@@ -139,14 +139,17 @@ EXPORT_SYMBOL(drm_exec_cleanup);
/* Track the locked object in the array */
static int drm_exec_obj_locked(struct drm_exec *exec,
- struct drm_gem_object *obj)
+ struct drm_gem_object *obj,
+ gfp_t gfp)
{
+ might_alloc(gfp);
+
if (unlikely(exec->num_objects == exec->max_objects)) {
size_t size = exec->max_objects * sizeof(void *);
void *tmp;
tmp = kvrealloc(exec->objects, size, size + PAGE_SIZE,
- GFP_KERNEL);
+ gfp);
if (!tmp)
return -ENOMEM;
@@ -179,7 +182,7 @@ static int drm_exec_lock_contended(struct drm_exec *exec)
dma_resv_lock_slow(obj->resv, &exec->ticket);
}
- ret = drm_exec_obj_locked(exec, obj);
+ ret = drm_exec_obj_locked(exec, obj, GFP_KERNEL);
if (unlikely(ret))
goto error_unlock;
@@ -215,6 +218,45 @@ int drm_exec_handle_contended(struct drm_exec *exec)
}
EXPORT_SYMBOL(drm_exec_handle_contended);
+/**
+ * drm_exec_trylock_obj - trylock a GEM object for use
+ * @exec: the drm_exec object with the state.
+ * @obj: the GEM object to lock.
+ *
+ * Trylock a GEM object for use and grab a reference to it.
+ *
+ * Returns: -EALREADY when object is already locked (can be suppressed by
+ * setting the DRM_EXEC_IGNORE_DUPLICATES flag), -ENOMEM when memory
+ * allocation failed, and zero for success. If the object was already
+ * locked, -EBUSY will be returned.
+ */
+int drm_exec_trylock_obj(struct drm_exec *exec, struct drm_gem_object *obj)
+{
+ int ret;
+
+ might_alloc(GFP_ATOMIC);
+
+ if (exec->prelocked == obj) {
+ drm_gem_object_put(exec->prelocked);
+ exec->prelocked = NULL;
+ return 0;
+ }
+
+ if (!dma_resv_trylock_ctx(obj->resv, &exec->ticket)) {
+ if (dma_resv_locking_ctx(obj->resv) == &exec->ticket)
+ return (exec->flags & DRM_EXEC_IGNORE_DUPLICATES) ? 0 : -EALREADY;
+ else
+ return -EBUSY;
+ }
+
+ ret = drm_exec_obj_locked(exec, obj, GFP_ATOMIC | __GFP_NOWARN);
+ if (ret)
+ dma_resv_unlock(obj->resv);
+
+ return ret;
+}
+EXPORT_SYMBOL(drm_exec_trylock_obj);
+
/**
* drm_exec_lock_obj - lock a GEM object for use
* @exec: the drm_exec object with the state
@@ -254,7 +296,7 @@ int drm_exec_lock_obj(struct drm_exec *exec, struct drm_gem_object *obj)
if (unlikely(ret))
return ret;
- ret = drm_exec_obj_locked(exec, obj);
+ ret = drm_exec_obj_locked(exec, obj, GFP_KERNEL);
if (ret)
goto error_unlock;
@@ -152,6 +152,7 @@ void drm_exec_init(struct drm_exec *exec, u32 flags, unsigned nr);
void drm_exec_fini(struct drm_exec *exec);
bool drm_exec_cleanup(struct drm_exec *exec);
int drm_exec_lock_obj(struct drm_exec *exec, struct drm_gem_object *obj);
+int drm_exec_trylock_obj(struct drm_exec *exec, struct drm_gem_object *obj);
void drm_exec_unlock_obj(struct drm_exec *exec, struct drm_gem_object *obj);
int drm_exec_prepare_obj(struct drm_exec *exec, struct drm_gem_object *obj,
unsigned int num_fences);
TTM needs to trylock dma_resv objects in a couple of places. However this functionality is missing in drm_exec. Introduce it. Note that in addition to the -EBUSY error returned on failure to take the lock, the operation may return -ENOMEM if there was a failure to allocate memory for the drm_exec held lock array. This failure mode could be avoided if the drm_exec structure instead maintained a linked list of locked objects, similar to i915. Cc: Christian König <christian.koenig@amd.com> Cc: Somalapuram Amaranath <Amaranath.Somalapuram@amd.com> Cc: Matthew Brost <matthew.brost@intel.com> Cc: <dri-devel@lists.freedesktop.org> Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com> --- drivers/gpu/drm/drm_exec.c | 50 +++++++++++++++++++++++++++++++++++--- include/drm/drm_exec.h | 1 + 2 files changed, 47 insertions(+), 4 deletions(-)