Commit 461fa7b0 authored by Ken Xue's avatar Ken Xue Committed by Alex Deucher
Browse files

drm/amdgpu: remove ctx->lock 



KMD reports a warning on holding a lock from drm_syncobj_find_fence,
when running amdgpu_test case “syncobj timeline test”.

ctx->lock was designed to prevent concurrent "amdgpu_ctx_wait_prev_fence"
calls and avoid dead reservation lock from GPU reset. since no reservation
lock is held in latest GPU reset any more, ctx->lock can be simply removed
and concurrent "amdgpu_ctx_wait_prev_fence" call also can be prevented by
PD root bo reservation lock.

call stacks:
=================
//hold lock
amdgpu_cs_ioctl->amdgpu_cs_parser_init->mutex_lock(&parser->ctx->lock);
…
//report warning
amdgpu_cs_dependencies->amdgpu_cs_process_syncobj_timeline_in_dep \
->amdgpu_syncobj_lookup_and_add_to_sync -> drm_syncobj_find_fence \
-> lockdep_assert_none_held_once
…
amdgpu_cs_ioctl->amdgpu_cs_parser_fini->mutex_unlock(&parser->ctx->lock);

Signed-off-by: default avatarKen Xue <Ken.Xue@amd.com>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent 8bbd4d83

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

+11 −5
Original line number Diff line number Diff line
@@ -127,8 +127,6 @@ static int amdgpu_cs_parser_init(struct amdgpu_cs_parser *p, union drm_amdgpu_cs 
		goto free_chunk;

	}



	mutex_lock(&p->ctx->lock);



	/* skip guilty context job */

	if (atomic_read(&p->ctx->guilty) == 1) {

		ret = -ECANCELED;
@@ -585,6 +583,16 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p, 
		}

	}



	/* Move fence waiting after getting reservation lock of

	 * PD root. Then there is no need on a ctx mutex lock.

	 */

	r = amdgpu_ctx_wait_prev_fence(p->ctx, p->entity);

	if (unlikely(r != 0)) {

		if (r != -ERESTARTSYS)

			DRM_ERROR("amdgpu_ctx_wait_prev_fence failed.\n");

		goto error_validate;

	}



	amdgpu_cs_get_threshold_for_moves(p->adev, &p->bytes_moved_threshold,

					  &p->bytes_moved_vis_threshold);

	p->bytes_moved = 0;
@@ -700,7 +708,6 @@ static void amdgpu_cs_parser_fini(struct amdgpu_cs_parser *parser, int error, 
	dma_fence_put(parser->fence);



	if (parser->ctx) {

		mutex_unlock(&parser->ctx->lock);

		amdgpu_ctx_put(parser->ctx);

	}

	if (parser->bo_list)
@@ -944,7 +951,7 @@ static int amdgpu_cs_ib_fill(struct amdgpu_device *adev, 
	if (parser->job->uf_addr && ring->funcs->no_user_fence)

		return -EINVAL;



	return amdgpu_ctx_wait_prev_fence(parser->ctx, parser->entity);

	return 0;

}



static int amdgpu_cs_process_fence_dep(struct amdgpu_cs_parser *p,
@@ -1363,7 +1370,6 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data, struct drm_file *filp) 
		goto out;



	r = amdgpu_cs_submit(&parser, cs);



out:

	amdgpu_cs_parser_fini(&parser, r, reserved_buffers);

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

+0 −2
Original line number Diff line number Diff line
@@ -230,7 +230,6 @@ static int amdgpu_ctx_init(struct amdgpu_device *adev, 


	kref_init(&ctx->refcount);

	spin_lock_init(&ctx->ring_lock);

	mutex_init(&ctx->lock);



	ctx->reset_counter = atomic_read(&adev->gpu_reset_counter);

	ctx->reset_counter_query = ctx->reset_counter;
@@ -352,7 +351,6 @@ static void amdgpu_ctx_fini(struct kref *ref) 
		}

	}

	amdgpu_ctx_set_stable_pstate(ctx, AMDGPU_CTX_STABLE_PSTATE_NONE);

	mutex_destroy(&ctx->lock);

	kfree(ctx);

}

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

+0 −1
Original line number Diff line number Diff line
@@ -49,7 +49,6 @@ struct amdgpu_ctx { 
	bool				preamble_presented;

	int32_t				init_priority;

	int32_t				override_priority;

	struct mutex			lock;

	atomic_t			guilty;

	unsigned long			ras_counter_ce;

	unsigned long			ras_counter_ue;