drm/vkms: No need for ->pages_lock in crc work anymore (e5ff5344) · Commits · 戴 / test

We're now guaranteed to no longer race against prepare_fb/cleanup_fb, which means we can access ->vaddr without having to hold a lock. Before the previous patches it was fairly easy to observe the cursor ->vaddr being invalid, but that's now gone, so we can upgrade to a full WARN_ON. Cc: Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com> Cc: Haneen Mohammed <hamohammed.sa@gmail.com> Cc: Daniel Vetter <daniel@ffwll.ch> Signed-off-by:

Daniel Vetter <daniel.vetter@intel.com> Reviewed-by:

Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com> Tested-by:

Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com> Signed-off-by:

Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190606222751.32567-11-daniel.vetter@ffwll.ch

drivers/gpu/drm/vkms/vkms_crc.c

+2 −11

Original line number	Diff line number	Diff line
		@@ -97,16 +97,10 @@ static void compose_cursor(struct vkms_crc_data *cursor_crc,
		cursor_obj = drm_gem_fb_get_obj(&cursor_crc->fb, 0);
		cursor_vkms_obj = drm_gem_to_vkms_gem(cursor_obj);

		mutex_lock(&cursor_vkms_obj->pages_lock);
		if (!cursor_vkms_obj->vaddr) {
		DRM_WARN("cursor plane vaddr is NULL");
		goto out;
		}
		if (WARN_ON(!cursor_vkms_obj->vaddr))
		return;

		blend(vaddr_out, cursor_vkms_obj->vaddr, primary_crc, cursor_crc);

		out:
		mutex_unlock(&cursor_vkms_obj->pages_lock);
		}

		static uint32_t _vkms_get_crc(struct vkms_crc_data *primary_crc,
		@@ -123,15 +117,12 @@ static uint32_t _vkms_get_crc(struct vkms_crc_data *primary_crc,
		return 0;
		}

		mutex_lock(&vkms_obj->pages_lock);
		if (WARN_ON(!vkms_obj->vaddr)) {
		mutex_unlock(&vkms_obj->pages_lock);
		kfree(vaddr_out);
		return crc;
		}

		memcpy(vaddr_out, vkms_obj->vaddr, vkms_obj->gem.size);
		mutex_unlock(&vkms_obj->pages_lock);

		if (cursor_crc)
		compose_cursor(cursor_crc, primary_crc, vaddr_out);

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