From 35b535db69589ea0025ec3f06df08f2e3faad26f Mon Sep 17 00:00:00 2001 From: Tejas Upadhyay Date: Fri, 8 May 2026 12:25:45 +0530 Subject: drm/buddy: Integrate lockdep annotations for gpu buddy manager gpu_buddy APIs are expected to be called with the driver-provided lock held, but there is no runtime enforcement of this contract. Add lockdep annotations to catch locking violations early. Introduce gpu_buddy_driver_set_lock() for the driver to register the lock that protects the buddy manager. Add gpu_buddy_driver_lock_held() assertions to all exported gpu_buddy and drm_buddy APIs that access/modify the manager state. The lock_dep_map field is only compiled in when CONFIG_LOCKDEP is enabled, adding zero overhead to production builds. Wire up xe_ttm_vram_mgr to register its mutex with the buddy manager after initialization. Assisted-by: Copilot:claude-opus-4.6 Suggested-by: Matthew Brost Signed-off-by: Tejas Upadhyay Reviewed-by: Matthew Auld Signed-off-by: Arunpravin Paneer Selvam Link: https://patch.msgid.link/20260508065544.4049240-2-tejas.upadhyay@intel.com --- include/linux/gpu_buddy.h | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) (limited to 'include/linux') diff --git a/include/linux/gpu_buddy.h b/include/linux/gpu_buddy.h index 5fa917ba5450..71941a039648 100644 --- a/include/linux/gpu_buddy.h +++ b/include/linux/gpu_buddy.h @@ -154,6 +154,7 @@ struct gpu_buddy_block { * @avail: Total free space currently available for allocation in bytes. * @clear_avail: Free space available in the clear tree (zeroed memory) in bytes. * This is a subset of @avail. + * @lock_dep_map: Annotates gpu_buddy API with a driver provided lock. */ struct gpu_buddy { /* private: */ @@ -179,8 +180,48 @@ struct gpu_buddy { u64 size; u64 avail; u64 clear_avail; +#ifdef CONFIG_LOCKDEP + struct lockdep_map *lock_dep_map; +#endif }; +#ifdef CONFIG_LOCKDEP +/** + * gpu_buddy_driver_set_lock() - Set the lock protecting accesses to GPU BUDDY + * @mm: Pointer to GPU buddy structure. + * @lock: the lock used to protect the gpu buddy. The locking primitive + * must contain a dep_map field. + * + * Call this to annotate gpu_buddy APIs which access/modify gpu_buddy manager + */ +#define gpu_buddy_driver_set_lock(mm, lock) \ + do { \ + struct gpu_buddy *__mm = (mm); \ + if (!WARN(__mm->lock_dep_map, "GPU BUDDY MM lock should be set only once.")) \ + __mm->lock_dep_map = &(lock)->dep_map; \ + } while (0) +#else +#define gpu_buddy_driver_set_lock(mm, lock) do { (void)(mm); (void)(lock); } while (0) +#endif + +#ifdef CONFIG_LOCKDEP +/** + * gpu_buddy_driver_lock_held() - Assert GPU BUDDY manager lock is held + * @mm: Pointer to the GPU BUDDY structure. + * + * Ensure driver lock is held. + */ +static inline void gpu_buddy_driver_lock_held(struct gpu_buddy *mm) +{ + if (mm->lock_dep_map) + lockdep_assert(lock_is_held_type(mm->lock_dep_map, 0)); +} +#else +static inline void gpu_buddy_driver_lock_held(struct gpu_buddy *mm) +{ +} +#endif + static inline u64 gpu_buddy_block_offset(const struct gpu_buddy_block *block) { -- cgit v1.2.3