| Message ID | 20181023093745.19060-1-david1.zhou@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm: fix deadlock of syncobj v6 | expand |
Am 23.10.18 um 11:37 schrieb Chunming Zhou: > v2: > add a mutex between sync_cb execution and free. > v3: > clearly separating the roles for pt_lock and cb_mutex (Chris) > v4: > the cb_mutex should be taken outside of the pt_lock around > this if() block. (Chris) > v5: > fix a corner case > v6: > tidy drm_syncobj_fence_get_or_add_callback up. (Chris) > > Tested by syncobj_basic and syncobj_wait of igt. > > Signed-off-by: Chunming Zhou <david1.zhou@amd.com> > Cc: Daniel Vetter <daniel@ffwll.ch> > Cc: Chris Wilson <chris@chris-wilson.co.uk> > Cc: Christian König <christian.koenig@amd.com> > Cc: intel-gfx@lists.freedesktop.org > Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> I've gone ahead and pushed this to drm-misc-next. Regards, Christian. > --- > drivers/gpu/drm/drm_syncobj.c | 156 ++++++++++++++++------------------ > include/drm/drm_syncobj.h | 8 +- > 2 files changed, 81 insertions(+), 83 deletions(-) > > diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c > index 57bf6006394d..b7eaa603f368 100644 > --- a/drivers/gpu/drm/drm_syncobj.c > +++ b/drivers/gpu/drm/drm_syncobj.c > @@ -106,6 +106,42 @@ struct drm_syncobj *drm_syncobj_find(struct drm_file *file_private, > } > EXPORT_SYMBOL(drm_syncobj_find); > > +static struct dma_fence > +*drm_syncobj_find_signal_pt_for_point(struct drm_syncobj *syncobj, > + uint64_t point) > +{ > + struct drm_syncobj_signal_pt *signal_pt; > + > + if ((syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) && > + (point <= syncobj->timeline)) { > + struct drm_syncobj_stub_fence *fence = > + kzalloc(sizeof(struct drm_syncobj_stub_fence), > + GFP_KERNEL); > + > + if (!fence) > + return NULL; > + spin_lock_init(&fence->lock); > + dma_fence_init(&fence->base, > + &drm_syncobj_stub_fence_ops, > + &fence->lock, > + syncobj->timeline_context, > + point); > + > + dma_fence_signal(&fence->base); > + return &fence->base; > + } > + > + list_for_each_entry(signal_pt, &syncobj->signal_pt_list, list) { > + if (point > signal_pt->value) > + continue; > + if ((syncobj->type == DRM_SYNCOBJ_TYPE_BINARY) && > + (point != signal_pt->value)) > + continue; > + return dma_fence_get(&signal_pt->fence_array->base); > + } > + return NULL; > +} > + > static void drm_syncobj_add_callback_locked(struct drm_syncobj *syncobj, > struct drm_syncobj_cb *cb, > drm_syncobj_func_t func) > @@ -114,115 +150,71 @@ static void drm_syncobj_add_callback_locked(struct drm_syncobj *syncobj, > list_add_tail(&cb->node, &syncobj->cb_list); > } > > -static int drm_syncobj_fence_get_or_add_callback(struct drm_syncobj *syncobj, > - struct dma_fence **fence, > - struct drm_syncobj_cb *cb, > - drm_syncobj_func_t func) > +static void drm_syncobj_fence_get_or_add_callback(struct drm_syncobj *syncobj, > + struct dma_fence **fence, > + struct drm_syncobj_cb *cb, > + drm_syncobj_func_t func) > { > - int ret; > + u64 pt_value = 0; > > - ret = drm_syncobj_search_fence(syncobj, 0, 0, fence); > - if (!ret) > - return 1; > + if (syncobj->type == DRM_SYNCOBJ_TYPE_BINARY) { > + /*BINARY syncobj always wait on last pt */ > + pt_value = syncobj->signal_point; > > - spin_lock(&syncobj->lock); > - /* We've already tried once to get a