From: Christian König Date: Sat, 4 Jul 2026 08:41:33 +0000 (+0200) Subject: drm/drm_exec: avoid indirect goto X-Git-Tag: v7.2-rc3~27^2~3^2~13 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=4e28aa8f7ee26d67a4addee6e3980f1cbf861b49;p=thirdparty%2Fkernel%2Flinux.git drm/drm_exec: avoid indirect goto The drm_exec component uses a variable with scope limited to the for() and an indirect goto to allow instantiating multiple macros in the same function. This unfortunately doesn't work well with certain compilers when the indirect goto can't be lowered to a direct jump. Switch the indirect goto to a direct goto, the drawback is that we now can't use the dma_exec_until_all_locked() macro in the same function multiple times. The is currently only one user of this and only as a hacky workaround which is about to be removed. So document that the __label__ statement should be used when the macro is used multiple times and fix the tests and the only use case where that is necessary. Suggested-by: Peter Zijlstra Signed-off-by: Christian König Fixes: 9920249a5288 ("drm/amdgpu: convert amdgpu_vm_lock_by_pasid() to drm_exec") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202606231854.7LeCtlLe-lkp@intel.com/ Closes: https://lore.kernel.org/oe-kbuild-all/202606232356.gwHMAJAW-lkp@intel.com/ Closes: https://lore.kernel.org/oe-kbuild-all/202606240753.kYjobJVl-lkp@intel.com/ Closes: https://lore.kernel.org/oe-kbuild-all/202606241110.iUga5vVw-lkp@intel.com/ Closes: https://lore.kernel.org/oe-kbuild-all/202607031446.1PWG18mN-lkp@intel.com/ Closes: https://lore.kernel.org/oe-kbuild-all/202607031837.HSmBj8pr-lkp@intel.com/ Closes: https://lore.kernel.org/oe-kbuild-all/202607040159.GopyEswS-lkp@intel.com/ Tested-by: Mikhail Gavrilov Reviewed-by: Dave Airlie Link: https://lore.kernel.org/r/20260704084133.122053-1-christian.koenig@amd.com --- diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c index fee4c94c2585..fc28d0fdad37 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c @@ -3011,6 +3011,8 @@ bool amdgpu_vm_handle_fault(struct amdgpu_device *adev, u32 pasid, is_compute_context = vm->is_compute_context; if (is_compute_context) { + __label__ drm_exec_retry; + /* Release the root PD lock since svm_range_restore_pages * might try to take it. * TODO: rework svm_range_restore_pages so that this isn't diff --git a/drivers/gpu/drm/tests/drm_exec_test.c b/drivers/gpu/drm/tests/drm_exec_test.c index 2fc47f3b463b..7a374e462348 100644 --- a/drivers/gpu/drm/tests/drm_exec_test.c +++ b/drivers/gpu/drm/tests/drm_exec_test.c @@ -180,19 +180,27 @@ static void test_multiple_loops(struct kunit *test) { struct drm_exec exec; - drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0); - drm_exec_until_all_locked(&exec) { - break; + __label__ drm_exec_retry; + + drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0); + drm_exec_until_all_locked(&exec) + { + break; + } + drm_exec_fini(&exec); } - drm_exec_fini(&exec); - drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0); - drm_exec_until_all_locked(&exec) { - break; + __label__ drm_exec_retry; + + drm_exec_init(&exec, DRM_EXEC_INTERRUPTIBLE_WAIT, 0); + drm_exec_until_all_locked(&exec) + { + break; + } + drm_exec_fini(&exec); } - drm_exec_fini(&exec); KUNIT_SUCCEED(test); } diff --git a/include/drm/drm_exec.h b/include/drm/drm_exec.h index 8725ba92ff91..cc2937185a9f 100644 --- a/include/drm/drm_exec.h +++ b/include/drm/drm_exec.h @@ -101,17 +101,6 @@ drm_exec_obj(struct drm_exec *exec, unsigned long index) #define drm_exec_for_each_locked_object_reverse(exec, obj) \ __drm_exec_for_each_locked_object_reverse(exec, obj, __UNIQUE_ID(drm_exec)) -/* - * Helper to drm_exec_until_all_locked(). Don't use directly. - * - * Since labels can't be defined local to the loop's body we use a jump pointer - * to make sure that the retry is only used from within the loop's body. - */ -#define __drm_exec_until_all_locked(exec, _label) \ -_label: \ - for (void *const __maybe_unused __drm_exec_retry_ptr = &&_label; \ - drm_exec_cleanup(exec);) - /** * drm_exec_until_all_locked - loop until all GEM objects are locked * @exec: drm_exec object @@ -119,9 +108,18 @@ _label: \ * Core functionality of the drm_exec object. Loops until all GEM objects are * locked and no more contention exists. At the beginning of the loop it is * guaranteed that no GEM object is locked. + * + * A global label name drm_exec_retry is used, if you need to use more than one + * instance of this macro in the same function the label needs to be made local + * to the block with the __label__ keyword. */ #define drm_exec_until_all_locked(exec) \ - __drm_exec_until_all_locked(exec, __UNIQUE_ID(drm_exec)) + for (bool const __maybe_unused __drm_exec_loop = false; \ + drm_exec_cleanup(exec);) \ + if (false) { \ +drm_exec_retry: __maybe_unused; \ + continue; \ + } else /** * drm_exec_retry_on_contention - restart the loop to grap all locks @@ -129,12 +127,14 @@ _label: \ * * Control flow helper to continue when a contention was detected and we need to * clean up and re-start the loop to prepare all GEM objects. + * The __drm_exec_loop check exists to prevent usage outside of an + * drm_exec_until_all_locked() loop. */ #define drm_exec_retry_on_contention(exec) \ do { \ if (unlikely(drm_exec_is_contended(exec))) \ - goto *__drm_exec_retry_ptr; \ - } while (0) + goto drm_exec_retry; \ + } while (__drm_exec_loop) /** * drm_exec_is_contended - check for contention @@ -154,12 +154,14 @@ static inline bool drm_exec_is_contended(struct drm_exec *exec) * * Unconditionally retry the loop to lock all objects. For consistency, * the exec object needs to be newly initialized. + * The __drm_exec_loop check exists to prevent usage outside of an + * drm_exec_until_all_locked() loop. */ #define drm_exec_retry(_exec) \ do { \ WARN_ON((_exec)->contended != DRM_EXEC_DUMMY); \ - goto *__drm_exec_retry_ptr; \ - } while (0) + goto drm_exec_retry; \ + } while (__drm_exec_loop) /** * drm_exec_ticket - return the ww_acquire_ctx for this exec context