Following error conditions are fixed:
    Ensure calls to delete a list element are safe
    Unpin MMIO and DOORBELL BOs only after map count goes to zero
    Print a warning message if unreserving VMs encounters an error

Signed-off-by: Ramesh Errabolu <ramesh.errab...@amd.com>
---
 .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  | 38 ++++++++++---------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index a1de900ba677..78b3efecc2f9 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -1013,14 +1013,14 @@ static void add_kgd_mem_to_kfd_bo_list(struct kgd_mem 
*mem,
        mutex_unlock(&process_info->lock);
 }
 
-static void remove_kgd_mem_from_kfd_bo_list(struct kgd_mem *mem,
+static void remove_kgd_mem_from_validate_list(struct kgd_mem *mem,
                struct amdkfd_process_info *process_info)
 {
        struct ttm_validate_buffer *bo_list_entry;
 
        bo_list_entry = &mem->validate_list;
        mutex_lock(&process_info->lock);
-       list_del(&bo_list_entry->head);
+       list_del_init(&bo_list_entry->head);
        mutex_unlock(&process_info->lock);
 }
 
@@ -1796,7 +1796,7 @@ int amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu(
 
 allocate_init_user_pages_failed:
 err_pin_bo:
-       remove_kgd_mem_from_kfd_bo_list(*mem, avm->process_info);
+       remove_kgd_mem_from_validate_list(*mem, avm->process_info);
        drm_vma_node_revoke(&gobj->vma_node, drm_priv);
 err_node_allow:
        /* Don't unreserve system mem limit twice */
@@ -1825,20 +1825,12 @@ int amdgpu_amdkfd_gpuvm_free_memory_of_gpu(
        unsigned long bo_size = mem->bo->tbo.base.size;
        struct kfd_mem_attachment *entry, *tmp;
        struct bo_vm_reservation_context ctx;
-       struct ttm_validate_buffer *bo_list_entry;
        unsigned int mapped_to_gpu_memory;
        int ret;
        bool is_imported = false;
 
        mutex_lock(&mem->lock);
 
-       /* Unpin MMIO/DOORBELL BO's that were pinned during allocation */
-       if (mem->alloc_flags &
-           (KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL |
-            KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP)) {
-               amdgpu_amdkfd_gpuvm_unpin_bo(mem->bo);
-       }
-
        mapped_to_gpu_memory = mem->mapped_to_gpu_memory;
        is_imported = mem->is_imported;
        mutex_unlock(&mem->lock);
@@ -1852,11 +1844,10 @@ int amdgpu_amdkfd_gpuvm_free_memory_of_gpu(
                return -EBUSY;
        }
 
-       /* Make sure restore workers don't access the BO any more */
-       bo_list_entry = &mem->validate_list;
-       mutex_lock(&process_info->lock);
-       list_del(&bo_list_entry->head);
-       mutex_unlock(&process_info->lock);
+       /* Make sure restore workers don't access the BO any more
+        * Ensure removal of BO from validate list is reentrant safe
+        */
+       remove_kgd_mem_from_validate_list(mem, process_info);
 
        /* No more MMU notifiers */
        amdgpu_mn_unregister(mem->bo);
@@ -1878,7 +1869,18 @@ int amdgpu_amdkfd_gpuvm_free_memory_of_gpu(
        list_for_each_entry_safe(entry, tmp, &mem->attachments, list)
                kfd_mem_detach(entry);
 
+       /* Return success even in case of error */
        ret = unreserve_bo_and_vms(&ctx, false, false);
+       if (unlikely(ret)) {
+               WARN_ONCE(ret, "Error in unreserving BO and associated VMs");
+               ret = 0;
+       }
+
+       /* Unpin MMIO/DOORBELL BO's that were pinned during allocation */
+       if (mem->alloc_flags &
+           (KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL |
+            KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP))
+               amdgpu_amdkfd_gpuvm_unpin_bo(mem->bo);
 
        /* Free the sync object */
        amdgpu_sync_free(&mem->sync);
@@ -2814,7 +2816,7 @@ int amdgpu_amdkfd_add_gws_to_process(void *info, void 
*gws, struct kgd_mem **mem
 bo_reservation_failure:
        mutex_unlock(&(*mem)->process_info->lock);
        amdgpu_sync_free(&(*mem)->sync);
-       remove_kgd_mem_from_kfd_bo_list(*mem, process_info);
+       remove_kgd_mem_from_validate_list(*mem, process_info);
        amdgpu_bo_unref(&gws_bo);
        mutex_destroy(&(*mem)->lock);
        kfree(*mem);
@@ -2832,7 +2834,7 @@ int amdgpu_amdkfd_remove_gws_from_process(void *info, 
void *mem)
        /* Remove BO from process's validate list so restore worker won't touch
         * it anymore
         */
-       remove_kgd_mem_from_kfd_bo_list(kgd_mem, process_info);
+       remove_kgd_mem_from_validate_list(kgd_mem, process_info);
 
        ret = amdgpu_bo_reserve(gws_bo, false);
        if (unlikely(ret)) {
-- 
2.35.1

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