6.6-stable review patch. If anyone has any objections, please let me know.
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From: Michał Winiarski michal.winiarski@intel.com
[ Upstream commit 071d583e01c88272f6ff216d4f867f8f35e94d7d ]
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@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20240823163048.2676257-4-micha... Acked-by: James Zhu James.Zhu@amd.com Acked-by: Christian König christian.koenig@amd.com Signed-off-by: Christian König christian.koenig@amd.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/drm_drv.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 63219695233f0..d453d710ef0c1 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -121,10 +121,19 @@ static void drm_minor_alloc_release(struct drm_device *dev, void *data) xa_erase(drm_minor_get_xa(minor->type), minor->index); }
+/* + * 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. + * Accel nodes are using a distinct major, so the minors are allocated in continuous 0-MAX + * range. + */ #define DRM_MINOR_LIMIT(t) ({ \ typeof(t) _t = (t); \ _t == DRM_MINOR_ACCEL ? XA_LIMIT(0, ACCEL_MAX_MINORS) : XA_LIMIT(64 * _t, 64 * _t + 63); \ }) +#define DRM_EXTENDED_MINOR_LIMIT XA_LIMIT(192, (1 << MINORBITS) - 1)
static int drm_minor_alloc(struct drm_device *dev, enum drm_minor_type type) { @@ -140,6 +149,9 @@ static int drm_minor_alloc(struct drm_device *dev, enum drm_minor_type type)
r = xa_alloc(drm_minor_get_xa(type), &minor->index, NULL, DRM_MINOR_LIMIT(type), GFP_KERNEL); + if (r == -EBUSY && (type == DRM_MINOR_PRIMARY || type == DRM_MINOR_RENDER)) + r = xa_alloc(&drm_minors_xa, &minor->index, + NULL, DRM_EXTENDED_MINOR_LIMIT, GFP_KERNEL); if (r < 0) return r;