From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A2170FF8875 for ; Wed, 29 Apr 2026 12:37:51 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E385F10E5F0; Wed, 29 Apr 2026 12:37:50 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="b0GyIgnc"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.10]) by gabe.freedesktop.org (Postfix) with ESMTPS id 68FFD10E3FC; Wed, 29 Apr 2026 12:37:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1777466270; x=1809002270; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=uvwwTlw8sSux4mzuMJdXdxSeijg5A5rmaU45lNpT88M=; b=b0GyIgnckw7YMihfo9HlFm9YYsVdtrHRKrICzY+kjpWAZqNxTWHYrQ6L 6n0FtvIRaoCYNxWibY/j4DR2V3g+bm4uKIA8DIwYdP5+Iw6IN6odX6JyP g3XtFzsRH9a+1fKQHmY54U5rrLwBJqLZ2n2uGjSysiXNDhhqm/be92LHy Dzlrj1L7aHV5QX4jbI2r72CyC15UQ5GmEG9Fu50r9/g472RSUdPJ6bvg7 W394fq2DVgjVj1tqB8YJahKAOibCAsiHtXj2lt4HkeMKcWFoYJVqr+XOf QRtMN3gigLHLSddpqxR2MZOWjgC2jCqJ3PXf7tKeAHtobft5Ocey3SvHl A==; X-CSE-ConnectionGUID: HZO5k5jcSOCelXwlysXzqw== X-CSE-MsgGUID: a+J4xmGySXmM3aPjrCcDsQ== X-IronPort-AV: E=McAfee;i="6800,10657,11771"; a="89769023" X-IronPort-AV: E=Sophos;i="6.23,206,1770624000"; d="scan'208";a="89769023" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by fmvoesa104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Apr 2026 05:37:49 -0700 X-CSE-ConnectionGUID: RxaHgfOSSQWJ8mcL5BYD/g== X-CSE-MsgGUID: pvMLky3BRWSeuPjvwN+Qrw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,206,1770624000"; d="scan'208";a="234123509" Received: from tejasupa-desk.iind.intel.com (HELO tejasupa-desk) ([10.190.239.37]) by orviesa008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Apr 2026 05:37:46 -0700 From: Tejas Upadhyay To: intel-xe@lists.freedesktop.org Cc: matthew.auld@intel.com, Arunpravin.PaneerSelvam@amd.com, dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, Tejas Upadhyay Subject: [PATCH] drm/buddy: Integrate lockdep annotations for gpu buddy manager Date: Wed, 29 Apr 2026 18:07:15 +0530 Message-ID: <20260429123714.3913374-2-tejas.upadhyay@intel.com> X-Mailer: git-send-email 2.52.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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: Claude:claude-opus-4.6 Signed-off-by: Tejas Upadhyay --- drivers/gpu/buddy.c | 11 ++++++++ drivers/gpu/drm/drm_buddy.c | 1 + drivers/gpu/drm/xe/xe_ttm_vram_mgr.c | 1 + include/linux/gpu_buddy.h | 41 ++++++++++++++++++++++++++++ 4 files changed, 54 insertions(+) diff --git a/drivers/gpu/buddy.c b/drivers/gpu/buddy.c index 52686672e99f..eb1457376307 100644 --- a/drivers/gpu/buddy.c +++ b/drivers/gpu/buddy.c @@ -437,6 +437,9 @@ int gpu_buddy_init(struct gpu_buddy *mm, u64 size, u64 chunk_size) root_count++; } while (size); +#ifdef CONFIG_LOCKDEP + mm->lock_dep_map = NULL; +#endif return 0; out_free_roots: @@ -538,6 +541,7 @@ void gpu_buddy_reset_clear(struct gpu_buddy *mm, bool is_clear) unsigned int order; int i; + gpu_buddy_driver_lock_held(mm); size = mm->size; for (i = 0; i < mm->n_roots; ++i) { order = ilog2(size) - ilog2(mm->chunk_size); @@ -580,6 +584,7 @@ EXPORT_SYMBOL(gpu_buddy_reset_clear); void gpu_buddy_free_block(struct gpu_buddy *mm, struct gpu_buddy_block *block) { + gpu_buddy_driver_lock_held(mm); BUG_ON(!gpu_buddy_block_is_allocated(block)); mm->avail += gpu_buddy_block_size(mm, block); if (gpu_buddy_block_is_clear(block)) @@ -633,6 +638,7 @@ void gpu_buddy_free_list(struct gpu_buddy *mm, { bool mark_clear = flags & GPU_BUDDY_CLEARED; + gpu_buddy_driver_lock_held(mm); __gpu_buddy_free_list(mm, objects, mark_clear, !mark_clear); } EXPORT_SYMBOL(gpu_buddy_free_list); @@ -1172,6 +1178,8 @@ int gpu_buddy_block_trim(struct gpu_buddy *mm, u64 new_start; int err; + gpu_buddy_driver_lock_held(mm); + if (!list_is_singular(blocks)) return -EINVAL; @@ -1287,6 +1295,8 @@ int gpu_buddy_alloc_blocks(struct gpu_buddy *mm, unsigned long pages; int err; + gpu_buddy_driver_lock_held(mm); + if (size < mm->chunk_size) return -EINVAL; @@ -1475,6 +1485,7 @@ void gpu_buddy_print(struct gpu_buddy *mm) { int order; + gpu_buddy_driver_lock_held(mm); pr_info("chunk_size: %lluKiB, total: %lluMiB, free: %lluMiB, clear_free: %lluMiB\n", mm->chunk_size >> 10, mm->size >> 20, mm->avail >> 20, mm->clear_avail >> 20); diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c index 841f3de5f307..faa025498de4 100644 --- a/drivers/gpu/drm/drm_buddy.c +++ b/drivers/gpu/drm/drm_buddy.c @@ -42,6 +42,7 @@ void drm_buddy_print(struct gpu_buddy *mm, struct drm_printer *p) { int order; + gpu_buddy_driver_lock_held(mm); drm_printf(p, "chunk_size: %lluKiB, total: %lluMiB, free: %lluMiB, clear_free: %lluMiB\n", mm->chunk_size >> 10, mm->size >> 20, mm->avail >> 20, mm->clear_avail >> 20); diff --git a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c index 5fd0d5506a7e..7ebc4d278c3b 100644 --- a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c +++ b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c @@ -322,6 +322,7 @@ int __xe_ttm_vram_mgr_init(struct xe_device *xe, struct xe_ttm_vram_mgr *mgr, if (err) return err; + gpu_buddy_driver_set_lock(&mgr->mm, &mgr->lock); ttm_set_driver_manager(&xe->ttm, mem_type, &mgr->manager); ttm_resource_manager_set_used(&mgr->manager, true); 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) { -- 2.52.0