openwrt_lede/target/linux/brcm2708/patches-4.4/0092-drm-vc4-bo-cache-locking-fixes.patch

From cc7b77efeca4e1c56f3634618cf152f8dc2c0a8d Mon Sep 17 00:00:00 2001
From: Eric Anholt <eric@anholt.net>
Date: Mon, 19 Oct 2015 08:23:18 -0700
Subject: [PATCH] drm/vc4: bo cache locking fixes.

Signed-off-by: Eric Anholt <eric@anholt.net>
---
 drivers/gpu/drm/vc4/vc4_bo.c  | 32 ++++++++++++++++++--------------
 drivers/gpu/drm/vc4/vc4_drv.h |  2 +-
 2 files changed, 19 insertions(+), 15 deletions(-)

--- a/drivers/gpu/drm/vc4/vc4_bo.c
+++ b/drivers/gpu/drm/vc4/vc4_bo.c
@@ -112,14 +112,14 @@ void vc4_bo_cache_purge(struct drm_devic
 {
 	struct vc4_dev *vc4 = to_vc4_dev(dev);
 
-	spin_lock(&vc4->bo_lock);
+	mutex_lock(&vc4->bo_lock);
 	while (!list_empty(&vc4->bo_cache.time_list)) {
 		struct vc4_bo *bo = list_last_entry(&vc4->bo_cache.time_list,
 						    struct vc4_bo, unref_head);
 		vc4_bo_remove_from_cache(bo);
 		vc4_bo_destroy(bo);
 	}
-	spin_unlock(&vc4->bo_lock);
+	mutex_unlock(&vc4->bo_lock);
 }
 
 struct vc4_bo *vc4_bo_create(struct drm_device *dev, size_t unaligned_size)
@@ -134,18 +134,18 @@ struct vc4_bo *vc4_bo_create(struct drm_
 		return NULL;
 
 	/* First, try to get a vc4_bo from the kernel BO cache. */
-	spin_lock(&vc4->bo_lock);
+	mutex_lock(&vc4->bo_lock);
 	if (page_index < vc4->bo_cache.size_list_size &&
 	    !list_empty(&vc4->bo_cache.size_list[page_index])) {
 		struct vc4_bo *bo =
 			list_first_entry(&vc4->bo_cache.size_list[page_index],
 					 struct vc4_bo, size_head);
 		vc4_bo_remove_from_cache(bo);
-		spin_unlock(&vc4->bo_lock);
+		mutex_unlock(&vc4->bo_lock);
 		kref_init(&bo->base.base.refcount);
 		return bo;
 	}
-	spin_unlock(&vc4->bo_lock);
+	mutex_unlock(&vc4->bo_lock);
 
 	/* Otherwise, make a new BO. */
 	for (pass = 0; ; pass++) {
@@ -215,7 +215,7 @@ vc4_bo_cache_free_old(struct drm_device
 	struct vc4_dev *vc4 = to_vc4_dev(dev);
 	unsigned long expire_time = jiffies - msecs_to_jiffies(1000);
 
-	spin_lock(&vc4->bo_lock);
+	mutex_lock(&vc4->bo_lock);
 	while (!list_empty(&vc4->bo_cache.time_list)) {
 		struct vc4_bo *bo = list_last_entry(&vc4->bo_cache.time_list,
 						    struct vc4_bo, unref_head);
@@ -223,14 +223,14 @@ vc4_bo_cache_free_old(struct drm_device
 			mod_timer(&vc4->bo_cache.time_timer,
 				  round_jiffies_up(jiffies +
 						   msecs_to_jiffies(1000)));
-			spin_unlock(&vc4->bo_lock);
+			mutex_unlock(&vc4->bo_lock);
 			return;
 		}
 
 		vc4_bo_remove_from_cache(bo);
 		vc4_bo_destroy(bo);
 	}
-	spin_unlock(&vc4->bo_lock);
+	mutex_unlock(&vc4->bo_lock);
 }
 
 /* Called on the last userspace/kernel unreference of the BO.  Returns
@@ -248,21 +248,25 @@ void vc4_free_object(struct drm_gem_obje
 	/* If the object references someone else's memory, we can't cache it.
 	 */
 	if (gem_bo->import_attach) {
+		mutex_lock(&vc4->bo_lock);
 		vc4_bo_destroy(bo);
+		mutex_unlock(&vc4->bo_lock);
 		return;
 	}
 
 	/* Don't cache if it was publicly named. */
 	if (gem_bo->name) {
+		mutex_lock(&vc4->bo_lock);
 		vc4_bo_destroy(bo);
+		mutex_unlock(&vc4->bo_lock);
 		return;
 	}
 
-	spin_lock(&vc4->bo_lock);
+	mutex_lock(&vc4->bo_lock);
 	cache_list = vc4_get_cache_list_for_size(dev, gem_bo->size);
 	if (!cache_list) {
 		vc4_bo_destroy(bo);
-		spin_unlock(&vc4->bo_lock);
+		mutex_unlock(&vc4->bo_lock);
 		return;
 	}
 
@@ -278,7 +282,7 @@ void vc4_free_object(struct drm_gem_obje
 
 	vc4->bo_stats.num_cached++;
 	vc4->bo_stats.size_cached += gem_bo->size;
-	spin_unlock(&vc4->bo_lock);
+	mutex_unlock(&vc4->bo_lock);
 
 	vc4_bo_cache_free_old(dev);
 }
@@ -465,7 +469,7 @@ void vc4_bo_cache_init(struct drm_device
 {
 	struct vc4_dev *vc4 = to_vc4_dev(dev);
 
-	spin_lock_init(&vc4->bo_lock);
+	mutex_init(&vc4->bo_lock);
 
 	INIT_LIST_HEAD(&vc4->bo_cache.time_list);
 
@@ -498,9 +502,9 @@ int vc4_bo_stats_debugfs(struct seq_file
 	struct vc4_dev *vc4 = to_vc4_dev(dev);
 	struct vc4_bo_stats stats;
 
-	spin_lock(&vc4->bo_lock);
+	mutex_lock(&vc4->bo_lock);
 	stats = vc4->bo_stats;
-	spin_unlock(&vc4->bo_lock);
+	mutex_unlock(&vc4->bo_lock);
 
 	seq_printf(m, "num bos allocated: %d\n", stats.num_allocated);
 	seq_printf(m, "size bos allocated: %dkb\n", stats.size_allocated / 1024);
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -49,7 +49,7 @@ struct vc4_dev {
 	} bo_stats;
 
 	/* Protects bo_cache and the BO stats. */
-	spinlock_t bo_lock;
+	struct mutex bo_lock;
 
 	/* Sequence number for the last job queued in job_list.
 	 * Starts at 0 (no jobs emitted).