> > +struct liveupdate_file_ops {
> > + int (*prepare)(struct file *file, void *arg, u64 *data);
> > + int (*freeze)(struct file *file, void *arg, u64 *data);
> > + void (*cancel)(struct file *file, void *arg, u64 data);
> > + void (*finish)(struct file *file, void *arg, u64 data, bool reclaimed);
> > + int (*retrieve)(void *arg, u64 data, struct file **file);
> > + bool (*can_preserve)(struct file *file, void *arg);
> > +};
>
> ops structures often have an owner = THIS_MODULE
Added here, and to subsystems.
>
> It wouldn't hurt to add it here too, and some appropriate module_get's
> though I didn't try to figure what happens if userspace races a module
> unload with other luo operations.
I added try_module_get()/module_put() to register/unregister functions.
> > +
> > +/**
> > + * struct liveupdate_file_handler - Represents a handler for a live-updatable
> > + * file type.
> > + * @ops: Callback functions
> > + * @compatible: The compatibility string (e.g., "memfd-v1", "vfiofd-v1")
> > + * that uniquely identifies the file type this handler supports.
> > + * This is matched against the compatible string associated with
> > + * individual &struct liveupdate_file instances.
> > + * @arg: An opaque pointer to implementation-specific context data
> > + * associated with this file handler registration.
>
> Why? This is not the normal way, if you want context data then
> allocate a struct driver_liveupdate_file_handler and embed a normal
> struct liveupdate_file_handler inside it, then use container_of.
Good point. I removed arg, and added handler as an argument to the
callback functions.
> > + fdt_for_each_subnode(file_node_offset, luo_file_fdt_in, 0) {
> > + bool handler_found = false;
> > + u64 token;
> > +
> > + node_name = fdt_get_name(luo_file_fdt_in, file_node_offset,
> > + NULL);
> > + if (!node_name) {
> > + panic("FDT subnode at offset %d: Cannot get name\n",
> > + file_node_offset);
>
> I think this approach will raise lots of questions..
>
> I'd introduce a new function "luo_deserialize_failure" that does panic
> internally.
>
> Only called by places that are parsing the FDT & related but run into
> trouble that cannot be savely recovered from.
Agreed. I added a new macro in luo_internal.h:
11 /*
12 * Handles a deserialization failure: devices and memory is in
unpredictable
13 * state.
14 *
15 * Continuing the boot process after a failure is dangerous
because it could
16 * lead to leaks of private data.
17 */
18 #define luo_restore_fail(__fmt, ...) panic(__fmt, ##__VA_ARGS__)
And use it in places where we panic during deserialization.
Pasha