On Fri, 28 Nov 2025 14:14:16 +0000 Alice Ryhl <[email protected]> wrote:
> In the previous commit we updated drm_gpuvm_bo_obtain_prealloc() to take > locks internally, which means that it's only usable in immediate mode. > In this commit, we notice that drm_gpuvm_bo_obtain() requires you to use > staged mode. This means that we now have one variant of obtain for each > mode you might use gpuvm in. > > To reflect this information, we add a warning about using it in > immediate mode, and to make the distinction clearer we rename the method > with a _locked() suffix so that it's clear that it requires the caller > to take the locks. > > Signed-off-by: Alice Ryhl <[email protected]> > --- > drivers/gpu/drm/drm_gpuvm.c | 16 +++++++++++++--- The gpuvm changes are Reviewed-by: Boris Brezillon <[email protected]> > drivers/gpu/drm/imagination/pvr_vm.c | 2 +- > drivers/gpu/drm/msm/msm_gem.h | 2 +- > drivers/gpu/drm/msm/msm_gem_vma.c | 2 +- > drivers/gpu/drm/nouveau/nouveau_uvmm.c | 2 +- > drivers/gpu/drm/xe/xe_vm.c | 4 ++-- > include/drm/drm_gpuvm.h | 4 ++-- > 7 files changed, 21 insertions(+), 11 deletions(-) > > diff --git a/drivers/gpu/drm/drm_gpuvm.c b/drivers/gpu/drm/drm_gpuvm.c > index > f08a5cc1d611f971862c1272987e5ecd6d97c163..9cd06c7600dc32ceee0f0beb5e3daf31698a66b3 > 100644 > --- a/drivers/gpu/drm/drm_gpuvm.c > +++ b/drivers/gpu/drm/drm_gpuvm.c > @@ -1832,16 +1832,26 @@ EXPORT_SYMBOL_GPL(drm_gpuvm_bo_find); > * count of the &drm_gpuvm_bo accordingly. If not found, allocates a new > * &drm_gpuvm_bo. > * > + * Requires the lock for the GEMs gpuva list. > + * > * A new &drm_gpuvm_bo is added to the GEMs gpuva list. > * > * Returns: a pointer to the &drm_gpuvm_bo on success, an ERR_PTR on failure > */ > struct drm_gpuvm_bo * > -drm_gpuvm_bo_obtain(struct drm_gpuvm *gpuvm, > - struct drm_gem_object *obj) > +drm_gpuvm_bo_obtain_locked(struct drm_gpuvm *gpuvm, > + struct drm_gem_object *obj) > { > struct drm_gpuvm_bo *vm_bo; > > + /* > + * In immediate mode this would require the caller to hold the GEMs > + * gpuva mutex, but it's not okay to allocate while holding that lock, > + * and this method allocates. Immediate mode drivers should use > + * drm_gpuvm_bo_obtain_prealloc() instead. > + */ > + drm_WARN_ON(gpuvm->drm, drm_gpuvm_immediate_mode(gpuvm)); > + > vm_bo = drm_gpuvm_bo_find(gpuvm, obj); > if (vm_bo) > return vm_bo; > @@ -1855,7 +1865,7 @@ drm_gpuvm_bo_obtain(struct drm_gpuvm *gpuvm, > > return vm_bo; > } > -EXPORT_SYMBOL_GPL(drm_gpuvm_bo_obtain); > +EXPORT_SYMBOL_GPL(drm_gpuvm_bo_obtain_locked); > > /** > * drm_gpuvm_bo_obtain_prealloc() - obtains an instance of the &drm_gpuvm_bo > diff --git a/drivers/gpu/drm/imagination/pvr_vm.c > b/drivers/gpu/drm/imagination/pvr_vm.c > index > 3d97990170bf6b1341116c5c8b9d01421944eda4..30ff9b84eb14f2455003e76108de6d489a13f61a > 100644 > --- a/drivers/gpu/drm/imagination/pvr_vm.c > +++ b/drivers/gpu/drm/imagination/pvr_vm.c > @@ -255,7 +255,7 @@ pvr_vm_bind_op_map_init(struct pvr_vm_bind_op *bind_op, > bind_op->type = PVR_VM_BIND_TYPE_MAP; > > dma_resv_lock(obj->resv, NULL); > - bind_op->gpuvm_bo = drm_gpuvm_bo_obtain(&vm_ctx->gpuvm_mgr, obj); > + bind_op->gpuvm_bo = drm_gpuvm_bo_obtain_locked(&vm_ctx->gpuvm_mgr, obj); > dma_resv_unlock(obj->resv); > if (IS_ERR(bind_op->gpuvm_bo)) > return PTR_ERR(bind_op->gpuvm_bo); > diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h > index > a4cf31853c5008e171c3ad72cde1004c60fe5212..26dfe3d22e3e847f7e63174481d03f72878a8ced > 100644 > --- a/drivers/gpu/drm/msm/msm_gem.h > +++ b/drivers/gpu/drm/msm/msm_gem.h > @@ -60,7 +60,7 @@ struct msm_gem_vm_log_entry { > * embedded in any larger driver structure. The GEM object holds a list of > * drm_gpuvm_bo, which in turn holds a list of msm_gem_vma. A linked vma > * holds a reference to the vm_bo, and drops it when the vma is unlinked. > - * So we just need to call drm_gpuvm_bo_obtain() to return a ref to an > + * So we just need to call drm_gpuvm_bo_obtain_locked() to return a ref to an > * existing vm_bo, or create a new one. Once the vma is linked, the ref > * to the vm_bo can be dropped (since the vma is holding one). > */ > diff --git a/drivers/gpu/drm/msm/msm_gem_vma.c > b/drivers/gpu/drm/msm/msm_gem_vma.c > index > 8316af1723c227f919594446c3721e1a948cbc9e..239b6168a26e636b511187b4993945d1565d149f > 100644 > --- a/drivers/gpu/drm/msm/msm_gem_vma.c > +++ b/drivers/gpu/drm/msm/msm_gem_vma.c > @@ -413,7 +413,7 @@ msm_gem_vma_new(struct drm_gpuvm *gpuvm, struct > drm_gem_object *obj, > if (!obj) > return &vma->base; > > - vm_bo = drm_gpuvm_bo_obtain(&vm->base, obj); > + vm_bo = drm_gpuvm_bo_obtain_locked(&vm->base, obj); > if (IS_ERR(vm_bo)) { > ret = PTR_ERR(vm_bo); > goto err_va_remove; > diff --git a/drivers/gpu/drm/nouveau/nouveau_uvmm.c > b/drivers/gpu/drm/nouveau/nouveau_uvmm.c > index > 79eefdfd08a2678fedf69503ddf7e9e17ed14c6f..d8888bd29cccef4b8dad9eff2bf6e2b1fd1a7e4d > 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_uvmm.c > +++ b/drivers/gpu/drm/nouveau/nouveau_uvmm.c > @@ -1207,7 +1207,7 @@ nouveau_uvmm_bind_job_submit(struct nouveau_job *job, > return -ENOENT; > > dma_resv_lock(obj->resv, NULL); > - op->vm_bo = drm_gpuvm_bo_obtain(&uvmm->base, obj); > + op->vm_bo = drm_gpuvm_bo_obtain_locked(&uvmm->base, > obj); > dma_resv_unlock(obj->resv); > if (IS_ERR(op->vm_bo)) > return PTR_ERR(op->vm_bo); > diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c > index > f602b874e0547591d9008333c18f3de0634c48c7..de52d01b0921cc8ac619deeed47b578e0ae69257 > 100644 > --- a/drivers/gpu/drm/xe/xe_vm.c > +++ b/drivers/gpu/drm/xe/xe_vm.c > @@ -1004,7 +1004,7 @@ static struct xe_vma *xe_vma_create(struct xe_vm *vm, > > xe_bo_assert_held(bo); > > - vm_bo = drm_gpuvm_bo_obtain(vma->gpuva.vm, &bo->ttm.base); > + vm_bo = drm_gpuvm_bo_obtain_locked(vma->gpuva.vm, > &bo->ttm.base); > if (IS_ERR(vm_bo)) { > xe_vma_free(vma); > return ERR_CAST(vm_bo); > @@ -2249,7 +2249,7 @@ vm_bind_ioctl_ops_create(struct xe_vm *vm, struct > xe_vma_ops *vops, > if (err) > return ERR_PTR(err); > > - vm_bo = drm_gpuvm_bo_obtain(&vm->gpuvm, obj); > + vm_bo = drm_gpuvm_bo_obtain_locked(&vm->gpuvm, obj); > if (IS_ERR(vm_bo)) { > xe_bo_unlock(bo); > return ERR_CAST(vm_bo); > diff --git a/include/drm/drm_gpuvm.h b/include/drm/drm_gpuvm.h > index > fdfc575b260360611ff8ce16c327acede787929f..0d3fc1f6cac9966a42f3bc82b0b491bfefaf5b96 > 100644 > --- a/include/drm/drm_gpuvm.h > +++ b/include/drm/drm_gpuvm.h > @@ -736,8 +736,8 @@ drm_gpuvm_bo_create(struct drm_gpuvm *gpuvm, > struct drm_gem_object *obj); > > struct drm_gpuvm_bo * > -drm_gpuvm_bo_obtain(struct drm_gpuvm *gpuvm, > - struct drm_gem_object *obj); > +drm_gpuvm_bo_obtain_locked(struct drm_gpuvm *gpuvm, > + struct drm_gem_object *obj); > struct drm_gpuvm_bo * > drm_gpuvm_bo_obtain_prealloc(struct drm_gpuvm_bo *vm_bo); > >
