[PATCH 1/3] drm/amdgpu: handle wrap around in reemit handling

[Alex Deucher]

Compare the sequence numbers directly.

Fixes: 77cc0da39c7c ("drm/amdgpu: track ring state associated with a fence")
Signed-off-by: Alex Deucher <alexander.deuc...@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
index fd8cca241da62..e270df30c2790 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
@@ -790,14 +790,19 @@ void amdgpu_ring_backup_unprocessed_commands(struct 
amdgpu_ring *ring,
        struct dma_fence *unprocessed;
        struct dma_fence __rcu **ptr;
        struct amdgpu_fence *fence;
-       u64 wptr, i, seqno;
+       u64 wptr;
+       u32 seq, last_seq;
 
-       seqno = amdgpu_fence_read(ring);
+       last_seq = amdgpu_fence_read(ring) & ring->fence_drv.num_fences_mask;
+       seq = ring->fence_drv.sync_seq & ring->fence_drv.num_fences_mask;
        wptr = ring->fence_drv.signalled_wptr;
        ring->ring_backup_entries_to_copy = 0;
 
-       for (i = seqno + 1; i <= ring->fence_drv.sync_seq; ++i) {
-               ptr = &ring->fence_drv.fences[i & 
ring->fence_drv.num_fences_mask];
+       do {
+               last_seq++;
+               last_seq &= ring->fence_drv.num_fences_mask;
+
+               ptr = &ring->fence_drv.fences[last_seq];
                rcu_read_lock();
                unprocessed = rcu_dereference(*ptr);
 
@@ -813,7 +818,7 @@ void amdgpu_ring_backup_unprocessed_commands(struct 
amdgpu_ring *ring,
                        wptr = fence->wptr;
                }
                rcu_read_unlock();
-       }
+       } while (last_seq != seq);
 }
 
 /*
-- 
2.51.0