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.winiar...@intel.com>
---
drivers/gpu/drm/drm_drv.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 8214a0b1ab7f..9432b1619602 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -122,6 +122,12 @@ 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.
+ */
idr_preload(GFP_KERNEL);
spin_lock_irqsave(&drm_minor_lock, flags);
r = idr_alloc(&drm_minors_idr,
@@ -129,6 +135,8 @@ static int drm_minor_alloc(struct drm_device *dev, unsigned
int type)
64 * type,
64 * (type + 1),
GFP_NOWAIT);
+ if (r == -ENOSPC)
+ r = idr_alloc(&drm_minors_idr, NULL, 192, 1 << MINORBITS,
GFP_NOWAIT);
spin_unlock_irqrestore(&drm_minor_lock, flags);
idr_preload_end();
--
2.37.3
