vmwgfx: Break out and comment vmw_execbuf_copy_fence_user

This function will be used also by the upcoming fence event code,
so break it out and add a comment about the functionality.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Jakob Bornecrantz <jakob@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
index 8a22f9d..f53b99d 100644 (file)
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
@@ -1037,6 +1037,71 @@ int vmw_execbuf_fence_commands(struct drm_file *file_priv,
        return 0;
 }
 
+/**
+ * vmw_execbuf_copy_fence_user - copy fence object information to
+ * user-space.
+ *
+ * @dev_priv: Pointer to a vmw_private struct.
+ * @vmw_fp: Pointer to the struct vmw_fpriv representing the calling file.
+ * @ret: Return value from fence object creation.
+ * @user_fence_rep: User space address of a struct drm_vmw_fence_rep to
+ * which the information should be copied.
+ * @fence: Pointer to the fenc object.
+ * @fence_handle: User-space fence handle.
+ *
+ * This function copies fence information to user-space. If copying fails,
+ * The user-space struct drm_vmw_fence_rep::error member is hopefully
+ * left untouched, and if it's preloaded with an -EFAULT by user-space,
+ * the error will hopefully be detected.
+ * Also if copying fails, user-space will be unable to signal the fence
+ * object so we wait for it immediately, and then unreference the
+ * user-space reference.
+ */
+static void
+vmw_execbuf_copy_fence_user(struct vmw_private *dev_priv,
+                           struct vmw_fpriv *vmw_fp,
+                           int ret,
+                           struct drm_vmw_fence_rep __user *user_fence_rep,
+                           struct vmw_fence_obj *fence,
+                           uint32_t fence_handle)
+{
+       struct drm_vmw_fence_rep fence_rep;
+
+       if (user_fence_rep == NULL)
+               return;
+
+       fence_rep.error = ret;
+       if (ret == 0) {
+               BUG_ON(fence == NULL);
+
+               fence_rep.handle = fence_handle;
+               fence_rep.seqno = fence->seqno;
+               vmw_update_seqno(dev_priv, &dev_priv->fifo);
+               fence_rep.passed_seqno = dev_priv->last_read_seqno;
+       }
+
+       /*
+        * copy_to_user errors will be detected by user space not
+        * seeing fence_rep::error filled in. Typically
+        * user-space would have pre-set that member to -EFAULT.
+        */
+       ret = copy_to_user(user_fence_rep, &fence_rep,
+                          sizeof(fence_rep));
+
+       /*
+        * User-space lost the fence object. We need to sync
+        * and unreference the handle.
+        */
+       if (unlikely(ret != 0) && (fence_rep.error == 0)) {
+               ttm_ref_object_base_unref(vmw_fp->tfile,
+                                         fence_handle, TTM_REF_USAGE);
+               DRM_ERROR("Fence copy error. Syncing.\n");
+               (void) vmw_fence_obj_wait(fence, fence->signal_mask,
+                                         false, false,
+                                         VMW_FENCE_WAIT_TIMEOUT);
+       }
+}
+
 int vmw_execbuf_process(struct drm_file *file_priv,
                        struct vmw_private *dev_priv,
                        void __user *user_commands,
@@ -1046,7 +1111,6 @@ int vmw_execbuf_process(struct drm_file *file_priv,
                        struct drm_vmw_fence_rep __user *user_fence_rep)
 {
        struct vmw_sw_context *sw_context = &dev_priv->ctx;
-       struct drm_vmw_fence_rep fence_rep;
        struct vmw_fence_obj *fence;
        uint32_t handle;
        void *cmd;
@@ -1140,38 +1204,8 @@ int vmw_execbuf_process(struct drm_file *file_priv,
                                    (void *) fence);
 
        vmw_clear_validations(sw_context);
-
-       if (user_fence_rep) {
-               fence_rep.error = ret;
-               fence_rep.handle = handle;
-               fence_rep.seqno = fence->seqno;
-               vmw_update_seqno(dev_priv, &dev_priv->fifo);
-               fence_rep.passed_seqno = dev_priv->last_read_seqno;
-
-               /*
-                * copy_to_user errors will be detected by user space not
-                * seeing fence_rep::error filled in. Typically
-                * user-space would have pre-set that member to -EFAULT.
-                */
-               ret = copy_to_user(user_fence_rep, &fence_rep,
-                                  sizeof(fence_rep));
-
-               /*
-                * User-space lost the fence object. We need to sync
-                * and unreference the handle.
-                */
-               if (unlikely(ret != 0) && (fence_rep.error == 0)) {
-                       BUG_ON(fence == NULL);
-
-                       ttm_ref_object_base_unref(vmw_fpriv(file_priv)->tfile,
-                                                 handle, TTM_REF_USAGE);
-                       DRM_ERROR("Fence copy error. Syncing.\n");
-                       (void) vmw_fence_obj_wait(fence,
-                                                 fence->signal_mask,
-                                                 false, false,
-                                                 VMW_FENCE_WAIT_TIMEOUT);
-               }
-       }
+       vmw_execbuf_copy_fence_user(dev_priv, vmw_fpriv(file_priv), ret,
+                                   user_fence_rep, fence, handle);
 
        if (likely(fence != NULL))
                vmw_fence_obj_unreference(&fence);