fence and failed. Now that we > - * have the lock, try one more time just to be sure we don't add a > - * callback when a fence has already been set. > - */ > - if (!list_empty(&syncobj->signal_pt_list)) { > - spin_unlock(&syncobj->lock); > - drm_syncobj_search_fence(syncobj, 0, 0, fence); > - if (*fence) > - return 1; > - spin_lock(&syncobj->lock); > - } else { > - *fence = NULL; > - drm_syncobj_add_callback_locked(syncobj, cb, func); > - ret = 0; > + if (pt_value == 0) > + pt_value += DRM_SYNCOBJ_BINARY_POINT; > } > - spin_unlock(&syncobj->lock); > > - return ret; > + mutex_lock(&syncobj->cb_mutex); > + spin_lock(&syncobj->pt_lock); > + *fence = drm_syncobj_find_signal_pt_for_point(syncobj, pt_value); > + spin_unlock(&syncobj->pt_lock); > + if (!*fence) > + drm_syncobj_add_callback_locked(syncobj, cb, func); > + mutex_unlock(&syncobj->cb_mutex); > } > > void drm_syncobj_add_callback(struct drm_syncobj *syncobj, > struct drm_syncobj_cb *cb, > drm_syncobj_func_t func) > { > - spin_lock(&syncobj->lock); > + mutex_lock(&syncobj->cb_mutex); > drm_syncobj_add_callback_locked(syncobj, cb, func); > - spin_unlock(&syncobj->lock); > + mutex_unlock(&syncobj->cb_mutex); > } > > void drm_syncobj_remove_callback(struct drm_syncobj *syncobj, > struct drm_syncobj_cb *cb) > { > - spin_lock(&syncobj->lock); > + mutex_lock(&syncobj->cb_mutex); > list_del_init(&cb->node); > - spin_unlock(&syncobj->lock); > + mutex_unlock(&syncobj->cb_mutex); > } > > static void drm_syncobj_init(struct drm_syncobj *syncobj) > { > - spin_lock(&syncobj->lock); > + spin_lock(&syncobj->pt_lock); > syncobj->timeline_context = dma_fence_context_alloc(1); > syncobj->timeline = 0; > syncobj->signal_point = 0; > init_waitqueue_head(&syncobj->wq); > > INIT_LIST_HEAD(&syncobj->signal_pt_list); > - spin_unlock(&syncobj->lock); > + spin_unlock(&syncobj->pt_lock); > } > > static void drm_syncobj_fini(struct drm_syncobj *syncobj) > { > struct drm_syncobj_signal_pt *signal_pt = NULL, *tmp; > > - spin_lock(&syncobj->lock); > + spin_lock(&syncobj->pt_lock); > list_for_each_entry_safe(signal_pt, tmp, > &syncobj->signal_pt_list, list) { > list_del(&signal_pt->list); > dma_fence_put(&signal_pt->fence_array->base); > kfree(signal_pt); > } > - spin_unlock(&syncobj->lock); > -} > - > -static struct dma_fence > -*drm_syncobj_find_signal_pt_for_point(struct drm_syncobj *syncobj, > - uint64_t point) > -{ > - struct drm_syncobj_signal_pt *signal_pt; > - > - if ((syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) && > - (point <= syncobj->timeline)) { > - struct drm_syncobj_stub_fence *fence = > - kzalloc(sizeof(struct drm_syncobj_stub_fence), > - GFP_KERNEL); > - > - if (!fence) > - return NULL; > - spin_lock_init(&fence->lock); > - dma_fence_init(&fence->base, > - &drm_syncobj_stub_fence_ops, > - &fence->lock, > - syncobj->timeline_context, > - point); > - > - dma_fence_signal(&fence->base); > - return &fence->base; > - } > - > - list_for_each_entry(signal_pt, &syncobj->signal_pt_list, list) { > - if (point > signal_pt->value) > - continue; > - if ((syncobj->type == DRM_SYNCOBJ_TYPE_BINARY) && > - (point != signal_pt->value)) > - continue; > - return dma_fence_get(&signal_pt->fence_array->base); > - } > - return NULL; > + spin_unlock(&syncobj->pt_lock); > } > > static int drm_syncobj_create_signal_pt(struct