[PATCH v2 03/10] drm/amdgpu: Keep a bo-reference per-attachment

[Errabolu, Ramesh]

[AMD Official Use Only - Internal Distribution Only]

Acked-by: Ramesh Errabolu <ramesh.errabolu at amd.com>

-----Original Message-----
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of Kuehling, Felix
Sent: Wednesday, April 21, 2021 8:31 PM
To: amd-gfx at lists.freedesktop.org; dri-devel at lists.freedesktop.org
Subject: [PATCH v2 03/10] drm/amdgpu: Keep a bo-reference per-attachment

For now they all reference the same BO. For correct DMA mappings they will refer to different BOs per-GPU.

Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>
---
 .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  | 22 ++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index fee4c64dd051..34c9a2d0028e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -489,11 +489,11 @@ static int kfd_mem_attach(struct amdgpu_device *adev, struct kgd_mem *mem,
 		struct amdgpu_vm *vm, bool is_aql,
 		struct kfd_mem_attachment **p_attachment)  {
-	int ret;
-	struct kfd_mem_attachment *attachment;
-	struct amdgpu_bo *bo = mem->bo;
+	unsigned long bo_size = mem->bo->tbo.base.size;
 	uint64_t va = mem->va;
-	unsigned long bo_size = bo->tbo.base.size;
+	struct kfd_mem_attachment *attachment;
+	struct amdgpu_bo *bo;
+	int ret;
 
 	if (!va) {
 		pr_err("Invalid VA when adding BO to VM\n"); @@ -510,6 +510,14 @@ static int kfd_mem_attach(struct amdgpu_device *adev, struct kgd_mem *mem,
 	pr_debug("\t add VA 0x%llx - 0x%llx to vm %p\n", va,
 			va + bo_size, vm);
 
+	/* FIXME: For now all attachments use the same BO. This is incorrect
+	 * because one BO can only have one DMA mapping for one GPU. We need
+	 * one BO per GPU, e.g. a DMABuf import with dynamic attachment. This
+	 * will be addressed one BO-type at a time in subsequent patches.
+	 */
+	bo = mem->bo;
+	drm_gem_object_get(&bo->tbo.base);
+
 	/* Add BO to VM internal data structures*/
 	attachment->bo_va = amdgpu_vm_bo_add(adev, vm, bo);
 	if (!attachment->bo_va) {
@@ -529,7 +537,7 @@ static int kfd_mem_attach(struct amdgpu_device *adev, struct kgd_mem *mem,
 
 	/* Allocate validate page tables if needed */
 	ret = vm_validate_pt_pd_bos(vm);
-	if (ret) {
+	if (unlikely(ret)) {
 		pr_err("validate_pt_pd_bos() failed\n");
 		goto err_alloc_pts;
 	}
@@ -540,15 +548,19 @@ static int kfd_mem_attach(struct amdgpu_device *adev, struct kgd_mem *mem,
 	amdgpu_vm_bo_rmv(adev, attachment->bo_va);
 	list_del(&attachment->list);
 err_vmadd:
+	drm_gem_object_put(&bo->tbo.base);
 	kfree(attachment);
 	return ret;
 }
 
 static void kfd_mem_detach(struct kfd_mem_attachment *attachment)  {
+	struct amdgpu_bo *bo = attachment->bo_va->base.bo;
+
 	pr_debug("\t remove VA 0x%llx in entry %p\n",
 			attachment->va, attachment);
 	amdgpu_vm_bo_rmv(attachment->adev, attachment->bo_va);
+	drm_gem_object_put(&bo->tbo.base);
 	list_del(&attachment->list);
 	kfree(attachment);
 }
--
2.31.1

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