[PATCH 01/83] mm: Add kfd_process pointer to mm_struct

[Oded Gabbay <oded.gabbay@gmail.com>]

This patch enables the KFD to retrieve the kfd_process
object from the process's mm_struct. This is needed because kfd_process
lifespan is bound to the process's mm_struct lifespan.

When KFD is notified about an mm_struct tear-down, it checks if the
kfd_process pointer is valid. If so, it releases the kfd_process object
and all relevant resources.

Signed-off-by: Oded Gabbay <oded.gabbay@amd.com>
---
 include/linux/mm_types.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 678097c..6179107 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -20,6 +20,10 @@
 struct hmm;
 #endif
 
+#ifdef CONFIG_HSA_RADEON
+struct kfd_process;
+#endif
+
 #ifndef AT_VECTOR_SIZE_ARCH
 #define AT_VECTOR_SIZE_ARCH 0
 #endif
@@ -439,6 +443,16 @@ struct mm_struct {
 	 */
 	struct hmm *hmm;
 #endif
+#if defined(CONFIG_HSA_RADEON) || defined(CONFIG_HSA_RADEON_MODULE)
+	/*
+	 * kfd always register an mmu_notifier we rely on mmu notifier to keep
+	 * refcount on mm struct as well as forbiding registering kfd on a
+	 * dying mm
+	 *
+	 * This field is set with mmap_sem old in write mode.
+	 */
+	struct kfd_process *kfd_process;
+#endif
 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS
 	pgtable_t pmd_huge_pte; /* protected by page_table_lock */
 #endif
-- 
1.9.1