drm_syncobj *syncobj, > @@ -249,14 +241,14 @@ static int drm_syncobj_create_signal_pt(struct drm_syncobj *syncobj, > fences[num_fences++] = dma_fence_get(fence); > /* timeline syncobj must take this dependency */ > if (syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) { > - spin_lock(&syncobj->lock); > + spin_lock(&syncobj->pt_lock); > if (!list_empty(&syncobj->signal_pt_list)) { > tail_pt = list_last_entry(&syncobj->signal_pt_list, > struct drm_syncobj_signal_pt, list); > fences[num_fences++] = > dma_fence_get(&tail_pt->fence_array->base); > } > - spin_unlock(&syncobj->lock); > + spin_unlock(&syncobj->pt_lock); > } > signal_pt->fence_array = dma_fence_array_create(num_fences, fences, > syncobj->timeline_context, > @@ -266,16 +258,16 @@ static int drm_syncobj_create_signal_pt(struct drm_syncobj *syncobj, > goto fail; > } > > - spin_lock(&syncobj->lock); > + spin_lock(&syncobj->pt_lock); > if (syncobj->signal_point >= point) { > DRM_WARN("A later signal is ready!"); > - spin_unlock(&syncobj->lock); > + spin_unlock(&syncobj->pt_lock); > goto exist; > } > signal_pt->value = point; > list_add_tail(&signal_pt->list, &syncobj->signal_pt_list); > syncobj->signal_point = point; > - spin_unlock(&syncobj->lock); > + spin_unlock(&syncobj->pt_lock); > wake_up_all(&syncobj->wq); > > return 0; > @@ -294,7 +286,7 @@ static void drm_syncobj_garbage_collection(struct drm_syncobj *syncobj) > { > struct drm_syncobj_signal_pt *signal_pt, *tmp, *tail_pt; > > - spin_lock(&syncobj->lock); > + spin_lock(&syncobj->pt_lock); > tail_pt = list_last_entry(&syncobj->signal_pt_list, > struct drm_syncobj_signal_pt, > list); > @@ -315,7 +307,7 @@ static void drm_syncobj_garbage_collection(struct drm_syncobj *syncobj) > } > } > > - spin_unlock(&syncobj->lock); > + spin_unlock(&syncobj->pt_lock); > } > /** > * drm_syncobj_replace_fence - replace fence in a sync object. > @@ -344,13 +336,14 @@ void drm_syncobj_replace_fence(struct drm_syncobj *syncobj, > drm_syncobj_create_signal_pt(syncobj, fence, pt_value); > if (fence) { > struct drm_syncobj_cb *cur, *tmp; > + LIST_HEAD(cb_list); > > - spin_lock(&syncobj->lock); > + mutex_lock(&syncobj->cb_mutex); > list_for_each_entry_safe(cur, tmp, &syncobj->cb_list, node) { > list_del_init(&cur->node); > cur->func(syncobj, cur); > } > - spin_unlock(&syncobj->lock); > + mutex_unlock(&syncobj->cb_mutex); > } > } > EXPORT_SYMBOL(drm_syncobj_replace_fence); > @@ -386,11 +379,11 @@ drm_syncobj_point_get(struct drm_syncobj *syncobj, u64 point, u64 flags, > if (ret < 0) > return ret; > } > - spin_lock(&syncobj->lock); > + spin_lock(&syncobj->pt_lock); > *fence = drm_syncobj_find_signal_pt_for_point(syncobj, point); > if (!*fence) > ret = -EINVAL; > - spin_unlock(&syncobj->lock); > + spin_unlock(&syncobj->pt_lock); > return ret; > } > > @@ -500,7 +493,8 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, > > kref_init(&syncobj->refcount); > INIT_LIST_HEAD(&syncobj->cb_list); > - spin_lock_init(&syncobj->lock); > + spin_lock_init(&syncobj->pt_lock); > + mutex_init(&syncobj->cb_mutex); > if (flags & DRM_SYNCOBJ_CREATE_TYPE_TIMELINE) > syncobj->type = DRM_SYNCOBJ_TYPE_TIMELINE; > else > diff --git a/include/drm/drm_syncobj.h b/include/drm/drm_syncobj.h > index 5e8c5c027e09..29244cbcd05e 100644 > --- a/include/drm/drm_syncobj.h > +++ b/include/drm/drm_syncobj.h > @@ -75,9 +75,13 @@ struct drm_syncobj { > */ > struct list_head cb_list; > /** > - * @lock: Protects syncobj list and write-locks &fence. > + * @pt_lock: Protects pt list. > */ > - spinlock_t lock; > + spinlock_t pt_lock; > + /** > + * @cb_mutex: Protects syncobj cb list. > + */ > + struct mutex cb_mutex; > /** > * @file: A file backing for this syncobj. > */
