drm/radeon/kms: IB locking dumps out a lockdep ordering issue
We sometimes lock IB then the ring and sometimes the ring then
the IB. This is mostly due to the IB locking not being well defined
about what data in the structs it actually locks. Define what I
believe is the correct behaviour and gets rid of the lock dep ordering
warning.
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_ring.c b/drivers/gpu/drm/radeon/radeon_ring.c
index 168a555..747b4bf 100644
--- a/drivers/gpu/drm/radeon/radeon_ring.c
+++ b/drivers/gpu/drm/radeon/radeon_ring.c
@@ -56,10 +56,12 @@
set_bit(i, rdev->ib_pool.alloc_bm);
rdev->ib_pool.ibs[i].length_dw = 0;
*ib = &rdev->ib_pool.ibs[i];
+ mutex_unlock(&rdev->ib_pool.mutex);
goto out;
}
if (list_empty(&rdev->ib_pool.scheduled_ibs)) {
/* we go do nothings here */
+ mutex_unlock(&rdev->ib_pool.mutex);
DRM_ERROR("all IB allocated none scheduled.\n");
r = -EINVAL;
goto out;
@@ -69,10 +71,13 @@
struct radeon_ib, list);
if (nib->fence == NULL) {
/* we go do nothings here */
+ mutex_unlock(&rdev->ib_pool.mutex);
DRM_ERROR("IB %lu scheduled without a fence.\n", nib->idx);
r = -EINVAL;
goto out;
}
+ mutex_unlock(&rdev->ib_pool.mutex);
+
r = radeon_fence_wait(nib->fence, false);
if (r) {
DRM_ERROR("radeon: IB(%lu:0x%016lX:%u)\n", nib->idx,
@@ -81,12 +86,17 @@
goto out;
}
radeon_fence_unref(&nib->fence);
+
nib->length_dw = 0;
+
+ /* scheduled list is accessed here */
+ mutex_lock(&rdev->ib_pool.mutex);
list_del(&nib->list);
INIT_LIST_HEAD(&nib->list);
+ mutex_unlock(&rdev->ib_pool.mutex);
+
*ib = nib;
out:
- mutex_unlock(&rdev->ib_pool.mutex);
if (r) {
radeon_fence_unref(&fence);
} else {
@@ -110,9 +120,10 @@
return;
}
list_del(&tmp->list);
- if (tmp->fence) {
+ INIT_LIST_HEAD(&tmp->list);
+ if (tmp->fence)
radeon_fence_unref(&tmp->fence);
- }
+
tmp->length_dw = 0;
clear_bit(tmp->idx, rdev->ib_pool.alloc_bm);
mutex_unlock(&rdev->ib_pool.mutex);
@@ -122,25 +133,24 @@
{
int r = 0;
- mutex_lock(&rdev->ib_pool.mutex);
if (!ib->length_dw || !rdev->cp.ready) {
/* TODO: Nothings in the ib we should report. */
- mutex_unlock(&rdev->ib_pool.mutex);
DRM_ERROR("radeon: couldn't schedule IB(%lu).\n", ib->idx);
return -EINVAL;
}
+
/* 64 dwords should be enough for fence too */
r = radeon_ring_lock(rdev, 64);
if (r) {
DRM_ERROR("radeon: scheduling IB failled (%d).\n", r);
- mutex_unlock(&rdev->ib_pool.mutex);
return r;
}
radeon_ring_ib_execute(rdev, ib);
radeon_fence_emit(rdev, ib->fence);
- radeon_ring_unlock_commit(rdev);
+ mutex_lock(&rdev->ib_pool.mutex);
list_add_tail(&ib->list, &rdev->ib_pool.scheduled_ibs);
mutex_unlock(&rdev->ib_pool.mutex);
+ radeon_ring_unlock_commit(rdev);
return 0;
}