From 919bb54e989c1edef87e9797be125c94c450fc65 Mon Sep 17 00:00:00 2001 From: Rodrigo Vivi Date: Wed, 21 Aug 2024 15:38:42 -0400 Subject: [PATCH] drm/xe: Fix missing runtime outer protection for ggtt_remove_node MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Defer the ggtt node removal to a thread if runtime_pm is not active. The ggtt node removal can be called from multiple places, including places where we cannot protect with outer callers and places we are within other locks. So, try to grab the runtime reference if the device is already active, otherwise defer the removal to a separate thread from where we are sure we can wake the device up. v2: - use xe wq instead of system wq (Matt and CI) - Avoid GFP_KERNEL to be future proof since this removal can be called from outside our drivers and we don't want to block if atomic is needed. (Brost) v3: amend forgot chunk declaring xe_device. v4: Use a xe_ggtt_region to encapsulate the node and remova info, wihtout the need for any memory allocation at runtime. v5: Actually fill the delayed_removal.invalidate (Brost) v6: - Ensure that ggtt_region is not freed before work finishes (Auld) - Own wq to ensures that the queued works are flushed before ggtt_fini (Brost) v7: also free ggtt_region on early !bound return (Auld) v8: Address the null deref (CI) v9: Based on the new xe_ggtt_node for the proper care of the lifetime of the object. v10: Redo the lost v5 change. (Brost) v11: Simplify the invalidate_on_remove (Lucas) Cc: Matthew Auld Cc: Paulo Zanoni Cc: Francois Dugast Cc: Thomas Hellström Cc: Matthew Brost Reviewed-by: Lucas De Marchi Link: https://patchwork.freedesktop.org/patch/msgid/20240821193842.352557-12-rodrigo.vivi@intel.com Signed-off-by: Rodrigo Vivi --- drivers/gpu/drm/xe/xe_ggtt.c | 106 ++++++++++++++++++----------- drivers/gpu/drm/xe/xe_ggtt_types.h | 6 ++ 2 files changed, 73 insertions(+), 39 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_ggtt.c b/drivers/gpu/drm/xe/xe_ggtt.c index 58d7cad2425b..b4a0cd2b62ed 100644 --- a/drivers/gpu/drm/xe/xe_ggtt.c +++ b/drivers/gpu/drm/xe/xe_ggtt.c @@ -161,6 +161,7 @@ static void ggtt_fini_early(struct drm_device *drm, void *arg) { struct xe_ggtt *ggtt = arg; + destroy_workqueue(ggtt->wq); mutex_destroy(&ggtt->lock); drm_mm_takedown(&ggtt->mm); } @@ -242,6 +243,8 @@ int xe_ggtt_init_early(struct xe_ggtt *ggtt) else ggtt->pt_ops = &xelp_pt_ops; + ggtt->wq = alloc_workqueue("xe-ggtt-wq", 0, 0); + drm_mm_init(&ggtt->mm, xe_wopcm_size(xe), ggtt->size - xe_wopcm_size(xe)); mutex_init(&ggtt->lock); @@ -276,6 +279,68 @@ static void xe_ggtt_initial_clear(struct xe_ggtt *ggtt) mutex_unlock(&ggtt->lock); } +static void ggtt_node_remove(struct xe_ggtt_node *node) +{ + struct xe_ggtt *ggtt = node->ggtt; + struct xe_device *xe = tile_to_xe(ggtt->tile); + bool bound; + int idx; + + if (!node || !node->ggtt) + return; + + bound = drm_dev_enter(&xe->drm, &idx); + + mutex_lock(&ggtt->lock); + if (bound) + xe_ggtt_clear(ggtt, node->base.start, node->base.size); + drm_mm_remove_node(&node->base); + node->base.size = 0; + mutex_unlock(&ggtt->lock); + + if (!bound) + goto