Quoting Patchwork (2018-10-23 13:26:51) > == Series Details == > > Series: drm: fix deadlock of syncobj v6 > URL : https://patchwork.freedesktop.org/series/51369/ > State : failure > > == Summary == > > = CI Bug Log - changes from CI_DRM_5020_full -> Patchwork_10540_full = > > == Summary - FAILURE == > > ==== Possible fixes ==== > > igt@syncobj_wait@reset-during-wait-for-submit: > shard-glk: INCOMPLETE (k.org#198133, fdo#103359) -> PASS +6 > > igt@syncobj_wait@wait-all-for-submit-complex: > shard-skl: INCOMPLETE (fdo#108490) -> PASS +3 > > igt@syncobj_wait@wait-all-for-submit-snapshot: > shard-hsw: INCOMPLETE (fdo#103540) -> PASS +6 > > igt@syncobj_wait@wait-for-submit-delayed-submit: > shard-kbl: INCOMPLETE (fdo#103665) -> PASS +6 > > igt@syncobj_wait@wait-for-submit-snapshot: > shard-apl: INCOMPLETE (fdo#103927) -> PASS +7 Which were the significant (and welcome) changes from the patch. -Chris
diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c index 57bf6006394d..b7eaa603f368 100644 --- a/drivers/gpu/drm/drm_syncobj.c +++ b/drivers/gpu/drm/drm_syncobj.c @@ -106,6 +106,42 @@ struct drm_syncobj *drm_syncobj_find(struct drm_file *file_private, } EXPORT_SYMBOL(drm_syncobj_find); +static struct dma_fence +*drm_syncobj_find_signal_pt_for_point(struct drm_syncobj *syncobj, + uint64_t point) +{ + struct drm_syncobj_signal_pt *signal_pt; + + if ((syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) && + (point <= syncobj->timeline)) { + struct drm_syncobj_stub_fence *fence = + kzalloc(sizeof(struct drm_syncobj_stub_fence), + GFP_KERNEL); + + if (!fence) + return NULL; + spin_lock_init(&fence->lock); + dma_fence_init(&fence->base, + &drm_syncobj_stub_fence_ops, + &fence->lock, + syncobj->timeline_context, + point); + + dma_fence_signal(&fence->base); + return &fence->base; + } + + list_for_each_entry(signal_pt, &syncobj->signal_pt_list, list) { + if (point > signal_pt->value) + continue; + if ((syncobj->type == DRM_SYNCOBJ_TYPE_BINARY) && + (point != signal_pt->value)) + continue; + return dma_fence_get(&signal_pt->fence_array->base); + } + return NULL; +} + static void drm_syncobj_add_callback_locked(struct drm_syncobj *syncobj, struct drm_syncobj_cb *cb, drm_syncobj_func_t func) @@ -114,115 +150,71 @@ static void drm_syncobj_add_callback_locked(struct drm_syncobj *syncobj, list_add_tail(&cb->node, &syncobj->cb_list); } -static int drm_syncobj_fence_get_or_add_callback(struct drm_syncobj *syncobj, - struct dma_fence **fence, - struct drm_syncobj_cb *cb, - drm_syncobj_func_t func) +static void drm_syncobj_fence_get_or_add_callback(struct drm_syncobj *syncobj, + struct dma_fence **fence, + struct drm_syncobj_cb *cb, + drm_syncobj_func_t func) { - int ret; + u64 pt_value = 0; - ret = drm_syncobj_search_fence(syncobj, 0, 0, fence); - if (!ret) - return 1; + if (syncobj->type == DRM_SYNCOBJ_TYPE_BINARY) { + /*BINARY syncobj always wait on last pt */ + pt_value = syncobj->signal_point; - spin_lock(&syncobj->lock); - /* We've already tried once to get a fence and failed. Now that we - * have the lock, try one more time just to be sure we don't add a - * callback when a fence has already been set. - */ - if (!list_empty(&syncobj->signal_pt_list)) { - spin_unlock(&syncobj->lock); - drm_syncobj_search_fence(syncobj, 0, 0, fence); - if (*fence) - return 1; - spin_lock(&syncobj->lock); - } else { - *fence = NULL; - drm_syncobj_add_callback_locked(syncobj, cb, func); - ret = 0; + if (pt_value == 0) + pt_value += DRM_SYNCOBJ_BINARY_POINT; } - spin_unlock(&syncobj->lock); - return ret; + mutex_lock(&syncobj->cb_mutex); + spin_lock(&syncobj->pt_lock); + *fence = drm_syncobj_find_signal_pt_for_point(syncobj, pt_value); + spin_unlock(&syncobj->pt_lock); + if (!*fence) + drm_syncobj_add_callback_locked(syncobj, cb, func); + mutex_unlock(&syncobj->cb_mutex); } void drm_syncobj_add_callback(struct drm_syncobj *syncobj, struct drm_syncobj_cb *cb, drm_syncobj_func_t func) { - spin_lock(&syncobj->lock); + mutex_lock(&syncobj->cb_mutex); drm_syncobj_add_callback_locked(syncobj, cb, func); - spin_unlock(&syncobj->lock); + mutex_unlock(&syncobj->cb_mutex); } void drm_syncobj_remove_callback(struct drm_syncobj *syncobj, struct drm_syncobj_cb *cb) { - spin_lock(&syncobj->lock); + mutex_lock(&syncobj->cb_mutex); list_del_init(&cb->node); - spin_unlock(&syncobj->lock); + mutex_unlock(&syncobj->cb_mutex); } static void drm_syncobj_init(struct drm_syncobj *syncobj) { - spin_lock(&syncobj->lock); + spin_lock(&syncobj->pt_lock); syncobj->timeline_context = dma_fence_context_alloc(1); syncobj->timeline = 0; syncobj->signal_point = 0; init_waitqueue_head(&syncobj->wq); INIT_LIST_HEAD(&syncobj->signal_pt_list); - spin_unlock(&syncobj->lock); + spin_unlock(&syncobj->pt_lock); } static void drm_syncobj_fini(struct drm_syncobj *syncobj) { struct drm_syncobj_signal_pt *signal_pt = NULL, *tmp; - spin_lock(&syncobj->lock); + spin_lock(&syncobj->pt_lock); list_for_each_entry_safe(signal_pt, tmp, &syncobj->signal_pt_list, list) { list_del(&signal_pt->list); dma_fence_put(&signal_pt->fence_array->base); kfree(signal_pt); } - spin_unlock(&syncobj->lock); -} - -static struct dma_fence -*drm_syncobj_find_signal_pt_for_point(struct drm_syncobj *syncobj, - uint64_t point) -{ - struct drm_syncobj_signal_pt *signal_pt; - - if ((syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) && - (point <= syncobj->timeline)) { - struct drm_syncobj_stub_fence *fence = - kzalloc(sizeof(struct drm_syncobj_stub_fence), - GFP_KERNEL); - - if (!fence) - return NULL; - spin_lock_init(&fence->lock); - dma_fence_init(&fence->base, - &drm_syncobj_stub_fence_ops, - &fence->lock, - syncobj->timeline_context, - point); - - dma_fence_signal(&fence->base); - return &fence->base; - } - - list_for_each_entry(signal_pt, &syncobj->signal_pt_list, list) { - if (point > signal_pt->value) - continue; - if ((syncobj->type == DRM_SYNCOBJ_TYPE_BINARY) && - (point != signal_pt->value)) - continue; - return dma_fence_get(&signal_pt->fence_array->base); - } - return NULL; + spin_unlock(&syncobj->pt_lock); } static int drm_syncobj_create_signal_pt(struct drm_syncobj *syncobj, @@ -249,14 +241,14 @@ static int drm_syncobj_create_signal_pt(struct drm_syncobj *syncobj, fences[num_fences++] = dma_fence_get(fence); /* timeline