[PATCH RFC POC 30/50] drm/vmwgfx: install the out-fence descriptor when the ioctl returns

[Christian Brauner]

Rely on the fd exit path machinery.

Signed-off-by: Christian Brauner (Amutable) <brau...@kernel.org>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c | 29 +++++++++++------------------
 1 file changed, 11 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c 
b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
index a9136a6523cb..9daa74a13485 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c
@@ -4109,15 +4109,17 @@ int vmw_execbuf_process(struct drm_file *file_priv,
        uint32_t handle = 0;
        int ret;
        int32_t out_fence_fd = -1;
+       const struct fd_slot *out_fd = NULL;
        struct sync_file *sync_file = NULL;
        DECLARE_VAL_CONTEXT(val_ctx, sw_context, 1);
 
        if (flags & DRM_VMW_EXECBUF_FLAG_EXPORT_FENCE_FD) {
-               out_fence_fd = get_unused_fd_flags(O_CLOEXEC);
-               if (out_fence_fd < 0) {
+               out_fd = fd_prepare(O_CLOEXEC);
+               if (IS_ERR(out_fd)) {
                        VMW_DEBUG_USER("Failed to get a fence fd.\n");
-                       return out_fence_fd;
+                       return PTR_ERR(out_fd);
                }
+               out_fence_fd = fd_prepare_fd(out_fd);
        }
 
        if (throttle_us) {
@@ -4256,28 +4258,21 @@ int vmw_execbuf_process(struct drm_file *file_priv,
                sync_file = sync_file_create(&fence->base);
                if (!sync_file) {
                        VMW_DEBUG_USER("Sync file create failed for fence\n");
-                       put_unused_fd(out_fence_fd);
+                       /* The reserved descriptor is released on return. */
                        out_fence_fd = -1;
 
                        (void) vmw_fence_obj_wait(fence, false, false,
                                                  VMW_FENCE_WAIT_TIMEOUT);
+               } else {
+                       /* Link the fence with the FD created earlier */
+                       fd_stage(out_fd, sync_file->file);
                }
        }
 
+       /* A staged sync file is dropped with the ioctl on error. */
        ret = vmw_execbuf_copy_fence_user(dev_priv, vmw_fpriv(file_priv), ret,
                                    user_fence_rep, fence, handle, 
out_fence_fd);
 
-       if (sync_file) {
-               if (ret) {
-                       /* usercopy of fence failed, put the file object */
-                       fput(sync_file->file);
-                       put_unused_fd(out_fence_fd);
-               } else {
-                       /* Link the fence with the FD created earlier */
-                       fd_install(out_fence_fd, sync_file->file);
-               }
-       }
-
        /* Don't unreference when handing fence out */
        if (unlikely(out_fence != NULL)) {
                *out_fence = fence;
@@ -4323,9 +4318,7 @@ int vmw_execbuf_process(struct drm_file *file_priv,
        if (header)
                vmw_cmdbuf_header_free(header);
 out_free_fence_fd:
-       if (out_fence_fd >= 0)
-               put_unused_fd(out_fence_fd);
-
+       /* A reserved descriptor is released on return. */
        return ret;
 }
 

-- 
2.53.0