回复: [PATCH 1/3] drm/amdgpu: use one client id per ring again

[Zhou, David(ChunMing)]

What will the situation result in?
Before step3, the step2 must have completed. step4 is expected from step3.

Regards,
David Zhou

Sent from my Huawei Mobile

-------- 原始邮件 --------
主题：[PATCH 1/3] drm/amdgpu: use one client id per ring again
发件人：Christian K鰊ig
收件人：amd-gfx at lists.freedesktop.org
抄送：

From: Christian König <christian.koenig at amd.com>

Otherwise we can run into the following situation:

1. Process A grabs ID 1 for ring 0.
2. Process B grabs ID 1 for ring 0.
3. Process A grabs ID 1 for ring 1.
4. Process A tries to reuse ID1 for ring 0 but things he doesn't need to flush.

Signed-off-by: Christian König <christian.koenig at amd.com>
Cc: stable at vger.kernel.org
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index f8615a4..7ac79d2 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -256,7 +256,7 @@ int amdgpu_vm_grab_id(struct amdgpu_vm *vm, struct amdgpu_ring *ring,
                 if (amdgpu_vm_is_gpu_reset(adev, id))
                         continue;

-               if (atomic64_read(&id->owner) != vm->client_id)
+               if (atomic64_read(&id->owner) != (vm->client_id + i))
                         continue;

                 if (job->vm_pd_addr != id->pd_gpu_addr)
@@ -310,7 +310,7 @@ int amdgpu_vm_grab_id(struct amdgpu_vm *vm, struct amdgpu_ring *ring,
         id->pd_gpu_addr = job->vm_pd_addr;
         id->current_gpu_reset_count = atomic_read(&adev->gpu_reset_counter);
         list_move_tail(&id->list, &adev->vm_manager.ids_lru);
-       atomic64_set(&id->owner, vm->client_id);
+       atomic64_set(&id->owner, vm->client_id + ring->idx);
         vm->ids[ring->idx] = id;

         job->vm_id = id - adev->vm_manager.ids;
@@ -1496,7 +1496,8 @@ int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm)
         for (i = 0; i < AMDGPU_MAX_RINGS; ++i)
                 vm->ids[i] = NULL;
         vm->va = RB_ROOT;
-       vm->client_id = atomic64_inc_return(&adev->vm_manager.client_counter);
+       vm->client_id = atomic64_add_return(AMDGPU_MAX_RINGS,
+                                           &adev->vm_manager.client_counter);
         spin_lock_init(&vm->status_lock);
         INIT_LIST_HEAD(&vm->invalidated);
         INIT_LIST_HEAD(&vm->cleared);
--
2.5.0

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