drm/shmem-helper: Align to page size in dumb_create

shmem helpers seem a bit sloppy here by automatically rounding up when
actually creating the buffer, which results in under-reporting of what
we actually have. Caught by igt/vgem_basic tests.
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210603164113.1433476-4-daniel.vetter@ffwll.ch

drivers/gpu/drm/drm_gem_shmem_helper.c

@@ -505,13 +505,13 @@ int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev,
 
 	if (!args->pitch || !args->size) {
 		args->pitch = min_pitch;
-		args->size = args->pitch * args->height;
+		args->size = PAGE_ALIGN(args->pitch * args->height);
 	} else {
 		/* ensure sane minimum values */
 		if (args->pitch < min_pitch)
 			args->pitch = min_pitch;
 		if (args->size < args->pitch * args->height)
-			args->size = args->pitch * args->height;
+			args->size = PAGE_ALIGN(args->pitch * args->height);
 	}
 
 	shmem = drm_gem_shmem_create_with_handle(file, dev, args->size, &args->handle);