From 7c722a7f44e0c1f9714084152226bc7bd644b7e3 Mon Sep 17 00:00:00 2001 From: Pasha Tatashin Date: Tue, 25 Nov 2025 11:58:36 -0500 Subject: liveupdate: luo_file: implement file systems callbacks This patch implements the core mechanism for managing preserved files throughout the live update lifecycle. It provides the logic to invoke the file handler callbacks (preserve, unpreserve, freeze, unfreeze, retrieve, and finish) at the appropriate stages. During the reboot phase, luo_file_freeze() serializes the final metadata for each file (handler compatible string, token, and data handle) into a memory region preserved by KHO. In the new kernel, luo_file_deserialize() reconstructs the in-memory file list from this data, preparing the session for retrieval. Link: https://lkml.kernel.org/r/20251125165850.3389713-7-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Pratyush Yadav Tested-by: David Matlack Cc: Aleksander Lobakin Cc: Alexander Graf Cc: Alice Ryhl Cc: Andriy Shevchenko Cc: anish kumar Cc: Anna Schumaker Cc: Bartosz Golaszewski Cc: Bjorn Helgaas Cc: Borislav Betkov Cc: Chanwoo Choi Cc: Chen Ridong Cc: Chris Li Cc: Christian Brauner Cc: Daniel Wagner Cc: Danilo Krummrich Cc: Dan Williams Cc: David Hildenbrand Cc: David Jeffery Cc: David Rientjes Cc: Greg Kroah-Hartman Cc: Guixin Liu Cc: "H. Peter Anvin" Cc: Hugh Dickins Cc: Ilpo Järvinen Cc: Ingo Molnar Cc: Ira Weiny Cc: Jann Horn Cc: Jason Gunthorpe Cc: Jens Axboe Cc: Joanthan Cameron Cc: Joel Granados Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Lennart Poettering Cc: Leon Romanovsky Cc: Leon Romanovsky Cc: Lukas Wunner Cc: Marc Rutland Cc: Masahiro Yamada Cc: Matthew Maurer Cc: Miguel Ojeda Cc: Myugnjoo Ham Cc: Parav Pandit Cc: Pratyush Yadav Cc: Randy Dunlap Cc: Roman Gushchin Cc: Saeed Mahameed Cc: Samiullah Khawaja Cc: Song Liu Cc: Steven Rostedt Cc: Stuart Hayes Cc: Tejun Heo Cc: Thomas Gleinxer Cc: Thomas Weißschuh Cc: Vincent Guittot Cc: William Tu Cc: Yoann Congal Cc: Zhu Yanjun Cc: Zijun Hu Signed-off-by: Andrew Morton --- kernel/liveupdate/luo_internal.h | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) (limited to 'kernel/liveupdate/luo_internal.h') diff --git a/kernel/liveupdate/luo_internal.h b/kernel/liveupdate/luo_internal.h index 1292ac47eef8..c8973b543d1d 100644 --- a/kernel/liveupdate/luo_internal.h +++ b/kernel/liveupdate/luo_internal.h @@ -40,6 +40,28 @@ static inline int luo_ucmd_respond(struct luo_ucmd *ucmd, */ #define luo_restore_fail(__fmt, ...) panic(__fmt, ##__VA_ARGS__) +/* Mimics list_for_each_entry() but for private list head entries */ +#define luo_list_for_each_private(pos, head, member) \ + for (struct list_head *__iter = (head)->next; \ + __iter != (head) && \ + ({ pos = container_of(__iter, typeof(*(pos)), member); 1; }); \ + __iter = __iter->next) + +/** + * struct luo_file_set - A set of files that belong to the same sessions. + * @files_list: An ordered list of files associated with this session, it is + * ordered by preservation time. + * @files: The physically contiguous memory block that holds the serialized + * state of files. + * @count: A counter tracking the number of files currently stored in the + * @files_list for this session. + */ +struct luo_file_set { + struct list_head files_list; + struct luo_file_ser *files; + long count; +}; + /** * struct luo_session - Represents an active or incoming Live Update session. * @name: A unique name for this session, used for identification and @@ -50,6 +72,7 @@ static inline int luo_ucmd_respond(struct luo_ucmd *ucmd, * previous kernel) sessions. * @retrieved: A boolean flag indicating whether this session has been * retrieved by a consumer in the new kernel. + * @file_set: A set of files that belong to this session. * @mutex: protects fields in the luo_session. */ struct luo_session { @@ -57,6 +80,7 @@ struct luo_session { struct luo_session_ser *ser; struct list_head list; bool retrieved; + struct luo_file_set file_set; struct mutex mutex; }; @@ -69,4 +93,18 @@ int luo_session_deserialize(void); bool luo_session_quiesce(void); void luo_session_resume(void); +int luo_preserve_file(struct luo_file_set *file_set, u64 token, int fd); +void luo_file_unpreserve_files(struct luo_file_set *file_set); +int luo_file_freeze(struct luo_file_set *file_set, + struct luo_file_set_ser *file_set_ser); +void luo_file_unfreeze(struct luo_file_set *file_set, + struct luo_file_set_ser *file_set_ser); +int luo_retrieve_file(struct luo_file_set *file_set, u64 token, + struct file **filep); +int luo_file_finish(struct luo_file_set *file_set); +int luo_file_deserialize(struct luo_file_set *file_set, + struct luo_file_set_ser *file_set_ser); +void luo_file_set_init(struct luo_file_set *file_set); +void luo_file_set_destroy(struct luo_file_set *file_set); + #endif /* _LINUX_LUO_INTERNAL_H */ -- cgit v1.2.3