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Commit 8a47cc9e authored by Christian König's avatar Christian König Committed by Dave Airlie
Browse files

drm/radeon: rework locking ring emission mutex in fence deadlock detection v2 



Some callers illegal called fence_wait_next/empty
while holding the ring emission mutex. So don't
relock the mutex in that cases, and move the actual
locking into the fence code.

v2: Don't try to unlock the mutex if it isn't locked.

Signed-off-by: default avatarChristian König <deathsimple@vodafone.de>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 3b7a2b24

drivers/gpu/drm/radeon/radeon.h

+2 −2
Original line number Diff line number Diff line
@@ -284,8 +284,8 @@ int radeon_fence_emit(struct radeon_device *rdev, struct radeon_fence *fence); 
void radeon_fence_process(struct radeon_device *rdev, int ring);

bool radeon_fence_signaled(struct radeon_fence *fence);

int radeon_fence_wait(struct radeon_fence *fence, bool interruptible);

int radeon_fence_wait_next(struct radeon_device *rdev, int ring);

int radeon_fence_wait_empty(struct radeon_device *rdev, int ring);

int radeon_fence_wait_next_locked(struct radeon_device *rdev, int ring);

int radeon_fence_wait_empty_locked(struct radeon_device *rdev, int ring);

struct radeon_fence *radeon_fence_ref(struct radeon_fence *fence);

void radeon_fence_unref(struct radeon_fence **fence);

unsigned radeon_fence_count_emitted(struct radeon_device *rdev, int ring);

drivers/gpu/drm/radeon/radeon_device.c

+4 −1
Original line number Diff line number Diff line
@@ -912,9 +912,12 @@ int radeon_suspend_kms(struct drm_device *dev, pm_message_t state) 
	}

	/* evict vram memory */

	radeon_bo_evict_vram(rdev);



	mutex_lock(&rdev->ring_lock);

	/* wait for gpu to finish processing current batch */

	for (i = 0; i < RADEON_NUM_RINGS; i++)

		radeon_fence_wait_empty(rdev, i);

		radeon_fence_wait_empty_locked(rdev, i);

	mutex_unlock(&rdev->ring_lock);



	radeon_save_bios_scratch_regs(rdev);

drivers/gpu/drm/radeon/radeon_fence.c

+29 −14
Original line number Diff line number Diff line
@@ -194,7 +194,7 @@ bool radeon_fence_signaled(struct radeon_fence *fence) 
}



static int radeon_fence_wait_seq(struct radeon_device *rdev, u64 target_seq,

				 unsigned ring, bool intr)

				 unsigned ring, bool intr, bool lock_ring)

{

	unsigned long timeout, last_activity;

	uint64_t seq;
@@ -249,8 +249,16 @@ static int radeon_fence_wait_seq(struct radeon_device *rdev, u64 target_seq, 
			if (seq != atomic64_read(&rdev->fence_drv[ring].last_seq)) {

				continue;

			}



			if (lock_ring) {

				mutex_lock(&rdev->ring_lock);

			}



			/* test if somebody else has already decided that this is a lockup */

			if (last_activity != rdev->fence_drv[ring].last_activity) {

				if (lock_ring) {

					mutex_unlock(&rdev->ring_lock);

				}

				continue;

			}
@@ -264,15 +272,17 @@ static int radeon_fence_wait_seq(struct radeon_device *rdev, u64 target_seq, 
					rdev->fence_drv[i].last_activity = jiffies;

				}



				/* change last activity so nobody else think there is a lockup */

				for (i = 0; i < RADEON_NUM_RINGS; ++i) {

					rdev->fence_drv[i].last_activity = jiffies;

				}



				/* mark the ring as not ready any more */

				rdev->ring[ring].ready = false;

				if (lock_ring) {

					mutex_unlock(&rdev->ring_lock);

				}

				return -EDEADLK;

			}



			if (lock_ring) {

				mutex_unlock(&rdev->ring_lock);

			}

		}

	}

	return 0;
@@ -287,7 +297,8 @@ int radeon_fence_wait(struct radeon_fence *fence, bool intr) 
		return -EINVAL;

	}



	r = radeon_fence_wait_seq(fence->rdev, fence->seq, fence->ring, intr);

	r = radeon_fence_wait_seq(fence->rdev, fence->seq,

				  fence->ring, intr, true);

	if (r) {

		return r;

	}
@@ -295,7 +306,7 @@ int radeon_fence_wait(struct radeon_fence *fence, bool intr) 
	return 0;

