From: Akash Goel Date: Thu, 20 Nov 2025 17:21:18 +0000 (+0000) Subject: drm/panthor: Avoid adding of kernel BOs to extobj list X-Git-Tag: v6.18.2~184 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0a3d0e94866352c9ecd75a50e361773ec06099f8;p=thirdparty%2Fkernel%2Fstable.git drm/panthor: Avoid adding of kernel BOs to extobj list [ Upstream commit ce04ec03a9c2c4f3e60e26f21311b25d5a478208 ] The kernel BOs unnecessarily got added to the external objects list of drm_gpuvm, when mapping to GPU, which would have resulted in few extra CPU cycles being spent at the time of job submission as drm_exec_until_all_locked() loop iterates over all external objects. Kernel BOs are private to a VM and so they share the dma_resv object of the dummy GEM object created for a VM. Use of DRM_EXEC_IGNORE_DUPLICATES flag ensured the recursive locking of the dummy GEM object was ignored. Also no extra space got allocated to add fences to the dma_resv object of dummy GEM object. So no other impact apart from few extra CPU cycles. This commit sets the pointer to dma_resv object of GEM object of kernel BOs before they are mapped to GPU, to prevent them from being added to external objects list. v2: Add R-bs and fixes tags Fixes: 8a1cc07578bf ("drm/panthor: Add GEM logical block") Signed-off-by: Akash Goel Reviewed-by: Boris Brezillon Reviewed-by: Steven Price Link: https://patch.msgid.link/20251120172118.2741724-1-akash.goel@arm.com Signed-off-by: Boris Brezillon Signed-off-by: Sasha Levin --- diff --git a/drivers/gpu/drm/panthor/panthor_gem.c b/drivers/gpu/drm/panthor/panthor_gem.c index 14ed09d700f2f..43471babff86c 100644 --- a/drivers/gpu/drm/panthor/panthor_gem.c +++ b/drivers/gpu/drm/panthor/panthor_gem.c @@ -144,6 +144,9 @@ panthor_kernel_bo_create(struct panthor_device *ptdev, struct panthor_vm *vm, bo = to_panthor_bo(&obj->base); kbo->obj = &obj->base; bo->flags = bo_flags; + bo->exclusive_vm_root_gem = panthor_vm_root_gem(vm); + drm_gem_object_get(bo->exclusive_vm_root_gem); + bo->base.base.resv = bo->exclusive_vm_root_gem->resv; if (vm == panthor_fw_vm(ptdev)) debug_flags |= PANTHOR_DEBUGFS_GEM_USAGE_FLAG_FW_MAPPED; @@ -167,9 +170,6 @@ panthor_kernel_bo_create(struct panthor_device *ptdev, struct panthor_vm *vm, goto err_free_va; kbo->vm = panthor_vm_get(vm); - bo->exclusive_vm_root_gem = panthor_vm_root_gem(vm); - drm_gem_object_get(bo->exclusive_vm_root_gem); - bo->base.base.resv = bo->exclusive_vm_root_gem->resv; return kbo; err_free_va: