drm/udl: Move vmap out of commit tail

Vmap operations may acquire the dmabuf reservation lock, which is not
allowed within atomic commit-tail functions. Therefore move vmap and
vunmap from the damage handler into prepare_fb and cleanup_fb callbacks.

The mapping is provided as GEM shadow-buffered plane. The functions in
the commit tail use the pre-established mapping for damage handling.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210208115538.6430-8-tzimmermann@suse.de

drivers/gpu/drm/udl/udl_modeset.c

@@ -15,6 +15,7 @@
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_damage_helper.h>
 #include <drm/drm_fourcc.h>
+#include <drm/drm_gem_atomic_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_gem_shmem_helper.h>
 #include <drm/drm_modeset_helper_vtables.h>
@@ -266,18 +267,17 @@ static int udl_aligned_damage_clip(struct drm_rect *clip, int x, int y,
 	return 0;
 }
 
-static int udl_handle_damage(struct drm_framebuffer *fb, int x, int y,
-			     int width, int height)
+static int udl_handle_damage(struct drm_framebuffer *fb, const struct dma_buf_map *map,
+			     int x, int y, int width, int height)
 {
 	struct drm_device *dev = fb->dev;
 	struct dma_buf_attachment *import_attach = fb->obj[0]->import_attach;
+	void *vaddr = map->vaddr; /* TODO: Use mapping abstraction properly */
 	int i, ret, tmp_ret;
 	char *cmd;
 	struct urb *urb;
 	struct drm_rect clip;
 	int log_bpp;
-	struct dma_buf_map map;
-	void *vaddr;
 
 	ret = udl_log_cpp(fb->format->cpp[0]);
 	if (ret < 0)
@@ -297,17 +297,10 @@ static int udl_handle_damage(struct drm_framebuffer *fb, int x, int y,
 			return ret;
 	}
 
-	ret = drm_gem_shmem_vmap(fb->obj[0], &map);
-	if (ret) {
-		DRM_ERROR("failed to vmap fb\n");
-		goto out_dma_buf_end_cpu_access;
-	}
-	vaddr = map.vaddr; /* TODO: Use mapping abstraction properly */
-
 	urb = udl_get_urb(dev);
 	if (!urb) {
 		ret = -ENOMEM;
-		goto out_drm_gem_shmem_vunmap;
+		goto out_dma_buf_end_cpu_access;
 	}
 	cmd = urb->transfer_buffer;
 
@@ -320,7 +313,7 @@ static int udl_handle_damage(struct drm_framebuffer *fb, int x, int y,
 				       &cmd, byte_offset, dev_byte_offset,
 				       byte_width);
 		if (ret)
-			goto out_drm_gem_shmem_vunmap;
+			goto out_dma_buf_end_cpu_access;
 	}
 
 	if (cmd > (char *)urb->transfer_buffer) {
@@ -336,8 +329,6 @@ static int udl_handle_damage(struct drm_framebuffer *fb, int x, int y,
 
 	ret = 0;
 
-out_drm_gem_shmem_vunmap:
-	drm_gem_shmem_vunmap(fb->obj[0], &map);
 out_dma_buf_end_cpu_access:
 	if (import_attach) {
 		tmp_ret = dma_buf_end_cpu_access(import_attach->dmabuf,
@@ -375,6 +366,7 @@ udl_simple_display_pipe_enable(struct drm_simple_display_pipe *pipe,
 	struct drm_framebuffer *fb = plane_state->fb;
 	struct udl_device *udl = to_udl(dev);
 	struct drm_display_mode *mode = &crtc_state->mode;
+	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
 	char *buf;
 	char *wrptr;
 	int color_depth = UDL_COLOR_DEPTH_16BPP;
@@ -400,7 +392,7 @@ udl_simple_display_pipe_enable(struct drm_simple_display_pipe *pipe,
 
 	udl->mode_buf_len = wrptr - buf;
 
-	udl_handle_damage(fb, 0, 0, fb->width, fb->height);
+	udl_handle_damage(fb, &shadow_plane_state->map[0], 0, 0, fb->width, fb->height);
 
 	if (!crtc_state->mode_changed)
 		return;
@@ -435,6 +427,7 @@ udl_simple_display_pipe_update(struct drm_simple_display_pipe *pipe,
 			       struct drm_plane_state *old_plane_state)
 {
 	struct drm_plane_state *state = pipe->plane.state;
+	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(state);
 	struct drm_framebuffer *fb = state->fb;
 	struct drm_rect rect;
 
@@ -442,17 +435,16 @@ udl_simple_display_pipe_update(struct drm_simple_display_pipe *pipe,
 		return;
 
 	if (drm_atomic_helper_damage_merged(old_plane_state, state, &rect))
-		udl_handle_damage(fb, rect.x1, rect.y1, rect.x2 - rect.x1,
-				  rect.y2 - rect.y1);
+		udl_handle_damage(fb, &shadow_plane_state->map[0], rect.x1, rect.y1,
+				  rect.x2 - rect.x1, rect.y2 - rect.y1);
 }
 
-static const
-struct drm_simple_display_pipe_funcs udl_simple_display_pipe_funcs = {
+static const struct drm_simple_display_pipe_funcs udl_simple_display_pipe_funcs = {
 	.mode_valid = udl_simple_display_pipe_mode_valid,
 	.enable = udl_simple_display_pipe_enable,
 	.disable = udl_simple_display_pipe_disable,
 	.update = udl_simple_display_pipe_update,
-	.prepare_fb = drm_gem_fb_simple_display_pipe_prepare_fb,
+	DRM_GEM_SIMPLE_DISPLAY_PIPE_SHADOW_PLANE_FUNCS,
 };
 
 /*