Revert "UBUNTU: SAUCE: drm/i915: Synchronize active and retire callbacks"

BugLink: https://bugs.launchpad.net/bugs/1877394
This reverts commit 26178734ddf4c4517108ce6ef1e7620cc43aa336.

Get rid of this so it can be replaced by an upstream fix.

Signed-off-by: Sultan Alsawaf <sultan.alsawaf@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c
index d0df1e0881c2a6c256049fd558f561a7b0c764f6..51dc8753b527921871ea95535841e11cca4dc41a 100644 (file)
--- a/drivers/gpu/drm/i915/i915_active.c
+++ b/drivers/gpu/drm/i915/i915_active.c
@@ -149,22 +149,8 @@ __active_retire(struct i915_active *ref, bool lock)
        }
 
        /* After the final retire, the entire struct may be freed */
-       if (ref->retire) {
-               if (ref->active) {
-                       bool freed = false;
-
-                       /* Don't race with the active callback, and avoid UaF */
-                       down_write(&ref->rwsem);
-                       ref->freed = &freed;
-                       ref->retire(ref);
-                       if (!freed) {
-                               ref->freed = NULL;
-                               up_write(&ref->rwsem);
-                       }
-               } else {
-                       ref->retire(ref);
-               }
-       }
+       if (ref->retire)
+               ref->retire(ref);
 }
 
 static void
@@ -255,8 +241,7 @@ void __i915_active_init(struct drm_i915_private *i915,
                        struct i915_active *ref,
                        int (*active)(struct i915_active *ref),
                        void (*retire)(struct i915_active *ref),
-                       struct lock_class_key *key,
-                       struct lock_class_key *rkey)
+                       struct lock_class_key *key)
 {
        debug_active_init(ref);
 
@@ -269,9 +254,6 @@ void __i915_active_init(struct drm_i915_private *i915,
        init_llist_head(&ref->preallocated_barriers);
        atomic_set(&ref->count, 0);
        __mutex_init(&ref->mutex, "i915_active", key);
-       ref->freed = NULL;
-       if (ref->active && ref->retire)
-               __init_rwsem(&ref->rwsem, "i915_active.rwsem", rkey);
 }
 
 static bool ____active_del_barrier(struct i915_active *ref,
@@ -375,20 +357,8 @@ int i915_active_acquire(struct i915_active *ref)
        if (err)
                return err;
 
-       if (!atomic_read(&ref->count) && ref->active) {
-               if (ref->retire) {
-                       /*
-                        * This can be a recursive call, and the mutex above
-                        * already protects from concurrent active callbacks, so
-                        * a read lock fits best.
-                        */
-                       down_read(&ref->rwsem);
-                       err = ref->active(ref);
-                       up_read(&ref->rwsem);
-               } else {
-                       err = ref->active(ref);
-               }
-       }
+       if (!atomic_read(&ref->count) && ref->active)
+               err = ref->active(ref);
        if (!err) {
                debug_active_activate(ref);
                atomic_inc(&ref->count);
@@ -512,19 +482,15 @@ int i915_request_await_active(struct i915_request *rq, struct i915_active *ref)
        return err;
 }
 
+#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)
 void i915_active_fini(struct i915_active *ref)
 {
-       if (ref->freed) {
-               *ref->freed = true;
-               up_write(&ref->rwsem);
-       }
-#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)
        debug_active_fini(ref);
        GEM_BUG_ON(!RB_EMPTY_ROOT(&ref->tree));
        GEM_BUG_ON(atomic_read(&ref->count));
        mutex_destroy(&ref->mutex);
-#endif
 }
+#endif
 
 static inline bool is_idle_barrier(struct active_node *node, u64 idx)
 {

diff --git a/drivers/gpu/drm/i915/i915_active.h b/drivers/gpu/drm/i915/i915_active.h
index aaec0a7735516401ef82d77a4b5b59716b15fa96..0ad7ef60d15f8590ded3f720ee97e09beb8b396e 100644 (file)
--- a/drivers/gpu/drm/i915/i915_active.h
+++ b/drivers/gpu/drm/i915/i915_active.h
@@ -362,13 +362,11 @@ void __i915_active_init(struct drm_i915_private *i915,
                        struct i915_active *ref,
                        int (*active)(struct i915_active *ref),
                        void (*retire)(struct i915_active *ref),
-                       struct lock_class_key *key,
-                       struct lock_class_key *rkey);
+                       struct lock_class_key *key);
 #define i915_active_init(i915, ref, active, retire) do {               \
        static struct lock_class_key __key;                             \
-       static struct lock_class_key __rkey;                            \
                                                                        \
-       __i915_active_init(i915, ref, active, retire, &__key, &__rkey); \
+       __i915_active_init(i915, ref, active, retire, &__key);          \
 } while (0)
 
 int i915_active_ref(struct i915_active *ref,
@@ -395,7 +393,11 @@ i915_active_is_idle(const struct i915_active *ref)
        return !atomic_read(&ref->count);
 }
 
+#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)
 void i915_active_fini(struct i915_active *ref);
+#else
+static inline void i915_active_fini(struct i915_active *ref) { }
+#endif
 
 int i915_active_acquire_preallocate_barrier(struct i915_active *ref,
                                            struct intel_engine_cs *engine);

diff --git a/drivers/gpu/drm/i915/i915_active_types.h b/drivers/gpu/drm/i915/i915_active_types.h
index 6619342eaa0dc7d119f64bb6b52cdc33b508f184..1854e7d168c1e0ffde852dc30b0f537b6ded6bce 100644 (file)
--- a/drivers/gpu/drm/i915/i915_active_types.h
+++ b/drivers/gpu/drm/i915/i915_active_types.h
@@ -12,7 +12,6 @@
 #include <linux/mutex.h>
 #include <linux/rbtree.h>
 #include <linux/rcupdate.h>
-#include <linux/rwsem.h>
 
 struct drm_i915_private;
 struct i915_active_request;
@@ -51,8 +50,6 @@ struct i915_active {
        struct rb_root tree;
        struct mutex mutex;
        atomic_t count;
-       struct rw_semaphore rwsem;
-       bool *freed;
 
        unsigned long flags;
 #define I915_ACTIVE_GRAB_BIT 0