drm/amdgpu: Add notifier lock for KFD userptrs

Add a per-process MMU notifier lock for processing notifiers from
userptrs. Use that lock to properly synchronize page table updates with
MMU notifiers.

Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Xiaogang Chen<Xiaogang.Chen@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h

@@ -29,6 +29,7 @@
 #include <linux/mm.h>
 #include <linux/kthread.h>
 #include <linux/workqueue.h>
+#include <linux/mmu_notifier.h>
 #include <kgd_kfd_interface.h>
 #include <drm/ttm/ttm_execbuf_util.h>
 #include "amdgpu_sync.h"
@@ -65,6 +66,7 @@ struct kgd_mem {
 	struct mutex lock;
 	struct amdgpu_bo *bo;
 	struct dma_buf *dmabuf;
+	struct hmm_range *range;
 	struct list_head attachments;
 	/* protected by amdkfd_process_info.lock */
 	struct ttm_validate_buffer validate_list;
@@ -75,7 +77,7 @@ struct kgd_mem {
 
 	uint32_t alloc_flags;
 
-	atomic_t invalid;
+	uint32_t invalid;
 	struct amdkfd_process_info *process_info;
 
 	struct amdgpu_sync sync;
@@ -131,7 +133,8 @@ struct amdkfd_process_info {
 	struct amdgpu_amdkfd_fence *eviction_fence;
 
 	/* MMU-notifier related fields */
-	atomic_t evicted_bos;
+	struct mutex notifier_lock;
+	uint32_t evicted_bos;
 	struct delayed_work restore_userptr_work;
 	struct pid *pid;
 	bool block_mmu_notifications;
@@ -180,7 +183,8 @@ int kfd_debugfs_kfd_mem_limits(struct seq_file *m, void *data);
 bool amdkfd_fence_check_mm(struct dma_fence *f, struct mm_struct *mm);
 struct amdgpu_amdkfd_fence *to_amdgpu_amdkfd_fence(struct dma_fence *f);
 int amdgpu_amdkfd_remove_fence_on_pt_pd_bos(struct amdgpu_bo *bo);
-int amdgpu_amdkfd_evict_userptr(struct kgd_mem *mem, struct mm_struct *mm);
+int amdgpu_amdkfd_evict_userptr(struct mmu_interval_notifier *mni,
+				unsigned long cur_seq, struct kgd_mem *mem);
 #else
 static inline
 bool amdkfd_fence_check_mm(struct dma_fence *f, struct mm_struct *mm)
@@ -201,7 +205,8 @@ int amdgpu_amdkfd_remove_fence_on_pt_pd_bos(struct amdgpu_bo *bo)
 }
 
 static inline
-int amdgpu_amdkfd_evict_userptr(struct kgd_mem *mem, struct mm_struct *mm)
+int amdgpu_amdkfd_evict_userptr(struct mmu_interval_notifier *mni,
+				unsigned long cur_seq, struct kgd_mem *mem)
 {
 	return 0;
 }