struct vfs_dir_entry_t *target_dentry = NULL;
+
+    // 找到父目录的dentry
+    {
+
+        char base_path[64] = {0};
+        switch (private_inode_info->type)
+        {
+        case DEV_TYPE_CHAR:
+            strcpy(base_path, "/dev/char");
+            break;
+        default:
+            retval = -ENOTSUP;
+            goto out;
+            break;
+        }
+
+        base_dentry = vfs_path_walk(base_path, 0);
+        // bug
+        if (unlikely(base_dentry == NULL))
+        {
+            BUG_ON(1);
+            retval = -ENODEV;
+            goto out;
+        }
+    }
+
+    // 遍历子目录，寻找拥有指定inode的dentry（暂时不支持一个inode对应多个dentry的情况）
+    // todo: 支持链接文件的卸载
+    struct List *tmp_list = NULL, *target_list = NULL;
+    list_for_each_safe(target_list, tmp_list, &base_dentry->subdirs_list)
+    {
+        target_dentry = list_entry(target_list, struct vfs_dir_entry_t, child_node_list);
+        if (target_dentry->dir_inode == private_inode_info->inode)
+        {
+            spin_lock(&target_dentry->lockref.lock);
+            retval = vfs_dentry_put(target_dentry);
+            if (retval < 0)
+            {
+                kerror("Error when try to unregister device");
+                spin_unlock(&target_dentry->lockref.lock);
+            }
+            else if (retval == 0) // 该设备的所有dentry均被卸载完成，不必继续迭代
+                break;
+        }
+    }
+    retval = 0;
+out:;
+    spin_unlock(&devfs_global_lock);
+    return retval;
+}
+
 /**
  * @brief 初始化devfs
  *

kernel/filesystem/devfs/devfs.h

@@ -17,4 +17,13 @@ void devfs_init();
  * @param ret_private_inode_info_ptr 返回的指向inode私有信息结构体的指针
  * @return int 错误码
  */
-int devfs_register_device(uint16_t device_type, uint16_t sub_type, struct vfs_file_operations_t *file_ops, struct devfs_private_inode_info_t **ret_private_inode_info_ptr);
+int devfs_register_device(uint16_t device_type, uint16_t sub_type, struct vfs_file_operations_t *file_ops, struct devfs_private_inode_info_t **ret_private_inode_info_ptr);
+
+/**
+ * @brief 卸载设备
+ * 
+ * @param private_inode_info 待卸载的设备的inode私有信息
+ * @param put_private_info 设备被卸载后，执行的函数
+ * @return int 错误码
+ */
+int devfs_unregister_device(struct devfs_private_inode_info_t * private_inode_info);

kernel/filesystem/devfs/internal.h

@@ -78,6 +78,8 @@ static inline void __devfs_fill_inode(struct vfs_dir_entry_t *dentry, struct vfs
     dentry->dir_inode->private_inode_info = private_inode_data;
     dentry->dir_inode->sb = &devfs_sb;
     dentry->dir_inode->attribute = inode_attr;
+    // 反向绑定inode
+    private_inode_data->inode = dentry->dir_inode;
 }
 
 /**