}



int radeon_fence_wait_next(struct radeon_device *rdev, int ring)

int radeon_fence_wait_next_locked(struct radeon_device *rdev, int ring)

{

	uint64_t seq;
@@ -305,20 +316,22 @@ int radeon_fence_wait_next(struct radeon_device *rdev, int ring) 
	 */

	seq = atomic64_read(&rdev->fence_drv[ring].last_seq) + 1ULL;

	if (seq >= rdev->fence_drv[ring].seq) {

		/* nothing to wait for, last_seq is already the last emited fence */

		return 0;

		/* nothing to wait for, last_seq is

		   already the last emited fence */

		return -ENOENT;

	}

	return radeon_fence_wait_seq(rdev, seq, ring, false);

	return radeon_fence_wait_seq(rdev, seq, ring, false, false);

}



int radeon_fence_wait_empty(struct radeon_device *rdev, int ring)

int radeon_fence_wait_empty_locked(struct radeon_device *rdev, int ring)

{

	/* We are not protected by ring lock when reading current seq

	 * but it's ok as wait empty is call from place where no more

	 * activity can be scheduled so there won't be concurrent access

	 * to seq value.

	 */

	return radeon_fence_wait_seq(rdev, rdev->fence_drv[ring].seq, ring, false);

	return radeon_fence_wait_seq(rdev, rdev->fence_drv[ring].seq,

				     ring, false, false);

}



struct radeon_fence *radeon_fence_ref(struct radeon_fence *fence)
@@ -410,14 +423,16 @@ void radeon_fence_driver_fini(struct radeon_device *rdev) 
{

	int ring;



	mutex_lock(&rdev->ring_lock);

	for (ring = 0; ring < RADEON_NUM_RINGS; ring++) {

		if (!rdev->fence_drv[ring].initialized)

			continue;

		radeon_fence_wait_empty(rdev, ring);

		radeon_fence_wait_empty_locked(rdev, ring);

		wake_up_all(&rdev->fence_drv[ring].queue);

		radeon_scratch_free(rdev, rdev->fence_drv[ring].scratch_reg);

		rdev->fence_drv[ring].initialized = false;

	}

	mutex_unlock(&rdev->ring_lock);

}

drivers/gpu/drm/radeon/radeon_pm.c

+1 −7
Original line number Diff line number Diff line
@@ -270,13 +270,7 @@ static void radeon_pm_set_clocks(struct radeon_device *rdev) 
	} else {

		struct radeon_ring *ring = &rdev->ring[RADEON_RING_TYPE_GFX_INDEX];

		if (ring->ready) {

			struct radeon_fence *fence;

			radeon_ring_alloc(rdev, ring, 64);

			radeon_fence_create(rdev, &fence, radeon_ring_index(rdev, ring));

			radeon_fence_emit(rdev, fence);

			radeon_ring_commit(rdev, ring);

			radeon_fence_wait(fence, false);

			radeon_fence_unref(&fence);

			radeon_fence_wait_empty_locked(rdev, RADEON_RING_TYPE_GFX_INDEX);

		}

	}

	radeon_unmap_vram_bos(rdev);

drivers/gpu/drm/radeon/radeon_ring.c

+1 −5
Original line number Diff line number Diff line
@@ -347,9 +347,7 @@ int radeon_ring_alloc(struct radeon_device *rdev, struct radeon_ring *ring, unsi 
		if (ndw < ring->ring_free_dw) {

			break;

		}

		mutex_unlock(&rdev->ring_lock);

		r = radeon_fence_wait_next(rdev, radeon_ring_index(rdev, ring));

		mutex_lock(&rdev->ring_lock);

		r = radeon_fence_wait_next_locked(rdev, radeon_ring_index(rdev, ring));

		if (r)

			return r;

	}
@@ -408,7 +406,6 @@ void radeon_ring_force_activity(struct radeon_device *rdev, struct radeon_ring * 
{

	int r;



	mutex_lock(&rdev->ring_lock);

	radeon_ring_free_size(rdev, ring);

	if (ring->rptr == ring->wptr) {

		r = radeon_ring_alloc(rdev, ring, 1);
@@ -417,7 +414,6 @@ void radeon_ring_force_activity(struct radeon_device *rdev, struct radeon_ring * 
			radeon_ring_commit(rdev, ring);

		}

	}

	mutex_unlock(&rdev->ring_lock);

}



void radeon_ring_lockup_update(struct radeon_ring *ring)