syncobj must take this dependency */ if (syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) { - spin_lock(&syncobj->lock); + spin_lock(&syncobj->pt_lock); if (!list_empty(&syncobj->signal_pt_list)) { tail_pt = list_last_entry(&syncobj->signal_pt_list, struct drm_syncobj_signal_pt, list); fences[num_fences++] = dma_fence_get(&tail_pt->fence_array->base); } - spin_unlock(&syncobj->lock); + spin_unlock(&syncobj->pt_lock); } signal_pt->fence_array = dma_fence_array_create(num_fences, fences, syncobj->timeline_context, @@ -266,16 +258,16 @@ static int drm_syncobj_create_signal_pt(struct drm_syncobj *syncobj, goto fail; } - spin_lock(&syncobj->lock); + spin_lock(&syncobj->pt_lock); if (syncobj->signal_point >= point) { DRM_WARN("A later signal is ready!"); - spin_unlock(&syncobj->lock); + spin_unlock(&syncobj->pt_lock); goto exist; } signal_pt->value = point; list_add_tail(&signal_pt->list, &syncobj->signal_pt_list); syncobj->signal_point = point; - spin_unlock(&syncobj->lock); + spin_unlock(&syncobj->pt_lock); wake_up_all(&syncobj->wq); return 0; @@ -294,7 +286,7 @@ static void drm_syncobj_garbage_collection(struct drm_syncobj *syncobj) { struct drm_syncobj_signal_pt *signal_pt, *tmp, *tail_pt; - spin_lock(&syncobj->lock); + spin_lock(&syncobj->pt_lock); tail_pt = list_last_entry(&syncobj->signal_pt_list, struct drm_syncobj_signal_pt, list); @@ -315,7 +307,7 @@ static void drm_syncobj_garbage_collection(struct drm_syncobj *syncobj) } } - spin_unlock(&syncobj->lock); + spin_unlock(&syncobj->pt_lock); } /** * drm_syncobj_replace_fence - replace fence in a sync object. @@ -344,13 +336,14 @@ void drm_syncobj_replace_fence(struct drm_syncobj *syncobj, drm_syncobj_create_signal_pt(syncobj, fence, pt_value); if (fence) { struct drm_syncobj_cb *cur, *tmp; + LIST_HEAD(cb_list); - spin_lock(&syncobj->lock); + mutex_lock(&syncobj->cb_mutex); list_for_each_entry_safe(cur, tmp, &syncobj->cb_list, node) { list_del_init(&cur->node); cur->func(syncobj, cur); } - spin_unlock(&syncobj->lock); + mutex_unlock(&syncobj->cb_mutex); } } EXPORT_SYMBOL(drm_syncobj_replace_fence); @@ -386,11 +379,11 @@ drm_syncobj_point_get(struct drm_syncobj *syncobj, u64 point, u64 flags, if (ret < 0) return ret; } - spin_lock(&syncobj->lock); + spin_lock(&syncobj->pt_lock); *fence = drm_syncobj_find_signal_pt_for_point(syncobj, point); if (!*fence) ret = -EINVAL; - spin_unlock(&syncobj->lock); + spin_unlock(&syncobj->pt_lock); return ret; } @@ -500,7 +493,8 @@ int drm_syncobj_create(struct drm_syncobj **out_syncobj, uint32_t flags, kref_init(&syncobj->refcount); INIT_LIST_HEAD(&syncobj->cb_list); - spin_lock_init(&syncobj->lock); + spin_lock_init(&syncobj->pt_lock); + mutex_init(&syncobj->cb_mutex); if (flags & DRM_SYNCOBJ_CREATE_TYPE_TIMELINE) syncobj->type = DRM_SYNCOBJ_TYPE_TIMELINE; else diff --git a/include/drm/drm_syncobj.h b/include/drm/drm_syncobj.h index 5e8c5c027e09..29244cbcd05e 100644 --- a/include/drm/drm_syncobj.h +++ b/include/drm/drm_syncobj.h @@ -75,9 +75,13 @@ struct drm_syncobj { */ struct list_head cb_list; /** - * @lock: Protects syncobj list and write-locks &fence. + * @pt_lock: Protects pt list. */ - spinlock_t lock; + spinlock_t pt_lock; + /** + * @cb_mutex: Protects syncobj cb list. + */ + struct mutex cb_mutex; /** * @file: A file backing for this syncobj. */