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Commit 637dd3b5 authored by Christian König's avatar Christian König Committed by Alex Deucher
Browse files

drm/amdgpu: prevent get_user_pages recursion 



Remember the tasks which are inside get_user_pages()
and ignore MMU callbacks from there.

Signed-off-by: default avatarChristian König <christian.koenig@amd.com>
Reviewed-by: default avatarFelix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 211dff55

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c

+38 −10
Original line number Diff line number Diff line
@@ -494,6 +494,11 @@ static void amdgpu_ttm_io_mem_free(struct ttm_bo_device *bdev, struct ttm_mem_re 
/*

 * TTM backend functions.

 */

struct amdgpu_ttm_gup_task_list {

	struct list_head	list;

	struct task_struct	*task;

};



struct amdgpu_ttm_tt {

	struct ttm_dma_tt	ttm;

	struct amdgpu_device	*adev;
@@ -501,6 +506,8 @@ struct amdgpu_ttm_tt { 
	uint64_t		userptr;

	struct mm_struct	*usermm;

	uint32_t		userflags;

	spinlock_t              guptasklock;

	struct list_head        guptasks;

};



/* prepare the sg table with the user pages */
@@ -530,9 +537,20 @@ static int amdgpu_ttm_tt_pin_userptr(struct ttm_tt *ttm) 
		unsigned num_pages = ttm->num_pages - pinned;

		uint64_t userptr = gtt->userptr + pinned * PAGE_SIZE;

		struct page **pages = ttm->pages + pinned;

		struct amdgpu_ttm_gup_task_list guptask;



		guptask.task = current;

		spin_lock(&gtt->guptasklock);

		list_add(&guptask.list, &gtt->guptasks);

		spin_unlock(&gtt->guptasklock);



		r = get_user_pages(current, current->mm, userptr, num_pages,

				   write, 0, pages, NULL);



		spin_lock(&gtt->guptasklock);

		list_del(&guptask.list);

		spin_unlock(&gtt->guptasklock);



		if (r < 0)

			goto release_pages;
@@ -783,6 +801,9 @@ int amdgpu_ttm_tt_set_userptr(struct ttm_tt *ttm, uint64_t addr, 
	gtt->userptr = addr;

	gtt->usermm = current->mm;

	gtt->userflags = flags;

	spin_lock_init(&gtt->guptasklock);

	INIT_LIST_HEAD(&gtt->guptasks);



	return 0;

}
@@ -800,18 +821,25 @@ bool amdgpu_ttm_tt_affect_userptr(struct ttm_tt *ttm, unsigned long start, 
				  unsigned long end)

{

	struct amdgpu_ttm_tt *gtt = (void *)ttm;

	struct amdgpu_ttm_gup_task_list *entry;

	unsigned long size;



	if (gtt == NULL)

		return false;



	if (gtt->ttm.ttm.state != tt_bound || !gtt->userptr)

	if (gtt == NULL || !gtt->userptr)

		return false;



	size = (unsigned long)gtt->ttm.ttm.num_pages * PAGE_SIZE;

	if (gtt->userptr > end || gtt->userptr + size <= start)

		return false;



	spin_lock(&gtt->guptasklock);

	list_for_each_entry(entry, &gtt->guptasks, list) {

		if (entry->task == current) {

			spin_unlock(&gtt->guptasklock);

			return false;

		}

	}

	spin_unlock(&gtt->guptasklock);



	return true;

}