drm/amdkfd: Check if there are kfd porcesses using adev by kfd_processes_count

During gpu hot-unplug need check if there are kfd porcesses still using the
being removed gpu before clean resources of the device. Current driver checks
if kfd_processes_table is empty. kfd processes are not terminated after
removed from kfd_processes_table immediately. They are still alive and may
access the device until kfd_process_wq work queue got ran.

Check kfd->kfd_processes_count value that is updated after kfd process got
uninitialized when its ref becomes zero.

Fixes: 6cca686dfce7 ("drm/amdkfd: kfd driver supports hot unplug/replug amdgpu devices")
Signed-off-by: Xiaogang Chen <xiaogang.chen@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit d12d05c4bc4c15585130af43e897923ff292df7b)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device.c b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
index 8ff97bf7d95a0b233f7bc50dc9372286acd1cc49..b7f8f7ff819834d23989e1f993d0d9e5060f4f26 100644 (file)
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
@@ -1737,37 +1737,6 @@ bool kgd2kfd_vmfault_fast_path(struct amdgpu_device *adev, struct amdgpu_iv_entr
        return false;
 }
 
-/* check if there is kfd process still uses adev */
-static bool kgd2kfd_check_device_idle(struct amdgpu_device *adev)
-{
-       struct kfd_process *p;
-       struct hlist_node *p_temp;
-       unsigned int temp;
-       struct kfd_node *dev;
-
-       mutex_lock(&kfd_processes_mutex);
-
-       if (hash_empty(kfd_processes_table)) {
-               mutex_unlock(&kfd_processes_mutex);
-               return true;
-       }
-
-       /* check if there is device still use adev */
-       hash_for_each_safe(kfd_processes_table, temp, p_temp, p, kfd_processes) {
-               for (int i = 0; i < p->n_pdds; i++) {
-                       dev = p->pdds[i]->dev;
-                       if (dev->adev == adev) {
-                               mutex_unlock(&kfd_processes_mutex);
-                               return false;
-                       }
-               }
-       }
-
-       mutex_unlock(&kfd_processes_mutex);
-
-       return true;
-}
-
 /** kgd2kfd_teardown_processes - gracefully tear down existing
  *  kfd processes that use adev
  *
@@ -1800,7 +1769,7 @@ void kgd2kfd_teardown_processes(struct amdgpu_device *adev)
        mutex_unlock(&kfd_processes_mutex);
 
        /* wait all kfd processes use adev terminate */
-       while (!kgd2kfd_check_device_idle(adev))
+       while (!!atomic_read(&adev->kfd.dev->kfd_processes_count))
                cond_resched();
 }