free_node; + + if (node->invalidate_on_remove) + xe_ggtt_invalidate(ggtt); + + drm_dev_exit(idx); + +free_node: + xe_ggtt_node_fini(node); +} + +static void ggtt_node_remove_work_func(struct work_struct *work) +{ + struct xe_ggtt_node *node = container_of(work, typeof(*node), + delayed_removal_work); + struct xe_device *xe = tile_to_xe(node->ggtt->tile); + + xe_pm_runtime_get(xe); + ggtt_node_remove(node); + xe_pm_runtime_put(xe); +} + +/** + * xe_ggtt_node_remove - Remove a &xe_ggtt_node from the GGTT + * @node: the &xe_ggtt_node to be removed + * @invalidate: if node needs invalidation upon removal + */ +void xe_ggtt_node_remove(struct xe_ggtt_node *node, bool invalidate) +{ + struct xe_ggtt *ggtt = node->ggtt; + struct xe_device *xe = tile_to_xe(ggtt->tile); + + node->invalidate_on_remove = invalidate; + + if (xe_pm_runtime_get_if_active(xe)) { + ggtt_node_remove(node); + xe_pm_runtime_put(xe); + } else { + queue_work(ggtt->wq, &node->delayed_removal_work); + } +} + /** * xe_ggtt_init - Regular non-early GGTT initialization * @ggtt: the &xe_ggtt to be initialized @@ -471,7 +536,9 @@ struct xe_ggtt_node *xe_ggtt_node_init(struct xe_ggtt *ggtt) if (!node) return ERR_PTR(-ENOMEM); + INIT_WORK(&node->delayed_removal_work, ggtt_node_remove_work_func); node->ggtt = ggtt; + return node; } @@ -488,45 +555,6 @@ void xe_ggtt_node_fini(struct xe_ggtt_node *node) kfree(node); } -/** - * xe_ggtt_node_remove - Remove a &xe_ggtt_node from the GGTT - * @node: the &xe_ggtt_node to be removed - * @invalidate: if node needs invalidation upon removal - */ -void xe_ggtt_node_remove(struct xe_ggtt_node *node, bool invalidate) -{ - struct xe_ggtt *ggtt = node->ggtt; - struct xe_device *xe = tile_to_xe(ggtt->tile); - bool bound; - int idx; - - if (!node || !node->ggtt) - return; - - bound = drm_dev_enter(&xe->drm, &idx); - if (bound) - xe_pm_runtime_get_noresume(xe); - - mutex_lock(&ggtt->lock); - if (bound) - xe_ggtt_clear(ggtt, node->base.start, node->base.size); - drm_mm_remove_node(&node->base); - node->base.size = 0; - mutex_unlock(&ggtt->lock); - - if (!bound) - goto free_node; - - if (invalidate) - xe_ggtt_invalidate(ggtt); - - xe_pm_runtime_put(xe); - drm_dev_exit(idx); - -free_node: - xe_ggtt_node_fini(node); -} - /** * xe_ggtt_node_allocated - Check if node is allocated in GGTT * @node: the &xe_ggtt_node to be inspected diff --git a/drivers/gpu/drm/xe/xe_ggtt_types.h b/drivers/gpu/drm/xe/xe_ggtt_types.h index 0e8822ae13fc..cb02b7994a9a 100644 --- a/drivers/gpu/drm/xe/xe_ggtt_types.h +++ b/drivers/gpu/drm/xe/xe_ggtt_types.h @@ -47,6 +47,8 @@ struct xe_ggtt { struct drm_mm mm; /** @access_count: counts GGTT writes */ unsigned int access_count; + /** @wq: Dedicated unordered work queue to process node removals */ + struct workqueue_struct *wq; }; /** @@ -61,6 +63,10 @@ struct xe_ggtt_node { struct xe_ggtt *ggtt; /** @base: A drm_mm_node */ struct drm_mm_node base; + /** @delayed_removal_work: The work struct for the delayed removal */ + struct work_struct delayed_removal_work; + /** @invalidate_on_remove: If it needs invalidation upon removal */ + bool invalidate_on_remove; }; /**