From 1cacd6894d5f4084f1581435e92d8a18d6721b25 Mon Sep 17 00:00:00 2001 From: Anshuman Gupta Date: Thu, 27 Oct 2022 14:52:42 +0530 Subject: [PATCH] drm/i915/dgfx: Grab wakeref at i915_ttm_unmap_virtual We had already grabbed the rpm wakeref at obj destruction path, but it also required to grab the wakeref when object moves. When i915_gem_object_release_mmap_offset() gets called by i915_ttm_move_notify(), it will release the mmap offset without grabbing the wakeref. We want to avoid that therefore, grab the wakeref at i915_ttm_unmap_virtual() accordingly. While doing that also changed the lmem_userfault_lock from mutex to spinlock, as spinlock widely used for list. Also changed if (obj->userfault_count) to GEM_BUG_ON(!obj->userfault_count). v2: - Removed lmem_userfault_{list,lock} from intel_gt. [Matt Auld] Fixes: ad74457a6b5a ("drm/i915/dgfx: Release mmap on rpm suspend") Suggested-by: Matthew Auld Signed-off-by: Anshuman Gupta Reviewed-by: Matthew Auld Link: https://patchwork.freedesktop.org/patch/msgid/20221027092242.1476080-3-anshuman.gupta@intel.com --- drivers/gpu/drm/i915/gem/i915_gem_mman.c | 19 ++++++---------- drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 38 ++++++++++++++++++++++---------- drivers/gpu/drm/i915/intel_runtime_pm.c | 2 +- drivers/gpu/drm/i915/intel_runtime_pm.h | 2 +- 4 files changed, 35 insertions(+), 26 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c index fd29a9053582..e63329bc8065 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c @@ -557,11 +557,13 @@ void i915_gem_object_runtime_pm_release_mmap_offset(struct drm_i915_gem_object * drm_vma_node_unmap(&bo->base.vma_node, bdev->dev_mapping); - if (obj->userfault_count) { - /* rpm wakeref provide exclusive access */ - list_del(&obj->userfault_link); - obj->userfault_count = 0; - } + /* + * We have exclusive access here via runtime suspend. All other callers + * must first grab the rpm wakeref. + */ + GEM_BUG_ON(!obj->userfault_count); + list_del(&obj->userfault_link); + obj->userfault_count = 0; } void i915_gem_object_release_mmap_offset(struct drm_i915_gem_object *obj) @@ -587,13 +589,6 @@ void i915_gem_object_release_mmap_offset(struct drm_i915_gem_object *obj) spin_lock(&obj->mmo.lock); } spin_unlock(&obj->mmo.lock); - - if (obj->userfault_count) { - mutex_lock(&to_i915(obj->base.dev)->runtime_pm.lmem_userfault_lock); - list_del(&obj->userfault_link); - mutex_unlock(&to_i915(obj->base.dev)->runtime_pm.lmem_userfault_lock); - obj->userfault_count = 0; - } } static struct i915_mmap_offset * diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c index e10e20b38645..9219a60a7f88 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c @@ -509,18 +509,9 @@ static int i915_ttm_shrink(struct drm_i915_gem_object *obj, unsigned int flags) static void i915_ttm_delete_mem_notify(struct ttm_buffer_object *bo) { struct drm_i915_gem_object *obj = i915_ttm_to_gem(bo); - intel_wakeref_t wakeref = 0; if (bo->resource && !i915_ttm_is_ghost_object(bo)) { - /* ttm_bo_release() already has dma_resv_lock */ - if (i915_ttm_cpu_maps_iomem(bo->resource)) - wakeref = intel_runtime_pm_get(&to_i915(obj->base.dev)->runtime_pm); - __i915_gem_object_pages_fini(obj); - - if (wakeref) - intel_runtime_pm_put(&to_i915(obj->base.dev)->runtime_pm, wakeref); - i915_ttm_free_cached_io_rsgt(obj); } } @@ -1098,12 +1089,15 @@ static vm_fault_t vm_fault_ttm(struct vm_fault *vmf) if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) goto out_rpm; - /* ttm_bo_vm_reserve() already has dma_resv_lock */ + /* + * ttm_bo_vm_reserve() already has dma_resv_lock. + * userfault_count is protected by dma_resv lock and rpm wakeref. + */ if (ret == VM_FAULT_NOPAGE && wakeref && !obj->userfault_count) { obj->userfault_count = 1; - mutex_lock(&to_i915(obj->base.dev)->runtime_pm.lmem_userfault_lock); + spin_lock(&to_i915(obj->base.dev)->runtime_pm.lmem_userfault_lock); list_add(&obj->userfault_link, &to_i915(obj->base.dev)->runtime_pm.lmem_userfault_list); - mutex_unlock(&to_i915(obj->base.dev)->runtime_pm.lmem_userfault_lock); + spin_unlock(&to_i915(obj->base.dev)->runtime_pm.lmem_userfault_lock); } if (wakeref & CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND) @@ -1169,7 +1163,27 @@ static u64 i915_ttm_mmap_offset(struct drm_i915_gem_object *obj) static void i915_ttm_unmap_virtual(struct drm_i915_gem_object *obj) { + struct ttm_buffer_object *bo = i915_gem_to_ttm(obj); + intel_wakeref_t wakeref = 0; + + assert_object_held_shared(obj); + + if (i915_ttm_cpu_maps_iomem(bo->resource)) { + wakeref = intel_runtime_pm_get(&to_i915(obj->base.dev)->runtime_pm); + + /* userfault_count is protected by obj lock and rpm wakeref. */ + if (obj->userfault_count) { + spin_lock(&to_i915(obj->base.dev)->runtime_pm.lmem_userfault_lock); + list_del(&obj->userfault_link); + spin_unlock(&to_i915(obj->base.dev)->runtime_pm.lmem_userfault_lock); + obj->userfault_count = 0; + } + } + ttm_bo_unmap_virtual(i915_gem_to_ttm(obj)); + + if (wakeref) + intel_runtime_pm_put(&to_i915(obj->base.dev)->runtime_pm, wakeref); } static const struct drm_i915_gem_object_ops i915_gem_ttm_obj_ops = { diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c index 6e7f5b38eb32..8b668ee35bd9 100644 --- a/drivers/gpu/drm/i915/intel_runtime_pm.c +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c @@ -648,6 +648,6 @@ void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm) init_intel_runtime_pm_wakeref(rpm); INIT_LIST_HEAD(&rpm->lmem_userfault_list); - mutex_init(&rpm->lmem_userfault_lock); + spin_lock_init(&rpm->lmem_userfault_lock); intel_wakeref_auto_init(&rpm->userfault_wakeref, rpm); } diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.h b/drivers/gpu/drm/i915/intel_runtime_pm.h index 9f50f109aa11..98b8b28baaa1 100644 --- a/drivers/gpu/drm/i915/intel_runtime_pm.h +++ b/drivers/gpu/drm/i915/intel_runtime_pm.h @@ -64,7 +64,7 @@ struct intel_runtime_pm { * but instead has exclusive access by virtue of all other accesses requiring * holding the runtime pm wakeref. */ - struct mutex lmem_userfault_lock; + spinlock_t lmem_userfault_lock; /* * Keep list of userfaulted gem obj, which require to release their -- 2.11.0