Having a limit of 64 DRM devices is not good enough for modern world where we have multi-GPU servers, SR-IOV virtual functions and virtual devices used for testing. Let's utilize full minor range for DRM devices. To avoid regressing the existing userspace, we're still maintaining the numbering scheme where 0-63 is used for primary, 64-127 is reserved (formerly for control) and 128-191 is used for render. For minors >= 192, we're allocating minors dynamically on a first-come, first-served basis. Signed-off-by: Michał Winiarski <michal.winiarski@xxxxxxxxx> --- drivers/gpu/drm/drm_drv.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 41799e4d0432..2c6e0b8d3b7a 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -119,8 +119,17 @@ static int drm_minor_alloc(struct drm_device *dev, unsigned int type) minor->type = type; minor->dev = dev; + /* + * DRM used to support 64 devices, for backwards compatibility we need to maintain the + * minor allocation scheme where minors 0-63 are primary nodes, 64-127 are control nodes, + * and 128-191 are render nodes. + * After reaching the limit, we're allocating minors dynamically - first-come, first-serve. + */ r = xa_alloc(&drm_minors_xa, &id, NULL, XA_LIMIT(64 * type, 64 * (type + 1) - 1), GFP_KERNEL); + if (r == -EBUSY) + r = xa_alloc(&drm_minors_xa, &id, NULL, + XA_LIMIT(192, (1 << MINORBITS) - 1), GFP_KERNEL); if (r < 0) return r; -- 2.37.3
